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June 1, 1998

Debbie Rahn/Jennifer McCarter
Headquarters, Washington, DC
(Phone: 202/358-1639)

Rob Navias
Johnson Space Center, Houston, TX
(Phone: 281/483-3671)

Release: J98-16

Ninth Shuttle-Mir Docking Mission Highlights STS-91

The first phase of the cooperative effort in space exploration between the United States and Russia will be completed in June 1998 with the launch of Space Shuttle Discovery on the ninth docking mission with the Russian Space Station Mir. The flight, designated STS-91, will deliver logistics and supplies to Mir and will bring home NASA Astronaut Andrew Thomas, who has been on the Russian complex since late January.

The STS-91 crew will be commanded by Charlie Precourt, who will be making his fourth Shuttle flight and third trip to Mir. The pilot, Dominic Gorie, will be making his first flight. There are four mission specialists assigned to STS-91. Franklin Chang-Diaz is serving as Mission Specialist-1 and the Payload Commander and will become only the third human to fly in space six times. Wendy Lawrence is making her third space flight as Mission Specialist-2 and flight engineer and is visiting Mir for the second time in less than a year. Janet Kavandi is Mission Specialist-3 and will be making her first flight. Valery Ryumin, a veteran Russian cosmonaut and manager of the Russian Mir program, will serve as Mission Specialist-4. STS-91 will be Ryumin’s fourth space flight, his first aboard the Space Shuttle. After Discovery docks to Mir and Thomas once again becomes a Shuttle crewmember, he will be designated as Mission Specialist-5 for the remainder of the mission as he completes his second space flight. Discovery is targeted for launch on June 2, 1998 from NASA's Kennedy Space Center Launch Complex 39-A. The current launch time of 6:10 p.m. EDT may vary slightly based on calculations of Mir's precise location in space at the time of liftoff due to Shuttle rendezvous phasing requirements. The STS-91 mission is scheduled to last 9 days, 19 hours, 53 minutes. An on-time launch on June 2nd and nominal mission duration would have Discovery landing back at Kennedy Space Center on June 12th at 2:03 p.m. EDT.

STS-91 will be the first docking of Discovery with the Mir. The first eight docking missions were conducted by Atlantis and Endeavour.

Discovery’s rendezvous and docking with the Mir actually begins with the precisely timed launch, setting the shuttle on a course for rendezvous with the orbiting Russian facility. Over the next two to three days, periodic firings of Discovery’s small jet thrusters will gradually bring Discovery to its linkup to Mir.

The STS-91 mission is part of the Phase One program which has consisted of nine Shuttle-Mir dockings and seven long duration flights of U.S. astronauts aboard the Russian space station.

This series of missions has expanded U.S. research on Mir by providing astronauts with a laboratory in orbit for long-term research, similar to the kind of continuous research capability which will exist on the new International Space Station. By the time Discovery lands, U.S. astronauts will have spent almost 1000 days aboard Mir, including more than 26 months continuously since the arrival of Shannon Lucid on the STS-76 mission in March 1996.

For the STS-91 mission, Discovery carries the single SPACEHAB module in the payload bay of the orbiter which will house experiments to be performed by the astronauts and serve as a cargo carrier for the items to be transferred to Mir and those to be returned to Earth.

The current Russian cosmonaut crew aboard Mir began its mission on January 31 when Mir 25 Commander Talgat Musabayev and Flight Engineer Nikolai Budarin were launched from the Baikonur Cosmodrome in Kazakstan along with French researcher Leopold Eyharts. They arrived on Mir on January 31. Eyharts returned to Earth three weeks later with Mir 24 cosmonauts Anatoly Solovyev and Pavel Vinogradov. Musabayev and Budarin are scheduled to return to Earth on or about August 10 when they are replaced by the Mir 26 crew of Commander Gennady Padalka, Flight Engineer Sergei Avdeyev and researcher Yuri Baturin, who are scheduled to be launched August 2 for an docking on August 4.

During the docked phase of STS-91, astronauts and cosmonauts will transfer from the Mir to the Shuttle the science samples collected by Thomas and his Mir colleagues. Crew members will also transfer hardware and supplies to Mir in support of the Mir 25 crew and future science investigations on the station. This continued research will focus on studies in the areas of Advanced Technology, Human Life Sciences, and Microgravity Research.

The commercial initiated research from the Advanced Technology discipline will evaluate new technologies and techniques using the Mir space station and the Shuttle as a test bed. Such research in reduced gravity will contribute to an enhanced knowledge base for implementation on the International Space Station and other space vehicles.

Human Life Sciences research consists of investigations that focus on the crew members adaptation to weightlessness in terms of skeletal muscle and bone changes, cardiovascular acclimatization, and psychological interactions. This set of investigations will continue the characterization of the integrated human response to a prolonged presence in space.

Microgravity research has the general goal of advancing scientific understanding through research in materials science. The QUELD furnace will heat capsules containing metallic binary systems, bring them to room temperature, and return them to Earth for analysis of the effects of microgravity on diffusion processes. This experiment will be performed using the Microgravity Isolation Mount (MIM).

Also flying on the STS-91 mission is the Alpha Magnetic Spectrometer (AMS) experiment. As part of its long-standing role in high energy physics research, the U.S. Department of Energy is supporting the scientific leadership and part of the funding for the AMS experiment that will fly in the payload bay of Discovery and later on the International Space Station.

The AMS experiment is the first time a high energy physics experiment will be placed in orbit. As high energy physicists seek to find out how the world works, they ask such basic questions as: What are the ultimate building blocks of matter and what are the fundamental forces through which these basic particles interact?

Researchers will use the AMS detector to search for both antimatter and "dark matter" to answer two specific questions: First, if equal amounts of matter and antimatter were produced at the beginning of the universe as described by the Big Bang scenario, and the galaxies we now see are made only of matter, where has the antimatter gone? Second, since the mass of a galaxy seems to be greater than the visible mass of all its stars, gas and dust, is there dark matter of a new kind that has eluded discovery?

Also flying in Discovery’s cargo bay will be four Get Away Special (GAS) and two Space Experiment Module (SEM) payloads that will examine the effects of microgravity on various plants and materials, study the way materials processing changes in space, look at new ways to extract oil from the Earth and clean up accidental spills in the environment as well as investigate the degree to which DNA is damaged by exposure to cosmic radiation in a space environment.

STS-91 will be the 24th flight of Discovery and the 91st mission flown since the start of the Space Shuttle program in April 1981.


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