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Mission insignia
Mission statistics
Mission name STS-41
Space shuttle Discovery
Launch pad 39-B
Launch date 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.
Mission duration 4days 02:10:04
Number of orbits 66
Orbital altitude 160 nautical miles (296 km)
Orbital inclination 28.45 degrees
Distance traveled 1,707,445 miles (2,747,866 km)
Crew photo
STS-41 crew.jpg
(L–R): Melnick, Cabana, Akers, Richards, Shepherd are pictured in front of the T-38 jet trainer
Related missions
Previous mission Next mission
STS-31 STS-31 STS-38 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".



Position Astronaut
Commander Richard N. Richards
Second spaceflight
Pilot Robert D. Cabana
First spaceflight
Mission Specialist 1 William M. Shepherd
Second spaceflight
Mission Specialist 2 Bruce E. Melnick
First spaceflight
Mission Specialist 3 Thomas D. Akers
First spaceflight

Mission parameters

  • Mass:
    • Orbiter Liftoff: 117,749 kilograms (259,590 lb)
    • Orbiter Landing: 89,298 kilograms (196,870 lb)
    • Payload: 28,451 kilograms (62,720 lb)
  • Perigee: 300 kilometres (160 nmi)
  • Apogee: 307 kilometres (166 nmi)
  • Inclination: 28.5°
  • Period: 90.6 min

Mission highlights

STS-41 launches from Kennedy Space Center, October 6, 1990.

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.

Ulysses after deployment

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, was 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 was used to fling Ulysses southward out of the orbital plane of the planets and on toward a solar south pole passage in 1994. The spacecraft crossed back over the orbital plane and made 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 hoped to determine how the genetic material in the root cells respond to microgravity. The information gained will be important 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's measurements with coordinated satellite observations, scientists can now calibrate their satellite instruments to insure the most accurate readings possible.

In 1990, a commercial expendable launch vehicle stranded an INTELSAT communication satellite in low orbit. Before STS-41, NASA was 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 were closely examined it was found that the INTELSAT's arrays were not significantly 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 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 STS-41 Physiological Systems Experiment, sponsored the Ames Research Center and Pennsylvania State University's Center for Cell Research, was to determine if pharmacological treatments would be effective in reducing or eliminating some of these disorders. Proteins, developed by Genentech of San Francisco, California, were administered to eight rats during the flight while another eight rats accompanying them on the flight did not receive the treatment.

Discovery launches from Launch Pad 39B, with Columbia in view from its position on Launch Pad 39A.
9/20/90 - Rare view of two space shuttles (STS-35 & STS-41) on adjacent KSC Launch Complex 39 pads. Discovery is on LC-39B in the background, Columbia is on LC-39A in the foreground.

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. This experiment was sponsored in part by the Battelle Advanced Materials Center for the Commercial Development of Space in Columbus, OH.

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 was later 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.

On October 10, 1990, at 6:57:18 a.m. PDT, Discovery landed at Edwards Air Force Base, CA on runway 22. Rollout distance was 8,276 feet (2,523 m) and the rollout time was 49 seconds (braking test). Discovery was returned to Kennedy Space Center on October 16, 1990.

Wake-up calls

A tradition for NASA human spaceflights since the days of Gemini, mission crews are played a special musical track at the start of each day in space. Each track is specially chosen, often by their families, and usually has a special meaning to an individual member of the crew, or is applicable to their daily activities.[1]

Flight Day Song Artist/Composer Played for
Day 2
Rise and Shine, Discovery! a group of Boeing employees Ulysses (spacecraft)
Day 3
Semper Paratus The Coast Guard Band Bruce Melnick
Day 4
Fanfare for the Common Man Aaron Copland
Day 5
The Highwayman The Highwaymen

See also


  1. ^ Fries, Colin (June 25, 2007). "Chronology of Wakeup Calls" (PDF). NASA. Retrieved 2007-08-13. 

External links



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