The final shuttle-Mir mission, STS-91 recovered NASA astronaut Andy Thomas from the Mir station and took Russian space chief and ex-cosmonaut Valeri Ryumin to Mir for an inspection tour of the ageing station. This was the first test of the super lightweight Aluminium-Lithium alloy external tank, designed to increase shuttle payload to the Mir / International Space Station orbit by 4,000 kg. At 22:15 GMT Discovery entered an initial 74 x 324 km x 51.6 deg orbit, with the OMS-2 burn three quarters of an hour later circulising the chase orbit. Discovery docked with the SO module on Mir at 17:00 GMT on June 4. NASA equipment was retrieved from the station, and Discovery undocked at 16:01 GMT on June 8, and landed on Runway 15 at Kennedy Space Center at 18:00 GMT on June 12.
NASA Official Mission Summary:
(9th and final Shuttle-Mir docking)
91st Shuttle mission
24th flight OV-103
9th Shuttle-Mir docking
Return of 7th and last U.S.
astronaut to live and work
First flight of Super Lightweight
First docking mission for Discovery
44th KSC landing
Charles J. Precourt, Commander (4th Shuttle flight)
Dominic L. Pudwill Gorie, Pilot (1st)
Wendy B. Lawrence, Mission Specialist (3rd)
Franklin R. Chang-Diaz, Mission Specialist (6th)
Janet Lynn Kavandi, Mission Specialist (1st)
Valery Victorovitch Ryumin, Mission Specialist (1st Shuttle, 1st Mir, 4th spaceflight)
Returning from Mir – Mir 25 crew member: Andrew S. W. Thomas, Mission Specialist and Cosmonaut Researcher (2nd Shuttle, 1st Mir)
Orbiter Preps (move to):
OPF 3 - Aug. 19, 1997 (temporary storage)
OPF 2 - Oct. 1, 1997 (temporary storage)
OPF 2 - Oct 30, 1997 (begin preflight processing)
VAB - April 12, 1998
Pad - May 2, 1998
June 2, 1998, 6:06:24 p.m. EDT. The countdown proceeded smoothly except for a slight delay in operations to load the external tank with cryogenic propellant to evaluate a few technical issues. As planned, launch managers determined the exact orbital location of the Mir space station during the countdown's T-9-minute built-in hold. The decision was then made to launch Discovery at 6:06 p.m. to achieve optimum Shuttle system performance and to accommodate Shuttle-Mir rendezvous activities.
June 12, 1998, 2:00:18 p.m. EDT, Runway 15, Kennedy Space Center, Fla. Rollout distance 11,730 feet (3,576 meters). Rollout time: one minute, four seconds. Mission duration: nine days, 19 hours, 54 minutes, two seconds. Landed on orbit 155. Logged 3.8 million statute miles. Landed on first opportunity at KSC, marking the 15th consecutive landing in Florida and 22nd in the last 23 missions.
Docking of Discovery to Mir , the first for that orbiter, occurred at 12:58 p.m., June 4, at an altitude of 208 miles. Hatches opened at 2:34 p.m. the same day. At hatch opening, Andy Thomas officially became a member of Discovery's crew, completing 130 days of living and working on Mir. The transfer wrapped up a total of 907 days spent by a total of seven U.S. astronauts aboard the Russian space station as long-duration crew members. During the next four days, the Mir 25 and STS-91 crews transferred more than 1,100 pounds of water, and almost 4,700 pounds of cargo experiments and supplies were exchanged between the two spacecraft.
During this time, long-term U.S. experiments aboard the Mir were moved into Discovery's middeck locker area and the SPACEHAB single module in the orbiter's payload bay, including the Space Acceleration Measurement System (SAMS) and the tissue engineering coculture (COCULT) investigations, as well as two crystal growth experiments. The crews also conducted Risk Mitigation Experiments (RME) and Human Life Sciences (HLS) investigations.
When the hatches closed for undocking at 9:07 a.m., June 8, and the spacecraft separated at 12:01 p.m. that day, the final Shuttle- Mir docking mission was concluded and Phase 1 of the International Space Station (ISS) program came to an end.
The Alpha Magnetic Spectrometer (AMS) flew for the first time on this mission. The AMS, designed to look for dark and missing matter in the universe, was powered up on Flight Day 1. Data originally planned to be sent to ground stations through Discovery's KU-band communications system was recorded onboard because of a problem with the KU-band system that prevented it from sending high-rate communications, including television signals, to the ground. The system was able to receive uplink transmissions. On June 3 the crew was able to set up a bypass system that allowed AMS data to be downlinked via S-band/FM communications when the orbiter came within range of a ground station. Data that could not be recorded by ground stations was recorded onboard throughout the mission.
The KU-band system failure was determined to be located in a component that was not accessible to the crew. The failure prevented television transmission throughout the mission. Television broadcasts from Mir were prevented by a problem between a Russian ground station and the mission control center outside of Moscow, limiting communications to audio only on NASA television.
Other experiments conducted by the Shuttle crew during the mission included a checkout of the orbiter's robot arm to evaluate new electronics and software and the Orbiter Space Vision System for use during assembly missions for the ISS. Also onboard in the payload bay were eight Get Away-Special experiments, while combustion, crystal growth and radiation monitoring experiments were conducted in Discovery's middeck crew cabin area.
First Launch: 1998.06.02.
Last Launch: 1998.06.12.
Duration: 9.83 days.
Attitude control problems solved:
During the period in which the Mir crew was solving these problems the attitude control was done by small thrusters of the Mir complex itself and Soyuz-TM27. The replacement of the attitude control computer by a new or by an old spare one did not help. TsUP transmitted to Mir the needed software. After loading this into the computer the word 'error' appeared on the screen. After the replacement of the Omega star tracker in the Kristall module or switching over to a reserve one the attitude control was activated again and worked well.
In the morning of 2.06.1998 the Russians successfully concluded the necessary tests and they started to activate the 11 gyrodynes. In the course of 2.06.1998 all gyrodynes spun at their maximum speed thus securing the accurate attitude control badly needed for the approach and docking of Discovery on 4.06.1998. Moreover Russian experts had stated that approach and docking also were possible when the attitude control was done by thrusters, but thus far this had not been necessary during previous Shuttle operations and consequently this has never been tried out.
During the period in which the crew was repairing and testing the attitude control systems radio traffic could be monitored far into the night. During these communications Musabayev got commands from TsUP and loaded these into the systems Svet and Simvol.
A considerable time there were no communications via this geostationary satellite. This is quite normal in periods in which the attitude cannot be maintained by the gyrodynes.
Chris v.d. Berg, NL-9165/A-UK3202.
The crew of Discovery uses the S-band possibilities for phone- and other communications. It might be possible that, as soon as this message reaches the users the Ku-band problem in Discovery has been solved, but if this is not the case let us hope that the Russians will extend the use of Altair-2 for communications.
Chris v.d. Berg, NL-9165/A-UK3202.
During the pass in the next orbit (70211, 1823-1835 UTC) the airseal checks had been done. Communications went via 143.625 as well as 130.165 mc. Musabayev was sitting near the hatch to Discovery and he and Budarin tried to establish a TV-link with TsUP. Altair-2 was not active and from the commands (for instance Anna-86) could be derived that the TV-link went via a UHF-channel and a tracking station in Russia. It lasted a long time before the TV-link was ready and TsUP received images. At 1828 UTC the hatches were open and Musabayev and Precourt could meet each other. Andy Thomas tried to meet his Discovery colleagues as soon as possible and Musabayev warned him to be careful. Just before LOS a lot of enthusiasm and laughter could be heard. During the pass in orb. 70212/213, 1959-2010 UTC, there was only Telemetry and Packet. Phone and images could be monitored via Altair-2 during the next pass (70214, 2113 UTC). Both crews were having diner together. Musabayev had said that he and his crew did not eat for 15 hours. The Discovery crew did not have a meal for 12 hours.
R0Mir transmitted the following CQ Packet Radio message:
I AM ABUT TO END MY TIME ON Mir AND I WANT TO THANK ALL THE HAM OPERATORS AROUND THE WORLD WHO HAVE SENT MESSAGES. I HOPE IT IS UNDERSTOOD THAT THE VOLUME OF TRAFFIC HAS MADE INDIVIDUAL RESPONSES IMPOSSIBLE BUT WE REALLY ENJOY YOUR MAIL. VOICE HAS BEEN VERY DIFFICULT PARTICULARLY OVER THE US AND EUROPE. TOO MANY TALKING AT ONCE. IN THE SHORT TIME I HAVE LEFT I WILL TRY TO DO VOICE, BUT ASK THAT REPEAT CALLERS STAY OFF THE AIR SO THAT I CAN GIVE NEW CALLERS A CHANCE FOR A CONTACT.
BEST WISHES TO ALL OF YOU. ANDY THOMAS
Chris v.d. Berg, NL-9165/A-UK3202.
The TV-reports from Mir of which only a few reached us via CNN were relayed by tracking stations inside Russia via UHF-channels. This could be derived from the use of the command code Anna-86 during VHF communications. These video links lasted shorter than those via Altair-2 and the quality was not so good and sometimes only black and white images were possible. From the Russian segment of the combination Discovery-Mir the Russians communicated with TsUP via their own VHF-channels. Discovery used for voice communications with Houston the S-band channel via the TDRS-es. During one of the communication windows on 5.06.98 Musabayev tried to get in contact with TsUP for a long time. He asked Charlie Precourt to warn TsUP Moscow via one of the American channels and this helped. The last months the Mir-crew regularly called TsUP in vain for long periods, even via Altair-2. Deteriorated motivation of the Capcoms at TsUP?
On 5.06.98, so 1 day after the docking of Discovery, Andy settled himself into the Shuttle and became a member of STS-91's crew. He regularly showed up inside the contours of the Mir-complex, but did no longer communicate from there with TsUP Moscow. Valeriy Viktorovich Ryumin: This leading designer of RKK Energiya and former Salyut-6 cosmonaut needed only a few days extra to bring his spaceflight record up to 365 days, so a full year. On 5.06.1998 he passed this limit and both crews celebrated this jubilee on board Mir. Musabayev offered for this opportunity guitar music. All styles were possible: Beatles, Russian- or Kazakh folk songs, even that of Vysotskiy. For Ryumin as a high-ranking official of RKK Energiya it was an excellent opportunity to execute an extensive inspection of Mir's systems.
Musabayev and Budarin were very pleased that this earthling could see by his own eyes the situation about which cosmonauts so often complained. He was displeased about the enormous mess within the station. In his opinion the abundance of useful, but also of superfluous and useless things, makes the work for cosmonauts, in particular new ones, extremely difficult. Behind a panel he found a lot of rubbish and he asked TsUP permission to get rid of that. Among this rubbish were some cables and TsUP did not give him this permission. He grumbled a little bit, but did not press the matter for he himself had ordered that cosmonauts always have to stick to decisions from flight control. During conversations with TsUP about technical matters Musabayev sometimes referred to Ryumin. For instance about the problems they had with the installation of camera's to document the departure of the Discovery. The brackets near certain portholes to fix these camera's did not fit. Ryumin said that the man at TsUP had to write this down in his report in red capital letters.
I have been listening to the voices of cosmonauts for some decades and it was a real sensation to hear this old stager again via my headphones. It felt as if a time machine had put me back 20 years.
Almost for a year the experts are struggling along with the 1000 dollar question how to locate the leakage in the hull of the Spektr module. Previous attempts to find these leakage by pumping fluorescent gasses through Spektr were unsuccessful. Mission STS-91 gave the last opportunity to try this again. The first test was executed on 6.06.1998 during the VHF-pass in orbit 70242, between 1756 and 1807 UTC. Budarin opened the valve of Spektr's hatch and inflated the fluorescent gasses into the module. Musabayev gave a count down so that everybody on board of Discovery could be alert with camera's and at portholes. During the test Budarin reported the pressures inside Spektr. These values were relatively low, not more than 55 MM mercury. Precourt reported that nothing could be seen with the naked eye. The test was repeated after the undocking of Discovery on 8.06.98. At 1124 UTC Discovery was station keeping right in front of the Mir-station while Musabayev and Budarin repeated the procedure and again Precourt reported that they did not see anything.
Let us hope that analyses on earth of the video recordings and photographs will help.
Departure of Discovery:
During the undocking communications went via VHF-channels. This took place during the pass in orbit 70272 (1554-1602 UTC). After some camera problems the images were transmitted via tracking stations in Russia. Altair-2 was not active. During the following orbit (70273) Altair-2 was active and images could be seen of the autonomously flying Discovery. The crew also transmitted video recordings of the farewell party just before the closing of the hatches to Discovery. Altair-2 stopped transmitting at 17.23.40 UTC, so just before the separation burn of Discovery, which took place at 1724 UTC. From 1732 UTC Mir communicated via the VHF channels in the 143 and 130 mc bands.
Chris v.d. Berg, NL-9165/A-UK3202.