STS-91

Infobox Space mission
mission_name = STS-91
insignia = Sts-91-patch.png shuttle = Discovery
launch_pad = 39-A
launch = June 2, 1998 6:06:24 p.m. EDT
landing = June 12, 1998 2:00:17 p.m. EDT, KSC
duration = 9 days, 19 hours, 55 minutes 1 second
altitude = 160 nautical miles (296 km)
inclination = 51.60 degrees
distance =
crew_photo = STS-91_crew.jpg
crew_caption =
previous = STS-90
next = STS-95

STS-91 was the final Space Shuttle mission to the "Mir" space station. It was flown by Space Shuttle "Discovery", and launched from Kennedy Space Center, Florida, on June 2, 1998.

Crew

*Charles J. Precourt (4), Commander
*Dominic L. Pudwill Gorie (1), Pilot
*Wendy B. Lawrence (3), Mission Specialist
*Franklin R. Chang-Diaz (6), Mission Specialist - flag|Costa Rica
*Janet L. Kavandi (1), Mission Specialist
*Valery Ryumin (4), Mission Specialist - flag|Russia

Landed and returned from Mir

*Andrew S. W. Thomas (2)

Mission parameters

*Mass:
**"Orbiter landing with payload:" 117,861 kg
**"Payload:" 16,537 kg
*Perigee: 350 km
*Apogee: 373 km
*Inclination: 51.7°
*Period: 91.8 min

9th Mir docking mission

*Docked: June 4, 1998, 16:58:30 UTC
*Undocked: June 8, 1998, 16:01:48 UTC
*Time Docked: 3 days, 23 h, 3 min, 18 s

Mission highlights

STS-91 marked the final Shuttle/Mir Docking Mission. This Phase 1 Program was a precursor to the International Space Station maintaining a continuous American presence in space and developing the procedures and hardware required for an international partnership in space.

STS-91 also carried the Alpha Magnetic Spectrometer Investigation (AMS) into space. The objectives of this investigation were to search for anti-matter and dark matter in space and to study astrophysics.

The mission was also the first to use the super lightweight external tank (SLWT) which was the same size, at convert|154|ft|m long and convert|27|ft|m in diameter, as the external tank used on previous launches, but convert|7500|lb|kg lighter. The tank was made of an aluminum lithium alloy and the tank's structural design had also been improved making it 30 percent stronger and 5 percent less dense. The walls of the redesigned hydrogen tank were machined in an orthogonal waffle-like pattern, providing more strength and stability than the previous design. These improvements would later provide additional payload capacity to the International Space Station.

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 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 (500 kg) of water, and almost 4,700 pounds (2,130 kg) 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 co-culture (COCULT) investigations, as well as two crystal growth experiments. The crews also conducted Risk Mitigation Experiments (RMEs) 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.

A prototype of 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 on board 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 on board 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 on board in the payload bay were eight Get Away Special experiments, while combustion, crystal growth and radiation monitoring experiments were conducted in "Discovery"’s mid-deck crew cabin area.

ee also

*Space science
*Space shuttle
*List of space shuttle missions
*List of human spaceflights chronologically

External links

* [http://science.ksc.nasa.gov/shuttle/missions/sts-91/mission-sts-91.html NASA mission summary]
* [http://www.nss.org/resources/library/shuttlevideos/shuttle91.htm STS-91 Video Highlights]