Ross Credit - www.spacefacts.de

Personal: Male, Married, Two children. Born in Crown Point, Indiana, USA. US Air Force US Air Force

Astronaut Career

Astronaut Group: NASA Group 9 - 1980. Active Entered space service: 19 May 1980. Number of Flights: 7.00. Total Time: 58.04 days. Number of EVAs: 9.00. Total EVA Time: 2.44 days.

NAME: Jerry L. Ross (Colonel, USAF)

NASA Astronaut

PERSONAL DATA:

Born January 20, 1948, in Crown Point, Indiana. Married to the former Karen S. Pearson of Sheridan, Indiana. They have two children. He enjoys softball, racquetball, woodworking, photography, model rocketry, and flying. His mother, Mrs. Phyllis E. Ross, resides in Crown Point. His father, Donald J. Ross, is deceased. Her parents, Mr. and Mrs. Morris D. Pearson, reside in Sheridan, Indiana.

EDUCATION:

Graduated from Crown Point High School, Crown Point, Indiana, in 1966; received bachelor of science and master of science degrees in Mechanical Engineering from Purdue University in 1970 and 1972, respectively.

ORGANIZATIONS:

Member of the Association of Space Explorers, the Air Force Association, Pi Tau Sigma; and a lifetime member of the Purdue Alumni Association.

SPECIAL HONORS:

Awarded the Defense Superior Service Medal, the Defense Meritorious Service Medal with 2 Oak Leaf Clusters, the Air Force Meritorious Service Medal with 1 Oak Leaf Cluster; named a Distinguished Graduate of the USAF Test Pilot School and recipient of the Outstanding Flight Test Engineer Award, Class 75B. Recipient of 5 NASA Space Flight Medals. Awarded the American Astronautical Society, Victor A. Prather Award (1985 and 1990), and Flight Achievement Award (1992 and 1996).

EXPERIENCE:

Ross, an Air Force ROTC student at Purdue University, received his commission upon graduation in 1970. After receiving his master's degree from Purdue in 1972, he entered active duty with the Air Force and was assigned to the Ramjet Engine Division of Air Force Aero-Propulsion Laboratory at Wright-Patterson Air Force Base, Ohio. He conducted computer-aided design studies on ramjet propulsion systems, served as the project engineer for captive tests of a supersonic ramjet missile using a rocket sled track, and as the project manager for preliminary configuration development of the ASALM strategic air-launched missile. From June 1974 to July 1975, he was the Laboratory Executive Officer and Chief of the Management Operations Office. Ross graduated from the USAF Test Pilot School's Flight Test Engineer Course in 1976 and was subsequently assigned to the 6510th Test Wing at Edwards Air Force Base, California. While on assignment to the 6510th's Flight Test Engineering Directorate, he was project engineer on a limited flying qualities evaluation of the RC-135S aircraft and, as lead B-1 flying qualities flight test engineer, was responsible for the stability and control and flight control system testing performed on the B-1 aircraft. He was also responsible, as chief B-1 flight test engineer, for training and supervising all Air Force B-1 flight test engineer crew members and for performing the mission planning for the B-1 offensive avionics test aircraft.

STS-61-B Astronaut Jerry Ross at threshold of airlock compartment following EVA... Credit- NASA

Ross has flown in 21 different types of aircraft, holds a private pilot's license, and has logged over 2,800 flying hours, the majority in military aircraft.

NASA EXPERIENCE:

In February 1979, Ross was assigned to the Payload Operations Division at the Lyndon B. Johnson Space Center as a payload officer/flight controller. In this capacity, he was responsible for the flight operations integration of payloads into the Space Shuttle.

Ross was selected as an astronaut in May 1980. His technical assignments since then have included: EVA, RMS, and chase team; support crewman for STS 41-B, 41-C and 51-A; spacecraft communicator (CAPCOM) during STS 41-B, 41-C, 41-D, 51-A and 51-D; Chief of the Mission Support Branch; member of the 1990 Astronaut Selection Board; and Acting Deputy Chief of the Astronaut Office. A veteran of five space flights, Ross has logged 850 hours in space, including nearly 23 hours on four spacewalks.

Ross was a mission specialist on the crew of STS 61-B which launched at night from Kennedy Space Center, Florida, on November 26, 1985. During the mission the crew deployed the MORELOS-B, AUSSAT II, and SATCOM Ku-2 communications satellites, conducted two 6-hour space walks to demonstrate Space Station construction techniques with the EASE/ACCESS experiments, and operated numerous other experiments. After completing 108 orbits of the Earth in 165 hours, STS 61-B Atlantis landed on Runway 22 at Edwards Air Force Base, California, on December 3, 1985.

Ross then flew as a mission specialist on the crew of STS-27, on board the Orbiter Atlantis, which launched from the Kennedy Space Center, Florida, on December 2, 1988. The mission carried a Department of Defense payload, as well as a number of secondary payloads. After 68 orbits of the earth in 105 hours, the mission concluded with a dry lakebed landing on Runway 17 at Edwards Air Force Base, California, on December 6, 1988.

Ross flew as a mission specialist on STS-37 aboard the Orbiter Atlantis. The mission launched from KSC on April 5, 1991, and deployed the 35,000 pound Gamma Ray Observatory. Ross performed two space walks totaling 10 hours and 49 minutes to manually deploy the stuck Gamma Ray Observatory antenna and to test prototype Space Station Freedom hardware. After 93 orbits of the Earth in 144 hours, the mission concluded with a landing on Runway 33, at Edwards Air Force Base, on April 11, 1991.

From April 26, 1993 through May 6, 1993, Ross flew as Payload Commander/Mission Specialist on STS-55 aboard the Orbiter Columbia. The mission launched from Kennedy Space Center and landed at Edwards Air Force Base, Runway 22, after 160 orbits of the Earth in 240 hours. Nearly 90 experiments were conducted during the German-sponsored Spacelab D-2 mission to investigate life sciences, material sciences, physics, robotics, astronomy, and the Earth and its atmosphere.

Most recently, Ross was a mission specialist on STS-74, NASA's second Space Shuttle mission to rendezvous and dock with the Russian Space Station Mir. STS-74 launched on November 12, 1995, and landed at Kennedy Space Center on November 20, 1995. During the 8 day flight the crew aboard Space Shuttle Atlantis attached a permanent docking module to Mir, conducted a number of secondary experiments, and transferred 1-1/2 tons of supplies and experiment equipment between Atlantis and the Mir station. The STS-74 mission was accomplished in 129 orbits of the Earth, traveling 3.4 million miles in 196 hours, 30 minutes, 44 seconds.

CURRENT ASSIGNMENT:

Colonel Ross will serve on the crew of STS-88, the first Space Shuttle mission to carry hardware to space for the assembly of the International Space Station. He is scheduled to conduct 3 space walks on this mission. Launch is targeted for July 1998.

• 27 November 1985 Flight: STS-61-B. Flight Up: STS-61-B. Flight Back: STS-61-B. Flight Time: 6.88 days.

• 2 December 1988 Flight: STS-27. Flight Up: STS-27. Flight Back: STS-27. Flight Time: 4.38 days.

• 5 April 1991 Flight: STS-37. Flight Up: STS-37. Flight Back: STS-37. Flight Time: 5.98 days.

• 25 April 1993 Flight: STS-55. Flight Up: STS-55. Flight Back: STS-55. Flight Time: 9.99 days.

• 12 November 1995 Flight: STS-74. Flight Up: STS-74. Flight Back: STS-74. Flight Time: 8.19 days.

• 3 December 1998 Flight: STS-88. Flight Up: STS-88. Flight Back: STS-88. Flight Time: 11.80 days.

• 8 April 2002 Flight: STS-110. Flight Up: STS-110. Flight Back: STS-110. Flight Time: 10.82 days.

19 May 1980 - NASA Astronaut Training Group 9 selected.. The group was selected to provide pilot, engineer, and scientist astronauts for space shuttle flights.. Qualifications: Pilots: Bachelor's degree in engineering, biological science, physical science or mathematics. Advanced degree desirable. At least 1,000 flight-hours of pilot-in-command time. Flight test experience desirable. Excellent health. Vision minimum 20/50 uncorrected, correctable to 20/20 vision; maximum sitting blood pressure 140/90. Height between 163 and 193 cm.

Mission Specialists: Bachelor's degree in engineering, biological science, physical science or mathematics and minimum three years of related experience or an advanced degree. Vision minimum 20/150 uncorrected, correctable to 20/20. Maximum sitting blood pressure of 140/90. Height between 150 and 193 cm..

If weather and spacecraft systems cooperate, Discovery will touch down at KSC at 11:04 a.m. Central time after having flown 134 orbits of the Earth. Deorbit ignition of the shuttle orbiter's maneuvering engines will occur at 9:53 a.m. CST to slow the spacecraft's forward velocity allowing it to drop back into the Earth's atmosphere. Returning as an unpowered hypersonic glider, Discovery will follow a ground track taking it across Texas and Louisiana before it sweeps out over the Gulf of Mexico and into Florida.

Weather was predicted to be marginal, near the acceptable limits for crosswind and with scattered to broken clouds.

There are two landing opportunities to KSC Saturday and two to Edwards Air Force Base, California. Discovery has a second chance to land at KSC at 12:45 p.m. CST or could land at Edwards at either 12:35 p.m. or 2:17 p.m. Weather at Edwards was predicted to be good on Saturday but unacceptable on Sunday. KSC weather will be marginal both days. Earlier Friday, entry Capcom Susan Still told Discovery Commander Curt Brown that the plan would be to try both opportunities into KSC before considering the Edwards landing.

If Discovery lands Saturday, the seven astronauts will spend the night at the landing site before returning to Houston mid-day on Sunday to a welcome at Ellington Field.

Earlier today, Commander Curt Brown and Pilot Steve Lindsey spent a good part of their day checking out important spacecraft systems for entry and landing. One of the three auxiliary power units was turned on to provide hydraulic power for a test of the orbiter's aerodynamic surfaces. The reaction control jets were test fired and the shuttle's communications equipment tested. One of the RCS jets leaked during testing and was isolated. It will have no effect on entry and landing.

At the end of the crew day, the Ku-band antenna which provides television and high-rate data relay was stowed for the duration of the mission.

If weather and spacecraft systems cooperate, Discovery will touch down at Kennedy Space Center at 11:04 a.m. Central time after completing 134 orbits of the Earth. Deorbit ignition of the orbiter's maneuvering engines will occur at 9:53 a.m. CST to slow the spacecraft's forward velocity, allowing it to drop back into the Earth's atmosphere. Returning as an unpowered hypersonic glider, Discovery will follow a ground track taking it across Texas and Louisiana before it sweeps out over the Gulf of Mexico and into Florida.

Weather in Florida is predicted to be near but within acceptable margins for crosswinds and clouds.

Today there are two landing opportunities at KSC and two to Edwards Air Force Base, California. Discovery has a second chance to land at KSC at 12:45 p.m. CST or could land at Edwards at either 12:35 p.m. or 2:17 p.m. Weather at Edwards is predicted to be good on Saturday but unacceptable on Sunday. KSC weather will be near margins both days. Flight controllers will try both opportunities into KSC before considering the Edwards landing.

Although a normal entry, approach, and landing are expected, precautionary plans are in place to accommodate a deployment of Discovery's drag chute during reentry. The Shuttle Training Aircraft that performs routine weather observations prior to landing and during final approach will also visually monitor Discovery's drag chute compartment.

If Discovery lands today, the astronauts will spend the night at KSC before returning to Houston mid-day on Sunday to a welcome at Ellington Field.

With temperatures hovering around 28 degrees Fahrenheit, the Proton and the Zarya Control Module were delivered by rail car to its launch pad with everything on track for launch Friday at 11:40 a.m. Baikonur time (1:40 a.m. EST, 12:40 a.m. CST, 6:40 a.m. GMT, 9:40 a.m. Moscow time). The Proton's rollout to the launch pad occurred after Russian and American officials met to give final approval for the launch, following a review of vehicle and booster systems.

The early forecast for Friday at Baikonur called for overcast skies and subfreezing temperatures, no constraint to the launch of an unmanned Russian booster. The Proton's three stages will be fueled with asymmetrical dimethylhydrazine and nitrogen tetroxide about six hours before launch. American flight controllers belonging to the Houston Support Group at the Russian Mission Control Center outside of Moscow have joined a team of flight controllers from the Khrunichev State Research and Production Space Center to keep tabs on final preparations for the start of the multinational project.

Khrunichev built Zarya under contract to prime contractor, Boeing, and will work in concert with American flight controllers to monitor Zarya's systems during launch and its early life on orbit. Another team of U.S. flight controllers will operate out of the International Space Station Flight Control Room at the Johnson Space Center in Houston to provide round-the-clock support for the lifetime of the International Space Station.

The Proton rocket weighs one and a half million pounds fully fueled and generates more than 2 and a half million pounds of thrust from its three stages during the 9 minute, 47 second-ride from launch pad to spacecraft separation.

Within seconds after the Zarya is separated from the Proton's third stage, a pre-programmed sequence of events will occur when the module's computers command the deployment of critical antennas and the Zarya's solar arrays, providing the new module with a wingspan of 80 feet for the generation of electricity.

Zarya's initial orbital altitude will be about 220 by 115 statute miles. The altitude will be circularized next week following a series of maneuvering system engine firings, placing Zarya in the proper orbit for the arrival of the shuttle Endeavour almost three weeks from now, carrying the Unity connecting module, or node. Zarya will be grappled by Endeavour astronaut Nancy Currie through the use of the shuttle's robot arm during the first assembly mission, STS-88, and will be mated to Unity, setting the stage for three spacewalks by Jerry Ross and Jim Newman to connect cables and install equipment for future Station construction flights.

Zarya began its third full day in space in an orbit 226 by 156 statute miles. During two separate engine firings, the module's orbit was raised on both sides placing it in a 248 by 194 statute mile orbit. One final altitude adjust maneuver is scheduled for early Tuesday morning that will nearly circularize the orbit at about 250 statute miles.

Zarya will then drift for two weeks, slowly dropping its orbit to an altitude of about 242 statute miles at which Endeavour and its crew will arrive on Dec. 6.

The first engine firing aboard Zarya occurred at 8:26 this morning Moscow time (12:26 a.m. EST). The 31 second burn changed the module's velocity by 21 feet per second. The second burn about an hour later, lasted nearly two minutes and changed the velocity by 78 feet per second.

System checks continued as well throughout the day as Zarya moved within tracking range of several linked ground sites across Russia. Each ground station pass allowed flight controllers in the Zarya control room and NASA's Houston Support Room to monitor the data flowing from computers onboard the module.

Other highlights from on-orbit checkouts aboard Zarya included completion of checkouts of its motion control system in the 'free flight' mode; confirmation of on board systems to monitor atmospheric temperatures inside the module; a test of the fire detection and suppression system, and deactivation of the Gas Analyzer.

The Gas Analyzer continues to show slightly higher humidity levels, but controllers believe this may be a simple calibration error. The unit's manufacturer is being consulted on this possibility.

Battery number 1 continued to indicate a higher charge than the other five batteries. Telemetry data is being analyzed to determine the discrepancy.

Yesterday's activities showed an indication of a possible failure to deploy of two small antennae elements in the Teleoperator Control System (TORU) manual docking system on Zarya. Russian specialists will conduct a more complete systems test later this week that will provide more data on the antenna system.

Plans for tomorrow in addition to the orbit raising burn, controllers will test Zarya's multiplexer-demultiplexer and monitor systems already checked out.

During times when Zarya is not actively performing systems checks or other operations, it is put into a slow spin to conserve fuel and maintain moderate temperatures on the spacecraft. Now at its higher altitude, Zarya is circling Earth every 91 minutes at inclination of 51.6 degrees to the equator.

Zarya remains in excellent condition overall with only a few minor mechanical issues under analysis that are not expected to pose any problems for the planned operations of the International Space Station. For one of the problems -- a potential glitch with the energy storage and discharging capability of one of six batteries housed in the Zarya module - flight controllers are planning to carry replacement parts aboard Endeavour that could be installed by the shuttle crew. The battery is still usable with the glitch, and even without any repairs performed, the problem would not be expected to have an impact on Endeavour's mission or following station operations, although it would decrease the amount of backup energy and battery systems available.

Station mission managers have decided to load two small replacement electronics boxes for the battery system, a current converter unit and a storage battery current regulator unit (referred to by the Russian acronym PTAB), aboard Endeavour along with associated cabling. A decision on whether the crew will be asked to install any of the equipment during the flight has not been made.

Tests of the battery system during the weekend have led Russian flight controllers to suspect the problem may most likely be within the storage battery current regulator unit (PTAB). Endeavour Mission Specialist Sergei Krikalev, a Russian cosmonaut, has performed a similar repair on equipment aboard the Mir Space Station.

Flight controllers also plan to request that Endeavour's crew use television cameras to view the antennas on Zarya associated with the Telerobotically Operated, or TORU, manual docking system. Recent signal-strength testing has indicated these antenna may be fully deployed, although the deployment cannot be confirmed from other data. The crew will inspect the antennas during a standard television survey of Unity and Zarya planned on Day 4 of Endeavour's flight. Mission Specialists Jerry Ross and Jim Newman are planned to traverse near the area of one of the TORU antennas during the third spacewalk planned for STS-88, as they move to the far end of Zarya to install a handrail. No spacewalking activities involving the antenna are planned, however.

The TORU system is a manually operated docking system that serves as a backup for the Kurs automated docking system, which is the primary docking system to be used for the arrival of the Service Module in summer 1999.

During times when Zarya is not actively performing systems checks or other operations, it is put into a slow spin to conserve fuel and maintain moderate temperatures on the spacecraft.

Zarya is circling Earth once every 92 minutes in an orbit of 250 by 240 statute miles.

During the last two days, work has centered on monitoring Zarya's systems and uplinking a minor software change to the computer to rectify a time synchronization problem with the ground. All other systems are performing as expected with no major activities planned prior to Saturday when Endeavour arrives with the Unity connecting module to begin the assembly of the new station.

The few minor technical issues still under analysis pose no problems for the shuttle mission, or the International Space Station's future performance. The potential glitch with one of Zarya's six batteries remains under investigation and replacement parts are being carried aboard Endeavour that could be installed by the shuttle crew, if the decision is made by mission managers to do so. The battery is still usable, and even without repairs, is not expected to have an impact on station operations.

The crew plans to use Endeavour's cameras to document the outside of Zarya during the final phase of the rendezvous and after its capture by the shuttle's robot arm to evaluate the position of two small antennae that make up part of the Telerobotically Operated (TORU) manual docking system. Experts on the ground believe the antennae are fully deployed based on recent signal strength tests, but won't be able to confirm their theory until camera views are available from Endeavour. In any case, the shuttle mission and its three spacewalks will continue as planned and no additional work by spacewalkers Jerry Ross and Jim Newman is foreseen at this time.

Weather forecasters continue to predict a 60 percent chance against launching with low clouds and rain showers expected during the brief 5 minute launch window that opens at 3:59 a.m. EST.

During times when no operational systems checks are conducted, Zarya is placed into a slow spin to conserve fuel and maintain moderate temperatures on the spacecraft. It is presently circling the Earth once every 92 minutes in an orbit of 249 by 241 statute miles.

The next launch attempt is tentatively scheduled for 2:36 a.m. CST Friday.

With the countdown clock at T-minus 4 minutes, STS-88 Commander Bob Cabana reported the alarm, forcing the countdown to be placed on hold. At a briefing following the launch attempt, Shuttle Launch Integration Manager Don McMonagle, said the alarm turned out to have been triggered by a sudden, brief dip in pressure that had never been seen before in one of the shuttle's three hydraulic systems.

The pressure change occurred when the auxiliary power units that provide pressure to the hydraulic lines shifted from low to high pressure after startup, McMonagle said, but then the pressure readings returned to normal and held steady. As hydraulic and instrumenta-ion engineers analyzed the data to identify what had caused the master alarm to sound and to assure that the systems were safe for flight, time ran out on Endeavour's ability to reach the Zarya control module, orbiting 240 statute miles above the Earth.

Once the launch had been postponed, support teams safed all of Endeavour's systems, drained the liquid hydrogen and liquid oxygen from the external tank and began recycling the shuttle for Friday's launch attempt. Engineers will review all of the data from today's launch attempt to ensure that all systems are functioning well.

Commander Bob Cabana, Pilot Rick Sturckow and Mission Specialists Nancy Currie, Jerry Ross, Jim Newman and Russian Cosmonaut Sergei Krikalev exited the shuttle and returned to crew quarters to rest for tomorrow's launch opportunity. The astronauts will awaken at mid-afternoon today and will sit down for the traditional prelaunch meal at 9:30 p.m. CST.

The countdown will resume at the T-11 hour mark at 10:46 a.m. CST, and. NASA Television coverage will begin at 9 p.m. CST tonight.

On December 5 at 22:25 GMT Nancy Currie unberthed the Unity space station node from the payload bay using the RMS arm. She then moved the Unity to a position docked to the Orbiter Docking System in the payload bay in readiness for assembly with the Russian-launched Zarya FGB ISS component. After rendezvous with the Zarya FGB module, on December 6 at 23:47 GMT Endeavour grappled Zarya with the robot arm, and at 02:07 GMT on December 7 it was soft docked to the PMA-1 port on Unity. After some problems hard dock was achieved at 02:48 GMT. Unity and Zarya then formed the core of the future International Space Station. Ross and Newman made three space walks to connect cables between Zarya and Unity, on December 7, 9 and 12. On the last EVA a canvas tool bag was attached to the exterior of Unity to provide tools for future station assembly workers. Docking cables were disconnected to prevent Unity and Zarya from inadvertently undocking. Following an internal examination of the embryonic space station, Endeavour undocked at 20:30 GMT on December 13. The SAC-A and Mightysat satellites were ejected from the payload bay on December 14 and 15. Deorbit burn was December 16 at 03:48 GMT, and Endeavour landed at 04:53:29 GMT, on Runway 15 at the Kennedy Space Center.

Payloads included:

• Sill: RMS arm No. 303
• Bay 1-2: Tunnel Adapter 002
• Bay 3-4: Orbiter Docking System/External Airlock (Boeing/Palmdale)
• Bay 7-13: Unity (Node 1) (Boeing/Huntsville), including the PMA-1 and PMA-2 docking adapters (Boeing/Huntington Beach)
• Bay 2 Port: GABA adapter with SAC-A satellite
• Bay 4 Starboard: Carrier with Tool Stowage Assembly
• Bay 5 Port: GABA adapter with two PFR space walk platforms and one PFR stanchion.
• Bay 5 Starboard: GABA adapter with two more PFR space walk platforms and one PFR stanchion.
• Bay 6 Port: GABA adapter with Mightysat
• Bay 6 Starboard: APC carrier with TCS laser rendezvous sensor
• Bay 7 Starboard: APC carrier with TCS laser rendezvous sensor
• Bay 13 Port: GABA adapter with SEM-7 and G-093 canisters
• Bay 13 Starboard: GABA adapter with IMAX Cargo Bay Camera

A series of precise maneuvering burns in the early portion of the flight will help Endeavour continue its pursuit of the Zarya control module. The orbital chase between the two spacecraft is scheduled to conclude on Sunday afternoon when Cabana maneuvers the Shuttle into close proximity with the first piece of the International Space Station and Currie uses the Shuttle's mechanical arm to grapple Zarya and dock it to the Unity connection module which will already be mated to the orbiter's docking mechanism.

Events onboard Endeavour during the first half of today's activities have included the two EVA crewmembers - Mission Specialists Jerry Ross and Jim Newman - performing a checkout of the SAFER or Simplified Aid for EVA Rescue unit. SAFER is a mini maneuvering system that can provide self-rescue capability for a spacewalker if they inadvertently become separated from the spacecraft during a spacewalk. Also this afternoon, the crew downlinked video taken inside the crew cabin during their ascent to orbit.

Later today Ross and Newman will setup the Orbiter Space Vision System equipment which provides the mechanical arm operator precise data on the position and alignment of hardware located in the area of the payload bay.

Also in preparation for the three planned spacewalks, the cabin pressure inside Endeavour will be lowered from its normal 14.7 psi setting down to 10.2. The lower cabin pressure will shorten the amount of time Newman and Ross have to breath pure oxygen to prevent nitrogen bubbles from forming in their blood stream, a condition commonly referred to as "the bends" while they operate in the 4 psi environment of their spacesuits.

Other activities later today will have Newman and Ross doing verification checks of the EVA suits they will use during their space walks as well as preparing the airlock area that they will use to transition into Endeavour's payload bay.

Currie will power up the Remote Manipulator System (RMS) mechanical arm to make sure it is ready to support Unity module unstow and installation activities on Saturday afternoon. She will also use the RMS arm to perform a photo survey of the payload bay.

There are no issues being worked by either the crew or the flight control team allowing all attention to remain focused on the mission objectives of this first ISS assembly flight.

The STS-88 crew will finish their first full day of work early tomorrow morning and will begin a sleep rest period at 5:36 a.m. Saturday morning with their next wake up call coming eight hours later at 1:36 p.m. tomorrow.

Following a smooth launch earlier today, Commander Bob Cabana, Pilot Rick Sturckow and Mission Specialists Nancy Currie, Jerry Ross, Jim Newman and Sergei Krikalev began preparing the orbiter for 12 days of operations to begin construction of the International Space Station. Endeavour is carrying the first American-built component of the station -- a connecting module named Unity -- in its cargo bay.

Just half an hour after lift-off, the shuttle's payload bay doors were opened. A few minutes later, the crew was given the go-ahead to begin orbit operations - preparing the vehicle for space flight activities. The Shuttle's KU-band antenna, which provides high data-rate and television transmissions, was successfully deployed. Crewmembers also activated the Hitchhiker payload, which includes the Mightysat and SAC-A satellites that will be deployed late in the mission.

The first of six engine firings to refining Endeavour's orbit and close the distance from the Zarya control module, launched from the Baikonur Cosmodrome in Kazakhstan on Nov. 20, also was completed early this morning. Final rendezvous maneuvers to bring Zarya (the Russian word for "sunrise") in close proximity with Endeavour is planned to take place on Sunday afternoon. Endeavour currently trails Zarya by approximatley 1,300 miles and is closing on Zarya at a rate of 675 miles per orbit.

All systems aboard Zarya, which will provide the initial control and command capabilities for the space station, continue to function well with the minor exception of one of six battery charging systems. Endeavour is carrying replacement parts for the system in the event they are needed.

After they wake up to begin Flight Day 2, Endeavour's crew will conduct a check out of the shuttle's robot arm that will be used to remove the Unity module from the payload bay and connect one of Unity's Preassurized Mating Adapters (PMA) to the orbiter's docking mechanism. The robot arm will also be used to grapple Zarya and dock it to the PMA located at the other end of the Unity connection module.

Other Flight Day 2 activities will include a check-out of the spacesuits that will be used in three spacewalks planned for the mission, as well as checks of the SAFER unit. SAFER or Simplified Aid for EVA Resuce, is a mini-maneuvering unit that can provide self-rescue capability for a spacesuited crew member who inadvertently separates from a spacecraft during a spacewalk.

All systems aboard Endeavour continue to perform well with the Shuttle currently flying in a 200 by 118 mile orbit, circling the Earth every 90 minutes.

The STS-88 launch begins the largest cooperative space construction project in history. Endeavour is scheduled to rendezvous with the U.S.-funded and Russian-built Zarya control module on Dec. 6. Zarya, which in Russian means sunrise, lifted off from the Baikonur Cosmodrome in Kazakstan, on Nov. 20.

After reaching orbit, Commander Bob Cabana, Pilot Rick Sturckow and Mission Specialists Nancy Currie, Jerry Ross, Jim Newman and Sergei Krikalev began preparing for the first of several engine firings that will bring Endeavour within robot arm's reach of Zarya. Along the way, the crew will use the same 50-foot-long arm Dec. 5 to remove the Unity module from the payload bay and connect it to the shuttle's docking hatch. Crew members will use the robot arm to grapple Zarya about 5:48 p.m. CST Dec. 6 and dock it to one of Unity's two Pressurized Mating Adapters.

Newman and Ross are scheduled to conduct the first of the mission's three space walks Dec. 7. The space walks will connect electrical and communications lines between Unity and Zarya, and prepare Unity's systems for activation.

At launch, Zarya was making its 222nd orbit of the Earth about 240 statute miles above the Kennedy Space Center. Russian flight controllers in Mission Control Korolev reported that all systems aboard Zarya, which will provide the initial control and command capabilities for the space station, were functioning well with the minor exception of one of six battery charging systems. Endeavour is carrying replacement parts for the system in the event they are needed.

After Endeavour undocks from the International Space Station on Dec. 13, the crew will deploy two small technology demonstration satellites called MightySat and the Argentine Satelite de Aplicaciones/Scientifico-A.

The astronauts are scheduled to begin their sleep period at 7:36 a.m. CST, and will awaken at 3:36 p.m. for their first full day in space.

At about 3:50 p.m. Central time, Mission Specialist Nancy Currie will power up the shuttle's 50-foot-long robotic arm and use it to grapple the Unity connecting module, a procedure scheduled to begin at 4:06 p.m. Currie then will hoist the 12.8-ton Unity module out of Endeavour's cargo bay and carefully place it in position perpendicular to the shuttle. One of the mating adapters on Unity, called pressurized mating adapter 1 (PMA-1), will be latched to Endeavour's docking system using a mechanism identical to that used during Shuttle/Mir dockings. Currie will maneuver Unity precisely to within a few inches of the Shuttle's docking mechanism and then put the mechanical arm into a "limp" mode. Commander Bob Cabana will then fire Endeavour's thrusters to force the mechanisms together.

Preparations for tomorrow's capture of Zarya will continue as the crew equalizes the air pressure between Endeavour and Unity's mating adapter. The astronauts then will enter the adapter to install caps on air vents between PMA-1 and Unity, and then readjust the Shuttle and mating adapter's air pressure to about 10.2 pounds per square inch. This equalization of air pressure between Unity's mating adapter and Endeavour's cabin is done to provide better structural performance of the docking mechanism during the capture and attachment of Zarya.

The crew also will perform a check of connections with the docking mechanism located on the other end of Unity, called PMA-2, that will attach to Zarya. For the check, the docking ring on that adapter will be extended and retracted using controls located on the aft flight deck of Endeavour. Unity and its two mating adapters will form a complex 15 feet wide and about 36 feet long - taller than a 3-story building - towering above Endeavour's payload bay.

This evening, astronauts Jerry Ross and Jim Newman will check out the various tools they will use during the three scheduled spacewalks to be conducted later in the flight, and begin an early set-up of the Shuttle airlock in preparation for that first spacewalk on Monday. Later, Commander Bob Cabana and Newman will check equipment needed for tomorrow's rendezvous with Zarya, including laptop computer displays and a hand-held laser ranging device. Checks also will be performed of the Orbiter Space Vision System, an alignment aid for operations with the Shuttle's mechanical arm that will be used during the capture and attachment of Zarya.

Newman and Russian cosmonaut Sergei Krikalev also will take time to take part in an on-line interview by the New York Times at 11:01 p.m. Central time.

Endeavour is trailing Zarya by about 7,600 statute miles, narrowing the distance to the Russian-built module by almost 500 statute miles with each orbit. Endeavour is orbiting the Earth every 90 minutes at an altitude of 202 statute miles. An engine firing will be performed late today to raise the Shuttle's orbit and adjust the rate at which Endeavour is closing in on Zarya, which is currently in an orbit of about 240 statute miles. All of Endeavour's systems are in excellent condition.

With the Russian-built Zarya Control Module orbiting about 16,000 nautical miles in front of Endeavour, Mission Specialist Nancy Currie successfully checked out the 50-foot-long robot arm she will use to grapple the Unity connecting module late this afternoon. Currie will lift Unity out of the shuttle's cargo bay and carefully position it perpendicular to the shuttle, ready for latching to the Orbiter Docking System in the front portion of the bay. Currie moved the robot arm around the cargo bay last night, offering an extensive television survey of Unity and its pressurized mating adapters.

Astronauts Jerry Ross and Jim Newman successfully tested all three of the space suits carried on Endeavour. They will use two of the suits during three space walks to hook up electrical cables and other connectors between Unity and Zarya. With the help of Pilot Rick Sturckow, the space walk choreographer on the flight, Ross and Newman also checked out a pair of jet-powered backpacks they will wear during the space walks as a precaution in the event they become untethered during their work in the void of space.

Endeavour's cabin pressure also was lowered to 10.2 pounds per square inch to set the stage for the space walks, which begin late Monday afternoon.

Commander Bob Cabana monitored the work as the astronauts extended the outer ring of the docking system on which Unity will be mounted later today, and Russian Cosmonaut Sergei Krikalev checked out other gear that will be used during Sunday's rendezvous to catch Zarya for its mating to Unity.

Endeavour is orbiting the Earth at an altitude of 202 statute miles, preparing to climb to about 240 statute miles for the rendezvous Sunday with Zarya. All of Endeavour's systems are functioning normally.

The astronauts are scheduled to be awakened at 1:36 p.m. Central time to begin their third day of work on orbit.

Deftly manipulating the shuttle's 50-foot-long robot arm, Currie placed Unity just inches above the extended outer ring on Endeavour's docking mechanism, enabling Commander Bob Cabana to fire downward maneuvering jets, locking the shuttle's docking system to one of two Pressurized Mating Adapters (PMA's) attached to Unity. The mating occurred at 5:45 p.m. Central time, as Endeavour sailed over eastern China.

The new connecting node, to which the Russian-built Zarya control module will be mated later today, towered almost three stories over Endeavour's cargo bay, awaiting the arrival of the Zarya, which was launched from Kazakstan on Nov. 20 on a Russian Proton rocket.

After Unity was attached to the docking mechanism, the vestibule running between Unity's PMA-2 and the Orbiter Docking System was pressurized and the hatch was opened. Cabana and Jerry Ross entered the new module's adapter for the first time and placed caps over vent valves in preparation for the crew's entrance into Unity later this week.

The astronauts also extended and retracted the docking ring on PMA-1, to which the Zarya module will be mated after it is grappled by Currie around 5:46 p.m. Central time this afternoon.

The grapple of Zarya will follow a carefully choreographed rendezvous by Cabana and Pilot Rick Sturckow. Mission Specialists Jim Newman and Sergei Krikalev will use a number of rendezvous tools and hand-held lasers to provide range and closure rate information as Endeavour narrows the gap between itself and the Zarya. The rendezvous will begin about 12:30 p.m., with the final major maneuver planned for about 3:14 p.m. This terminal initiation burn will place Endeavour on a path to arrive about 500 feet below Zarya for the start of the final phase of the rendezvous.

Working from the aft flight deck, Cabana will manually guide Endeavour in a looping maneuver to a point 250 feet above Zarya, where he will slowly close in on the 21-ton module for its grapple by Currie. Zarya will be the heaviest object ever handled by the shuttle's robot arm, exceeding the Compton Gamma Ray Observatory by about 7,000 pounds.

Once Zarya is mated to Unity, the International Space Station components will rise some 76 feet above Endeavour's bay and have a combined weight of 35 tons. When it is fully assembled a few years from now, the new station will span the length of a football field and have a mass of more than a million pounds.

While Endeavour orbits the Earth at an altitude of about 241 by 134 statute miles, Zarya continues in orbit at an altitude of about 240 statute miles with all of its systems operating in excellent fashion.

Before the astronauts began an abbreviated 7-hour sleep period at 3:36 a.m. Central time, Cabana fired the shuttle's jets to keep a safe distance from a spent Delta II rocket casing during the sleep period. U.S. Space Command had alerted Mission Control that the shuttle would be passing near the debris from a Nov. 6 launch of communications satellites from Vandenberg Air Force Base, Calif., and Flight Director John Shannon decided to have Cabana make the maneuver to ensure the crew's sleep would not need to be interrupted.

When the crew awakens at 10:36 a.m. to begin preparations for their rendezvous, Endeavour will be about 20 miles farther away from Zarya than originally planned. However, the rendezvous burn schedule will not be affected.

Endeavour's crew will begin the final stages of a rendezvous with the Zarya module with an engine firing planned at about 1:30 p.m. CST, when Endeavour is at a point about 55 statute miles behind Zarya. That burn will slow the rate at which the shuttle is closing on the module. The final phase of the rendezvous will begin at about 3:15 p.m. CST, when Endeavour performs a terminal phase initiation engine firing, or TI burn, at a point about 9 statute miles behind Zarya. The TI burn will place Endeavour on a path to arrive about 600 feet directly below Zarya on its next orbit of the Earth. With the three-story-high Unity connecting module latched upright in the shuttle's payload bay, Cabana will take manual control of the shuttle at about 4:45 p.m. CST as it moves to within about a half-mile of Zarya. Cabana and Pilot Rick Sturckow will execute a sequence of maneuvers that will bring Endeavour from 600 feet below Zarya along a circular path, passing about 350 feet in front of it and finally reaching a point about 250 feet directly above the module.

From there, Cabana will fly Endeavour down toward the Zarya, relying on views from television cameras in the shuttle's payload bay to align the module, since Unity obstructs the view out of the cockpit windows. Mission Specialist Nancy Currie will operate Endeavour's outstretched arm for the capture of Zarya. Mission Specialists Jim Newman and Sergei Krikalev will assist with the rendezvous, using a hand-held laser to provide range and closing rate information as Endeavour narrows the gap with Zarya.

When the edge of Endeavour's payload bay is within 10 feet of Zarya, Currie will use the robotic arm to capture the module, about 5:46 p.m. CST. She then will maneuver it into a position precisely aligned above Unity's docking mechanism. The 21-ton Zarya will be the most massive object ever moved with the robotic arm, more than three tons heavier than the Compton Gamma Ray Observatory that was released using the arm on Space Shuttle mission STS-37.

Once the Zarya and Unity docking mechanisms are aligned and positioned only inches apart, Currie will put the arm into a "limp" mode while Cabana fires Endeavour's thrusters to force the mechanisms together, about 7:36 p.m. CST.

Zarya is 41.2 feet long and 13.5 feet wide at its widest point. Once attached to Unity, the new station will tower about 76 feet above Endeavour's payload bay and have a solar array span of about 78 feet and a combined mass of approximately 80,000 pounds. When fully assembled in 2004, the International Space Station will be larger than a football field and have a mass of more than one million pounds.

Following the mating of Unity with Zarya, Sturckow and Mission Specialist Jerry Ross will begin early preparations for the crew's entry into the new station, planned for Thursday, and begin setting up equipment for tomorrow's planned spacewalk by Ross and Newman to connect power and data cables between Unity and Zarya.

Using the shuttle's 50-foot-long robot arm, astronaut Nancy Currie plucked Zarya out of orbit at 5:47 p.m. Central time Sunday, more than 16 days after it was launched on a Russian Proton rocket from the Baikonur Cosmodrome in Kazakstan as the first component of the new station. After slowly and carefully aligning Zarya's docking mechanism with a comparable mechanism on Unity's Pressurized Mating Adapter-1, Commander Bob Cabana fired Endeavour's downward jets at 8:07 p.m. to drive the two large modules together.

Initial attempts to firmly latch Zarya and Unity together while the shuttle's robot arm was attached to Zarya's grapple fixture were unsuccessful. But after Currie ungrappled the module, hooks and latches between Zarya and Unity engaged at 8:48 p.m., forming a tightly sealed, 35-ton, 76-foot-tall structure rising from Endeavour's payload bay, the size of a seven-story building.

Currie used the robot arm cameras to conduct a detailed survey of Zarya, focusing on two antennas belonging to the Telerobtically Operated Rendezvous System (TORU), which failed to deploy following launch on Nov. 20. Flight controllers concluded that the pyrotechnic pins holding the antennas in place actually fired, but the antennas did not unfurl as planned. The antennas, which are part of a backup navigational aid system, are emitting signal strength in their current position and pose no problem for future station operations. But flight controllers are considering having astronaut Jerry Ross conduct a more thorough survey of the antennas while affixed to the end of the shuttle's robot arm during the first space walk he and Jim Newman will conduct Monday night. Mission managers have not decided whether Ross and Newman will be called upon to manually deploy the antennas on a future space walk.

The first space walk, scheduled to begin about 4:30 p.m. Central time today, may begin earlier if Ross and Newman are ready to depressurize Endeavour's external airlock ahead of schedule. During the planned 6 ½-hour excursion, Ross and Newman will hook up electrical cables and connectors between Zarya and Unity, enabling power to flow into the U.S. component for the first time. That will allow Unity's avionics, computers and heaters to be activated to set the stage for the ultimate shifting of command and control and the origination of the power for the International Space Station from the Russian components to the U.S components once the American-built Destiny laboratory is joined to the station in February 2000.

Russian and American flight controllers also are continuing discussions on the possible swap out of a suspect component for one of Zarya's six batteries. The battery is not discharging properly in its automatic mode. A replacement unit is available for installation if mission managers approve the plan. The battery is operational and poses no threat to future station operations even if left in its current configuration.

The astronauts are scheduled to begin an eight-hour sleep period at 3:36 a.m. Central time and will be awakened at 11:36 a.m. to prepare for the first space walk of the flight.

Endeavour and the International Space Station are orbiting the Earth at an altitude of 240 statute miles with all systems in excellent shape.

Today's space walk, scheduled to begin about 4:30 p.m. Central time, may begin earlier if Ross and Newman are ready to depressurize Endeavour's external airlock ahead of schedule. This space walk, which will last 6-1/2 hours, will focus on connecting computer and electrical cables between Unity, the two mating adapters attached to either end of Unity, and Zarya. In all, Ross and Newman will make about 40 connections during the spacewalk. This will enable power to flow to Unity for the first time in orbit and will permit Unity's avionics, computers and heaters to be activated.

Ross and Newman will begin today's space walk by readying Endeavour's payload bay for their activities. Then, as Ross rides on the shuttle's robot arm, he will install mating plugs and jumper cables to reroute power through Unity while Newman releases cables from where they were secured for launch on the mating adapter between Unity and Endeavour, called Pressurized Mating Adapter 2 (PMA 2). Ross and Newman will begin "plugging in" the cables and locking them into place, and then pull a thermal cover over each connector. The space walkers will next install a safety slidewire that will hold their tethers as they connect cables between the modules.

They will repeat the cable connection process again as they make connections between Unity, Zarya and the mating adapter that attaches Unity to Zarya, labeled Pressurized Mating Adapter 1 (PMA 1). Finally, they will remove thermal covers from Unity's two exterior computers, known as multiplexer-demultiplexers (MDMs), which are mounted on PMA 1.

Once the cables are connected, Russian ground controllers will send commands to Zarya to begin providing power to Unity, powering up Unity's exterior computers. At that point, Commander Bob Cabana and Mission Specialist Sergei Krikalev will send commands to the exterior computers to prepare them to accept ground commands that will activate systems aboard Unity.

Before reentering Endeavour's airlock at the conclusion of the space walk, Ross and Newman may, if time allows, perform a close-up inspection of the Telerobotically Operated Rendezvous System (TORU) on the Zarya module. Although flight controllers are confident the pyrotechnic pins holding the TORU antennas did deploy as expected, the two antennas did not unfurl as planned following Zarya's launch on Nov. 20. The antennas are part of a backup rendezvous system and are emitting signal strength in their current position and pose no problem for future station operations. At this point, there are no plans for Ross and Newman to attempt to manually deploy the antennas on a future space walk.

Early this morning, Russian and American flight controllers decided to have Krikalev replace a battery current converter unit in Zarya suspected of not working properly. A spare unit is carried aboard Endeavour. Krikalev has performed a similar activity in the past during stays on the Mir space station and will perform the task during the time the crew is inside Zarya on Thursday.

Endeavour and the International Space Station are orbiting the Earth at an altitude of about 240 statute miles with all systems in excellent shape.

Following yesterday's 7-hour, 21-minute spacewalk, Mission Specialists Jim Newman and Jerry Ross will relax today beginning preparations for tomorrow's spacewalk, the second of three planned during this mission. Ross, Newman and Mission Specialists Nancy Currie and Sergei Krikalev will set up and prepare equipment for tomorrow's spacewalk. This evening, all six astronauts will gather to review procedures prior to Ross and Newman's second excursion into space tomorrow.

Flight controllers will conduct command checks between Mission Control, Houston, and Mission Control, Moscow, to verify the ability to command Zarya from Houston via the Moscow control center. In preparation for the crew's entry into the International Space Station on Thursday, the mating adapter between Unity and Zarya, Pressurized Mating Adapter 1 (PMA 1) will be pressurized via remote commands from Moscow and checked for leaks. Flight controllers in Houston also will power on filters and fans and monitor temperatures inside Unity as heaters warm up the module prior to Thursday's entry.

Cabana and Sturckow will fire Endeavour's primary reaction control jets shortly after 2:30 CST this afternoon for about 22 minutes to raise the altitude of the International Space Station by about 5-1/2 statute miles. An opportunity for a second reboost maneuver is available later in the flight as well.

At 5:41 p.m. this evening, Cabana, Sturckow and Currie will be interviewed by ABC News/Discovery Channel and MSNBC. Once these activities are completed, the crew will have off-duty time starting around 7:30 CST this evening.

Endeavour and the International Space Station are orbiting the Earth at an altitude of about 240 statute miles with all systems in excellent shape.

Working smoothly and ahead of schedule, Ross and Newman mated 40 cables and connectors running 76 feet from the Zarya control module to Unity as the 35-ton station towered over the cargo bay of the shuttle Endeavour.

The two veteran space walkers began their excursion at 4:10 p.m. Central time, quickly pressing ahead with the connection of crucial data and power cables between Zarya and Unity. Ross and Newman also installed handrails and other hardware that will help space walkers move around the station on upcoming assembly missions, completing all of the connections within three hours. At various times, robot arm operator Nancy Currie moved Ross and Newman around the station modules on the end of the shuttle's manipulator system to conduct their work.

As Endeavour and the International Space Station passed over Russian ground stations, commands were sent from the Russian flight control team to activate a pair of Russian-American voltage converters, enabling power to flow from Zarya to Unity for the first time. International Space Station flight controllers in Houston saw Unity's systems come to life at 9:49 p.m., confirming perfect electrical continuity between the two modules. Unity's systems were then activated, including a pair of data relay boxes serving as the brain and nervous system for the U.S.-built component. Near the end of the space walk, Ross removed thermal covers from the relay boxes after Unity's heaters began to control the module's temperature.

With Pilot Rick Sturckow serving as the space walk choreographer, Newman was raised on the robot arm to the Zarya module to take a close look at a pair of Russian rendezvous antennas that did not fully deploy following the module's launch on Nov. 20. The so-called TORU system serves as a backup to the automatic Kurs system on Zarya, providing navigational data for spacecraft approaching the Russian component for docking. Russian flight controllers say the TORU antennas are emitting signal strength, but space station managers wanted additional engineering data so they can decide on a course of action for deploying the antennas.

Shortly before the space walk ended, Ross broke the record for most cumulative extravehicular activity time by a U.S. astronaut of 29 hours and 41 minutes previously held by former astronaut Tom Akers during five space walks on STS-49 and STS-61. Ross, who completed his fifth space walk tonight, now has 30 hours and 8 minutes of time spent in the void of space.

About an hour after Endeavour's astronauts were scheduled begin an eight-hour sleep period at 3:36 a.m. Central time, Cabana asked if the wake-up time could be postponed. Mission Control agreed, and the crew now will be awakened at 12:06 p.m. to begin its sixth day in orbit. The astronauts plan to raise the altitude of the International Space Station by about 3 1/2 statute miles Tuesday by firing Endeavour's jets in the first of two planned reboost maneuvers. The crew also will take half a day off to relax and enjoy the view from orbit after a busy start to the first International Space Station assembly flight.

Endeavour and the station are orbiting at an altitude of 242 statute miles with all systems in excellent shape.

Commander Bob Cabana and Pilot Rick Sturckow fired Endeavour's steering jets in a staccato fashion for about 22 minutes Tuesday to gradually raise the highest point of the shuttle and attached station's orbit about 5½ statute miles to 248 miles. Throughout its lifetime, the station's altitude will be periodically raised to maintain a proper orbit.

With all Endeavour and station systems in excellent shape, astronauts Jerry Ross and Jim Newman prepared for a second space walk later today to set up a communications system in the Unity module that will allow U.S. flight controllers to monitor Unity's systems. The so-called S-band early communications system includes two boxy antennas that will be installed on the outside of Unity as one of today's first tasks, and avionics gear that will be set up inside Unity on Thursday after astronauts enter the module for the first time. A test of the system's videoconferencing capability is planned after Thursday's installation.

Ross and Newman also will remove launch restraints over four hatchways on the Unity connecting node to which future station modules and an airlock will be attached. The hatchways, or Common Berthing Mechanisms, serve as docking ports for new hardware that will be delivered to the station over the next 18 months.

Near the end of today's space walk, Newman will use a grappling hook in an attempt to unfurl one of two balky antennas on Zarya's backup rendezvous navigation system. The antennas would be used to transmit range and closure rate information to approaching spacecraft heading for dockings with the Russian control module. It is believed that stiff cabling or interference from thermal blankets on Zarya may be preventing the antennas from fully extending, even though pyrotechnic pins have fired to enable the antennas to roll free from their spools. Pending final approval from mission managers, Newman will attempt to free the antenna on the nadir port of Zarya today. If successful, the same procedure may be used to free the antenna on the zenith port Saturday.

Before the astronauts began an eight-hour sleep period, International Space Station flight controllers in Houston reported that Unity's lower Pressurized Mating Adapter had warmed enough to permit astronauts to enter the module Thursday. Heaters were activated for the first time late Monday after power from Zarya was connected to the U.S. component.

The astronauts are scheduled to be awakened at 10:36 a.m. Central time to begin space walk preparations. The space walk by Ross and Newman is scheduled to get under way about 3 p.m. Central time, but could begin as soon as the astronauts are ready to depressurize Endeavour's airlock.

Today's 6-1/2-hour space walk by Newman and Mission Specialist Jerry Ross is scheduled to begin about 3 p.m. Central time, but may start earlier if the astronauts are ready to depressurize Endeavour's airlock ahead of schedule. Ross and Newman will install two box-like antennas on the outside of the Unity module that are part of the S-band early communications system. The antennas will allow U.S. flight controllers to monitor Unity's systems. Additional S-band electronics gear will be set up inside Unity on Thursday after astronauts enter the module for the first time. The spacewalkers also will connect an external video cable between Zarya and the S-band system. This cable will support early communications videoconferencing from Zarya. The system's videoconferencing capability will be tested after Thursday's installation. Newman, positioned on the end of Endeavour's robot arm, then will install a sunshade over one of Unity's externally mounted computers.

Ross and Newman will remove launch restraints over four hatchways on the Unity module to which future station modules, an early exterior framework and a cupola will attach. The hatchways, or Common Berthing Mechanisms, serve as docking ports for new hardware that will be delivered to the station during the next 18 months. Then Newman will install insulating covers on the trunnion pins that held Unity in the Shuttle's cargo bay.

If time allows toward the end of today's spacewalk, and pending final approval from U.S. and Russian managers, Ross and Newman may try to free one of two balky antennas on the TORU system, Zarya's backup rendezvous navigation system. Still attached to the robot arm, Newman would use an extendable, 10-foot-long grappling hook in an attempt to unfurl the antenna. Flight controllers believe that stiff cabling or interference from thermal blankets on Zarya may be preventing the antennas from fully extending, even though pyrotechnic pins have fired to enable the antennas to roll free from their spools. If Newman is successful, the same procedure may be used to free the second antenna on Saturday during the third and final spacewalk.

The last task for today will be to disconnect and stow cables that were used by Endeavour's crew to control the docking mechanism, called the Androgynous Peripheral Attach System (APAS), that docked Zarya to Unity earlier in the mission. With that system never again to be opened, the cable used by Endeavour to control it, which runs along Pressurized Mating Adapter 2 (PMA 2), will be disconnected on this spacewalk as a "get-ahead task" for future assembly missions when PMA 2, currently the adapter to which Endeavour is docked, will be moved. Ross and Newman also will spend some time bundling umbilicals on the exterior of Zarya and ensuring that the markings used by the Space Vision System robotic arm alignment aid are not obstructed by any cables.

After the spacewalk is complete, Currie will use Endeavour's robot arm to survey the payload bay and videotape all of the Space Vision System targets on Unity and Zarya.

Systems on board Endeavour and the International Space Station continue to operate smoothly.

Pilot Rick Sturckow and Mission Specialist Nancy Currie will continue their work removing access panels inside Unity and unstowing hardware that will be used by visiting astronauts on future assembly missions.

Commander Bob Cabana, Sturckow and Currie will work inside Unity to locate part of a missing mid-bay rack pivot fitting, which was lost yesterday. Following removal of launch restraint bolts, the lock ring fell behind the panel during attempts to install it on the rack. The pivot fitting will allow the entire equipment rack to be tilted forward.

After turning off the lights and ventilation system, Endeavour's crew will close the hatch and leave Zarya for the final time just before 4 p.m. Central time. Prior to closing the hatch, Endeavour's life support systems will be used to increase the station and Shuttle atmospheric pressure to 15 pounds per square inch, a little above sea level pressure on Earth. Then, as each hatch is closed in the station, the crew will lower the pressure slightly to keep positive air pressure on the inside of each hatch to assist in sealing the hatches. Dessicant bags will be installed in Unity's portable, battery-operated fans to remove humidity from the module and the portable fans will be left running. The crew's final exit from Unity is set for just after 5:30 p.m. today.

After they have completed exiting the station, Cabana and Sturckow will lower the pressure inside Endeavour from 14.7 pounds per square inch to 10.2 pounds per square inch in anticipation of tomorrow's spacewalk. The lower air pressure will reduce the amount of time Newman and Ross must spend breathing pure oxygen before beginning their spacewalk on Saturday and going to the lower pressure of their spacesuits, 4.3 pounds per square inch of pure oxygen.

The oxygen pre-breathe protocol removes nitrogen from the bloodstream to prevent a potentially dangerous malady commonly referred to as the "bends," caused when nitrogen bubbles form in the bloodstream. Newman and Ross also will pre-breathe pure oxygen from masks for about an hour today during the depressurization of Endeavour as part of the protocol.

Later, Newman will complete a performance evaluation of the Orbiter Space Vision System targets, part of an alignment aid for operations with the Shuttle's mechanical arm. Endeavour's crew will be interviewed by CNN and CBS News at 7:36 p.m. Central time.

Preparations will get under way late this evening for tomorrow's third and final spacewalk by Newman and Ross. With Sturckow's assistance, they will prepare the tools they will use, then check out the Simplified Aid for Extravehicular Activity Rescue (SAFER) backpacks, which are a type of space "life jacket" that provides the capability for spacewalking astronauts to fly back to the station should they become untethered. During tomorrow's spacewalk, Ross will check out a new valve on the unit, firing the backpack's jets while remaining tethered to Endeavour.

Endeavour and the International Space Station remain in excellent shape.

Jerry Ross and Jim Newman began the second of three planned space walks for the STS-88 mission at 2:33 p.m. Central time Wednesday, and immediately set out to install two boxy antennas on the side of the Unity module that will enable U.S. flight controllers to monitor that component's systems and provide basic videoconferencing for the first permanent occupants of the station in January 2000. The so-called "early" S-band communications system will be completed later today when the astronauts install hardware inside Unity. The system will provide more capability to retrieve data and telemetry from Unity, which otherwise would be available only as the new International Space Station passed over Russian ground stations.

Ross and Newman pressed ahead with the removal of launch restraint pins on the four hatchways on the body of Unity to which additional station modules and truss structures will be mated on future assembly missions. The two space walkers also installed a sunshade over Unity's two data relay boxes to ensure that they will be protected against harsh sunlight as the station circles the Earth.

Near the end of the space walk, Newman was hoisted to the Zarya control module on the end of Endeavour's robot arm so that he could use a grappling hook to free a backup rendezvous system antenna. After nudging the antenna with the grappling device, the pole popped out to its fully extended position as the shuttle passed over the northeast coast of Australia. The astronauts will attempt to free a duplicate antenna that is jammed on the other side of Zarya during their final space walk Saturday.

Ross and Newman returned to Endeavour's external airlock and began to repressurize it at 9:35 p.m., completing a 7 hour, 2 minute excursion. So far, they have worked outside Endeavour a total of 14 hours and 23 minutes. This was the third space walk for Newman and the sixth for Ross, who now has spent 37 hours, 10 minutes in the void of space -- a U.S. record.

Later today, the astronauts will enter the International Space Station for the first time as they open hatches to Unity and Zarya. If all goes as planned, the astronauts will climb aboard Unity around 1:15 p.m. Central time to complete installation of the S-band communication system in the U.S. component, and float into Zarya about an hour and a half later to unstow hardware that will be used by visiting astronauts on future assembly missions.

After arriving in Zarya, cosmonaut Sergei Krikalev will install a new battery charging unit in the Russian module. One of Zarya's six batteries has experienced a problem discharging stored energy in its automatic configuration. Krikalev has swapped out an identical component during two previous flights on the Russian Space Station Mir.

The astronauts will begin an eight-hour sleep period at 2:36 a.m. Central time and be awakened at 10:36 a.m. to begin their eighth day of work in orbit.

Endeavour and the International Space Station are flying at an altitude of 248 statute miles with all of their systems in excellent shape.

After opening the hatch between Unity and the Pressurized Mating Adapter that connects it to Endeavour, the astronauts will climb aboard Unity about 1:15 p.m. CST. Once inside, Commander Bob Cabana and Mission Specialists Jerry Ross and Jim Newman will install portable fans and lights. They also will complete installation of the S-band communication system in the U.S. component. Pilot Rick Sturckow will remove some access panels inside Unity and unstow hardware that will be used by visiting astronauts on future assembly missions.

Less than 90 minutes after entering Unity, the astronauts will float into the Zarya module, where Mission Specialist Sergei Krikalev and Currie will install a new battery charging unit. One of Zarya's six batteries has experienced a problem discharging stored energy in its automatic configuration. Krikalev has swapped out an identical component during two previous flights on the Russian space station Mir. Sturckow and Currie also will remove launch restraint bolts from some of the panels inside Zarya. These bolts were installed before launch to ensure that none of the panels popped open during launch. Astronauts will remove some of these bolts today as a "get-ahead" task to expedite access to the panels during future space station assembly missions. Cabana, Ross and Newman will check out the early communications system's videoconferencing capability.

Ross, Newman and Krikalev then will begin transferring equipment and supplies from Endeavour for use by future inhabitants of the space station, including the first crew to begin a permanent human presence on the space station in January 2000.

During the entry into the International Space Station today, the crew will open a total of six hatches in the following order: the hatch on Endeavour's docking system; the hatch to Unity's mating adapter (designated PMA-2); the hatch to Unity; the hatch from Unity to the upper mating adapter (designated PMA-1); the hatch to Zarya's spherical pressurized adapter (PA); and finally, a hatch between the spherical pressurized adapter on Zarya and the main Zarya instrument module, Zarya's main compartment.

Prior to beginning the sequence of hatch openings, the crew will bring the air pressure inside Endeavour to 14.7 pounds per square inch, the same pressure as at sea level on Earth. Then, the crew will go through a procedure to equalize the air pressure on both sides of each hatch prior to opening them.

About 8:45 p.m. Central time this evening, the entire crew will gather inside the station for an interview with KNX Radio in Los Angeles and KARE-TV in Minneapolis, MN, Cabana's home town.

Endeavour and the International Space Station remain in excellent shape.

After spending the day unstowing final items and installing air ducts for the Russian-built Zarya control module and the U.S.-built Unity module, Commander Bob Cabana and Russian Cosmonaut Sergei Krikalev closed the hatch to Zarya at 4:41 p.m. Central time. They closed a series of additional hatches as the crew made its way back to Endeavour, finally swinging the door to Unity shut at 6:26 p.m. This ended the first excursion by astronauts into the international outpost, an excursion that lasted 28 hours and 32 minutes.

Left behind were tools, supplies and clothing for the crew that will visit the station during the next shuttle assembly flight in May, and for the first crew members who will establish a permanent occupancy of the station in January 2000.

Back inside Endeavour, the astronauts completed preparations for a third and final space walk Saturday by Jerry Ross and Jim Newman to tidy up cable configurations. Ross and Newman plan to disconnect several jumper cables used to route power from Zarya to Unity before permanent electrical connections were made and disconnect cables used to permanently lock the two modules' docking mechanisms together. In addition, tool bags will be stowed on the side of Unity's uppermost Pressurized Mating Adapter for use by space walkers Tammy Jernigan and Dan Barry on the STS-96 assembly mission in May.

Near the end of Saturday's space walk, Ross plans to use a grappling hook to try to free the second of two jammed antennas that are part of Zarya's backup rendezvous system. Just as Newman did on Wednesday, Ross will use the device to pry the balky antenna free to its fully extended position while attached to the end of Endeavour's robot arm.

The space walk is scheduled to begin about 3:06 p.m. Central time Saturday, but could get under way earlier if Ross and Newman are ahead of schedule in their space walk preparations.

With all of their work complete, Endeavour's crew members will undock from the newly outfitted station at 2:25 p.m .Sunday, leaving the 35-ton complex to fly on its own for the next five months. Through an S-band communications system installed in Unity by the astronauts, station flight controllers will be able to monitor the health of Unity and Zarya as the complex orbits the Earth.

The astronauts will begin an eight-hour sleep period at 2:36 a.m. Central time Saturday and will be awakened at 10:36 a.m. to begin space walk preparations.

Endeavour and the International Space Station are orbiting the Earth at and altitude of 246 statute miles with all of their systems in excellent shape.

Reflecting the international cooperation involved in building the largest space complex in history, Commander Bob Cabana and Russian Cosmonaut Sergei Krikalev opened the hatch to the U.S.-built Unity connecting module at 1:54 p.m. Central time Thursday and floated into the new station together.

The rest of the crew followed and began turning on lights and unstowing gear in the roomy hub to which other modules will be connected in the future. Each passageway within Unity was marked by a sign leading the way into tunnels to which new modules will be connected.

About an hour later, at 3:12 p.m., Cabana and Krikalev opened the hatch to the Russian-built Zarya control module, which will be the nerve center for the station in its embryonic stage. Joined by Pilot Rick Sturckow and Mission Specialists Jerry Ross, Jim Newman and Nancy Currie, Cabana and Krikalev hailed the historic entrance into the International Space Station and said the hatch opening signified the start of a new era in space exploration.

Ross and Newman went right to work in Unity, completing the assembly of an early S-band communications system that will allow flight controllers in Houston to send commands to Unity's systems and to keep tabs on the health of the station with a more extensive communications capability than exists through Russian ground stations. The astronauts also conducted a successful test of the videoconferencing capability of the early communications system, which will be used by the first crew to permanently occupy the station in January 2000. Newman downlinked greetings to controllers in the station flight control room in Houston and to astronaut Bill Shepherd, who will command the first crew and live aboard the station with Krikalev and Cosmonaut Yuri Gidzenko.

Krikalev and Currie replaced a faulty unit in Zarya which controlled the discharging of stored energy from one of the module's six batteries. The battery had not been working properly in its automatic configuration, but the new unit was functioning normally shortly after it was installed.

The astronauts also unstowed hardware and logistical supplies stored behind panels in Zarya, relocating the items for use by the shuttle crew that will visit the station in May and Shepherd's expedition crew. Late this afternoon, the astronauts will complete their initial outfitting of the station.

The hatches to Zarya and Unity will be closed before Endeavour undocks from the new station Sunday, leaving the new complex to orbit the Earth unpiloted.

The astronauts begin an eight-hour sleep period at 2:36 a.m. Central time this morning and will be awakened at 10:36 a.m. to begin their ninth of day in orbit.

Endeavour and the International Space Station are circling the globe every 90 minutes at an altitude of 247 statute miles with all systems operating in excellent shape.

This afternoon's spacewalk, set to begin about 3:06 p.m. CST, could get under way earlier if Mission Specialists Jerry Ross and Jim Newman are ahead of schedule in their space walk preparations. Today's activities will be devoted mostly to tasks that ready the station for future assembly work.

The crew's first job will be to release some cable ties on four cables connected on an earlier space walk, three located on Unity's upper mating adapter and one on its lower adapter, to relieve tension on the lines. Flight controllers noted the cable tension from camera views of the station, and they are concerned that leaving the cables as they are would not allow enough play in them to accommodate cyclical heating and cooling that occurs between orbital night and day. The space walkers also will check an insulation cover on one cable connection on the lower Pressurized Mating Adapter (PMA 2) to make sure it is fully installed.

Ross and Newman then will attach a bag of tools - wrenches, power grip tools, ratchets and foot restraints - on the side of Unity's upper mating adapter (PMA 1). Astronauts Tammy Jernigan and Dan Barry will use these tools during their space walk next May during the STS-96 assembly mission. Ross and Newman also will inspect bubbling paint that has been noted on some of the Orbiter Space Vision System targets on Unity.

Next, the space walkers will disconnect cables that the crew used to operate the docking mechanism on Unity's upper mating adapter when Zarya was docked earlier in the mission. Also, Ross will use a 10-foot-long grappling hook to try to free the second of two jammed antennas that are part of Zarya's backup rendezvous navigation system. The first antenna was successfully deployed on a space walk Wednesday by Newman using the same method. After the antenna deploy, Ross will stow the grappling hook on the outside of Zarya, and he and Newman will install a handrail at the far end of the module.

Near the end of the space walk, after packing up their tools , the astronauts will do a detailed photographic survey of the space station from top to bottom. Finally, each astronaut will test fire the Simplified Aid for Extravehicular Activity Rescue (SAFER) jet backpacks they are wearing, a type of space "lifejacket," that would allow an astronaut to fly back to the station if they should ever become untethered. During an earlier flight test on STS-86, a valve failed and prevented the propulsion jets on the backpack from firing. The valve was redesigned and extensively tested on the ground and today's in-flight test will assist in verifying the new design.

With the first steps in the orbital construction of the International Space Station completed, Endeavour is planned to undock from the new outpost at 2:25 p.m. CST on Sunday, leaving the 7-story, 35-ton complex to fly on its own for the next five months. Station flight controllers will be able to monitor the health of the station through an S-band communications system installed in Unity by the astronauts.

Endeavour and the International Space Station are orbiting the Earth at an altitude of 246 statute miles with all systems operating normally.

Having begun its on-orbit assembly, Endeavour's astronauts are now preparing for their departure from the International Space Station this afternoon.

At 2:25 p.m. CST, Pilot Rick Sturckow will undock Endeavour from the station and back the shuttle away to a distance of 450 feet above the station before beginning a nose-forward fly-around just before 2:45 p.m. CST. During Endeavour's one and a half revolutions of the station, the astronauts will conduct a detailed photographic survey of the new outpost. About an hour later, Sturckow will fire Endeavour's jets to separate from the station, leaving it to fly unpiloted for the next five months. The next visit to the station will be by the STS-96 crew in May on an assembly and resupply mission.

Once Endeavour departs the area of the station, the crew will have a few hours of scheduled off-duty time. At about 8:15 p.m. CST, Commander Bob Cabana and Sturckow will fire one of Endeavour's large Orbital Maneuvering System engines for about 10 seconds as part of the SIMPLEX experiment, a Department of Defense study tracking Shuttle engine firings from various radar sites, this one from a site located in Peru. At about 8:30 p.m. CST, the entire crew will gather for interviews by ABC Radio, Associated Press Radio and the Associated Press.

Cabana, Sturckow and Mission Specialist Jerry Ross will deploy the SAC-A satellite from Endeavour's payload bay around 10:30 p.m. CST. SAC-A is a small, self-contained, non-recoverable satellite built by the Argentinean National Commission of Space Activities. The cube-shaped, 590-pound satellite will test and characterize the performance of new equipment and technologies that may be used in future scientific or operational missions. The payload includes a differential global positioning system, a magnetometer, silicon solar cells, a charge-coupled device Earth camera and a whale tracker experiment.

Near the end of the crew's day, Ross, Newman and Russian cosmonaut Sergei Krikalev will stow some of the tools used during yesterday's space walk, as Mission Specialist Nancy Currie increases Endeavour's cabin pressure to 14.7 pounds per square inch.

All systems on board Endeavour and the space station remain in excellent shape as they orbit at an altitude of 247 statute miles.

The third and final space walk of the flight by astronauts Jerry Ross and Jim Newman began at 2:33 p.m. Central time Saturday. Working close to the timeline, Ross and Newman accomplished all of the tasks planned for the excursion. The astronauts stowed a tool bag on the U.S.-built Unity connecting module and disconnected umbilicals used to drive the docking mechanisms that mated it with the Russian-built Zarya control module last week. They also installed a handrail on Zarya for use by future space walkers, and a made a detailed photographic survey of the station for review by engineers over the next several months.

Standing at the end of the shuttle's robot arm, Ross duplicated the accomplishment of Newman last Wednesday, freeing a jammed backup rendezvous system antenna on Zarya with a grappling hook. Ross found the antenna to be a bit stubborn, but after tapping it and nudging it several times, the antenna finally rolled out from its spool to the fully deployed position.

Before returning to Endeavour's airlock, Ross and Newman also tested out jet-powered backpacks they wore for use in the unlikely event they could become untethered during station assembly work. The jet packs seemed to use a bit more nitrogen gas than had been planned, but flight controllers said the engineering objectives of the brief test were met.

In all, Ross and Newman spent 21 hours and 22 minutes outside Endeavour in the initial assembly of the station. Ross now has completed seven space walks totaling 44 hours and 9 minutes, more than any other American space walker. Newman moved into third place on the all-time U.S. space-walking list, with a total of 28 hours and 27 minutes on four excursions.

After the space walk ended, Pilot Rick Sturckow depressurized the vestibule between Endeavour's docking system and the docking adapter at the base of Unity, setting the stage for today's undocking from the International Space Station at 2:25 p.m. Central time.

Sturckow will be at the controls of Endeavour during undocking, backing the shuttle away to a distance of 450 feet above the station before beginning a nose-forward fly-around. One and a half revolutions of the station are expected to provide ample time for the astronauts to conduct a detailed photographic survey of the outpost. Sturckow will fire Endeavour's jets at 3:52 p.m. to separate from the station, leaving it to fly unpiloted for the next five months. The next visit to the station will be by the STS-96 crew in May on an assembly and resupply mission.

Endeavour's astronauts began an eight-hour sleep period at 2:36 a.m. and will awaken at 10:36 a.m. Central time to begin preparations for undocking.

Endeavour and the station are orbiting at an altitude of 247 statute miles with all systems in excellent shape.

At the time of crew wake-up, Endeavour was about 222 statute miles ahead of the space station and pulling away from the station by about 12 statute miles per orbit. The SAC-A satellite, deployed by Commander Bob Cabana last night, trails Endeavour by about 35 statute miles.

Crew members will focus their activities today on preparing for their scheduled return to the Kennedy Space Center on Tuesday night. Cabana and Pilot Rick Sturckow will spend a good part of the day checking out spacecraft systems for entry and landing. At about 2:30 p.m. CST, the commander and pilot will begin checkout of the flight control systems and the performance of aerodynamic surfaces and flight controls. About an hour later, the flight crew will conduct a hot fire test of Endeavour's reaction control system jets.

Shortly before 5 p.m. CST, the crew will gather for its traditional in-flight crew news conference talking with reporters at NASA centers and at Canadian Space Agency Headquarters in St. Hubert, Quebec.

After about 3 hours of off-duty time, Cabana, Sturckow and Mission Specialist Jerry Ross will eject another small satellite from a canister in Endeavour's payload bay. MightySat is a 705-pound U.S. Air Force/Phillips Laboratory satellite that will demonstrate several advanced technologies, including a composite structure, advanced solar cells, a microparticle impact detector, advanced electronics and a shock device. Deployment is set for 8:09 p.m. CST.

The crew will wrap up the day's activities as they begin configuring Endeavour's cabin and stowing equipment in preparation for tomorrow's planned landing. Just before12:30 a.m. CST on Tuesday, Sturckow will stow the Ku-band antenna, which provides high data-rate relay and television. The flight control teams in the Mission Control Center also are preparing for Tuesday's landing in Florida. Preliminary weather forecasts indicate possible scattered clouds and rain showers in the vicinity of the landing site for Tuesday's scheduled 9:54 p.m. CST landing.

Endeavour is orbiting the Earth at an altitude of 247 statute miles with all systems on the space shuttle and space station operating normally.

With Endeavour more than 340 miles in front of the new station, the astronauts tested the shuttle's aerosurfaces and steering jets to ensure the ship's controllability during reentry to the Earth's atmosphere. All of Endeavour's systems were declared in good working order, enabling the astronauts to stow equipment used during the flight in preparation for their high-speed homecoming.

International Space Station flight controllers report that all systems on the new complex are functioning normally as the station orbits the Earth at an altitude of 246 statute miles, the Unity module facing the Earth and the Zarya module facing deep space. The station was commanded to spin slowly at one revolution every 30 minutes to maintain the proper heating and cooling while it flies unpiloted for the next five months. The next shuttle assembly mission to the station is STS-96, scheduled for launch aboard Discovery in May.

Late last night, at 8:09 p.m. Central time, the astronauts completed the final task of the flight, deploying a 700-pound Air Force technology satellite called MightySat as Endeavour sailed over Indonesia. MightySat will send back data on the effect of the space environment on composite materials and advanced solar power cells.

The six astronauts will begin an eight-hour sleep period at 3:36 a.m. and be awakened at 11:36 a.m. to begin final landing preparations.

If all goes as planned, Endeavour's cargo bay doors will swing shut at 6:07 p.m., after which the astronauts will climb into their launch and entry suits and strap into their seats. Commander Bob Cabana, Pilot Rick Sturckow and Flight Engineer Nancy Currie will be joined on the flight deck for entry by Mission Specialist Jim Newman, while crew mates Jerry Ross and Sergei Krikalev will be seated down on the middeck.

Scattered to broken clouds and no rain showers are predicted for Kennedy Space Center at landing time. If the forecast holds, Entry Flight Director John Shannon will give the green light to fire Endeavour's twin braking rockets at 8:47 p.m. Central time. The deorbit burn will slow the shuttle by 349 feet per second, allowing it to descend back to Earth. Landing is scheduled at 9:54 p.m. Central time on runway 3-3 at the Shuttle Landing Facility to complete a 4.6-million-mile mission, the 10th night landing in shuttle program history.

A backup landing opportunity is available at KSC 90 minutes later, at 11:30 p.m. Central time (12:30 a.m. Eastern time Wednesday). Mission managers decided not to call up landing support at the backup landing site at Edwards Air Force Base, Calif., for this evening's opportunities.

Endeavour is orbiting the Earth at an altitude of 246 statute miles, with all of its systems in excellent shape.

If weather cooperates, Endeavour will touch down at the Kennedy Space Center at 9:54 p.m. CST after completing 185 orbits of the Earth. A deorbit firing of the Shuttle's maneuvering engines will occur at 8:47 p.m. CST to slow the spacecraft's forward velocity, allowing it to drop back into the Earth's atmosphere. Returning as an unpowered, hypersonic glider, Endeavour will follow a ground track that takes it over the Mexico-Guatemala border and across the Gulf of Mexico, making U.S. landfall over the Ft. Meyers/Sarasota, Florida, area before heading in for a landing at runway 33.

If all goes as planned, Endeavour's cargo bay doors will swing shut at 6:07 p.m., after which the astronauts will climb into their launch and entry suits and strap into their seats. Commander Bob Cabana, Pilot Rick Sturckow and Flight Engineer Nancy Currie will be joined on the flight deck for entry by Mission Specialist Jim Newman, while crew mates Jerry Ross and Sergei Krikalev will be seated down on the middeck.

Forecasters are keeping a close watch on weather in the vicinity of the landing site, with current predictions calling for scattered clouds at 3,000 feet with a chance of showers within 30 miles of the Shuttle Landing Facility. Forecasters predict about a 70 percent chance of acceptable weather for the first of tonight's two landing opportunities.

If the forecast holds, Entry Flight Director John Shannon will give the green light to fire Endeavour's two orbital maneuvering system engines at 8:47 p.m. CST. The deorbit burn will slow the shuttle by 349 feet per second, allowing it to descend back to Earth. Landing is scheduled at 9:54 p.m. CST, completing a 4.6-million-mile mission.

Weather conditions are expected to be somewhat better for tonight's second landing opportunity at KSC, with forecasters indicating an 80 percent chance of favorable weather. For the second opportunity, a deorbit burn at 10:24 p.m. CST would see Endeavour land at 11:30 p.m. CST. Mission managers have decided not to call up landing support at the backup landing site at Edwards Air Force Base, Calif., for this evening's opportunities. However, Edwards will be called up for backup landing support on Wednesday should landing at KSC tonight be waved off.

The crew will remain at KSC on Wednesday, returning to Houston's Ellington Field about 2 p.m. Thursday.

Endeavour is orbiting the Earth at an altitude of 246 statute miles with all of its systems in excellent shape.

While weather forecasts in the final days of the mission had indicated that rain showers might delay the astronauts return, the weather cleared, allowing Entry Flight Director John Shannon to give a "go" for the deorbit burn which occurred at 8:46 p.m. CST.

Tonight's landing at KSC marked the 10th night landing in the history of the Shuttle program. It was also the 17th straight landing at Kennedy Space Center and the 24th in the last 25 Shuttle missions to land at the Florida spaceport.

While Endeavour is back on firm ground, 246 miles above, the new International Space Station continues to orbit with all systems functioning normally. The current orientation of the ISS has the Unity module facing the Earth and the Zarya module facing deep space. The station is also in a slow rotation at one revolution every 30 minutes to maintain the proper heating and cooling. The next shuttle assembly mission to the station is STS-96, scheduled for launch aboard Discovery in May.

Cabana and his crewmates, Pilot Rick Sturckow, Mission Specialists Nancy Currie, Jim Newman, Jerry Ross and Sergei Krikalev will remain in Florida until Thursday morning when they are scheduled to return to Houston. The STS-88 crew are scheduled to land at Ellington Field, near the Johnson Space Center at approximately 10:30 a.m. CST where they will be welcomed home with a crew return ceremony.

The two five-second engine firings, performed 45 minutes apart on December 21, slightly raised the station's orbit. The firings, which used both of Zarya's large thrusters simultaneously, checked the performance of the station software that will be used for docking with the Russian-provided Service Module, an early living quarters for the station. At this time, no further engine firings are planned prior to the start of a rendezvous with the Service Module next year.

The Service Module is targeted for a July 1999 launch aboard a Russian Proton rocket. Prior to the Service Module's launch, the Space Shuttle Discovery is scheduled to visit the station in May 1999, carrying supplies to be stored in the interior and a Russian-built spacewalkers' cargo crane to be installed on the exterior.

Following the engine tests, flight controllers in the Zarya Flight Control Room at Mission Control, Korolev - near Moscow, Russia - maneuvered the station back into a naturally stable spinning orientation to conserve propellant and moderate temperatures on the spacecraft. Called an X-nadir spin, the orientation has the Unity module pointed toward Earth and Zarya pointed toward deep space with the station slowly spinning a few tenths of a degree per second. It is the standard orientation for the station until the arrival of Discovery in May. About once each week, however, controllers turn on the station's steering jets and maneuver it into position to update the guidance system and perform other checkouts or activities as needed.

Other activities performed on the station this week included deep-cycling, individually fully discharging and then recharging, each of Zarya's six batteries. The battery deep-cycling procedure is a standard housekeeping activity that will be performed a couple of times each month to optimize the batteries' performance. Flight controllers also successfully tested the Telerobotically Operated Rendezvous (TORU) system on Zarya, a manually-operated backup rendezvous system for which two stuck antennas were freed by astronauts Jerry Ross and Jim Newman during a spacewalk on Space Shuttle mission STS-88.

Flight controllers in Houston and Moscow continue to monitor the station around the clock. No major activities or checkouts are planned for next week, and all station systems are operating normally. The International Space Station is in an orbit with a high point of 256 statute miles and a low point of 248 statute miles, circling Earth once every 92 minutes.

Today's space walk - the 45th in space shuttle history and the fourth of the International Space Station era - began at 9:56 p.m. Central time Saturday night, and concluded at 5:51 a.m. Sunday, lasting 7 hours, 55 minutes. The longest spacewalk was conducted by STS-49 Astronauts Rick Heib, Pierre Thuot and Tom Akers, which lasted 8 hours, 29 minutes on May 13 and 14, 1992.

During today's spacewalk, Jernigan and Barry transferred and installed two cranes from the shuttle's payload bay to locations on the outside of the station. They also installed two new portable foot restraints that will fit both American and Russian space boots, and attached three bags filled with tools and handrails that will be used during future assembly operations. Once those primary tasks were accomplished, Jernigan and Barry installed an insulating cover on a trunnion pin on the Unity module, documented painted surfaces on both the Unity and Zarya modules, and inspected one of two early communications system antennas on the Unity.

Throughout the space walk, Jernigan and Barry were assisted by their crew mates as Mission Specialist Ellen Ochoa operated the Shuttle's robot arm to maneuver Jernigan around Discovery's cargo bay, and Canadian Space Agency astronaut Julie Payette acted as "choreographer" of the spacewalk from Discovery's flight deck.

The excursion raised the total number of International Space Station era space walks to four, with the total time spent on construction activities now standing at 29 hours, 17 minutes. STS-88 Astronauts Jerry Ross and Jim Newman spent 21 hours, 22 minutes outside Endeavour during their three space walks.

The crew is scheduled to begin its sleep shift at 8:50 a.m. today and will receive a wake-up call from Mission Control at 4:50 p.m. The crew is scheduled to open a series of hatches connecting Discovery with the International Space Station and enter the new facility about 7:35 p.m. Central time to begin the transfer of equipment and logistical supplies from the Shuttle to the station. They'll also conduct repairs on battery charging systems in Zarya and a balky communications system in Unity.

Logistics transfer activities will dominate the on-orbit day as all crew members will moves supplies from the Spacehab module to designated locations in the International Space Station. By the end of docked operations, Discovery's crew will have transferred almost 3,000 pounds of items, including clothing, sleeping bags, water, medical support equipment, maintenance spares and computer support and maintenance equipment into the orbiting complex to support future resident crews. This transfer effort is being managed by Mission Specialist Ellen Ochoa is managing this effort while Payette stands ready inside the station to receive the goods. At the start of today's work, the transfer was about 70 percent complete.

Payette and Commander Kent Rominger exchanged greetings and discussed the mission with Canada's Prime Minister Jean Cretien and Science Minister John Manley and also answered questions from students across Canada.

Later, at 11:00 p.m. CDT on NASA TV, the entire crew will answer questions from both U.S. and Canadian reporters.

Finally, at 4:20 a.m. Wednesday, Rominger, Pilot Rick Husband and Ochoa will be interviewed by Good Morning America, KFDA-TV in Amarillo, Texas and KUSA-TV in Denver, Colorado. Rominger is a native of Del Norte, Colorado and Husband is a native of Amarillo, Texas.

Near the end of the day, Ochoa again will conduct a transfer status briefing with the ground to confirm the day's completed transfer tasks. The astronauts will begin an eight-hour sleep period at 7:50 a.m. Wednesday and wake up to begin Flight Day Eight at 3:50 p.m.

Discovery and the International Space Station are in excellent health orbiting 240 miles above the Earth.

Weather permitting, Discovery's computers will ignite the twin breaking rockets on the tail just before midnight to slow the vehicle toward a descent through the atmosphere high above the Pacific Ocean. The ground track shows the orbiter navigating its way to its seaside home at the Kennedy Space Center from the south after crossing Costa Rica, Cuba, the Florida Everglades, and East of Lake Okechobee.

The forecast for landing still shows a chance of rain within 30 miles of the runway and a possibility of crosswind violations on the 3-mile-long concrete Shuttle Landing Facility. The runway of choice for tonight's landing is Runway 15. The final turn to align the shuttle with the runway would be out over the water with landing from the northwest to the southeast. If landing is delayed one orbit, touchdown one orbit later at 2:38 a.m. CDT.

Following crew wakeup at 4 p.m. today, the astronauts began the final preparations for landing, including closing the hatches to the Spacehab module, which has served as the cargo transfer compartment throughout the flight. The wakeup music was "The Longest Day," to commemorate what spacecraft communicator in Mission Control Mario Runco called a "landing of a different kind." His reference was to the 55th anniversary of the Allied troop landing on the beaches of Normandy during World War II that occurred on June 6, 1944.

If all goes as planned, Discovery's cargo bay doors will swing shut at 9:18 p.m., after which the astronauts will climb into their launch and entry suits and strap into their seats. Commander Kent Rominger, Pilot Rick Husband and Flight Engineer Ellen Ochoa will be joined on the flight deck for entry by Mission Specialist Julie Payette. Tammy Jernigan, Dan Barry and Valery Tokarev will be seated down on the middeck for entry.

If landing occurs on the first opportunity, Discovery will have covered 3.8 million miles during the mission. STS-96 will be the 11th shuttle mission to end in darkness. Five previous flights have ended at Edwards AFB in California and five at KSC.

Discovery swooped out of darkness as Commander Kent Rominger set the shuttle and his crewmates down on Runway 15 at the Shuttle Landing Facility in Florida to successfully complete the first shuttle mission of the year.

Rominger and Pilot Rick Husband fired Discovery's orbital maneuvering system engines just before midnight Saturday over Thailand to enable the spaceship to drop out of orbit for its high speed return to Earth.

Traveling in an almost due northerly ground track, Discovery crossed over Costa Rica, the southern Caribbean, northwest Cuba, and the Florida Everglades before honing in on the Kennedy Space Center for the 18th consecutive landing at the Florida spaceport.

Rominger and Husband were joined on the flight deck for entry and landing by Flight Engineer Ellen Ochoa and Mission Specialist Julie Payette, while Mission Specialists Tammy Jernigan, Dan Barry and Valery Tokarev were seated down in the middeck.

After landing, Discovery's astronauts were scheduled to undergo routine medical exams and be reunited with their families before spending the rest of the day relaxing in Florida.

The crew is expected to return to Houston early Monday afternoon, with their crew arrival at Ellington Field planned for about 1:30 p.m. The STS-96 crew's return to Ellington is open to the public.

With the Chandra X-Ray Observatory undergoing what so far has been a flawless checkout on orbit for future scientific investigations, Commander Eileen Collins and Pilot Jeff Ashby successfully exercised Columbia's aerosurfaces and fired all of its steering jets late Monday night, confirming that the Shuttle is ready to support its high speed return to Earth.

With all systems operating in good fashion, Mission Specialists Cady Coleman, Steve Hawley and Michel Tognini stowed all of their hardware and deactivated secondary experiments in preparation for tonight's landing opportunities at the Florida spaceport.

The astronauts have two chances to land tonight, the first calling for a firing of the orbital maneuvering system engines in a braking maneuver at 9:19 p.m. Central time tonight. That will slow Columbia down by 250 feet per second, allowing it to drop out of orbit for its hour-long entry back to Earth. If all goes as planned, landing will occur on Runway 3-3 at the Kennedy Space Center at 10:20 p.m. Central Daylight time, after Collins executes an overhead right hand turn to align Columbia with the southeast to northwest approach to the 3-mile long landing strip. This will be the 12th night landing in Shuttle program history.

If weather somehow prevents a landing on the first opportunity, a backup opportunity exists 90 minutes later. The alternate landing site at California's Edwards Air Force Base will not be called up for landing support tonight.

Additional opportunities for landing will be available on Wednesday at both landing sites if weather prevents Columbia from coming home tonight. The forecast, however, looks very favorable, with only a few clouds predicted near the Shuttle Landing Facility and a slight chance of a thundershower offshore at the time of touchdown.

The astronauts began an eight-hour sleep period at 6:31 a.m. Central time this morning and will be awakened at 2:31 this afternoon to begin deorbit preparations.

The first major task will be the closing of Columbia's cargo bay doors at about 6:40 this evening, followed by the astronauts climbing into their launch and entry suits shortly before 8 p.m. Entry Flight Director John Shannon and his team of flight controllers will receive updated weather forecasts throughout the late afternoon and evening before a "go-no go" decision for the deorbit burn is issued around 9 p.m.

Assuming clear weather, the orbiter should be visible as it streaks across the night sky over Texas, Lousiana, and then Florida. In Houston, Columbia should appear in the northern sky at about 10:05 p.m. CDT before the 10:20 landing.

If Columbia lands this evening, the astronauts are due back at Ellington Field in Houston around mid-morning on Wednesday. An exact time for crew arrival will be firmed up after landing.

Columbia is orbiting the Earth every 90 minutes at an altitude of 179 statute miles with all systems operating normally.

The first major task will be the closing of Columbia's cargo bay doors at about 6:40 this evening, followed by the astronauts climbing into their launch and entry suits shortly before 8 p.m. The entry flight control team led by Flight Director John Shannon will receive updated weather forecasts throughout the late afternoon and evening before a "go-no go" decision for the deorbit burn is issued around 9 p.m.

There are two opportunities to land Tuesday night. The first begins with a deorbit burn on orbit 79 at 9:19 p.m. with a landing at 10:20 p.m. at Kennedy Space Center Florida. Columbia's orbital maneuvering engines will fire, slowing the 100-ton spacecraft by 250 feet per second, enough to drop it into the atmosphere halfway around the world. Columbia's unpowered glide through the atmosphere will heat a plasma layer around the heat-protecting tiles and creating a brilliant streak across the night sky for many ground observers. The Orbiter will cross Baja California and northwest Mexico, bisect Texas from west to east and pass over southern Louisiana on its way to Florida. Weather permitting, ground observers will be able to see the entry path about 100 miles on each side of the track. Columbia will cross Texas between 10 and 10:05 p.m. and a few minutes later will overfly Louisiana. Present plans call for a right turn to line up with runway 33, a southeast to northwest landing.

The second opportunity is one orbit later with an engine firing at 10:54 p.m. CDT and a landing at KSC at 11:55 p.m. The groundtrack is similar to the previous orbit's entry path.

Edwards Air Force Base will not be called up for support Tuesday night because of the good chances for landing at KSC.

Flight controllers will be keeping an eye on the weather in Florida. The primary threat to ending Columbia's mission at the Shuttle Landing Facility there is the possibility of thunderstorms within 30 miles, most likely to the west. Winds and cloud cover were not a concern leading up to the engine firing.

If Columbia lands at Kennedy Space Center it will be the 12th night landing in the Shuttle program's history. Five of those have been at Edwards Air Force Base in California and the rest have been at KSC. There have been 18 consecutive landings at KSC and 25 of the last 26 have been there. The last Edwards landing was in March 1996 with the STS-76 mission.

Additional opportunities for landing will be available on Wednesday at both landing sites if weather prevents Columbia from coming home tonight.

If Columbia lands this evening, the astronauts are due back at Ellington Field in Houston around mid-morning on Wednesday. An exact time for crew arrival will be firmed up after landing.

Columbia is orbiting the Earth every 90 minutes at an altitude of 179 statute miles with all systems operating normally.

Astronauts Steve Smith and John Grunsfeld on Friday installed a transmitter that sends scientific data from Hubble to the ground. The transmitter replaced one that failed in 1998. A second transmitter had successfully carried the load without any disruption to Hubble scientific operations. Since the transmitters are considered very reliable, they were not designed to be replaced in orbit and special tools were developed to make the job easier.

Smith and Grunsfeld also installed a solid state digital recorder, replacing an older mechanical reel-to-reel recorder version. The digital Solid State Recorder provides more than 10 times the storage capacity of the old unit. They also applied new insulation on two equipment bay doors.

Both the transmitter and the recorder checked out normally on early tests by telescope controllers.

Two previous space walks on Wednesday and Thursday had completed the highest priority tasks of the mission. Those tasks included installation of six new gyroscopes and six Voltage/Temperature Improvement Kits, giving Hubble a new computer 20 times faster and with six times the memory of the old computer, and replacement of one of Hubble's three Fine Guidance Sensors.

Friday's space walk lasted 8 hours and 8 minutes, ending at 9:25 p.m., making it the fourth longest in history. Part of the reason for the length of the space walk was difficulty in hooking Grunsfeld's suit up to orbiter power after he had returned to Discovery's airlock. Friday's space walk brings the total time of STS-103 extravehicular activity to 24 hours, 33 minutes. This mission's three space walks bring the total amount of time spent servicing Hubble to 93 hours, 13 minutes. Space Shuttle Program space walks now total 317 hours, 3 minutes. And Steve Smith now is the astronaut with the second longest combined space walk time, with 35 hours, 33 minutes behind only Jerry Ross, with 44 hours, 11 minutes.

Discovery is in an orbit with a high point of 380 miles and a low point of 363 miles. All of the orbiter's systems continued to function normally.

STS-103 Commander Curt Brown, along with Pilot Scott Kelly, first performed checks of the Flight Control System by activating one of the three Auxiliary Power Units aboard Discovery to allow them to test the various aerosurfaces that will be used to steer the Shuttle once it has re-entered the atmosphere. The crew then did a check of the Reaction Control System, the maneuvering jets that steer Discovery while the Shuttle is in space. Both the FCS and RCS checkouts were without issue, with all systems ready to support Discovery's return to Earth.

The weather forecast for the two available landing sites is very good for both a nominal end of mission as well as the two extension days that are planned into every Shuttle flight. The prediction for KSC on Monday is for only a few clouds at the upper levels and very good visibility. The only possible concern is crosswinds that are predicted to be near the peak of what is allowed at the three-mile-long Shuttle Landing Facility at KSC. Weather at the alternate landing site at NASA's Dryden Flight Research Center in Edwards, California also is predicted to be very good on Monday, with only a few high clouds and light winds. The extended forecast for both landing sites on Tuesday and Wednesday shows continued favorable weather.

At tonight's mission status briefing, Entry Flight Director Wayne Hale said that given the very good forecast at both landing sites for the next three days, the Shuttle team's current plan for Monday afternoon would be to try for the first two landing opportunities at KSC. If Discovery cannot land on one of those opportunities and the weather forecast for Tuesday and Wednesday remains the same, Discovery and her crew would be kept in orbit one additional day to try and allow a KSC landing on Tuesday. Shuttle managers would like to land at KSC if possible in order to avoid the work associated with transporting an orbiter from California back to Florida.

The first opportunity to land at KSC on Monday takes place on orbit 118 with a deorbit burn at 3:06 p.m. CST and a landing at KSC at 4:18 p.m. The second opportunity on orbit 119 would have a deorbit burn taking place at 4:49 p.m. and a landing at KSC at 6:00 p.m. CST. A third and final opportunity for a KSC landing is available on orbit 120 if needed. The third opportunity has a deorbit burn at 6:32 p.m. and landing at 7:43 p.m. CST.

Should the extended weather forecast change, there are landing opportunities at the Edwards site on the same three orbits, along with an additional opportunity on orbit 121.

The STS-103 crew will begin a planned eight-hour sleep period at 11:20 p.m. this evening. A wake-up call from Mission Control to begin what should be their final day in space for this flight will come at 7:20 a.m. on Monday.

The crew's day began with a wake-up call from Mission Control, "The Cup of Life," sung by Ricky Martin. The music was the official song of France '98 World Cup Soccer and was played for Mission Specialist #2, Jean-Francois Clervoy of the European Space Agency at the request of his son.

Entry Flight Director Wayne Hale and his team of flight controllers have three attempts to bring Discovery home to Florida today. The first opportunity would see a firing of the Shuttle's large orbital maneuvering system engines at 3:06 p.m. to drop Discovery out of orbit and begin its high speed reentry toward Earth. Landing would occur at 4:18 p.m. Central time (5:18 p.m. EST).

The second opportunity would see a deorbit burn at 4:48 p.m., resulting in a landing at 6:01 p.m. Central time (7:01 p.m. EST). The final opportunity for the day would have the deorbit burn occurring at 6:31 p.m. with landing to follow at 7:43 p.m. Central (8:43 p.m. EST). If Discovery lands on either of the last two opportunities, Commander Curt Brown and his crew would make the 13th night landing in Shuttle program history.

The entry flight controllers will be receiving updated weather forecasts throughout the day, however the initial prediction is for favorable weather with a few high level clouds. Earlier predictions of cross winds at or near acceptable limits appear to be trending in a positive direction. Weather at the alternate landing site at NASA's Dryden Flight Research Center in Edwards, California also is predicted to be very good today although KSC is the prime landing site for today's opportunities.

After waving off the first landing opportunity of the day because of a concern with cross winds at the landing site, the crew was given a "go" to perform the deorbit burn which came at 4:48 p.m. CST and caused Discovery to fall out of its 380 statute mile high orbit to start the journey home to the Kennedy Space Center.

With Commander Curt Brown at the controls, Discovery touched down at 6:01 p.m CST on Runway 33 at the three mile long Shuttle Landing Facility runway at KSC to complete a mission spanning almost 3.3 million miles. Pilot Scott Kelly, Flight Engineer Jean-Francois Clervoy and Mission Specialist Michael Foale joined Brown on the flight deck for entry and landing. Mission Specialists Steve Smith, John Grunsfeld and Claude Nicollier were seated down in the middeck. The end of the STS-103 mission marked the 20th consecutive landing at the Florida spaceport and the 13th night landing in the history of the Shuttle program.

Left behind in orbit, the Hubble Space Telescope now features six new gyroscopes, six new voltage/temperature improvement kits, a new onboard computer, a new solid state recorder and new data transmitter, a new fine guidance sensor along with new insulation on parts of the orbiting telescope.

The STS-103 crew will spend the evening in Florida before returning to Houston on Tuesday. The crew is expected to leave Patrick Air Force Base in Cocoa Beach, FL at approximately 1:30 p.m. CST. The crew should land at Ellington Field at about 5 p.m. where the seven astronauts will be greeted by JSC management and center employees. The crew return ceremony will occur at Hangar 990 and is open to the general public.

Because of the 24-hour-a-day activity aboard Endeavour, the six crewmembers are divided into two teams. Blue Team members Dom Gorie, Janice Voss and Mamoru Mohri began the first mapping swath, covering a 140-mile-wide path, at about 11:31 p.m. Friday. It was the beginning of coverage of more than 70 percent of the Earth's land surface. The mapping will cover an area between 60 degrees north and 56 degrees south, where about 95 percent of the Earth's population lives.

The Red Team, led by Mission Commander Kevin Kregel, includes Mission Specialists Janet Kavandi and Gerhard Thiele. Their first shift was intense. It included deployment and checkout of the almost 200-foot mast supporting the outboard antenna structure. It is the largest rigid structure ever deployed in space. The Red Team began its sleep period at about 10:45 p.m. Friday and is scheduled to be awakened at 6:44 this morning.

After mast deployment, tests revealed that the mast's damping system, designed as a kind of a shock absorber for the mast, was not working as expected. Flight controllers decided to leave the dampers in their locked position. Calculations showed that the mast was at no risk without the dampers activated.

All planned science data takes have been acquired successfully and all indications from the telemetry show that the radars are performing nominally. Data has been sent to JPL for analysis and early indications are that the data is of excellent quality. Additional reports about mapping results are expected about 12:00 noon CST.

Shortly after 5:30 a.m. Saturday, Voss and Gorie held a news conference with correspondents from NBC and CNN.

Saturday is scheduled to be the first full day of Shuttle Radar Topography Mission mapping. Endeavour systems continued to function normally.

So far, the Shuttle Radar Topography Mission has imaged 44.7 million square miles, or about 93.9 percent of the target area, at least once. About 33.4 million square miles or 70.1 percent of the target area has been imaged at least twice. The target area extends from 60 degrees north latitude to 56 degrees south latitude. That covers all the Southern Hemisphere landmasses except Antarctica and Northern Hemisphere land south of Hudson Bay and St. Petersburg, Russia. It is home to about 95 percent of Earth's population.

At the scheduled end of mapping operations, more than 99.9 percent of the area will have been imaged at least once. More than 94.6 percent of it will be covered at least twice, and almost half will be imaged at least three times. All but about 80,000 square miles of targeted land will have been covered. The areas that will not be covered are in small, scattered segments, mostly in North America and most of them already accurately mapped.

Endeavour's radar, gathering data in 140-mile-wide swaths as the spacecraft orbits at 17,500 miles per hour, images 40,000 square miles each minute. Data from this mission will, after a year or more of processing, produce the most accurate and most uniform global topography maps ever made.

The EarthKAM, a digital camera mounted at an overhead window on Endeavour's flight deck, has sent down about 2,200 images so far, and the number is growing. On four previous shuttle flights, EarthKAM sent down a total of 2,018 images.

The camera takes pictures for middle school students working on projects in Earth science, geography, space sciences and other topics. Through the Internet, their schools' mission operations centers are linked to the EarthKAM Mission Operations Center at the University of California at San Diego, which sends up photo targets and receives the images. Except for setup, initial camera pointing and lens changes, no crew involvement is required for normal operations.

On Saturday, Endeavour's crew carried out the seventh and final trim burn and flycast maneuver of the flight. The maneuver keeps the spacecraft at the proper altitude for mapping and is designed to reduce the stresses on the mast and minimize the loads at the tip.

Blue Team members, Pilot Dom Gorie and Mission Specialists Janice Voss and Mamoru Mohri, are on duty and continue mapping operations. Commander Kevin Kregel and Mission Specialists Gerhard Thiele and Janet Kavandi, the Red Team, are sleeping. They are to be awakened at 10:14 a.m. CST.

Endeavour's systems continue to perform well as it orbits about 150 statute miles above the surface.

The mast folded smoothly into its nine-foot-long canister in Endeavour's payload bay during the 18 minute retraction operation that astronauts began at 7:17 a.m. Central Time. The crew flipped the outboard antenna structure over to its stowed position, then began retracting the mast itself. As each of the 86 bays of the mast entered the canister, the bay's corners were captured in spiraling grooves inside the canister, much like those in a rifle barrel.

Completion of the final portion of stowing the SRTM mast was delayed when the three latches on the lid of the mast canister failed to engage as expected. Suspecting that the cold thermal temperatures the mast experienced while deployed were reducing the flexibility of the system, flight controllers had the astronauts work procedures to warm up the mast canister while increasing the torque pull of the canister motors. The efforts of Endeavour's crew and Mission Control were rewarded at 9:50 a.m. Central time when all three latches on the mast canister closed, securing the SRTM payload for the ride home to Earth.

Radar data gathering concluded at 5:54 a.m. after a final sweep across Australia. During 222 hours and 23 minutes of mapping, Endeavour's radar images filled 332 high density tapes and covered 99.98 percent of the planned mapping area - land between 60 degrees north latitude and 56 degrees south latitude - at least once and 94.6 percent of it twice. Only about 80,000 square miles in scattered areas remained unimaged, most of them in North America and most already well mapped by other methods. Enough data were gathered to fill the equivalent of 20,000 CD's.

The EarthKAM, a digital camera mounted at an overhead window on Endeavour's flight deck, has been shut down for the remainder of the flight, after sending to Earth about 2,600 digital images of the planet's surface. On four previous shuttle flights EarthKAM sent down a total of 2,018 images.

Later today, Endeavour's crew will turn its attention to returning home. Check out of the flight control surfaces and orbiter thruster jets is scheduled to begin at noon. After the orbiter systems checks are complete, the crew will begin stowing the cabin for tomorrow's return to the Kennedy Space Center with landing scheduled for 3:50 p.m. Central Time Tuesday.

After wrapping up mapping operations at 5:54 a.m. Central time today with a final pass over Australia, Endeavour's crew retracted the 200-foot mast into its payload bay canister. The mast, the longest rigid structure ever deployed in space, supported the Shuttle Radar Topography Mission's external antenna structure during more than 222 hours of data gathering.

Mast retraction proceeded smoothly as each of its 86 external sections, or bays, folded into the nine-foot-long canister during the 18-minute retraction procedure. Final mast stowage was delayed when the three latches on the lid of the mast canister failed to engage as expected. The first two efforts failed to secure the latches, but the third attempt succeeded and all three latches on the mast canister were activated at 9:50 a.m. Central time.

The SRTM mapped almost 100 percent of all planned sites around the world, a total area of more than 47.6 million square miles. The area mapped four times represents more than twice the area of the United States. SRTM project scientist Dr. Mike Kobrick called SRTM "a truly outstanding achievement." New images released today showed Fiji; the San Francisco Bay area; Pasadena, CA; the San Andreas Fault near Palmdale, CA; and an animated fly-around from Pasadena to Palmdale along the San Andreas Fault.

This afternoon, Commander Kevin Kregel, Pilot Dom Gorie and flight engineer Janet Kavandi tested Endeavour's flight control surfaces and reaction control system thrusters. Deactivation and stowage of radar mapping hardware and the Ku antenna were completed, and members of the Red Team - Kregel, Kavandi and Gerhard Thiele -- began cabin stowage. The Blue Team - Gorie, payload commander Janice Voss and Japanese astronaut Mamoru Mohri -- will complete stowage tomorrow morning. The Blue Team began its sleep period at 5:44 p.m., and will be awakened at 1:14 a.m. Tuesday.

There are three landing opportunities available tomorrow, two at Kennedy Space Center in Florida, the third at Edwards, CA. The first opportunity would bring Endeavour back to KSC at 3:50 p.m. Central. There is another opportunity one orbit later, with a KSC landing at 5:22 p.m. Central. The third opportunity would see Endeavour land at Edwards at 6:48 p.m. Central time. The previous 20 shuttle missions have ended with landings at KSC. The last Edwards landing was STS-76 in March 1996. The primary concerns for a KSC landing are strong crosswinds and a low layer of clouds. Weather conditions at KSC are not expected to improve Wednesday or Thursday, and are expected to deteriorate at Edwards after Tuesday.

During 225 hours of operation during this mission, EarthKam took 2,715 images. Over 75 middle schools from around the world participated. The previous record number of images for a single flight was 670 on STS-86. The total number of images for this flight alone far exceeded the combined total from all previous flights.

With Commander Kevin Kregel at the controls, Endeavour touched down at 5:22 p.m Central time on Runway 33 at the three mile long Shuttle Landing Facility to complete a mission spanning almost 4.7 million statute miles. Pilot Dom Gorie, Flight Engineer Janet Kavandi and Mission Specialist Janice Voss joined Kregel on the flight deck for entry and landing. Mission Specialist Mamoru Mohri from NASDA, the Japanese space agency, and European Space Agency astronaut Gerhard Thiele were seated down in the middeck. The end of the STS-99 mission marked the 21st consecutive landing at the Florida spaceport.

After waving off the first landing opportunity of the day because of high cross winds at the landing site, the crew was given a "go" to perform the deorbit burn which came at 4:24 p.m. Central time and caused Endeavour to fall out of its 150 statute mile high orbit to start the journey home to the Kennedy Space Center.

The data brought home by Endeavour's crew was collected during more than 222 hours of around-the-clock radar mapping operations and is enough to fill more than 20,000 CDs. The information gathered on the STS-99 Shuttle Radar Topography Mission will be used to produce global maps more accurate than any available today.

The STS-99 crew will spend the evening in Florida before returning to Houston on Wednesday. The crew should land at Ellington Field in Houston near the Johnson Space Center at about 1:30 p.m. Central time where the six astronauts will be greeted by JSC management and center employees. The crew return ceremony will occur at Hangar 990 and is open to the general public.

Shortly after 7 p.m. today, Commander Jim Halsell, Pilot Scott Horowitz and Flight Engineer Jeff Williams successfully test fired Atlantis' steering jets and verified the performance of the various aerosurfaces that will be used during Atlantis' high-speed return to Earth. This checkout of Atlantis' flight control surfaces and systems is a routine activity on the day prior to landing to verify that all required systems are operating as expected. The tests were monitored by Entry flight director John Shannon from Mission Control in Houston.

As Halsell, Horowitz and Williams conducted their work from the flight deck, crewmates Mary Ellen Weber, Jim Voss, Susan Helms and Yury Usachev continued stowing away equipment used over the past nine days on orbit. Throughout the five days of docked operations with the International Space Station, the Spacehab module in Atlantis' payload bay served as a way station for more than 3,000 pounds of material transferred between the two vehicles. As the astronauts prepare for their Memorial Day landing, they will ensure that equipment housed in that module -- and in Atlantis' crew cabin -- is properly stowed and secured in place.

Midway through the crew day -- about 11 p.m. -- the astronauts will gather for a final review of entry and landing procedures, and then will continue their stowage activities. Williams and Voss, who conducted a 6 1/2 hour space walk earlier in the mission, also will pack up and stow away their spacesuits and associated hardware.

The crew will take time from tonight's entry preparations to talk with reporters located at the Johnson Space Center in Texas, the Kennedy Space Center in Florida and the Russian Mission Control Center outside of Moscow in an interview scheduled to begin at 10:41 p.m.

Preliminary weather forecasts for Monday morning's landing indicate a slight possibility of rain within 30 miles of the landing site, and cross winds in excess of acceptable limits. The weather forecasts will be refined over the course of the next 24 hours in preparation for landing. For a 1:20 a.m. Central time landing at KSC, Atlantis' orbital maneuvering system engines would be fired in a deorbit burn at 12:13 a.m. In the event weather precludes a landing on the first opportunity, a second opportunity exists for a landing in Florida on the next orbit, with a deorbit burn at 1:50 a.m. resulting in a 2:56 a.m. landing.

Commander Jim Halsell flew Atlantis to a nighttime touchdown at the Florida spaceport at 1:20 a.m. Central time to complete a 4,076,000 mile mission, the second Shuttle flight of the year. It was the 14th nighttime landing in Shuttle history and the 22nd consecutive mission to end with a landing at KSC. Halsell was joined on Atlantis' flight deck by Pilot Scott Horowitz, Flight Engineer Jeff Williams and Mission Specialist Mary Ellen Weber. Crewmates Susan Helms, Jim Voss and Yury Usachev were seated down on the orbiter's middeck for entry and landing.

Atlantis returned to Earth after Flight Director John Shannon determined that crosswinds at the Kennedy Space Center's three-mile long landing strip were gentle and steady, enabling him to give the astronauts the green light to come home on time. Halsell fired the Shuttle's braking rockets at 12:12 a.m. Central time, allowing Atlantis to drop out of orbit for its high-speed descent. Atlantis passed over southern Mexico and the Gulf of Mexico before crossing over the Sarasota / Ft. Myers area of Florida en route to the Cape. Atlantis broke the quiet of the pre-dawn hours in Central Florida with a double sonic boom just minutes before touchdown, heralding its arrival at the landing site as it went subsonic.

Left in orbit is the renovated International Space Station, equipped with an upgraded electrical system, new fans, filters, fire extinguishers, smoke detectors and communications gear. ISS flight controllers report that the complex is functioning in excellent condition. The Station is orbiting at an altitude of about 238 statute miles, awaiting the arrival of its next component, the Russian Service Module "Zvezda", which is scheduled to be launched on a modified Proton rocket from the Baikonur Cosmodrome in Kazakhstan in July. The ISS will automatically rendezvous and dock with "Zvezda" about two weeks after the new module is placed in orbit.

Atlantis will now be processed for the next Shuttle flight in early September to return to the International Space Station with another crew for the outfitting and supply of the newly arrived Service Module. That flight, STS-106, will be led by veteran Commander Terry Wilcutt.

The STS-101 astronauts will spend Memorial Day relaxing with their families in Florida before returning to Houston Tuesday afternoon at around 1:30 p.m. Central time for a welcoming ceremony at Ellington Field near the Johnson Space Center. JSC employees and families are invited to attend the ceremony.

After launch, Russian ground controllers monitored the module's systems through four ground site passes spaced an hour and a half apart. All systems were reported to be in good shape and operating as expected.

Today, Zvezda's propellant system and thruster jets were tested and verified to be in good working shape. Two test firings of the engines took place about 45 minutes apart in preparation for major rendezvous maneuvers scheduled tomorrow. The first was at 11:27 p.m. Wednesday EDT (7:27 a.m. Moscow time today). While it was a test burn only, it did serve as a small rendezvous maneuver for the module on its way to a linkup with the ISS. The result of the burn was a 2 mph (1 meter per second) increase in speed, placing the module in an orbit 210 by 106 statute miles (339 by 172 kilometers). The second burn, about 45 minutes later, occurred at 12:14 a.m. EDT today (8:14 a.m. in Moscow). It too, resulted in a change of velocity of 2 mph and raised the low end of the orbit another 3 statute miles. Again, both burns were designed as test burns to verify systems were working properly and ready to support major rendezvous maneuvers.

Other checkouts today included analyzing telemetry that verified the twin solar array drive motors were operating properly in pointing them toward the sun to gather energy for storage in the four batteries inside the module. Those batteries are reported to be working properly. Four additional batteries will be installed in the module during the next Space Shuttle visit to the International Space Station set for early September.

The solar arrays were repositioned for the two test burns to minimize any vibrations imparted during the engine firings. After the burns, the solar arrays were moved back to their normal operating positions.

Also completed was a test of the inertial navigation and star tracker navigation systems to verify the module can be reoriented for maneuvers and rendezvous burn.

During the four ground passes yesterday, telemetry showed that one of the two docking targets was not deployed. The target, however, would only be used during a manual docking, which is not planned on the service module's mission. Russian specialists believe the target actually is deployed and that sensors are not reading correctly. This is no impact to the docking by the ISS to the service module planned for 8:46 p.m. EDT on July 25.

The first two rendezvous maneuvers currently are scheduled for Friday at 1:19 a.m. EDT (9:19 a.m. in Moscow) and 1:54 a.m. EDT (9:54 a.m. Moscow time). The burns will raise both sides of the orbit - the first by an average of 30 miles) to 222 by 127 statute miles (354 x 240 kilometers) and the second by an average of 43 miles to 232 by 160 miles (373 x 257 kilometers).

Zvezda Rendezvous Burn Plan Reference: International Space Station altitude is 235 statute miles (376 kilometers). Time/DateVelocity ChangeTarget AltitudePurpose11:27 p.m. EDT,
July 122 mph, (1 m/s)210 x 106 statute miles,
(339 x 172 kilometers) Test burn
(Completed)12:13 a.m. EDT,
July 132 mph, (1 m/s)210 x 109 miles,
(339 x 175.5 km) Test burn
(Completed)1:19 a.m. EDT,
July 1436 mph, (16 m/s)222 x 127 miles,
(358 x 204 km) Altitude adjust1:54 a.m. EDT,
July 1444 mph, (20 m/s) 232 x 160 miles,
(373 x 257 km) Altitude adjust

At 8 a.m. EDT today, Zvezda was on its 22nd orbit in space traveling northeasterly across the southern Pacific Ocean.

Zvezda now is handling all attitude maneuvers of the 60-ton complex through its own Motion Control System following the automatic docking last Tuesday night. Since then, leak checks have been performed verifying a tight seal between Zarya and Zvezda.

Additionally, commanding through the Unity node's early communications system was transferred to Zvezda as well, meaning that equipment can be powered via ground commands sent from Moscow, through Houston and up to the station. Russian ground stations continue to serve as the primary method of sending commands and receiving data from the ISS. Prior to the transition of computer control, Zvezda's three computers were rebooted to allow them to synchronize properly before the formal swap.

The remainder of this week will see flight controllers oversee routine battery cycling aboard Zarya and an automatic docking system test in preparation for the arrival of the Progress supply vehicle being readied for launch on Sunday.

The Progress, in final processing at the Baikonur Cosmodrome in Kazakhstan, will ride to orbit on a Soyuz rocket with liftoff tentatively scheduled for 2:30 p.m. Eastern Time on Aug. 6. At present, docking is scheduled for 3:46 on the afternoon of Aug. 8. NASA TV will cover the docking live, but not the launch.

At just under 120 feet in length, and a wingspan of 95 feet (Zvezda's solar arrays), the ISS when visible is the third brightest object crossing the night sky. Only the Moon and Venus shine brighter.

Commander Terry Wilcutt, Pilot Scott Altman along with Mission Specialists Ed Lu, Rick Mastracchio, Dan Burbank, Yuri Malenchenko and Boris Morukov received their wake up call from Mission Control at 6:46 p.m. Central. The wake up song, "YMCA" was played for Scott Altman at the request of his wife.

The seven STS-106 astronauts will shortly begin the final preparations for undocking. Atlantis is scheduled to separate from the station at 10:44 p.m. while the two spacecraft are flying over the northeastern portion of the Ukraine.

The initial separation will be performed by springs in the docking mechanism that will gently push the shuttle away from the station. Both Atlantis and the station's steering jets will be shut off to avoid any inadvertent firings during this initial separation.

Once the docking mechanism's springs have pushed Atlantis away to a distance of about two feet, when the docking devices will be clear of one another, Altman will turn the shuttle's steering jets back on and fire them to begin very slowly moving away from the station. From the aft flight deck, Altman will manually control Atlantis within a tight corridor as he separates from the station, essentially reversing the task performed by Wilcutt when Atlantis docked.

Atlantis will continue away to a distance of about 450 feet, where Altman will begin the close fly-around of the station, first crossing a point directly behind, then directly underneath and then again above the station. Altman will circle the station twice in 90 minutes as the crew records views of the exterior with still photography and video. As Atlantis crosses directly above the station for the second time, Altman will fire Atlantis' jets to perform a final separation.

Early on Monday, all seven astronauts will conduct an in-flight press conference during which they will answer questions from reporters at various NASA centers and the Russian mission control center outside of Moscow. The press conference is scheduled to begin at 2:11 a.m. CDT.

Atlantis' astronauts will get some off duty time just after 3 a.m. Central before they turn in for an eight hour sleep period at 9:46 a.m. When they wake up early Monday evening, the crew will checkout the orbiter systems used for reentry and landing and secure equipment and transfer items in preparation for landing at Kennedy Space Center at 2:56 a.m. Central on Wednesday.

After carefully watching cross winds at the Shuttle Landing Facility and receiving real-time observations from Chief Astronaut Charlie Precourt flying weather reconnaissance in Florida, entry flight director LeRoy Cain decided to wave-off today's two opportunities to bring the crew home.

Weather conditions at KSC are not expected to improve over the next two days as a high-pressure system over the eastern seaboard is expected to remain in place producing windy conditions, possible low cloud decks, and rain in the vicinity of the shuttle's Shuttle Landing Facility runway. There are two opportunities to land Monday at KSC or at the West Coast landing site at Edwards Air Force Base. Weather conditions in California are expected to improve over the course of the next two days, while KSC's weather is expected to remain the same or degrade further.

There are two landing opportunities tomorrow in Florida and three in California. The second KSC and first Edwards opportunities are on the same orbit, six minutes apart. The first landing opportunity - to KSC - would see a deorbit burn of Discovery's orbital maneuvering system engines at 12:44 p.m. with landing to follow at 1:51 p.m. The second opportunity is one orbit later with a 2:21 p.m. deorbit burn resulting in a landing at 3:28 p.m.

The first of the day's opportunities to Edwards Air Force Base would see a deorbit burn at 2:18 p.m. with landing at 3:22 p.m. The second would have Discovery's deorbit burn take place at 3:51 p.m. with landing at 4:58 p.m. and the final opportunity one orbit later with an engine firing at 5:28 p.m. resulting in a landing at 6:34 p.m.

It is highly unlikely that the crew would be asked to remain suited up for reentry for multiple landing opportunities. A reentry strategy will be developed overnight and through the morning tomorrow to take best advantage of landing conditions at the two sites.

Discovery's crew will go to bed tonight shortly after nine and be awakened tomorrow at 5:17 a.m. to once again begin preparations for a return trip home.

A high pressure system sitting over the eastern seaboard is expected to produce windy conditions that could result in cross winds in excess of acceptable limits at the time of today's planned landing. Mission managers will closely watch weather conditions in Florida today, working with the Spaceflight Meteorology Group in Houston and complemented by real-time weather observations by Chief Astronaut Charlie Precourt flying the Shuttle Training Aircraft at the landing site.

The crew was awakened at 5:17 a.m. today to begin landing preparations to the sounds of the U.S. Air Force theme "Off We Go Into the Wild Blue Yonder." Mission Commander - and Air Force Colonel - Brian Duffy quickly responded that "You had a couple of us standing and singing up here looking out the window, looking at the wild blue yonder and hoping to enter it today."

If weather conditions permit and the crew is given a "go" to begin their deorbit preparations, they will close Discovery's payload bay doors at 9:27 a.m., the crew will put on their pressurized launch and entry suits and strap into their seats just after 11 a.m. Entry Flight Director LeRoy Cain is expected to poll the flight control team for the final decision for the de-orbit burn 20 minutes prior to the planned firing of Discovery's orbital maneuvering system engines at 12:07 p.m. which will set the STS-92 crew up for a landing at KSC at 1:14 p.m. CDT. There is a back up landing opportunity one orbit later if needed. The second opportunity would involve a de-orbit burn at 1:43 p.m. and landing at 2:50 p.m. CDT.

For a landing on that first opportunity, at the time of the de-orbit burn, Discovery will be above the Indian Ocean, passing over the northern portion of Sumatra. The burn will last just under 3 ½ minutes and the change in velocity will cause Discovery to fall out of orbit and begin the trip home. A little more than 35 minutes later, while flying over the Pacific Ocean, South of Easter Island, the vehicle will begin to encounter the upper portions of Earth's atmosphere in the portion of the flight known as entry interface. With the Shuttle's speed still above Mach 25, temperatures outside the vehicle will quickly climb near 3,000 degrees F.

The final portion of Discovery's flight path will see the Shuttle pass over Central America along the Honduras-Nicaragua border, the western portion of the Caribbean Sea, the western most portion of Cuba and the Gulf of Mexico before crossing the Florida coastline, flying over the Everglades and Lake Okeechobee before arriving on the east coast of Florida near Cape Canaveral.

As Discovery reaches the vicinity of Kennedy Space Center, Commander Brian Duffy will take over manual control of the Shuttle. He will execute a 223-degree turn to line Discovery up for a final approach to runway 1-5 at KSC's Shuttle Landing Facility.

If all goes as planned and Discovery touches down on the 3 mile long runway at 1:14 p.m., it will have traveled approximately 4.5 million miles over 11 days, bringing to an end the 100th mission in Shuttle program history.

Discovery has two landing opportunities Monday at KSC, where the weather is expected to be questionable, and three at Edwards Air Force Base in California. The second KSC and first Edwards opportunities are on the same orbit, six minutes apart. Edwards will be activated for a possible Monday landing, but weather there is expected to be marginal. Weather conditions at KSC are not expected to improve over the next two days, while improvement in California is forecast.

For the first Monday landing opportunity - to KSC - Discovery would fire its orbital maneuvering system engines at 12:43 p.m. CDT to begin its descent from orbit, with landing to follow at 1:51 p.m. The second Florida opportunity is one orbit later with a 2:21 p.m. deorbit burn resulting in a landing at 3:28 p.m.

The first opportunity to Edwards would see a deorbit burn at 2:15 p.m. CDT with landing at 3:23 p.m. The second would have Discovery's deorbit burn take place at 3:51 p.m. with landing at 4:58 p.m. and the final opportunity one orbit later with an engine firing at 5:29 p.m. and landing at 6:35 p.m.

Flight controllers in Houston will work through Monday morning to develop a landing plan based on conditions at the two sites.

After "deorbit backout" -- undoing their preparation to come home on Sunday -- the crew spent much of the afternoon relaxing and communicating with their families via computer. STS-92 Mission Commander Brian Duffy, Pilot Pam Melroy and Mission Specialists Leroy Chiao, Bill McArthur, Mike Lopez-Alegria, Jeff Wisoff and Koichi Wakata, are scheduled to go to bed tonight shortly after 9 p.m. and be awakened at 5:17 a.m. Monday.

The International Space Station, from which Discovery undocked Friday, continued to function well. The station flight control room in the Mission Control Center continued to monitor systems on board. They watched and commanded heaters on the huge gyroscopes on the newly installed Z1 truss. The gyros will provide attitude control for the ISS, and the heaters are designed to protect them from damage by the cold of space.

The station trails Discovery by 248 statute miles. The distance is increasing by 5.4 miles each 90-minute orbit of the Earth.

Discovery touched down at 4 p.m. CDT and rolled to a stop on Edward's concrete runway at 4:0l, for a mission elapsed time of 12 days, 21 hours and 43 minutes.

The astronauts fired Discovery's orbital maneuvering system engines for the deobrit burn at 2:52 p.m. as the spacecraft was over the Indian Ocean, north of Madagascar and east of Kenya. Discovery felt the first traces of the atmosphere about 78 statute miles over the South Pacific, just south of the Tropic of Capricorn and east of Australia. The spacecraft passed south of Hawaii and crossed the California coast over Los Angeles. By the time it landed at Edwards, Discovery had traveled more than 5.3 million statute miles.

Commander Brian Duffy, Pilot Pam Melroy and Mission Specialists Leroy Chiao, Bill McArthur, Jeff Wisoff, Mike Lopez-Alegria and NASDA Astronaut Koichi Wakata spent 6 days, 21 hours and 23 minutes docked to the ISS. They left a larger and more complete station that they had helped prepare for the early November arrival of the first station crew. They added two major components, increasing the mass of the ISS by about 10 tons to a total of about 80 tons.

In addition to the total of 27 hours, 19 minutes spent outside the station on the four spacewalks, -- two each by Chiao, McArthur, Wisoff and Lopez-Alegria, the astronauts spent 27 hours and 4 minutes inside, completing connections with the new elements and transferring equipment and supplies for the Expedition 1 crew.

Discovery's crew is scheduled to spend Tuesday night at Edwards. They are to return to Houston on Wednesday, where the crew return ceremony will be held at Ellington Field's Hangar 990 at about 1:30 p.m.

Discovery is targeting a landing later today, after poor weather conditions in Florida and California kept the crew in space two days longer than originally planned. Duffy and his crew mates - Pilot Pam Melroy and Mission Specialists Leroy Chiao, Bill McArthur, Jeff Wisoff, Mike Lopez-Alegria and NASDA Astronaut Koichi Wakata - will begin their preparations for a return trip to Earth about 8:30 this morning, in anticipation of a landing at either the Kennedy Space Center or Edwards Air Force Base later today.

With continuing strong winds, cloud cover and rain at the Florida landing site, a landing there today remains unlikely. However, there is one opportunity for the crew to land in Florida if weather conditions improve significantly. That opportunity would see a deorbit burn at 1:21 p.m. with landing to follow at 2:28 p.m. An opportunity to return to KSC one orbit earlier, on Orbit 200, has already been ruled out due to the crew's activity timeline

On the west coast, improving weather conditions at Edwards Air Force Base hold promise for Discovery's return. Entry Flight Director LeRoy Cain and his team will watch over the weather this morning and likely will adjust the crew's deorbit timeline to focus on the Edwards opportunities today.

On the first of two opportunities to land at Edwards today, Discovery's orbital maneuvering system engines would fire in a deorbit burn at 2:52 p.m. as it passes over the Indian Ocean, just north of Madagascar and east of Kenya, and land at 3:59 p.m. Discovery would encounter the first traces of the atmosphere while flying over the South Pacific, just south of the Tropic of Capricorn and east of Australia and continue its flight over the Pacific, passing well South of the Hawaiian Islands before arriving on the west coast of the United States. As it heads into Edwards Air Force Base, Discovery will pass just south of the Santa Rosa and Santa Cruz Islands before crossing the California coastline over Los Angeles.

There is a second opportunity to Edwards with a deorbit burn starting the descent at 4:29 p.m. and landing at 5:35 p.m. A landing today brings to a close the 100th mission in Shuttle program history on a mission that paved the way for the first residents of the orbiting International Space Station.

Deployment of the port wing was delayed while ground controllers studied an apparent slackness in one of two blankets that make up the starboard structure. They believe that two tensioning cables had jumped off their guides during deployment. Despite that anomaly, the starboard array is functioning well and producing electricity. The slackness should have no effect on its ability to produce power for the space station.

Deployment of the second solar wing brings to 240 feet the span of the station's solar arrays. This array is 38 feet across and can produce as much as 60 kilowatts. It has a 15-year designed lifetime. It is the first of four such arrays that eventually will supply power to the station, enabling it to conduct basic and applied research in its microgravity environment.

The deployment was scheduled to begin with Endeavour and the space station in daylight and with television available so that array experts could watch the deployment from Mission Control. The port wing began to move from the two boxes that housed its two solar blankets and the mast canister between them that housed the lattice structure that pushed their ends outward, after a computer command by Endeavour commander Brent Jett. The deployment was slow, with stops and starts. It was completed, after two rows of solar panels stuck together were shaken lose by slightly retracting, then extending the arrays again, at 8:46 p.m.

Jett and the other four astronauts aboard, pilot Mike Bloomfield and mission specialists Joe Tanner, Carlos Noriega and Canadian Marc Garneau, had a relatively quiet day Monday. They conducted an extensive camera survey of the starboard array before deployment of its twin began. They also did housekeeping chores and monitored Endeavour systems before their scheduled sleep period beginning about 11 p.m.

Aboard the space station, the Expedition One crew, commander Bill Shepherd and cosmonauts Yuri Gidzenko and Sergei Krikalev, continued their work to outfit the ISS. After a wakeup tone at midnight - about the time the Endeavour crew went to bed -- the station crew installed a dust collector fan, collected condensate water samples, replaced a microprocessor and made observations of Patagonian glaciers. They will meet face-to-face with Endeavour crewmembers on Friday, after all three spacewalks by Tanner and Noriega have been completed.

The second of those spacewalks is scheduled for Tuesday. Its main purpose is to install data and power cables to allow the space station to use electricity generated by the new solar arrays.

Commander Ken Cockrell, Pilot Mark Polansky and Mission Specialists Bob Curbeam, Marsha Ivins and Tom Jones were ordered to stay in orbit for an extra day after Entry Flight Director LeRoy Cain concluded that crosswinds at the 3-mile long Shuttle Landing Facility were out of limits despite crystal clear skies. Atlantis' crew had only two opportunities today in which to return to Earth.

The astronauts closed the Shuttle's cargo bay doors just after 8 a.m. Central time this morning as Cain and his team of flight controllers closely monitored the winds in Florida. Chief Astronaut Charlie Precourt provided real-time observations as he flew the Shuttle Training Aircraft over the landing strip, a Gulfstream jet modified to mimic the landing characteristics of Atlantis.

Throughout the morning, winds were observed to be gusting in excess of the 15 knot crosswind limit for a daytime landing, and at 11:47 a.m. Central time, Cain called off today's landing efforts. Word of the waveoff was radioed up to Cockrell by Spacecraft Communicator Scott Altman in Mission Control.

Atlantis will have two opportunities again tomorrow in which to land at the Kennedy Space Center. The first, on orbit 185, calls for a firing of Atlantis' braking rockets at 11:21 a.m. Central time with a landing on KSC's Shuttle runway at 12:27 p.m. Central time. Atlantis' cargo bay doors would be closed at around 8:40 a.m. Monday in preparation for that first landing opportunity. A backup opportunity is also available on the following orbit, with a deorbit firing of the orbital maneuvering system engines at 12:57 p.m. Central time and a landing at 2:03 p.m. Central time. The weather forecast for the Cape tomorrow is promising, with only scattered clouds, a possibility of one deck of broken clouds, and somewhat lighter winds which are predicted to be acceptable for landing.

The backup landing site at California's Edwards Air Force Base is forecast to have unacceptable weather, with broken clouds, high winds and a chance of showers.

Shortly after today's landing attempts were called off, Atlantis' astronauts reopened the Shuttle's payload bay doors and removed their launch and entry suits to begin their bonus day in space. The astronauts will begin an eight-hour sleep period at 7:43 p.m. Central time tonight and will be awakened at 3:43 a.m. Monday to begin their pre-landing preparations.

Atlantis continues to orbit the Earth in excellent shape, completing an orbit of the Earth every 90 minutes at an altitude of 237 statute miles.

Aboard the International Space Station, Expedition One Commander Bill Shepherd, Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev spent a relaxing day off aboard the orbital outpost and will enjoy an off-duty day again on Monday.

As was the case on Sunday, flight controllers tried to bring Commander Ken Cockrell, Pilot Mark Polansky and Mission Specialists Bob Curbeam, Marsha Ivins and Tom Jones home during two landing opportunities which were available at the Florida spaceport, but winds continued to gust out of limits, higher than the 15- knot crosswind limit permissible for a Shuttle landing. Weather at the backup landing site at Edwards Air Force Base, California was also unacceptable with high winds and rainshowers in the area of the Mojave Desert.

Finally, at 12:13 p.m. Central time, Entry Flight Director LeRoy Cain called off today's landing attempts and directed his team to try to bring Atlantis home on Tuesday to KSC when the forecast calls for slightly improved weather and lighter winds. There are two landing opportunities at the Kennedy Space Center on Tuesday with the first opportunity calling for the firing of Atlantis' braking rockets on orbit 200 at 10:20 a.m. Central time, resulting in a landing at the Cape at 11:27 a.m. Central time. The second opportunity would begin with the deorbit burn maneuver on orbit 201 at 11:56 a.m. Central time and a landing at the Kennedy Space Center at 1:02 p.m. Central time.

Two landing opportunities also are available on the next two orbits at Edwards. The first of the Edwards' opportunities would call for the deorbit burn at 1:27 p.m. Central time and a landing at 2:33 p.m. Central time. The final opportunity of the day on Tuesday for Edwards would involve a deorbit burn at 3:04 p.m. Central time and a landing at 4:09 p.m. Central time. The weather at Edwards is also expected to be better, with a chance of broken cloud decks and lighter winds than were observed today.

Landing support will also be called up for the White Sands Space Harbor at Northrup Strip in New Mexico, which has three landing opportunities available, although all efforts will be made to try to bring Atlantis home in either Florida or California. After reopening Atlantis' cargo bay doors, the astronauts removed their launch and entry suits and will spend the rest of the day relaxing. They are scheduled to begin an eight-hour sleep period at 7:13 p.m. Central time tonight and will be awakened at 3:13 a.m. Tuesday to resume landing preparations.

Aboard the International Space Station, Expedition One Commander Bill Shepherd, Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev wrapped up an extended weekend in which they relaxed in preparation for a busy week of work which begins Tuesday with the continuing activation of systems in the newly installed Destiny laboratory. The crew will also prepare for the undocking and redocking of its Soyuz vehicle Saturday from the aft end of the Zvezda module to the nadir port of the Zarya module, in anticipation of the arrival of an unmanned Progress resupply ship at the Station at the end of the month.

Atlantis is orbiting the Earth in excellent shape at an altitude of 237 statute miles.

The Kennedy Space Center remains the primary target for today's landing, with two opportunities to bring Atlantis and its crew home. The initial forecast for today shows generally acceptable conditions for landing, with a slight concern for some clouds produced by offshore sea breeze and possible crosswinds at the three-mile long landing strip. The first opportunity for the day would call for a deorbit burn at 10:21 a.m. Central time, resulting in a landing at 11:27 a.m. Central time. The second opportunity would begin with a deorbit burn at 11:56 a.m. Central time with a landing at 1:02 p.m.

Landing opportunities are also available on the following two orbits at the backup landing site at Edwards Air Force Base in California. Weather conditions on the West Coast are marginal, however, with the possibility of rain within 30 miles of the landing site. The first of the Edwards' opportunities would call for the deorbit burn at 1:27 p.m. Central time and a landing at 2:33 p.m. The final opportunity of the day to Edwards would involve a deorbit burn at 3:04 p.m. and a landing at 4:09 p.m.

The White Sands Space Harbor at Northrup Strip in New Mexico has three landing opportunities available as well, and may be considered as a possible landing site, although all efforts will focus on returning Atlantis either to Florida or California. Entry Flight Director LeRoy Cain intends to employ the three best opportunities of the day in an effort to bring the two-week flight to a close.

Atlantis has enough propellent and consumables to stay aloft until at least Wednesday, if necessary.

The STS-98 astronauts - Ken Cockrell, Mark Polansky, Bob Curbeam, Marsha Ivins and Tom Jones - were awakened at 3:13 a.m. to the sounds of "Should I Stay or Should I Go" by the Clash, as they prepared for their return trip to Earth.

Aboard the International Space Station, now about 1,100 miles behind Atlantis, Expedition One Commander Bill Shepherd, Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev started a busy work week today preparing for Saturday's relocation of their Soyuz vehicle. The crewmembers will deactivate key ISS systems early Saturday morning, then climb into their pressure suits to board the Soyuz capsule for a 40-minute maneuver in which the Soyuz will be undocked from its current location on the aft end of the Zvezda module and redocked to the nadir port of the Zarya module. That will make room for a Progress resupply vehicle due to arrive later this month.

All systems on board Atlantis are performing well and ready to support today's landing efforts as the orbiter continues to circle the Earth at an altitude of 237 statute miles.

The crew was awakened to the song "She Blinded Me With Science" performed by Thomas Dolby and played in recognition of the laboratory outfitting and initial station scientific work enabled by Discovery's flight. As the crew awoke, Mission Control informed Commander Jim Wetherbee of the mission's extension.

Discovery will now spend almost nine days docked to the station, allowing ground controllers and the crew more time to ensure all necessary items are stowed away correctly aboard the Leonardo cargo module. Leonardo, filled with equipment to return to Earth, now will be detached from the station and latched back in Discovery's payload bay early Sunday morning, a day later than originally planned. Discovery will undock from the station late Sunday night, spend Monday checking landing equipment, and return to Earth about midnight Tuesday. Discovery is planned to fire its deorbit engines at 10:55 p.m. Tuesday, descending to a touchdown at the Kennedy Space Center, at 11:59 p.m.

The crews will spend today continuing to pack items aboard the Leonardo logistics module for return to Earth. In addition, all crewmembers will participate in a press conference from the Destiny laboratory at 2:39 a.m., fielding questions from reporters at NASA centers across the United States and at the Russian control center outside Moscow.

Later, Wetherbee will initiate a second hour-long gentle reboost of the station, using the shuttle's small steering jets to raise the complex's altitude by several miles. A third reboost session may be performed before Discovery departs the station.

Discovery and the International Space Station are in excellent condition as they circle the Earth once every 92 minutes.

Landing is scheduled for 11:56 p.m. CST Tuesday (12:56 a.m. EST Wednesday), but Entry Flight Director Wayne Hale and his team are carefully watching weather conditions at the primary landing site. With low clouds, possible rain and gusty crosswinds expected at Kennedy Space Center in Florida, Hale decided to activate support at Edwards Air Force Base in California on Wednesday when conditions are expected to be at their best this week.

The first landing opportunity begins with a deorbit burn on Orbit 200 at 10:50 p.m. CST Tuesday and ends with landing at 11:56 p.m. in Florida. The second opportunity on Orbit 201 starts with an engine firing at 12:26 a.m. CST Wednesday and ends with landing in Florida at 1:31 a.m. The third chance calls for an Orbit 202 deorbit burn at 1:57 a.m. CST Wednesday and landing at Edwards at 3:02 a.m. The final prospect of the crew day begins with an engine firing at 3:33 a.m. CST Wednesday and ends with a California landing at 4:38 a.m.

Wetherbee and the shuttle crew - Pilot Jim Kelly and Mission Specialists Andy Thomas and Paul Richards - spent the day packing for the trip home and completing checks of the steering jets and flight controls the shuttle will use. They also fired Discovery's orbital maneuvering system engines to adjust the shuttle's orbit and optimize landing opportunities, testing the braking rockets they use to begin re-entering the Earth's atmosphere.

ISS Expedition One Commander Bill Shepherd and crewmates Yuri Gidzenko and Sergei Krikalev took time out from their packing to answer questions posed by three television news reporters. Tonight, the returning Expedition One crew members will set up the reclining seats to help ease the stress of landing on their bodies, which have not experienced gravity for four and a half months.

Meanwhile, the Expedition Two crew aboard the station - Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss - began settling into their new home and shift schedule. Awakening at midnight Tuesday, they began their daily exercise regimen and set up the station toilet for use by its first female crew member.

The crew aboard Discovery is scheduled to begin its sleep shift at 7:42 a.m. CST and wake up to begin final landing preparations at 3:42 p.m. Bedtime for the station crew is 3:30 p.m. CST.

Mission Control Houston recognized the importance of today's activities sending up a congratulatory message from Canadian Astronaut Steve MacLean and playing the Canadian anthem, "Oh Canada" before the two space walkers - Scott Parazynski and Chris Hadfield - floated back into Endeavour. Hadfield became the first Canadian to conduct a spacewalk today as he worked to install the Canadian built and provided Canadarm2 robotic arm.

"It really just opens the door to what all of us can be doing here internationally, beginning to explore space as a planet," said Hadfield.

Parazynski and Hadfield spent 7 hours and 10 minutes working outside the station, installing first an Ultrahigh Frequency (UHF) antenna before turning their attention to the station's new robotic arm. They floated out of Endeavour's airlock at 6:45 a.m. central time and about two hours later had installed and deployed the UHF antenna on the Destiny module of the station.

With that complete, the two astronauts turned their attention to installing the new station robotic arm. The main boom was deployed at 10 a.m. central, and a few minutes later, at 10:10 a.m. Hadfield and Parazynski began unfolding the arm as Endeavour and the station flew 238 miles over the Atlantic Ocean.

With the new arm secured in its pallet attached to the exterior of the Destiny laboratory, Hadfield and Parazynski connected cables to give the arm power and allow it to accept computer commands from inside the lab. After unfolding the arm, they used a pistol grip tool to properly secure a series of expandable fasteners that keep the booms rigidized in position. The two space walkers experienced some difficulty ensuring an appropriate torque level had been placed on the fasteners. By taking the pistol grip tool from automatic to manual mode, Hadfield and Parazynski securely tightened the bolts in place, completing their activities for the day and beginning to clean up the payload bay before returning to Endeavour.

Today's spacewalk, which concluded at 1:55 p.m., was the 19th conducted to assemble the International Space Station. A second spacewalk scheduled for Tuesday will focus on establishing permanent power connections between the arm and station and performing a thorough checkout.

At 1:53 p.m., Flight Engineers Susan Helms and Jim Voss, on board the station, commanded the first motion of the new station robotic arm as they flew 242 miles over the Indian Ocean crossing the eastern coast of Africa. All indications are that the arm operated perfectly in this initial commanding.

Tomorrow, just before 5:30 a.m., Helms and Voss will "walk" the arm off the pallet and attach it to a grapple fixture on the Destiny module. On Wednesday morning, they will use the station arm to hand the pallet to the shuttle arm. In a procedure that will take about 3 ½ hours from start-to-finish, the pallet will be transferred from one arm to the other and berthed back in Endeavour's payload bay for return to Earth

Endeavour's 50 foot-long robotic arm will be pressed into service once again Monday morning as Pilot Jeff Ashby grapples the Italian Space Agency-provided "Raffaello" logistics module and docks it to the Unity module. Early Tuesday morning, the Expedition Two crew - Voss, Helms and Commander Yury Usachev - will enter Raffaello and begin transferring the supplies, equipment and experiment racks loaded inside.

After a busy day on orbit for both crews, the station crew will go to sleep at 5:31 p.m., followed 10 minutes later by Endeavour's crew. Mission Control will wake up Commander Kent Rominger, Ashby, Mission Specialists John Phillips, Yuri Lonchakov, Umberto Guidoni, Hadfield and Parazynski at 1:41 a.m. Monday. The station crew is scheduled to wake up at 2:01 a.m.

Today's work will include testing nitrogen and oxygen lines that will be used during future shuttle missions to replenish the airlock's tanks of high-pressure oxygen and nitrogen; testing the airlock's space walk equipment; and installing valves that will connect Quest to the station's environmental control system. In addition to checking and activating Quest's systems, the crews will remove the motor controllers from the airlock's berthing mechanism, which are no longer needed now that the airlock is firmly attached to the station.

The shuttle crew's day began at 4:04 p.m. with a wake-up call from Mission Control playing the song "No Woman No Cry" by Bob Marley for Mission Specialist Mike Gernhardt. On board the space station, Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms awoke at 5:04 p.m.

After the airlock was attached to the station early Sunday morning, and the first part of its checkout was completed, the shuttle and station crews held a ribbon cutting for the new addition. Station Commander Yury Usachev and Atlantis Commander Steve Lindsey cut a white ribbon that had been strung across the entrance of Quest's crew lock. Lindsey and Usachev made two cuts to the ribbon, each on either side of the word Quest to christen the new compartment. This evening's checkout of Quest will help prepare for the mission's third space walk, scheduled for Thursday evening. That space walk, during which two air tanks will be installed on Quest, will be the first to originate from the new airlock.

Yesterday, a decision was made to bring home a spare space suit aboard Atlantis that had experienced a leaking battery. Controllers were worried that the leaking battery may have damaged portions of the suit and decided to bring the suit home for inspection and cleaning. The originial plan had been to leave the suit aboard the station for use by future crews.

All systems continue to function normally aboard both the Space Shuttle Atlantis and the International Space Station. Later this evening, a little after 8 p.m., the shuttle's engines will be used to perform an hour-long reboost of the station's altitude.

Once they swap out their custom-made Soyuz capsule seat liners with those belonging to Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms, Culbertson, Dezhurov and Tyurin will become the third trio of residents to inhabit the complex, while Usachev, Voss and Helms become members of Discovery's crew.

The Soyuz serves as a crew return vehicle in the unlikely event it should become necessary to leave the station.

Official handover of command of the ISS from Usachev to Culbertson will take place on August 20, shortly before Discovery undocks from the Station.

After the crew transfer is complete, the oncoming ISS residents will begin a comprehensive handover with their departing counterparts, receiving briefings on Station systems, the current configuration of hardware and computers and procedures they will employ during their first days on board the outpost.

Mission Specialist Pat Forrester will use Discovery's robot arm to move the Italian-built Leonardo cargo module from the shuttle's payload bay to the nadir docking port of the Station's Unity module so it can be unloaded of more than three tons of supplies and equipment for the newly arrived Expedition Three crew. Leonardo also contains racks of scientific experiments which will greatly enhance the scientific research on board the ISS over the next few months. Leonardo will be installed on the Station late this morning.

Other equipment will be transferred throughout the day from Discovery's middeck lockers to the ISS as the crews work in concert to set the stage for the Expedition Three mission.

The joined spacecraft are orbiting at an average altitude of about 244 statute miles, completing an orbit of the Earth every 90 minutes. Both craft are in good condition.

Discovery is about 1,300 statute miles ahead of the space station and widening the gap by about 50 miles per 90-minute orbit. The seven-member crew - Commander Scott Horowitz, Pilot Rick Sturckow, Mission Specialists Dan Barry and Pat Forrester, along with the returning Expedition Two crew members, Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss - were awakened at 3:10 a.m. CDT to begin a day with two landing opportunities at Florida's Kennedy Space Center. Weather conditions in Florida hold promise for today's landing, but the entry team of flight controllers will be watching for a chance of rain near the landing site.

The first opportunity would see a deorbit burn at 10:37 a.m., resulting in an 11:46 a.m. CDT (12:46 p.m. EDT) landing. Discovery would descend across southern Mexico, cross the Bay of Campeche, skirt the northwestern tip of the Yucatan Peninsula, and cross the Gulf of Mexico before making landfall on Florida's western coast. For the second opportunity, the deorbit burn would occur at 12:17 p.m. The shuttle would cross northern Mexico, descend over the Rio Grande near Laredo, and fly along the Gulf Coast before crossing the Florida peninsula for a 1:23 p.m. landing.

Aboard the International Space Station, the Expedition Three crew - Commander Frank Culbertson and Cosmonauts Vladimir Dezhurov and Mikhail Tyurin - were awakened a little after midnight for the undocking of the Progress 4 vehicle. That spacecraft was moved to make way for the Progress 5 cargo vehicle which launched at 4:24 a.m. Tuesday from the Baikonur Cosmodrome in Kazakhstan and is scheduled to dock at the rear of the space station's Zvezda Service Module about 5 a.m. tomorrow.

Progress 4 docked to the space station last May 22 with a cargo of equipment, food, fuel and spare computer parts. After unloading, it was refilled with trash. Just before 1 a.m. flight controllers at Moscow's Mission Control Center sent the command for it to undock. About three minutes later, springs pushed it away from the station, and three minutes after that, Progress jet thrusters were fired to increase the separation rate. At about 4 a.m. a deorbit burn command initiated its descent to fiery destruction in the Earth's atmosphere.

Discovery is circling the Earth every 90 minutes at an average altitude of about 240 statute miles. Systems aboard the shuttle and the space station are functioning well.

The station was about 250 statute miles above the central Indian Ocean as Endeavour rocketed away from Launch Pad 39-B at the Kennedy Space Center, FL, on time at 4:19 p.m. CST. Endeavour will close in on the station for the next two days and dock with the complex on Friday to begin a week-long stay.

Endeavour is commanded by Dom Gorie with Mark Kelly serving as pilot. Mission Specialists are Linda Godwin and Dan Tani. Also aboard Endeavour are station Expedition Four crew members Commander Yuri Onufrienko and Flight Engineers Carl Walz and Dan Bursch, who are beginning more than five months in orbit.

Endeavour will bring home the Expedition Three station crew, Commander Frank Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin, who have been aboard the station since mid-August. In addition to the new crew, Endeavour is carrying more than three tons of food, supplies and equipment in the Raffaello logistics module to the orbiting outpost.

Endeavour's crew will spend the next few hours unpacking equipment, setting up computers and conducting the first of periodic engine firings that will occur over the next two days to refine the shuttle's approach to the station. The shuttle crew will begin a sleep period at 11:19 p.m. CST and will be awakened at 7:19 a.m. CST Thursday. On Thursday, Endeavour's crew will check out the shuttle's equipment and systems that will be needed for Friday's final approach and docking to the International Space Station. Docking is planned for just after 2 p.m. CST Friday. On Saturday, the Raffaello module will be lifted from the shuttle payload bay using Endeavour's robotic arm and attached to a station berthing port to be unloaded. Godwin and Tani are planned to conduct a four-hour space walk on Monday to install insulation around two solar array rotation mechanisms. Raffaello will be returned to the shuttle payload bay later in the mission and brought back to Earth.

In addition to a new station crew and supplies, Endeavour is carrying a host of scientific investigations, including experiments from space agencies, schools and universities across the United States, Europe and South America as well as a small satellite that has involved more than 25,000 students in 26 countries.

The crew, Commander Dom Gorie, Pilot Mark Kelly, Mission Specialists Linda Godwin and Dan Tani, Expedition Four Commander Yury Onufrienko, Flight Engineer Carl Walz and Flight Engineer Dan Bursch, was awakened by the song "Soul Spirit" and "Put a Little Love in Your Life," sung by Bursch's daughter and her second-grade classmates.

The crew will spend the day preparing shuttle systems for docking with the International Space Station, which is scheduled for about 2 p.m. CST Friday. Preparations include powering up the shuttle's robotic arm and checking out the airlock and the space suits that will be used on Monday's planned four-hour spacewalk by Godwin and Tani to place thermal blankets on the motors that rotate the solar arrays atop the P6 truss.

In addition to performing the spacewalk, other activities during the mission include a crew exchange on board the space station Saturday and the transfer of more than three tons of cargo. The cargo, housed in the Raffaello logistics module that will be attached to the Unity module, includes food, supplies and equipment that the Expedition Four Crew will use during its stay on the station. The Expedition Three crew, Commander Frank Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin have been living aboard the space station since mid-August and will return home on Endeavour.

Also on board Endeavour is a host of scientific investigations, including experiments from other space agencies, schools and universities across the United States, Europe and South America. Two experiments located in the Multiple Application Customized Hitchhiker-1 (MACH-1) in the shuttle payload bay had already completed 15% and 10% of their mission objectives by the time the crew went to sleep last night. Those experiments are the Capillary Pumped Loop Experiment (CAPL) and the Prototype Synchrotron Radiation Detector (PSRD) respectively. The CAPL demonstrates a multiple evaporator capillary pumped loop system and the PSRD measures cosmic ray background data.

Joined by flight controllers in Mission Control, the crews observed the playing of the U.S. and Russian national anthems at 7:46 a.m. CST, the three-month anniversary of the first impact at the World Trade Center.

"In stark contrast to the international cooperation and unity in our effort to take mankind literally to the stars, we are reminded of our loss and sorrow due to the acts of violence and terror in an unprecedented attack on freedom, democracy and civilization itself," STS-108 Lead Flight Director Wayne Hale told the crews from Mission Control. "More than 3,000 people perished this day three months ago, including more than 200 citizens from countries that are family members of the International Space Station program -- Canada, Italy, France, Germany, Japan and Russia."

Caps honoring the New York Police Department, New York Fire Department, New York Port Authority and New York Office of Emergency Management are being displayed in Mission Control. Aboard Endeavour are U.S. flags that will be distributed to heroes and family members of victims of the attacks when the shuttle returns to Earth. Also on the shuttle are several other commemorative items, including a U.S. flag found at the World Trade Center site after the attacks.

The shuttle crew found out this morning that it will spend an extra day in space as mission managers extended Endeavour's flight to a duration of 12 days. Landing is now scheduled for Monday. The extra day will allow Endeavour's crew to assist with additional maintenance tasks on the station, including work on a treadmill and air conditioner.

The crews' work today focused on the continued transfer of equipment and supplies to and from the station. So far, more than 5,000 pounds of supplies and experiments have been moved to the station from Endeavour and the Raffaello cargo module. The transferred items have included more than 850 pounds of food, 1,000 pounds of clothing and other crew provisions, 300 pounds of experiments and associated equipment, 800 pounds of space walking gear, and 600 pounds of medical equipment. Endeavour's crew will begin a sleep period at 10:19 p.m. CST tonight and awaken at 6:19 a.m. CST Wednesday, a day that will continue the packing and unpacking onboard and include the station treadmill maintenance work.

The crewmembers took a few breaks from their schedule during the week to field questions from a Cleveland, Ohio, television station and a New York, N.Y., radio station during an event on Thursday and to address more than 650 educators from across the United States on Friday that were gathered in Houston for the Eighth Annual International Space Station Educators Conference.

Maintenance activities included some minor repairs on the Active Rack Isolation System (ARIS), replacing the hard drive of one of the command and control computers, troubleshooting the slight echo usually heard during space-to-ground communications, removing the automated docking system from the Russian Progress resupply vehicle and installing a laptop computer in the Quest airlock. The ARIS dampens the vibrations caused by movement by the crew in an effort to isolate the sensitive science experiments located in the Destiny Laboratory. A shock absorber pushrod was replaced after malfunctioning because of normal wear and tear on the system.

The crew replaced the hard drive on the third and final command and control computer with the new solid-state mass memory unit that is expected to operate better in the microgravity environment than the spinning disk type hard drive. The new unit is now activated and operating well.

Ground controllers in Mission Control Houston and Moscow are guiding the crew through several tests of the station's communications system. The crew is trying several configurations of the system to help find a solution to an echo. The echo does not impact flight operations, but slightly decreases the quality of the audio heard on the ground.

Columbia's main landing gear touched down at 3:32 a.m. CST, completing a mission that covered 3,941,705 statue miles.

Commander Scott Altman, Pilot Duane Carey, and Mission Specialist/Flight Engineer Nancy Currie brought Columbia smoothly back to Earth. They fired the shuttle's orbital maneuvering system engines at 2:23 a.m., while Columbia was over the Indian Ocean, to begin their descent from orbit.

Their ground track took them across the Pacific Ocean and the coast of Baja California, then on an almost due east heading across the southern United States. The plasma trail of the orbiter was visible as it passed over Houston to some flight controllers at Houston's Mission Control Center who took a moment to go outside and watch it move quickly across the northern sky.

Florida weather remained good for the landing, though there had been some concern earlier in the day about formation of ground fog. It did not materialize, and Columbia landed right on time.

Mission Specialists John Grunsfeld, Jim Newman, Rick Linnehan and Mike Massimino completed the five spacewalks, working in teams of two on alternate days. They gave the Hubble new solar arrays, an advanced new camera and installed a cooling system to revive another instrument. They also installed a new power control unit to route electricity from the arrays to batteries and instruments, and a new reaction wheel assembly to help point the telescope.

Tuesday's landing was the 58th for a shuttle at Kennedy Space Center and the 14th night landing there. Five other missions have ended with night landings at Edwards Air Force Base, Calif.

• Bay 1-2: Orbiter Docking System - 1800 kg + 3 EMU spacesuits - 360 kg
• Bay 4-13: S0 Truss - 12623 kg. The S0 truss, built by Boeing/Huntington Beach, was 13.4 m long and 4.6 m in diameter. The main truss had a hexagonal cross section. One face carried fluid, power and data cables, while another face carried the rails for the Mobile Transporter. The S0 contained avionics, GPS antennae, and a radiation dose monitor. The S0 would be attached to the LCA (Lab Cradle Assembly) which was attached to the top of the Destiny lab module in 2001. Attached to S0 were:
  • 4 x MTS (Module to Truss Structure) struts. These were used to connect it to the Destiny module
  • Airlock Spur. This was a 4.2 m beam that hinged out to connect to the Quest module and had handrails for spacewalkers
  • Mobile Transporter (MT). This was made by TRW Astro Aerospace in Carpinteria and was an 885 kg, 2.7 m long truck which moved on the S0 rails to transfer heavy cargo along the truss.
• Sill: RMS arm - 410 kg
• Total: 15193 kg

Commander Mike Bloomfield, Pilot Steve Frick, Flight Engineer Ellen Ochoa and spacewalkers Steve Smith, Rex Walheim, Jerry Ross and Lee Morin rocketed away from Launch Pad 39-B at the Kennedy Space Center at 3:44 p.m. Central time as the ISS orbited over the Atlantic Ocean due east of the northeastern United States at an altitude of 240 statute miles.

Launch occurred with only 12 seconds left in the 5-minute launch window due to a brief delay caused by a momentary ground launch system software glitch at the Launch Control Center at the Florida spaceport which paused the countdown at the T-minus 5-minute mark. Once the problem was solved, the countdown resumed.

Atlantis' launch marked a milestone as Ross became the first human to fly in space seven times, breaking a record of six flights previously held by Ross and fellow American astronauts John Young, Story Musgrave, Franklin Chang-Diaz and Curt Brown. No Russian cosmonaut has flown in space more than five times.

Now in their fifth month in orbit, Expedition Four Commander Yury Onufrienko and Flight Engineers Carl Walz and Dan Bursch were able to watch Atlantis' launch through a video uplink from flight controllers in Houston. Atlantis' arrival will mark the first visitors for the Expedition Four crewmembers since their launch back in December.

Less than nine minutes later, Atlantis and its crewmembers settled into orbit as work began to prepare the shuttle for its planned 11-day mission and for a series of rendezvous maneuvers to reach the station on Wednesday morning. Atlantis will actually have to lap the ISS as a result of those maneuvers before its scheduled docking with the outpost Wednesday.

After Atlantis' payload bay doors are opened and approval is given for the start of orbital operations, the seven crewmembers will unstow computers and other gear required for the mission.

If all goes as planned, Atlantis will link up to the station Wednesday just after 11 a.m. Central time, setting the stage for the installation of the S0 (S-Zero) Truss on Thursday morning on the Destiny Laboratory and the first of four spacewalks to mate and activate the new component to Destiny. The S-Zero Truss will serve as a platform upon which other trusses will be attached and additional solar arrays will be mounted in future assembly flights to form a structure longer than the length of a football field. The new truss will also serve as a primary electrical switching station to route power from the stations' arrays to various modules and components.

The shuttle crew will begin its first sleep period at 8:44 p.m. Central time and will be awakened at 4:44 Tuesday morning to begin its first full day in orbit, designed to test the ship's robot arm, spacesuits and rendezvous equipment which will be used over the next few days.

With docking scheduled at 11:06 a.m. Central time (1606 GMT) tomorrow, Commander Mike Bloomfield, Pilot Steve Frick and Mission Specialists Rex Walheim, Ellen Ochoa, Lee Morin, Jerry Ross and Steve Smith verified all of Atlantis' equipment, setting the stage for the orbiter's linkup to a docking port at the forward end of the station's Destiny Laboratory.

Docking is planned over south central China, southwest of Shanghai. The crew will be up early Wednesday to complete preparations and to execute a number of engine firings to draw Atlantis close to the ISS for its eventual docking.

Expedition Four Commander Yury Onufrienko and Flight Engineers Carl Walz and Dan Bursch tidied up their orbital home and completed routine maintenance on the eve of the arrival of their first visitors since they were launched to the ISS back in December. After docking and hatch opening tomorrow, the two crews will run through a dress rehearsal of procedures which will be used on Thursday to maneuver the large S0 (S-Zero) Truss structure from Atlantis' cargo bay for mating to a capture device at the top of Destiny.

Four spacewalks will be conducted by two teams of spacewalkers to electrically and structurally connect the new truss to the ISS. The 13 and a half-ton S-Zero is the mainframe for a series of trusses to follow which will expand the station to a length of a football field.

Late today, Bloomfield and Frick executed a rendezvous maneuver by firing Atlantis' reaction control system jets to refine the shuttle's path to the space station. Several larger engine firings will be conducted Wednesday morning to slow Atlantis' approach to the station, setting up its final path for linkup to the ISS.

With all of its systems functioning in excellent shape, Atlantis orbits the Earth at an altitude of around 220 statute miles. The crew began an eight-hour sleep period at 7:44 Central time this evening and will be awakened at 3:44 Wednesday morning.

The crew will spend today testing and preparing shuttle equipment that will be used to rendezvous and dock with the complex and to install the first and central station truss segment delivered by Atlantis. The crew will power up and test the shuttle's robotic arm, check spacesuits, set up television cameras for the rendezvous activities and prepare the shuttle docking mechanism for contact with the station at 11:06 a.m. Wednesday. Atlantis' mission is to install the 44-foot-long S-Zero (S0) truss on the station, a central girder segment that is one of the most complex pieces of the International Space Station ever launched. The segment is filled with electrical, computer and cooling connections as well as navigation and robotics equipment, including a space railway.

Commander Mike Bloomfield, Pilot Steve Frick, and mission specialists Ellen Ochoa, Steve Smith, Rex Walheim, Jerry Ross and Lee Morin were awakened at 4:44 a.m. to the song "The Best Years of Our Lives" performed by the Baha Men.

Ochoa and Ross, who has now flown in space more times - seven - than any other astronaut, will take a break from the their work onboard Atlantis about 10:44 a.m. CDT for interviews by two Indianapolis, IN, television stations and the Associated Press. Ross is an Indiana native. Late this afternoon, Atlantis' orbital maneuvering system engines will be fired to adjust the rate at which the shuttle is closing in on the station and maintain its course toward a Wednesday morning docking.

On board the station, the Expedition 4 crew, Commander Yury Onufrienko and flight engineers Carl Walz and Dan Bursch, also awoke at 3:44 a.m. to an alarm-clock-like tone. They have synchronized their sleep schedule to match that of the Atlantis crew to prepare for docked operations.

About two hours after Atlantis docks to the station, the hatches between the two spacecraft will open and Onufrienko, Bursch and Walz will greet their first visitors since beginning their stay aboard the orbiting laboratory last December. After a welcome and safety briefing, all 10 astronauts and cosmonauts will begin transferring equipment and supplies between the two vehicles.

Both crews will jointly review plans for installation of the S-Zero (S0) Truss, including procedures for Thursday's scheduled spacewalk, the first of four during this mission. Ochoa and Bursh will maneuver the station's robotic arm, Canadarm2, through a rehearsal of the motions it will use Thursday to pluck the 44-foot, 27,000 pound truss segment from the shuttle's cargo bay and install it atop the station's U.S. laboratory Destiny.

Major systems aboard Atlantis and the space station continue to function well.

Commander Mike Bloomfield guided Atlantis to a linkup with the forward docking port of the station's Destiny Laboratory at 11:05 a.m. Central time as the two vehicles sailed at an altitude of 240 statute miles. The docking culminated a textbook rendezvous executed by Bloomfield and Pilot Steve Frick. As Atlantis docked, Expedition Four Flight Engineer Dan Bursch, a Navy Captain, rang the ISS ship's bell to greet the arriving shuttle crew.

About two hours later, at 1:07 p.m. Central time as the two craft flew over New Zealand, hatches swung open between Atlantis and the station, and the ten crew members greeted one another inside Destiny, marking the arrival of the first visitors for Expedition Four Commander Yury Onufrienko, Flight Engineer Carl Walz and Bursch since they entered the ISS in December for the start of their six-month mission.

After a safety briefing for the shuttle astronauts by Onufrienko, the two crews began to transfer gear for the first spacewalk tomorrow by Steve Smith and Rex Walheim as well as experiments to be housed in Destiny.

Ellen Ochoa joined Bursch to brush up on procedures for the use of the station's Canadarm2 robotic arm tomorrow which will be employed to grapple and unberth the 13 1/2 ton S0 (S-Zero) Truss from Atlantis' cargo bay for mating to a capture device at the top of Destiny. Smith, Walheim, Jerry Ross and Lee Morin will conduct four spacewalks to electrically and structurally mate the S-Zero to Destiny over the next week. Ochoa maneuvered the arm and verified it is in good working order to support the S-Zero operations on Thursday.

Smith and Walheim set up all the equipment in the Quest Airlock on the ISS from which they will mount the first of the four spacewalks to deploy two of the four mounting struts to Destiny and to bring power to the new truss from the U.S. Laboratory. Ochoa is scheduled to grapple the S-Zero around 5 a.m. Central time with the first spacewalk set to get underway around 10 a.m.

Atlantis and the ISS are in excellent shape, orbiting the Earth every ninety minutes in an orbit inclined 51.6 degrees to either side of the Equator.

The two crews began an eight-hour sleep period at 7:44 Central time this evening and will be awakened at 3:44 Thursday morning for the fourth day of the mission.

On Friday, April 12, NASA Administrator Sean O'Keefe will deliver an address on future agency policy entitled, "Pioneering the Future", originating from Syracuse University. The address will be seen on NASA Television beginning at 1 p.m. Central time.

During the S-Zero installation, Atlantis Commander Mike Bloomfield and Pilot Steve Frick operated the shuttle's robotic arm to provide additional camera views to Ochoa and Bursch, who were working in the Destiny Lab at one of the robotic workstations. The truss will serve as the backbone for future station expansion to the length of a football field. S-Zero contains navigational devices, computers, cooling and power systems necessary to attach additional laboratories to the complex.

Within minutes after the new truss was temporarily latched to the Destiny Lab, mission specialists Rex Walheim and Steve Smith left the station's Quest Airlock at 9:36 a.m. Central time to begin the first of four spacewalks of the mission to electrically and structurally mate S-Zero to the station.

Smith and Walheim first unfurled and firmly attached two of four mounting struts on the truss to Destiny before deploying trays of avionics equipment and cables on the truss which include power, data and fluid lines connecting Destiny to the S-Zero. They also attached an umbilical system from the truss to the Mobile Transporter housed on the forward face of the huge girder. The umbilical will enable the Transporter, which is the first railcar in space, to move up and down the length of the station to position the ISS robotic arm for future assembly work. Two other struts on the truss will be mated to Destiny Saturday during the second spacewalk, permanently bolting the truss to the Laboratory.

Working deliberately to connect all of the critical power connections, Walheim spent the day working at the end of the station's Canadarm2, the first time the large arm has been used as a form of cherry picker to maneuver astronauts during assembly work at the ISS. Smith operated as a so-called "free-floater", tethered to the station and to various work sites around the truss itself. Atlantis astronaut Jerry Ross and ISS Flight Engineer Carl Walz took turns choreographing the spacewalk from the aft flight deck of the shuttle.

With all but two tasks successfully completed, Smith and Walheim returned to Quest late this afternoon and ended their spacewalk at 5:24 p.m. Central time, completing a 7 hour, 48 minute excursion. It was the 35th spacewalk devoted to station assembly and the 10th staged from the station itself. As Smith and Walheim wrapped up their work, flight controllers reported that the activation of the S-Zero Truss had begun and that all of the initial systems appear to be in excellent shape.

Time ran out before Smith and Walheim could install two circuit breakers on the truss, but that task will be picked up on a subsequent spacewalk.

After a long and tedious day, the shuttle and station crew members were scheduled to begin an eight-hour sleep period at 7:44 p.m. Central time and will be awakened just before 4 a.m. Friday.

The Atlantis crew - Commander Mike Bloomfield, Pilot Steve Frick and mission specialists Rex Walheim, Ellen Ochoa, Lee Morin, Jerry Ross and Steve Smith - was awakened at 3:44 a.m. by the University of California-Berkeley fight song performed by the school band and "All Right Now," performed by the Stanford University band. Ochoa requested the songs be played for crewmates Walheim and Smith who attended the rival schools.

On board the station, the Expedition 4 crew, Commander Yury Onufrienko and flight engineers Carl Walz and Dan Bursch, also awoke at 3:44 a.m. to an alarm-clock-like tone. Both crews are ready to support the addition of the new segment to the station.

Ochoa, assisted by Bursch, will command the space station robotic arm, Canadarm2, to grapple S0 about 5 a.m. Canadarm2 will lift the truss segment out and away from Atlantis' cargo bay and temporarily install it on the U.S. laboratory Destiny. The Lab Cradle Assembly will provide a semi-rigid structural hold until the truss segment is permanently attached during four spacewalks this week.

The first spacewalk is set to begin about 10 a.m. today as Smith, wearing the suit with solid red stripes, and Walheim, in a solid white suit, float out of the station's Quest airlock. After initial setup procedures, their tasks during the 6½ hour venture include attaching two of four S0 mounting struts to Destiny, as well as an avionics tray that contains power, data and fluid cables and an umbilical system connected to the Mobile Transporter. If time permits, Smith will remove a launch support beam and also go inside the truss to install two circuit breakers.

Ochoa and Bursch will move Walheim on Canadarm2 to worksites throughout the spacewalk. Bloomfield and Frick will use the shuttle's robotic arm cameras to take video of the spacewalkers while Ross guides them through the outlined procedures.

Atlantis Commander Mike Bloomfield, Pilot Steve Frick, and Mission Specialists Ellen Ochoa, Rex Walheim, Lee Morin, Jerry Ross and Steve Smith - and the Expedition Four crew - Commander Yury Onufrienko and Flight Engineers Carl Walz and Dan Bursch - spent their day transferring equipment and science experiments between the shuttle and the station. They also transferred oxygen from the shuttle to one of four high-pressure gas tanks on the Quest Airlock. The tanks are used to repressurize the airlock at the end of each spacewalk staged from the module.

Station flight controllers reported that four new computers on the S-Zero truss were tested successfully, as were new devices to determine the station's orientation relative to the Earth, Global Positioning System navigational antennas and the Thermal Control System for the 13 ½ ton girder, which will be the backbone for other trusses and solar array towers to be mounted on the station in the next year.

The two crews transferred a number of experiments from Atlantis to the station's Destiny Laboratory and reviewed plans for the second and third spacewalks of the mission Saturday and Sunday to continue the outfitting of the new truss.

Saturday's spacewalk by Ross and Morin is scheduled to begin around 9:30 a.m. Central time. The two spacewalkers will complete the bolting of two aft struts on the truss to Destiny, forming a secure structural mate between S-Zero and the Laboratory. Ross and Morin will also attach a second umbilical system to the truss' Mobile Transporter, a form of rail car that will eventually move the station's robotic arm some 350 feet up and down the entire length of the completed truss.

The two crews enjoyed some off duty time this afternoon and are scheduled to begin their sleep period at 7:44 p.m. Both crews will be awakened Saturday at 3:44 a.m.

The Atlantis crew - Commander Mike Bloomfield, Pilot Steve Frick, and mission specialists Ellen Ochoa, Rex Walheim, Lee Morin, Jerry Ross and Steve Smith - was awakened at 3:44 a.m. Central time by the song "Testify to Love," by Wynonna Judd played for Bloomfield from his family. On board the station, the Expedition 4 crew, Commander Yury Onufrienko and flight engineers Carl Walz and Dan Bursch, awoke about 30 minutes later.

Morin and Ross will move an experimental plant growth chamber to a rack inside the station's Destiny lab. This experiment will replace a protein crystal growth experiment that will return to Earth on board Atlantis. Walheim and Ochoa will install a freezer in the lab for future crystal samples.

Oxygen and nitrogen will be transferred from Atlantis to the station to refill the airlock high-pressure tanks with the gasses breathed by spacewalkers. The crew will also prepare for and review the procedures for the next two spacewalks, on Saturday and Sunday, to continue hookup of the S0 Truss.

Systems on the S0 Truss are functioning well after its installation Thursday. Friday, ground controllers will activate the Global Positioning System and the Rate Gyro Assembly located on S0 that will begin providing navigation and attitude data for the station.

Crewmembers will take a break to talk with reporters from MSNBC, CBS Radio Network and WWJ-TV in Detroit at 11:28 a.m. At 1 p.m. NASA television will switch to live coverage of NASA Administrator Sean O'Keefe's address on "Pioneering the Future." The address will be replayed on NASA TV at 3 p.m.

After two hours of time off during the afternoon, both crews are scheduled to begin their sleep period at 7:44 p.m.

Dubbed the "Silver Team" by their colleagues because of their age, 54-year old Jerry Ross and 49-year old Lee Morin of Atlantis' crew had little trouble extending and bolting the final two struts of the new S-Zero (S0) truss to the Destiny Laboratory, insuring that the centerpiece for the future expansion of the station would be permanently secured to accept additional trusses and solar array towers over the next year. The station will ultimately span some 350 feet from end to end, the length of a football field.

The first two struts of the truss were mated to Destiny on Thursday by the other Atlantis spacewalking team, Steve Smith and Rex Walheim, who will venture back outside Sunday to continue the outfitting of the truss and to reroute electrical power to the station's 58-foot long robotic arm.

Morin worked at the end of the ISS' Canadarm 2 throughout the day during his first spacewalk, while Ross, America's most experienced spacewalker and the most flown space traveler in history, remained tethered to the station to provide "free-floating" support during the eighth spacewalk of his career.

Smith, Walheim and Expedition Four Flight Engineer Dan Bursch helped choreograph the spacewalk from Atlantis' aft flight deck, while shuttle crew member Ellen Ochoa and station Flight Engineer Carl Walz took turns maneuvering Morin as they operated Canadarm2 from a robotic work station inside Destiny.

Shuttle and station Commanders Mike Bloomfield and Yury Onufrienko and shuttle Pilot Steve Frick provided photographic and television support for the spacewalk, the 36th devoted to ISS assembly over the past 3 ½ years.

After the truss struts were bolted in space, Ross and Morin removed a series of panels and clamps that provided structural support for the truss during its launch in Atlantis' cargo bay.

The spacewalkers then began work to install a backup device containing an umbilical reel for the Mobile Transporter railcar on the truss that will provide redundancy to a similar device mounted on the truss Thursday. The two sets of umbilicals for the Mobile Transporter, which is designed to move the robotic arm up and down the length of the completed station truss, provide power, data and video capability for the system, which will be tested for the first time in orbit Monday.

Ross tried to remove a restraining bolt on the mechanism which, if required, can cut the umbilical cable should it snag during its operation, but the bolt proved to be a bit balky and did not back out of its socket as planned. Flight controllers decided not to spend additional time troubleshooting the stubborn bolt today after engineers determined that the cable cutter cannot inadvertently fire in its current configuration. The backup umbilical system is operating normally and the stubborn bolt will be dealt with on one of the mission's two remaining spacewalks. The primary umbilical system installed Thursday is also operating normally.

The spacewalk, which was conducted out of the station's Quest Airlock, began at 9:09 a.m. Central time and concluded at 4:39 p.m. as Ross and Morin repressurized the outer compartment of the two-chamber module.

Late today, Frick fired Atlantis' steering jets in a one-hour procedure to slowly reboost the space station by about 2 statute miles. It was the first of three scheduled reboost maneuvers to eventually raise the orbit of the ISS by about 6 statute miles before Atlantis departs the station on Wednesday.

The ten shuttle and station crew members are scheduled to begin their eight-hour sleep period at 7:44 p.m. and will awaken Sunday just before 4 a.m. to begin preparations for the third spacewalk of the flight.

The Atlantis crew - Commander Mike Bloomfield, Pilot Steve Frick, and mission specialists Ellen Ochoa, Rex Walheim, Steve Smith, Morin and Ross - was awakened at 3:44 a.m. by the song "Voodoo Chile," by Jimi Hendrix. It was played for Morin, who will be making his first spacewalk, at the request of his wife. On board the station, the Expedition 4 crew, Commander Yury Onufrienko and flight engineers Carl Walz and Dan Bursch, also were awakened at 3:44 a.m.

During their 6½-hour spacewalk Ross, wearing a spacesuit with broken red stripes, and Morin, wearing a spacesuit with diagonal broken stripes, will complete the structural attachment of S0's remaining two struts to the station's Destiny laboratory. With all four of the struts attached to Destiny, S0 will be able to support its design loads, including the solar arrays that will be on the ends of the truss at assembly complete.

After attaching the struts, Ross and Morin will remove the large metal rods used to support S0 during launch and store them on the truss. The pair will also attach a second cable system to the Mobile Transporter, which will eventually enable the space station's robotic arm, Canadarm2, to ride a railway along the truss structure.

For today's spacewalk Morin will be working from a platform at the end of the Canadarm2, operated by Ochoa. Using the shuttle robotic arm cameras, Bloomfield and Frick will take photographs and video of the spacewalkers. Walheim will coordinate the spacewalk from inside.

Both crews are scheduled to begin their eight-hour sleep period at 7:44 p.m.

The stage is now set for the inaugural run Monday of the so-called Mobile Transporter, a flatcar designed to transport the space station's robotic arm up and down an integrated truss system that will span the length of a football field.

Within minutes after starting their spacewalk at 8:48 a.m. Central time, Steve Smith and Rex Walheim released a claw-like device on the top of the Destiny Laboratory to which the new 13 ½ ton S-Zero (S0) truss was initially attached on Thursday. With the truss' four large struts now securely bolted to Destiny, the claw was no longer needed.

Smith and Walheim then reconfigured a number of connectors providing electricity to the 58-foot-long Canadarm2 robotic arm on the station so it can be powered from the S-Zero truss rather than Destiny. The arm has two sets, or "strings" of avionics equipment for its operation. As Smith and Walheim worked deliberately, one set of avionics was rewired and tested, followed by a separate set of redundant avionics.

Smith spent most of the day riding at the end of the shuttle's robotic arm, which was operated by Pilot Steve Frick during the rewiring of its companion station arm. Walheim was the so-called "free-floating" astronaut, tethered to the station to assist Smith. It was the seventh spacewalk of Smith's career. He is the second most experienced U.S. spacewalker behind crewmate Jerry Ross, who helped choreograph today's excursion from inside Atlantis with the help of Lee Morin. It was Walheim's second spacewalk.

With Canadarm2 successfully rewired and both of its electrical, data and video circuit sets checked out, Smith and Walheim pressed ahead to release clamps which secured the Mobile Transporter to the S-Zero truss during its launch last week. The railcar, which weighs about 1900 pounds, will be commanded Monday by ground controllers to move about 32 feet up and down the truss at a glacial speed of a little less than one inch per second in the first test of its computers, drive motors, suspension unit, video and data umbilicals and the first section of rails on the S-Zero.

The railcar, and an associated Mobile Base System device to be installed on the transporter in early June on the next shuttle assembly flight to the ISS, will ultimately enable the robotic arm to travel to various worksites on the expanding trusses of the station for future construction. The Mobile Base System will be the platform upon which the Canadarm2 will attach itself to be driven up and down the length of the ISS.

The only task not completed today was the attachment of a 14-foot ladder called the Airlock Spur from the S-Zero truss to the Quest Airlock designed to simplify the path for future spacewalkers moving back and forth from the truss to the airlock itself.

As the spacewalk neared its completion, final diagnostic tests of the newly wired station arm were taking longer than planned, and because the Canadarm2 is required for the airlock ladder to be pivoted away from the truss to Quest, flight controllers decided to defer its installation until the final spacewalk on Tuesday.

Smith and Walheim finally returned to Quest and completed their spacewalk at 3:15 p.m. Central time with the repressurization of the airlock.

Atlantis astronaut Ellen Ochoa and ISS Expedition Four crew member Dan Bursch backed up Frick in the operation of the shuttle's robot arm during today's spacewalk, the 37th devoted to space station assembly. Commander Mike Bloomfield documented the spacewalk from Atlantis' aft flight deck while Expedition Four Commander Yury Onufrienko and Flight Engineer Carl Walz continued to transfer supplies from the shuttle to the station for future use.

Late today, Frick conducted an hour-long reboost of the ISS, using Atlantis' steering jets to move the station higher by about two statute miles. It was the second of three planned maneuvers to raise the station's altitude and the second in as many days.

The ten crew members are scheduled to begin an eight-hour sleep period at 7:44 p.m. Central time tonight and will be awakened just before 4 a.m. to prepare for the testing of the new Mobile Transporter.

They are scheduled to step out of the station's Quest airlock at 9:34 a.m. Their first task is to release a claw atop the lab that temporarily secured the truss to it during the initial installation. Walheim, wearing a solid white spacesuit, will release the latch as Smith, wearing a spacesuit with red stripes, begins making connections to route power, data, and video through the truss for later operation of the space station robotic arm, Canadarm2. During the 6½-hour spacewalk, Smith will be working from a platform on the station arm, operated by Mission Specialist Ellen Ochoa and Flight Engineer Dan Bursch.

Walheim will install circuit breakers in the truss, a task left over from the first spacewalk, which lasted 7½ hours. Together they will then turn their attention to the Mobile Transporter, spending about 45 minutes releasing its many launch restraints and removing a small thermal cover from a radiator on the railcar. Then they return to work on the electrical connections for about another hour and a half.

After transferring tools and testing sensors on the side of S0, the last task will be to install the Airlock Spur. The 14-foot beam, fitted with handrails, will stretch from Quest to the forward side of S0, helping future spacewalkers work more efficiently.

Inside the shuttle/station complex, Mission Specialists Lee Morin and Jerry Ross will coach the spacewalkers through the outlined tasks. Shuttle Commander Mike Bloomfield and Pilot Steve Frick will provide photographic and video support during the spacewalk, using Atlantis' robotic arm.

Atlantis' crew was awakened about 3:52 a.m. by the song "All Star," performed by Smash Mouth from the Shrek movie soundtrack. The song was played for Walheim by his family.

Onboard the space station, Expedition Four Commander Yury Onufrienko, Flight Engineer Carl Walz and Bursch were awakened at 3:44 a.m. Both crews are scheduled to begin their sleep period at 7:44 p.m.

Expedition Four Flight Engineer Carl Walz sent commands from a laptop computer to the Mobile Transporter to move off of its launch position on the forward face of the new S-Zero (S0) truss, and at 7:22 a.m., the flatcar began its slow trek to an initial worksite 17 feet down a rail which spans the entire 44 feet of the girder.

It took only a half hour to traverse the distance, but sensitive software in the transporter prevented an automatic latching of the railcar to the worksite. Ground controllers accomplished the latching through a methodical series of commands.

Engineers believe that the subtle effects of weightlessness are causing the railcar to "lift" off its tracks by a microscopic distance, thus interfering with magnetic sensors that tell the transporter its position relative to each worksite. The effect is that the sensors are losing contact with magnetic positioning strips on the truss rail, preventing an automatic latching of the transporter. Manual commanding of the latching is working however, and the system is said to be in excellent working order.

The Mobile Transporter software controls about 20 motors, directing it to travel from one point to another, latch itself down to the truss, and plug itself into a power source. The transporter must latch with about three tons of force to insure a stable platform for the eventual mounting of the Canadarm2 robotic arm. On the next shuttle assembly flight to the ISS in June, a platform called the Mobile Base System will be mounted to the transporter upon which Canadarm 2 will eventually be attached so it can travel the length of a football field to support future assembly of station components.

Late today, the transporter traveled to a second worksite where manual latching commands were again required, then inched back to the first worksite, where the railcar was parked at 5:40 p.m. Central time and manually latched in place for a final time to await the arrival of the Mobile Base System component on the STS-111 mission. In all, the transporter traveled 72 feet from worksite to worksite at a glacial pace of about one inch per second.

Engineers believe a minor software modification may restore the transporter's ability to automatically latch itself to any worksite. All other transporter systems functioned perfectly throughout its initial test.

Atlantis Commander Mike Bloomfield, Pilot Steve Frick, Mission Specialists Ellen Ochoa, Rex Walheim, Lee Morin, Jerry Ross and Steve Smith, and Expedition Four Commander Yury Onufrienko and Flight Engineers Walz and Dan Bursch spent the day monitoring the transporter tests and continued the transfer of equipment and supplies from Atlantis to the station.

In addition, about 100 pounds of oxygen and 30 pounds of nitrogen have been transferred from Atlantis to the tanks on the Quest Airlock to support future spacewalk activity.

The fourth and final spacewalk of the flight will be conducted on Tuesday by Ross and Morin beginning around 9:30 a.m. Central time. At the start of the planned 6 ½ hour excursion, Ross and Morin will pivot a 14-foot ladder away from the S-Zero truss for attachment to Quest to act as a pathway for future spacewalkers. They will also install external lights on the Unity module, test microswitches on the sides of the S-Zero truss which will be used to confirm the attachment of future truss segments, troubleshoot a balky bolt on a cable cutting system on the Mobile Transporter and tie down a portion of insulation on one of four navigational antennas on the S-Zero.

The ten Shuttle and Station crew members are scheduled to begin an eight-hour sleep period at 7:44 p.m. Central time and will be awakened shortly before 4 a.m. Tuesday to prepare for the final spacewalk of the mission.

Ground controllers in mission control will command the Mobile Transporter to move up and down the truss three times, testing its computers, drive motors, suspension unit, video and data umbilicals, and the railway itself. The railcar will travel a total of about 71 feet at speeds of 1, 0.4 and 0.1 of an inch per second, stopping at future worksites to test its ability to latch and unlatch itself to the railway.

This is the first time that a software-controlled movable robot has been used on an orbiting vehicle. The Mobile Transporter software controls about 20 motors, directing it to travel from one point to another, latch itself down to the truss, and plug itself into a power source. The Mobile Transporter ultimately will move the station's robotic arm, Canadarm2, along the orbiting laboratory's 356-foot Integrated Truss.

The Atlantis crew - Commander Mike Bloomfield, Pilot Steve Frick, Mission Specialists Ellen Ochoa, Rex Walheim, Lee Morin, Jerry Ross and Steve Smith - was awakened at 3:48 a.m. to "Magic Carpet Ride" by Steppenwolf, dedicated to Smith. The station crew - Commander Yury Onufrienko, Flight Engineers Carl Walz and Dan Bursch - was awakened at 4:14 a.m.

The crews will continue to transfer equipment between the two spacecraft and will review procedures for the fourth and final spacewalk of the mission, scheduled for Tuesday.

The 10 crewmembers will participate in a news conference with media representatives at NASA centers in Florida and Houston and at Mission Control- Moscow. The event will be carried live on NASA television beginning at 11:47 a.m. CDT. Afterwards, the crews will have a few hours off. Both crews are scheduled to begin their eight-hour sleep period at 7:44 p.m.

Ross and Morin began the fourth and final spacewalk of the STS-110 mission and the 38th devoted to space station construction at 9:29 a.m. Central time, first pivoting a 14-foot beam called the Airlock Spur from the S-Zero truss to the Quest Airlock to provide a quick pathway for future spacewalkers working on truss assembly.

Ross then conducted tests of switches on both sides of the 44-foot long truss to insure they will work properly later this year in confirming the attachment of additional truss segments to the S-Zero. The main truss of the ISS will eventually stretch more than 350 feet, longer than a football field.

The two spacewalking grandfathers pressed ahead to install floodlights on the station's Unity connecting module and the Destiny Laboratory which will provide illumination for future spacewalkers as they move around the expanding outpost.

Ross and Morin then affixed a work platform on the station for future construction work, installed electrical converters and circuit breakers, dressed up a piece of insulation around one of the four navigational antennas on the truss and attached shock absorbers to the new Mobile Transporter railcar. The shock absorbers will prevent vibrations to the station's robotic arm from the future use of carts on the truss which will be used to move spacewalkers from one end of the station to another.

The only tasks not accomplished were the removal of a balky bolt from a backup cable cutting device on one of two umbilical systems for the Mobile Transporter, which was successfully tested on Monday and the installation of a gas analyzer on the truss which proved to be faulty.

The bolt will have no impact on the operation of the flatcar, upon which a Mobile Base System platform will be mounted in June as the ultimate base for the transport of the station's robotic arm up and down the length of the ISS. The gas analyzer was considered the lowest priority of the flight.

With all of their major work completed, Ross and Morin returned to the Quest Airlock and concluded the spacewalk at 4:06 p.m. Central time.

Atlantis Mission Specialist Ellen Ochoa and Expedition Four Flight Engineer Dan Bursch operated the station's Canadarm2 robotic arm to move Ross around the ISS during the spacewalk while Morin operated as the "free-floating" spacewalker, tethered to the station to assist Ross in the final tasks of the mission. For Ross, America's most experienced spacewalker, it was his ninth excursion to conduct work in the void of space during his career, totaling 58 hours and 18 minutes of spacewalking time. Only Russian cosmonaut Anatoly Solovyev has performed more spacewalks in human spaceflight history. Today's spacewalk was the second for Morin. Rex Walheim and Expedition Four crew members Carl Walz helped choreograph the spacewalk from Atlantis' aft flight deck.

While the spacewalkers went about their work, Shuttle and Station Commanders Mike Bloomfield and Yury Onufrienko, Pilot Steve Frick, and Steve Smith continued their transfer of equipment to and from both Atlantis and the ISS and provided photographic and television support to Ross and Morin.

With all of the objectives having been successfully accomplished for the mating and outfitting of the S-Zero truss to the ISS, the stage is set for Wednesday's final farewells between the two crews and undocking of Atlantis from the station at 1:31 p.m. Central time as the two craft sail some 244 statute miles above the north Atlantic due west of Ireland. Atlantis is scheduled to land at the Kennedy Space Center early Friday afternoon.

The shuttle crewmembers will begin an eight-hour sleep period tonight at 7:14 p.m. Central time followed thirty minutes later by the station crew. Atlantis' crew will be awakened at 3:14 a.m. Wednesday to prepare for undocking. The station crew will be awakened an hour later.

Work during the 6½-hour spacewalk includes installation a 14-foot beam extending from Quest to the newly installed S-Zero (S0) Truss to help spacewalkers maneuver around the station more efficiently. They will install halogen work lights on the Unity module and the U.S. laboratory, Destiny -- the 40-watt lamps are five times more powerful than standard 40-watt lamps and will shine a 9- by 7-foot elliptical beam of light 20 feet away. The spacewalkers will setup and partially assemble a work platform.

Ross, working from the station's robotic arm, also will install shock absorbers to either side of the Mobile Transporter to provide a barrier and attach point between the railcar and future hand-propelled carts that will be used by spacewalkers.

Morin will deploy an instrument to measure and characterize the radiation environment outside the station. He also will troubleshoot a balky bolt on a redundant cable cutting system on the Mobile Transporter. A successful test run of that railcar concluded late Monday when ground controllers commanded it to latch onto the railway and plug into a power source. The railcar is ready to receive the Mobile Base System during the next shuttle mission, STS-111, giving the station's Canadarm2 points of attachment on the rail-car base capable of moving along the station's Integrated Truss.

Additional tasks include installing handrails on S0, relocating tools for STS-111 spacewalks, adjusting a thermal blanket partly obstructing a GPS antenna on S0, performing photo and video documentation of station components and checking out a gauge that is designed to detect minute amounts of gas in the environment of space.

The Atlantis crew - Commander Mike Bloomfield, Pilot Steve Frick, Mission Specialists Ellen Ochoa, Rex Walheim, Steve Smith, Morin, and Ross- was awakened at 3:44 a.m. to "I Am an American," performed by the Purdue University Marching band. It was dedicated to Purdue graduate Ross. The station crew - Commander Yury Onufrienko, Flight Engineers Carl Walz and Dan Bursch - was also awakened at 3:44 a.m.

Farewells and closing of the hatches between the spacecraft is set to begin about 10:30 a.m. About 1:30 p.m., Atlantis astronaut Jerry Ross will send commands to release the docking mechanism. The initial separation will be provided by springs that will gently push the shuttle away from the station. When Atlantis is about two feet away from the station and the docking devices are clear of one another, Pilot Steve Frick will fire Atlantis' steering jets to begin slowly moving away.

About 45 minutes after undocking, when Atlantis is 450 feet away, Frick will fly the shuttle around the station 1¼ times. The flyaround is set to begin at 2:16 p.m. and will last about an hour. Atlantis will move directly over the station, then behind it, underneath it, and back in front, where the flyaround began. The last quarter-circle brings the shuttle directly above the station. Finally, Frick will fire Atlantis' jets to move away from the station about 3:15 p.m. Atlantis is scheduled to land at the Kennedy Space Center at 11:26 a.m. CDT Friday.

Atlantis leaves behind the newly installed S-Zero (S0) Truss, the first part of the main truss that will support cooling and power systems essential for the addition of future international laboratories to the station. All of the S0 systems have been operating well since its attachment to the station's U.S. laboratory Destiny on Thursday.

The shuttle also delivered additional supplies and science experiments for the station crew to work with during its final weeks on the station. The Expedition Four crew - Commander Yury Onufrienko and Flight Engineers Carl Walz and Dan Bursch - is scheduled to return to Earth aboard the space shuttle Endeavour in June.

The Atlantis crew - Commander Mike Bloomfield, Frick, Mission Specialists Ellen Ochoa, Rex Walheim, Steve Smith, Lee Morin, and Ross- was awakened at 3:44 a.m. to "Noah," performed by Frick when he was a teen-ager. The station crew was awakened at 4:14 a.m.

After more than a week of joint operations between the shuttle and station crews, Pilot Steve Frick backed Atlantis away to a distance of about 400 feet in front of the outpost, where he began a 1 1/4 lap flyaround of the ISS, newly equipped with the 27,000 pound S-Zero truss, the first segment of a truss structure which will ultimately expand the station to the length of a football field. Aboard the station, Flight Engineer Dan Bursch rang a ship's bell in the Unity module to mark Atlantis' departure in what has become a tradition.

Finally, at 3:15 p.m., as Atlantis flew directly above the station, Frick fired the shuttle's jets one more time in a separation maneuver to depart the station for good.

Left behind on the ISS are Expedition Four Commander Yury Onufrienko and Flight Engineers Carl Walz and Bursch, now in their 133rd day in space and their 131st day on board the outpost.

Also left behind on the station were more than a ton of supplies, almost 200 pounds of oxygen and nitrogen for the station's Quest Airlock, 1,463 pounds of water and the new truss, which will serve as a backbone for future station construction and a power switching station for new solar arrays to be delivered to the ISS next year. Atlantis's week-long visit to the ISS was the 13th shuttle mission devoted to station assembly and resupply.

Earlier today, Commander Mike Bloomfield, Frick and Mission Specialists Rex Walheim, Ellen Ochoa, Steve Smith, Lee Morin and Jerry Ross completed final transfers of logistical supplies to the station and bid farewell to their station counterparts in the Destiny Laboratory. Hatches between the station and the shuttle swung shut at 11:04 a.m. Central time and leak checks were performed to insure that all was in order for the undocking.

As Atlantis' crew turns its attention to preparations for landing at the Kennedy Space Center Friday afternoon, the Expedition Four crew will prepare to button up the ISS temporarily and enter its Soyuz return craft early Saturday for a brief flyover from one docking port to another.

With Onufrienko at the controls, the Soyuz will undock from the station's Zarya nadir docking port at around 4 a.m. Central time Saturday, back out to a distance of about 250 feet and redock to the Pirs Docking Compartment 35 minutes later. That will clear the Zarya docking port for the arrival of a new Soyuz return vehicle and a three-man taxi crew on April 27 for a week-long visit.

Both Atlantis and the International Space Station are in excellent shape following their joint mission. Atlantis' astronauts are scheduled to begin an eight-hour sleep period at 6:44 p.m. Central time and will be awakened just before 3 a.m. Thursday for what is expected to be their final full day in orbit.

The crew - Commander Mike Bloomfield, Pilot Steve Frick, Mission Specialists Ellen Ochoa, Rex Walheim, Lee Morin, Jerry Ross and Steve Smith - was awakened at 2:44 a.m. to "Somewhere Over the Rainbow," performed by Bloomfield's daughter.

Bloomfield, Frick and Ochoa will test fire the reaction control system jets and flight control surfaces that will be used to guide Atlantis through the atmosphere on Friday morning. Atlantis is scheduled to return to the Kennedy Space Center in Florida at 11:26 a.m. CDT Friday where preliminary weather forecasts for landing are favorable.

Crewmembers will take a break from their on orbit work today to talk with media representatives from CNN, WDIV-TV in Detroit and the Fox News Network this morning in an interview beginning at 9:14

Atlantis' orbital maneuvering jets will be fired twice today. Once will be for scientists to look at the exhaust's effects on radar echoes and effects of orbital kinetic energy on the ionosphere. The other firing will reduce the cross range for Friday's backup landing opportunity in Florida. Walheim, Morin, Ross and Smith will continue to pack away equipment and supplies onboard the shuttle and prepare the cabin for landing.

On board the International Space Station the Expedition 4 crew - Commander Yury Onufrienko and Flight Engineers Dan Bursch and Carl Walz - was awakened at 3 a.m. They are preparing for their next visitors, a Soyuz taxi crew slated to arrive April 27. Onufrienko, Walz and Bursch, will board the current Soyuz spacecraft and move it from its location on the Zarya docking port to the Pirs docking compartment on Saturday to make room for the replacement Soyuz.

The crew of Atlantis will begin a scheduled eight-hour sleep period at 6:14 p.m. today, waking just after 2 a.m. Friday to prepare for reentry and landing of Atlantis concluding a successful mission to the station.

Commander Mike Bloomfield, Pilot Steve Frick and Flight Engineer Ellen Ochoa activated one of three hydraulic power units on Atlantis and tested all of the shuttle's aerosurfaces to ensure that Atlantis will have full controllability during its high-speed return to Earth Friday. Bloomfield and Frick then test-fired Atlantis' steering jets, which were declared ready to support entry and landing.

Bloomfield, Frick and Ochoa joined crewmates Rex Walheim, Lee Morin, Jerry Ross and Steve Smith to stow all of the equipment they have used over the past 10 days and parked the shuttle's KU-band dish antenna in preparation for the closing of Atlantis' cargo bay doors early Friday morning.

Atlantis has two landing opportunities at the Kennedy Space Center on Friday. The first begins with the firing of Atlantis' braking rockets at 10:20 a.m. Central time, enabling the shuttle to drop out of orbit for its hour-long descent back to Earth and a touchdown on the 3-mile long Shuttle Landing Facility at KSC at 11:26 a.m. Central time. In the unlikely event weather prevents a landing on the first opportunity, a second opportunity is available for a Florida landing, beginning with the deorbit burn of the orbital maneuvering system engines on Atlantis at 11:59 a.m. Central time, resulting in a landing at KSC at 1:03 p.m. Central time.

The weather forecast calls for very favorable conditions for landing at the Florida spaceport Friday, with only scattered clouds and light winds expected. As a result, the backup landing site at California's Edwards Air Force Base was not called up for support Friday. Atlantis has enough consumables to stay in orbit, if necessary, until Monday.

Meanwhile, on board the ISS, Expedition Four Commander Yury Onufrienko and Flight Engineers Carl Walz and Dan Bursch spent a relatively quiet day in the wake of a week of joint operations with Atlantis' crew to install and activate the S-Zero (S0) truss and the Mobile Transporter railcar on the complex. Both of the new components continue to be checked out and are said to be in excellent shape.

Onufrienko, Walz and Bursch will spend part of the day Friday deactivating some of the ISS systems as they prepare to board their Soyuz return vehicle early Saturday for a brief flyover from its current docking location at the nadir port of the Zarya module to the Pirs Docking compartment. The relocation of the Soyuz, which is expected to take about 35 minutes, will begin with undocking Saturday at 4:02 a.m. Central time (902 GMT). Coverage of the operation on NASA Television begins at 3 a.m. Central time (800 GMT).

The movement of the Soyuz 3 vehicle from Zarya to Pirs opens the Zarya port for the arrival of a new Soyuz 4 craft on April 27 by a three-man "taxi" crew comprised of Commander Yuri Gidzenko, formerly of the Expedition One crew, Flight Engineer Roberto Vittori of the European Space Agency and South African spaceflight participant Mark Shuttleworth. They will be launched from the Baikonur Cosmodrome in Kazakhstan on April 25 and will spend about a week in joint operations with the Expedition Four crew before departing from Pirs in the Soyuz 3 craft on the night of May 4.

The crew of Atlantis was scheduled to begin a scheduled eight-hour sleep period at 6:14 p.m. today, and will be awakened just after 2 a.m. Friday to prepare for entry and landing. All shuttle and ISS systems are operating normally.

If Atlantis lands on Friday, the STS-110 astronauts will return home to Ellington Field in Houston near the Johnson Space Center at around 1 p.m. Central time Saturday.

Atlantis has two landing opportunities at KSC today. The first begins with the firing of Atlantis' braking rockets at 10:20 a.m. and a landing at 11:26 a.m. CDT. A second opportunity for a Florida landing would see the deorbit burn at 11:59 a.m. and a landing at KSC at 1:03 p.m. CDT. Forecasts call for favorable weather for landing in Florida Friday, with only scattered clouds expected. The backup-landing site at California's Edwards Air Force Base was not called up today. Atlantis has enough consumables to stay in orbit until Monday.

The crew of Atlantis - Commander Mike Bloomfield, Pilot Steve Frick, and Mission Specialists Ellen Ochoa, Rex Walheim, Lee Morin, Jerry Ross and Steve Smith - was awakened at 2:21 a.m. by the song "Message in a Bottle," performed by The Police.

Meanwhile, aboard the ISS, Expedition 4 Commander Yury Onufrienko and Flight Engineers Carl Walz and Dan Bursch monitored station systems this morning during another reboost of the orbiting laboratory. The Progress cargo ship's jets were fired to raise the station's altitude a little more than half a mile. During the STS-110 mission, Atlantis did three station reboosts, totaling about six miles.

The station crew also will deactivate some ISS systems today to prepare to board the Soyuz return vehicle early Saturday for its 35-minute move from the nadir port of the Zarya module to the Pirs Docking compartment. The relocation of the Soyuz will begin with undocking Saturday at 4:02 a.m. Coverage on NASA Television begins at 3 a.m.

The move frees the Zarya port for the arrival of a new Soyuz 4 craft on April 27 with a three-man "taxi" crew comprised of Commander Yuri Gidzenko, Flight Engineer Roberto Vittori of the European Space Agency and South African spaceflight participant Mark Shuttleworth. They will be launched from the Baikonur Cosmodrome in Kazakhstan on April 25 and will spend about a week aboard the station before departing in the Soyuz 3 craft May 4.

Commander Mike Bloomfield eased Atlantis to a textbook landing on runway 3-3 at the Florida spaceport at 11:27 a.m. Central time under clear skies and light winds. Bloomfield, Pilot Steve Frick and Mission Specialists Rex Walheim, Ellen Ochoa, Lee Morin, Jerry Ross and Steve Smith completed an 11-day flight in which four spacewalks were conducted to deliver and activate the new S-Zero (S0) girder to the ISS, which will serve as the centerpiece for a truss that will eventually span the length of a football field. Solar arrays will be mounted on the truss as well as new station modules. The S-Zero component will also serve as a switching station for electricity from the station's solar arrays to ISS elements. In addition, the truss is a base for the first rail system in space through the use of its Mobile Transporter and the upcoming Mobile Base System to be delivered to the ISS in June on which the station's robotic arm will be affixed to move up and down the length of the outpost.

The shuttle crewmembers were scheduled to depart Atlantis about an hour after landing to be driven back to the crew quarters at KSC for medical tests and reunions with their families.

The STS-110 astronauts will return home to Hangar 990 at Ellington Field in Houston near the Johnson Space Center at around 1 p.m. Central time Saturday for a welcome home ceremony. The public is invited to attend.

Meanwhile, aboard the ISS, Expedition Four Commander Yury Onufrienko and Flight Engineers Carl Walz and Dan Bursch spent the day configuring station systems for the temporary closure of the complex early Saturday in advance of a short departure in their Soyuz return vehicle and a relocation of the craft to another docking port.

Onufrienko, Walz and Bursch will board their Soyuz return vehicle early Saturday for a brief flyover from its current docking location at the nadir port of the Zarya module to the Pirs Docking compartment. The relocation of the Soyuz, which is expected to take about 35 minutes, will begin with undocking Saturday at 4:02 a.m. Central time (902 GMT). Coverage of the operation on NASA Television begins at 3 a.m. Central time (800 GMT).

The movement of the Soyuz 3 vehicle from Zarya to Pirs opens the Zarya port for the arrival of a new Soyuz 4 craft on April 27 by a three-man "taxi" crew comprised of Commander Yuri Gidzenko, who served on the first resident crew of the ISS, Flight Engineer Roberto Vittori of the European Space Agency and South African spaceflight participant Mark Shuttleworth. They will be launched from the Baikonur Cosmodrome in Kazakhstan on April 25 and will spend about a week in joint operations with the Expedition Four crew before departing from Pirs in the Soyuz 3 craft on the night of May 4.

Major systems aboard the ISS continue to function well as the station orbits at an average altitude of about 247 statute miles.

Aboard Endeavour are Commander Ken Cockrell, Pilot Paul Lockhart, Mission Specialists Franklin Chang-Díaz and Philippe Perrin of the French Space Agency, CNES, along with Expedition 5 Commander Valery Korzun and Flight Engineers Peggy Whitson and Sergei Treschev. As Endeavour launched from Florida, the space station orbited 240 statute miles over the southern Indian Ocean west of Perth, Australia.

Aboard the ISS, Expedition 4 Commander Yury Onufrienko and Flight Engineers Carl Walz and Dan Bursch are wrapping up their 182nd day in space, their 180th day on the station. Walz and Bursch will break the U.S. record for the longest single space flight - 188 days - set by astronaut Shannon Lucid in 1996. Another record was equaled today as Chang-Díaz became only the second human to fly in space seven times, tying a mark set in April by Jerry Ross on the STS-110 mission.

Less than nine minutes after launch, Endeavour and its crewmembers settled into orbit and work began to prepare the shuttle for its planned 12-day mission.

Endeavour is scheduled to dock to the station Friday afternoon, setting the stage for the handover between the Expedition 4 and Expedition 5 station crews. Three spacewalks are scheduled during the mission by Chang-Díaz and Perrin. The first two will help install and activate the Mobile Base System, a platform that will be mated to the Mobile Transporter on the S-Zero (S0) Truss. The new platform will allow the station's Canadarm2 robotic arm to "walk off" the Destiny Laboratory onto the Mobile Base System so it can be transported up and down the length of the ISS for future assembly tasks. On the third spacewalk, Chang-Díaz and Perrin will replace a faulty wrist roll joint on the station's robotic arm that has experienced an electrical problem in one of its two data and power channels.

The shuttle crew will go to sleep at 10:23 p.m., and will be awakened at 6:23 a.m. Thursday to begin its first full day in orbit.

Aboard Endeavour, Commander Ken Cockrell, Pilot Paul Lockhart, Mission Specialists Philippe Perrin and Franklin Chang-Díaz and Expedition Five Commander Valery Korzun and Flight Engineers Peggy Whitson and Sergei Treschev, were awakened at 6:23 a.m. Central time by the song "Gettin' Jiggy Wit It," by Will Smith. The song was played for Korzun, who will soon take command of the space station.

The Expedition Four crewmembers - Commander Yury Onufrienko and Flight Engineers Carl Walz and Dan Bursch - are in their 183rd day in space, their 181st day aboard the ISS. They will return to Earth aboard Endeavour after six months in orbit on June 17.

In preparation for docking Friday, Perrin and Chang-Díaz will set up a centerline camera to help Cockrell with views of the station's docking mechanism during Endeavour's final approach tomorrow and will test the orbiter docking system ring. Cockrell and Lockhart will fire the shuttle's jets to raise the altitude of Endeavour and draw it closer to the station. The maneuvers will bring the shuttle about 46 statute miles behind the station by Friday morning.

Cockrell and Perrin will also activate the shuttle's robotic arm and use its cameras to survey the contents of the payload bay, including the Leonardo Multi-Purpose Logistics cargo module, the Mobile Base System and the replacement wrist roll joint for the station's robotic arm, Canadarm2, as well as debris shields for the Zvezda Service Module. Chang-Díaz and Perrin will install these components during three spacewalks scheduled for the mission. Today, they will prepare their spacesuits for use out of the Quest Airlock on the station next week.

Later this morning, Cockrell and Chang-Díaz will participate in a live conversation with Costa Rican President Abel Pacheco and reporters from two Hispanic television networks. Costa Rican-born Chang-Díaz tied the human spaceflight record yesterday when he launched on his seventh mission. Astronaut Jerry Ross set the record in April during the STS-110 mission.

It was the second of two spacewalks for the Expedition Five crew, the fourth of Korzun's career and the first for Treschev. Today's excursion was the 43rd spacewalk in support of ISS assembly and maintenance and the 18th staged from the station itself. 25 spacewalks at the ISS have originated from visiting space shuttles. While Korzun and Treschev worked outside, Flight Engineer Peggy Whitson tended to station systems and choreographed the spacewalk from inside Zvezda.

Whitson and Korzun conducted a 4 hour, 25 minute spacewalk on August 16 to install six micrometeoroid debris shields on Zvezda.

After a slight delay to track down a small pressure leak across the hatch between Zvezda and the Zarya module, Korzun and Treschev opened the hatch to Pirs at 12:27 a.m. Central time (527 GMT) as the ISS flew over Russia at an altitude of 235 statute miles. They went to work right away, installing a frame on the Zarya as a "parking place" for modular equipment to be temporarily stowed during future ISS assembly spacewalks and hardware on Zarya which will better route tethers for spacewalkers working around the Russian segment of the station.

The two Russian spacewalkers then exchanged trays of experiments in suitcase-like devices on Zvezda for NASDA, the Japanese Space Agency, which measure the effect of the space environment on engineering materials.

With that work accomplished, Korzun and Treschev completed a task left over from the previous spacewalk ten days ago. They replaced an experiment on the outside of Zvezda called Kromka, which measures the amount of residue emitted from the module's jet thruster firings. Deflectors previously installed on Zvezda have significantly reduced the buildup of residue on the hull of the module.

The final job for Korzun and Treschev was the installation of two additional ham radio antennas on Zvezda to enhance amateur radio operations in the future. ISS residents frequently conduct conversations with "hams" back on Earth.

After retrieving their tools, Korzun and Treschev returned to Pirs and closed the hatch at 5:48 a.m. Central time (1048 GMT) to wrap up their excursion.

The next series of spacewalks to be conducted at the ISS is planned for October when two shuttle astronauts, Dave Wolf and Piers Sellers, conduct three excursions from the Quest Airlock on the STS-112 mission aboard Atlantis to help install and activate the S1 (Starboard One) truss segment, further expanding the station's backbone.

The first steps in changing Atlantis from a spaceship to an airplane are to test its aero surfaces, required as the orbiter begins to interact with the upper atmosphere on reentry and landing. Also tested today are the thruster jets on the nose and tail of Atlantis which maneuver the vehicle prior to dropping below 400,000 feet in altitude following the deorbit burn.

Atlantis' computers systematically deactivate these jets when desired air pressure readings are detected at various stages throughout entry and landing.

The crew of Commander Jeff Ashby, Pilot Pam Melroy and Mission Specialists Dave Wolf, Sandy Magnus, Piers Sellers and Cosmonaut Fyodor Yurchikhin spend the day stowing equipment, supplies and belongings in preparation for tomorrow's anticipated return to the Kennedy Space Center in Florida.

At 11:46 this morning, the crew will discuss the success of the mission with media representatives from the AP Radio Network, KMOX Radio of St. Louis and WISH-TV of Indianapolis. The interview will air on NASA Television.

Behind the shuttle at a distance of 120 miles (193 kilometers), the ISS Expedition Five crew of Commander Valery Korzun, NASA ISS Science Officer Peggy Whitson and Cosmonaut Sergei Treschev are preparing for their next visitors, a Soyuz taxi crew scheduled to arrive late this month. The taxi crew will return to Earth in the Soyuz at the station, which is nearing its certified on orbit life limit.

The shuttle crew began its last full day on orbit with a wakeup call from Mission Control at 2:18 a.m. The song "These are the Days" performed by Natalie Merchant was played for Sellers at the request of his wife.

Atlantis' crew sleep begins at about 6:30 this evening and the crew will be awakened at 2:16 a.m. Friday to begin landing preparations.

With weather of little concern today, Commander Jeff Ashby piloted the shuttle to its 60th landing at KSC at 10:44 a.m. CDT. The deorbit burn occurred an hour earlier as Atlantis flew high above the southwestern Indian Ocean, dropping the shuttle out of orbit for the high-speed reentry and landing.

Atlantis' ground track carried it above Central America and western Cuba before crossing the west coast of Florida south of Tampa. Ashby took over manual control of Atlantis at an altitude of 50,000 feet, guiding the 200,000 pound shuttle through a 290-degree right turn to line up with Runway 33.

Meanwhile, aboard the International Space Station, the Expedition Five crew was able to watch Atlantis' safe landing while the three crewmembers continue to unpack and stow supplies delivered by the shuttle crew. Commander Valery Korzun, NASA ISS Science Officer Peggy Whitson and Cosmonaut Sergei Treschev are in their 135th day in space (133rd aboard the station).

Their next visitors are the three members of a Soyuz Taxi Crew scheduled to deliver a fresh rescue spacecraft to the station later this month. Expedition Five's ride home will be aboard Endeavour scheduled to launch no earlier than Nov. 10 bringing another truss segment and the Expedition Six crew.

Atlantis will be hauled into its hangar later today to begin preparations for its next mission to the station in March 2003 on the STS-114 mission.

Atlantis' six crewmembers are expected to hold a news conference at about 4 p.m. today on NASA Television and plan to return to the Johnson Space Center in Houston Saturday at about 5:30 p.m.

During the week, Expedition 5 packed, checked and labeled experiment racks, and did a dry run of the installation of the Port One (P1) truss segment onto the ISS using the Canadarm2. The crew also performed maintenance on the VOA (volatile organics analyzer), which looks for volatile organic compounds in the station's atmosphere, and replaced a cable on the station's treadmill. They also set up the EarthKam equipment to give over 2,000 students and teachers across the U.S. and Japan a chance to take pictures of the Earth using a remotely controlled camera aboard the station. Whitson deactivated the camera Friday, but Expedition 6 will reactivate it for use during its mission.

The space shuttle Endeavour will deliver the Expedition 6 crew, along with the P1 truss, to the station during the STS-113 mission. The P1 will be the third segment of the station's integrated truss system to be launched this year. Part of the station's backbone, it is one of 11 such truss segments that will support cooling radiators power-producing solar arrays and a railroad on which the Canadarm2 can move.

Preparations continue for the launch next week of Endeavour to the ISS next week.

Work aboard the orbiting outpost resumed on Jan. 2, highlighted by a practice fire drill, set-up of the ultrasound equipment associated with the Human Research Facility and a leak check of the Quest airlock module using a jumper hose that is being evaluated for future support of airlock window replacements. The ultrasound equipment provides enlarged, three-dimensional images of the heart and other organs, muscles and blood vessels for both research and diagnostic applications.

The following day was dedicated to sound level measurements inside the various modules of the space station, part of an on-going effort to characterize the level of noise inside the station, and operation of the Zeolite Crystal Growth experiment, which scientists are using in an effort to grow crystals larger than can be grown on Earth. Zeolites form the backbone of the chemical processing industry. Larger, purer zeolite crystals could increase the amount of gasoline that can be produced from a barrel of oil, making the petrochemical industry more efficient.

Budarin worked with a Russian plant-growth experiment, and on inventories of Russian medical equipment and supplies and videotapes available for use on the station. He also conducted an inspection of the aft docking port of the Zvezda Service Module, where a Progress resupply vehicle will dock in February.

The crew is scheduled to enjoy a fairly relaxed weekend, with weekly housekeeping activities and routine private family and medical conferences on tap.

Bowersox is scheduled to resume work Monday with the FOOT (Foot/Ground Reaction Forces During Spaceflight), which looks at how the hips, legs and feet move in the absence of gravity, and at what changes occur in bones and muscles using a special pair of tights with 20 sensors.

Red Team members Commander Rick Husband, Mission Specialists Kalpana Chawla and Laurel Clark and Israeli Payload Specialist Ilan Ramon completed the first data collection sessions with the Combustion Module in the Spacehab research module housed in Columbia's cargo bay. One of three experiments housed in the Combustion Module --- the study of Laminar Soot Processes (LSP) --- is designed to gain a better understanding of soot formation, oxidation and radiative properties within flames.

Additional data was gleaned from the Mechanics of Granular Materials experiment (MGM) in the Spacehab module, which is providing information on the behavior of saturated sand when exposed to confining pressures in microgravity. The experiment could provide engineers with valuable data for strengthening buildings against earthquakes.

Work was also accomplished with a series of biomedical experiments studying the human body's response to weightlessness --- particularly dealing with protein manufacturing in the absence of a gravity environment, bone and calcium production, the formation of chemicals associated with renal stones and how saliva and urine change in space relative to any exposure to viruses.

Experiments continued with the MEIDEX cameras in the cargo bay observing dust storms in the Mediterranean region and with the SOLSE experiment, geared to studying the amount of ozone in the Earth's atmosphere by using a special imaging spectrometer in the payload bay to look across the limb of the Earth during specifically scheduled orbits.

Columbia's Blue Team science cadre --- Pilot Willie McCool and Mission Specialists Dave Brown and Mike Anderson --- planned to continue the more than 80 experiments on board Columbia following their wakeup call this afternoon. The Red team will begin its eight-hour sleep period just before 9 p.m. Central time.

Earlier today, TV cameras in the Spacehab research module captured Ramon conducting work with the Combustion Module. He reported that the materials science facility was operating perfectly as are all of the other experiment facilities aboard Columbia.

Aboard the International Space Station, Commander Ken Bowersox, Flight Engineer Nikolai Budarin and ISS Science Officer Don Pettit completed their second month in space by enjoying an off-duty day. The crew will return to a full complement of scientific research activities, exercise and routine ISS maintenance work on Monday. The ISS crew is working a schedule, which calls for them to be awakened every morning at 12:00 a.m. Central time and for their 8 1/2 hour sleep period to begin at 3:30 p.m. CST.

The ISS crew was informed that replacement parts for the Microgravity Science Glovebox will be ready for launch on the next Progress resupply vehicle to the ISS on February 2. With docking of that cargo ship to the ISS planned for Feb. 4, virtually all of the science planned for the facility during Expedition 6 will be accomplished as initially planned.

All systems aboard Columbia and the ISS continue to function well.

Red team members Commander Rick Husband, Mission Specialists Kalpana Chawla and Laurel Clark and Israeli Payload Specialist Ilan Ramon conducted additional data takes with the Mechanics of Granular Materials experiment located in the Spacehab Research Module in Columbia's cargo bay. The MGM experiment is providing information on the behavior of saturated sand when exposed to confining pressures in microgravity. The experiment could provide engineers valuable data for strengthening buildings against earthquakes.

The Red team is working what amounts to the day shift on orbit, while the Blue team --- Pilot Willie McCool, Mission Specialist Dave Brown and Payload Commander Mike Anderson --- is working the overnight shift. The division of the two teams into 12-hour shifts assures that scientific research is conducted round-the-clock.

One of the host of experiments in the Spacehab science lab --- the Microbial Physiology Flight Experiment --- was monitored by Clark as she studied how specific fungi react to the absence of gravity for long periods of time.

Additional data was acquired by Anderson and Ramon with an experiment in the Combustion Module in the Spacehab --- the study of Laminar Soot Processes (LSP) --- designed to gain a better understanding of soot formation, oxidation and radiative properties within flames. Two other experiments studying flame properties in space in the large Spacehab furnace are to be conducted throughout the course of the flight.

Work was also accomplished with a series of biomedical experiments studying the human body's response to weightlessness --- particularly dealing with protein manufacturing in the absence of a gravity environment, bone and calcium production, the formation of chemicals associated with renal stones and how saliva and urine change in space relative to any exposure to viruses. The crewmembers also continued periodic blood draws to study how their bodies are adapting to the microgravity environment.

Experiments continued with the MEIDEX cameras in the cargo bay observing thunderstorms to capture images of sprites, which are associated with discharges from the tops of thunderclouds into the Earth's upper atmosphere, and with the SOLSE experiment, studying the amount of ozone in the Earth's upper atmosphere by using a special imaging spectrometer in the payload bay to look across the limb of the Earth during specifically scheduled orbits.

Having been awakened just after 4 p.m. Central time, McCool, Brown and Anderson planned to continue the more than 80 experiments on board Columbia. The Red team will begin its eight-hour sleep period just after 8 p.m. Central time.

This afternoon, flight controllers observed a minor electrical current spike in one of two systems designed to collect and distribute water produced from condensation buildup caused by the operation of the cooling system in the Spacehab Research Module in the cargo bay.

An identical system sprung a leak under the floorboards of Spacehab last night and was shut down. The secondary system had been operating normally until the electrical spike was observed at around 1:15 p.m. A plan was implemented to reconfigure a valve in Columbia, allowing cool air from the shuttle to flow into the science module, thus enabling the module's temperatures to remain at a level that will not require the use of Spacehab's cooling system, while preventing any further buildup of condensation. Later, an air duct was routed from Columbia to the Spacehab to increase the flow of cool air into the science facility.

Flight controllers plan to continue their analysis of the Spacehab cooling issue throughout the night, with no impact expected to science operations.

Aboard the International Space Station, Expedition 6 Commander Ken Bowersox, Flight Engineer Nikolai Budarin and ISS Science Officer Don Pettit entered their third month in orbit today with a full complement of scientific research activities, exercise and routine ISS maintenance work.

The three ISS crewmembers conducted a number of cardiovascular tests, unloaded samples from a Zeolite Crystal Growth experiment in the Destiny laboratory that has completed its work for this Expedition. The Russian Vozdukh carbon dioxide removal system in the Zvezda Module, which shut down last week, is now operating normally following the weekend replacement of a valve. The U.S. segment CO2 removal system, which has been operating in place of Vozdukh, was powered down as a result of the Vozdukh revival.

All other station systems are operating normally as are all the systems aboard the shuttle Columbia, which, like the ISS, is orbiting the Earth every 90 minutes.

A Russian Progress resupply ship arrived at the station last week delivering a ton of food, fuel, clothing and other materials that should sustain Commander Ken Bowersox, Flight Engineer Nikolai Budarin, and NASA ISS Science Officer Don Pettit through at least the end of June, if required.

The Progress' engines were used Tuesday to boost the altitude of the ISS by about 6 miles to an average 248-mile orbit. This was the first of three planned maneuvers to prepare the station for the arrival of a new Soyuz return spacecraft in late April. During the reboost maneuver, scientific accelerometers in the Destiny lab measured vibrations from the engines to help scientists study how motion may affect delicate microgravity experiments.

Bowersox, Pettit and Budarin spoke with reporters gathered at various NASA centers across the country in their first news conference since the Columbia accident. Most questions focused on the crew's reaction and thoughts on Columbia's astronauts and how the accident might affect their mission.

"We've had time to grieve our friends," Bowersox said. "When you're up here this long, you can't just bottle up your emotions and focus all the time. It's important for us to acknowledge that the people on STS-107 were our friends and we had a connection with them and that we feel their loss. Each of us had a chance to shed some tears. But now it's time to move forward and we're doing that slowly. This press conference today is a huge step that's helping us move along towards our normal objectives and fulfilling our mission here."

Thursday, Bowersox and Pettit operated Canadarm2, the Space Station Robotic Manipulator System. The activities helped maintain the crew's proficiency in using the Robotic Work Station in Destiny to control the system as they performed checkout procedures to validate the arm's capabilities in space.

Early this week, flight controllers noticed a slight decrease in the flow of air through the Inter-Module Valve system between the various components of the station. Bowersox and Pettit removed several fans in the ductwork and cleaned lint and dust from the filters, significantly increasing the airflow.

Troubleshooting of the Microgravity Science Glovebox by specialists from the European Space Agency and the Payload Operations Center at Marshall Space Flight Center continues. Last week, a circuit breaker tripped when Pettit installed replacement parts that arrived on the Progress. Pettit powered down the equipment until the experts develop a plan for him to implement on orbit.

Lu spent much of his time inside the U.S. Destiny laboratory setting up and performing science investigations. He installed a protein crystal growth experiment in the Microgravity Science Glovebox that will be operated by European Space Agency Astronaut Pedro Duque of Spain, who will arrive at the Station Oct. 20 with the oncoming Expedition 8 crew. Duque, who is flying to the Station on a Soyuz spacecraft under a commercial contract between ESA and the Russian Aviation and Space Agency, will return to Earth Oct. 28 with Malenchenko and Lu.

A soldering experiment that is providing insight into how solder connections in space can be improved and an automated Earth observation camera system were also set up by Lu in the lab. This week, Lu worked with the Fluid Dynamics Investigation, which scientists believe will help alleviate problems with mixing samples for tissue growth experiments. Those samples are housed in a bioreactor, which allows three-dimensional tissue cells, like those in the human body, to grow.

As part of an educational project to help inspire the next generation of explorers, Lu used well-known objects to videotape center-of-mass demonstrations. Using a screwdriver, a compact disc player, a cassette tape and a ruler, he showed how these objects behave differently without gravity. The video will be distributed to science centers across the country for use in lesson plans and future exhibits.

Malenchenko conducted science experiments in the Russian segment of the Space Station. They included biomedical studies of the human body in microgravity as well as observations of thunderstorm activity, the world's ocean biology and studies of how space-based predictions of man-made disasters could be made.

The maintenance activities onboard the Station included Malenchenko inspecting fire sensors in the Zarya control module and checking systems in the Pirs Docking Compartment. Both Lu and Malenchenko did monthly maintenance on the treadmill and resistive exercise equipment.

Lu also configured the U.S. laptop computers so the Expedition 8 crew can begin using them when it arrives. The oncoming resident crew, Commander and NASA ISS Science Officer Mike Foale and Flight Engineer Alexander Kaleri, along with Duque, are set to launch from the Baikonur Cosmodrome in Kazakhstan at 12:37 a.m. CDT Oct. 18.