STS-41

Mission Insignia
Missing image Sts-41-patch.jpg
Mission Statistics
Mission:	STS-41
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 days, 2 hours, 10 minutes, 4 seconds.
Orbit Altitude:	160 nautical miles (296 km)
Orbit Inclination:	28.45 degrees
Distance Traveled:	1,707,445 miles (2,747,866 km)
Crew photo

Crew

• Richard N. Richards (flew on STS-28, STS-41, STS-50 & STS-64), Commander
• Robert D. Cabana (flew on STS-41, STS-53, STS-65 & STS-88), Pilot
• William M. Shepherd (flew on STS-27, STS-41, STS-42 & ISS Expedition 1), Mission Specialist 1
• Bruce E. Melnick (flew on STS-41 & STS-49), Mission Specialist 2
• Thomas D. Akers (flew on STS-41, STS-49, STS-61 & STS-79), 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 from the payload bay. Ulysses, a joint project between the European Space Agency and NASA, will be the first spacecraft to study the Sun's polar regions. Its voyage to the Sun began with a sixteen month trip to Jupiter where the planet's gravitational energy will fling Ulysses southward out of the orbital plane of the planets and on toward a solar south pole passage in 1994. The spacecraft will cross back over the orbital plane and make a solar north pole passage in 1995. By the time Discovery touched down at Edwards Air Force Base, Ulysses had 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 an ambitious schedule of science experiments. Flowering plant samples were grown in 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 (March 1989) revealed chromosome damage in root tip cells but no damage to control plants on Earth. By studying plant samples carried on Discovery, researchers hope to determine how the genetic material in the root cells respond to microgravity. This information will be of importance to future space travelers on 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 continuing research to improve Space Shuttle safety. In a specially designed chamber, called the Solid Surface Combustion Experiment, a strip of paper was burned and filmed to gain an understanding of the development of flame and its movement in the absence of convection currents. This experiment was sponsored by the Lewis Research Center and Mississippi State University.

Atmospheric ozone depletion is an environmental problem of worldwide concern. NASA's NIMBUS-7 satellite and NOAA's TIROS satellites provide daily data to permit researchers to detect ozone trends. The Shuttle Solar Backscatter Ultraviolet Instrument, from the Goddard Space Flight Center, carried an ozone detector instrument identical to those on the satellites. By comparing Discovery measurements with coordinated satellite observations, scientists can calibrate their satellite instruments to insure the most accurate readings possible.

Earlier this year, a commercial expendable launch vehicle stranded an INTELSAT communication satellite in low orbit. NASA is evaluating a possible Shuttle rescue mission in 1992. In preparation for this rescue, solar arrays, similar to those on the satellite, were exposed to the conditions of low orbit to determine if they were in any way altered by the atomic oxygen present. The returned arrays will be closely examined to judge if INTELSAT's arrays and its other systems will be seriously damaged by those effects, thereby posing retrieval risks.

Previous research has shown that during the process of adapting to microgravity, animals and humans experience loss of bone mass, cardiac deconditioning, and, after prolonged periods (>30 days), develop symptoms similar to that of terrestrial disuse osteoporsis. The goal of the Physiological Systems Experiment, sponsored the Ames Research Center and Pennsylvania State University's Center for Cell Research, is to determine if pharmacological treatments might be effective in reducing or eliminating some of these disorders. Proteins, developed by Genetech of San Francisco, CA, were administered to eight rats during the flight while another eight rats accompanying them on the flight did not receive the treatment. An intensive examination of rat tissues is underway to evaluate the effectiveness of the treatment.

The Investigations into Polymer Membrane Processing experiment was conducted 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. Information from this experiment, sponsored in part by the Battelle Advanced Materials Center for the Commercial Development of Space in Columbus, OH, is providing information that will lead to improved membrane processing technologies.

During open periods in the STS-41 crew schedule, the astronauts video taped a number of demonstrations as part of an effort to create an educational video tape for the middle school level students. The tape will be distributed nationwide through NASA's Teacher Resource Center network.

Additional crew activities included experimenting with a voice command system to control onboard television cameras and monitoring ionizing radiation exposure 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).

Related articles

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

External links

• NASA mission summary (http://science.ksc.nasa.gov/shuttle/missions/sts-41/mission-sts-41.html)