STS-41

STS-41

Discovery launches from Launch Complex 39B, with Columbia in view from its position on LC-39A.
Mission type	Spacecraft deployment
Operator	NASA
COSPAR ID	1990-090A
SATCAT №	20841
Mission duration	4 days, 2 hours, 10 minutes, 4 seconds
Distance travelled	2,747,866 kilometers (1,707,445 mi)
Orbits completed	66
Spacecraft properties
Spacecraft	Space Shuttle Discovery
Launch mass	117,749 kilograms (259,592 lb)
Landing mass	89,298 kilograms (196,868 lb)
Payload mass	28,451 kilograms (62,724 lb)
Crew
Crew size	5
Members	Richard N. Richards Robert D. Cabana Bruce E. Melnick William M. Shepherd Thomas D. Akers
Start of mission
Launch date	6 October 1990, 11:47:15 UTC
Launch site	Kennedy LC-39B
End of mission
Landing date	10 October 1990, 13:57:18 UTC
Landing site	Edwards Runway 22
Orbital parameters
Reference system	Geocentric
Regime	Low Earth
Perigee	300 kilometers (160 nmi)
Apogee	307 kilometers (166 nmi)
Inclination	28.45 degrees
Period	90.6 min
(L–R): Melnick, Cabana, Akers, Richards, Shepherd are pictured in front of the T-38 jet trainer Space Shuttle program ← STS-31 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

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

Crew seating arrangements

Seat[1]	Launch	Landing	Seats 1–4 are on the Flight Deck. Seats 5–7 are on the Middeck.
S1	Richards	Richards
S2	Cabana	Cabana
S3	Melnick	Akers
S4	Shepherd	Shepherd
S5	Akers	Melnick

Mission highlights

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

Ulysses after deployment

Discovery lifted off on 6 October 1990 at 7:47:15 am EDT. Liftoff occurred 12 minutes after a two-and-a-half-hour launch window opened that day at 7:35 am EDT. STS-41 featured the heaviest payload to date; Discovery weighed 259,593 lb (117.749 Mg) .

The primary payload was the ESA-built Ulysses spacecraft to explore the polar regions of Sun. Attached to Ulysses were two upper stages, the Inertial Upper Stage (IUS) and a mission-specific Payload Assist Module-S (PAM-S), combined together for first time to send Ulysses toward an out-of-ecliptic trajectory. Other payloads and experiments included the 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).

Six hours after Discovery's launch, Ulysses 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 Ulysses 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 flown on STS-29 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 was of importance to future space travelers on long-term expeditions, researchers on the planned Space Station Freedom, and may contribute to advances in intensive farming practices on Earth.

Understanding fire behavior in microgravity was 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. At the time, NASA's NIMBUS-7 satellite and NOAA's TIROS satellites provided 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 were able to calibrate their satellite instruments to insure the most accurate readings possible.

In 1990, a commercial expendable launch vehicle stranded an INTELSAT VI 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. When the returned arrays were closely examined, it was found that the 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 experienced loss of bone mass, cardiac deconditioning, and after prolonged periods (over 30 days), developed symptoms similar to that of terrestrial disuse osteoporsis. The goal of the STS-41 Physiological Systems Experiment, sponsored by 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.

20 September 1990 – 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 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 10 October 1990, at 6:57:18 am 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 (including a braking test). Discovery was returned to Kennedy Space Center on 16 October 1990.

Wake-up calls

NASA began a tradition of playing music to astronauts during the Gemini program, which was first used to wake up a flight crew during Apollo 15. 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.^[2]

Flight Day	Song	Artist/Composer	Played for
Day 2	Rise and Shine, Discovery!	a group of Boeing employees	Ulysses
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

• List of human spaceflights
• List of Space Shuttle missions
• Outline of space science
• Space Shuttle

References

 This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.

1. "STS-41". Spacefacts. Retrieved 26 February 2014.
2. Fries, Colin (25 June 2007). "Chronology of Wakeup Calls" (PDF). NASA. Retrieved 13 August 2007.

External links

• NASA mission summary
• STS-41 Video Highlights