STS-41

Infobox Space mission
mission_name = STS-41
insignia = Sts-41-patch.png shuttle = Discovery
launch_pad = 39-B
launch = October 6, 1990, 7:47:15 a.m. EDT
landing = October 10, 1990, 6:57:18 a.m. PDT, Runway 22, Edwards Air Force Base, Calif.
duration = 4/02:10:04
altitude = 160 nautical miles (296 km)
inclination = 28.45 degrees
orbits = 66
distance = 1,707,445 miles (2,747,866 km)
crew_photo = STS-41 crew.jpg
crew_caption = (L–R): Melnick, Cabana, Akers, Richards, Shepherd are pictured in front of the T-38 jet trainer
previous = STS-31
next = STS-38

STS-41 was the eleventh mission of the Space Shuttle "Discovery". The four-day mission with a primary objective to launch the "Ulysses" probe as part of the "International Solar Polar Mission".

Crew

"(total flights to date in parentheses)"

*Richard N. Richards (2), Commander
*Robert D. Cabana (1), Pilot
*William M. Shepherd (2), Mission Specialist 1
*Bruce E. Melnick (1), Mission Specialist 2
*Thomas D. Akers (1), Mission Specialist 3

Mission parameters

*Mass:
**"Orbiter Liftoff:" 117,749 kg
**"Orbiter Landing:" 89,298 kg
**"Payload:" 21,473 kg
*Perigee: 300 km
*Apogee: 307 km
*Inclination: 28.5°
*Period: 90.6 min

Mission highlights

October 6, 1990, 7:47:15 a.m. EDT. Liftoff occurred 12 minutes after two-and-a-half-hour launch window opened at 7:35 a.m. EDT, October 6. Heaviest payload to date. Launch Weight: 259,593 lb (117.749 Mg) .

Primary payload, ESA-built Ulysses spacecraft to explore polar regions of Sun, deployed. Two upper stages, Inertial Upper Stage (IUS) and a mission-specific Payload Assist Module-S (PAM-S), combined together for first time to send Ulysses toward out-of- ecliptic trajectory. Other payloads and experiments: Shuttle Solar Backscatter Ultraviolet (SSBUV) experiment; INTELSAT Solar Array Coupon (ISAC); Chromosome and Plant Cell Division Experiment (CHROMEX); Voice Command System (VCS); Solid Surface Combustion Experiment (SSCE), Investigations into Polymer Membrane Processing (IPMP); Physiological Systems Experiment (PSE); Radiation Monitoring Experiment III (RME III); Shuttle Student involvement Program (SSIP) and Air Force Maui Optical Site (AMOS) experiment.

Six hours after "Discovery"'s launch, the Ulysses spacecraft was deployed fromthe payload bay. Ulysses, a joint project between the European Space Agencyand NASA, was the first spacecraft to study the Sun's polar regions. It'svoyage to the Sun began with a sixteen month trip to Jupiter where the planet'sgravitational energy was used to fling Ulysses southward out of the orbital plane ofthe planets and on toward a solar south pole passage in 1994. The spacecraftcrossed back over the orbital plane and made a solar north pole passage in1995. By the time Discovery touched down at Edwards Air Force Base, Ulysseshad already traversed one million miles (1.6 Gm) on its five year mission.

With the Ulysses spacecraft on its way, the STS-41 crew began anambitious schedule of science experiments. Flowering plant samples were grownin the CHROMEX-2 module in a Kennedy Space Center and State University of New York at Stony Brook experiment. An earlier version of the experiment (March1989) revealed chromosome damage in root tip cells but no damage to controlplants on Earth. By studying plant samples carried on Discovery, researchershoped to determine how the genetic material in the root cells respond tomicrogravity. The information gained will be important to future space travelerson long-term expeditions, to researchers on the planned Space Station Freedom,and may contribute to advances in intensive farming practices on Earth.

Understanding fire behavior in microgravity is part of the continuingresearch to improve Space Shuttle safety. In a specially designed chamber,called the Solid Surface Combustion Experiment, a strip of paper was burned andfilmed to gain an understanding of the development of flame and its movement inthe absence of convection currents. This experiment was sponsored by the LewisResearch Center and Mississippi State University.

Atmospheric ozone depletion is an environmental problem of worldwideconcern. NASA's NIMBUS-7 satellite and NOAA's TIROS satellites provide dailydata to permit researchers to detect ozone trends. The Shuttle SolarBackscatter Ultraviolet Instrument, from the Goddard Space Flight Center,carried an ozone detector instrument identical to those on the satellites. Bycomparing Discovery measurements with coordinated satellite observations,scientists can now calibrate their satellite instruments to insure the mostaccurate readings possible.

In 1990, a commercial expendable launch vehicle stranded anINTELSAT communication satellite in low orbit. Before STS-41, NASA was evaluating a possibleShuttle rescue mission in 1992. In preparation for this rescue, solar arrays,similar to those on the satellite, were exposed to the conditions of low orbitto determine if they were in any way altered by the atomic oxygen present. Thereturned arrays were closely examined it was found that the INTELSAT's arrays were notsignificantly damaged. Based on this finding, NASA went ahead and carried out STS-49 in 1992.

Until STS-41, previous research had shown that during the process of adapting tomicrogravity, animals and humans experience loss of bone mass, cardiac
deconditioning, and, after prolonged periods (>30 days), develop symptomssimilar to that of terrestrial disuse osteoporsis. The goal of the STS-41Physiological Systems Experiment, sponsored the Ames Research Center andPennsylvania State University's Center for Cell Research, was to determine ifpharmacological treatments would be effective in reducing or eliminating someof these disorders. Proteins, developed by Genentech of San Francisco, CA, wereadministered to eight rats during the flight while another eight ratsaccompanying them on the flight did not receive the treatment.

The Investigations into Polymer Membrane Processing experiment wasconducted to determine the role convection currents play in membrane formation.Membranes are used in commercial applications for purification of medicines,kidney dialysis, and water desalination. This experiment was sponsored in part bythe Battelle Advanced Materials Center for the CommercialDevelopment of Space in Columbus, OH.

During open periods in the STS-41 crew schedule, the astronauts videotaped a number of demonstrations as part of an effort to create an educationalvideo tape for the middle school level students. The tape was later distributednationwide through NASA's Teacher Resource Center network.

Additional crew activities included experimenting with a voice commandsystem to control onboard television cameras and monitoring ionizing radiationexposure to the crew within the orbiter cabin.

October 10, 1990, 6:57:18 a.m. PDT, Runway 22, Edwards Air Force Base, CA. Rollout distance: 8,276 feet (2.523 km). Rollout time: 49 seconds (braking test). Orbiter returned to KSC October 16,1990. Landing Weight: 196,869 lb (89.298 Mg).

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-41/mission-sts-41.html NASA mission summary]
* [http://www.nss.org/resources/library/shuttlevideos/shuttle36.htm STS-41 Video Highlights]