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.