STS-39

Infobox Space mission
mission_name = STS-39
insignia = STS-39 patch.svg|165px
shuttle = Discovery
launch_pad = 39-A
launch = April 28, 1991 7:33:14 a.m. EDT
landing = May 6, 1991, 2:55:35 p.m. EDT, Runway 15, Kennedy Space Center, Fla.
duration = 8/07:22:23
altitude = 140 nautical miles (259 km)
inclination = 57.0 degrees
orbits = 134
distance = 3,470,000 miles (5,584,423 km)
crew_photo = Sts-39 crew.jpg
crew_caption =
previous = STS-37
next = STS-40

STS-39 was the code for a mission of the Space Shuttle Discovery.

Crew

"(total flights to date in parentheses)"

* Michael L. Coats (3), Commander
* L. Blaine Hammond, Jr.(1), Pilot
* Guion S. Bluford Jr.(3), Mission Specialist 1
* Gregory J. Harbaugh (1), Mission Specialist 2
* Richard J. Hieb (1), Mission Specialist 3
* Donald R. McMonagle (1), Mission Specialist 4
* Charles L. Veach (1), Mission Specialist 5

Mission parameters

*Mass:
**"Orbiter landing with payload:" 95,846 kg
**"Payload:" 5,663 kg
*Perigee: 248 km
*Apogee: 263 km
*Inclination: 57.0°
*Period: 89.6 min

Mission highlights

April 28, 1991, 7:33:14 a.m. EDT. Launch originally scheduled for March 9, but during processing work at Pad A, significant cracks found on all four lug hinges on the two external tank umbilical door drive mechanisms. NASA managers opted to roll back the vehicle to the VAB on March 7, and then to OPF for repair. Hinges replaced with units taken from orbiter "Columbia", and reinforced. "Discovery" returned to pad on April 1, launch re-set for April 23. Mission again postponed when, during prelaunch external tank loading, a transducer on high-pressure oxidizer turbopump for main engine number three showed readings out of specification. Transducer and its cable harness were replaced and tested. Launch was rescheduled for April 28. Launch weight: 247,373 lb (112,207 kg).

Dedicated Department of Defense mission. Unclassified payload included Air Force Program-675 (AFP675); Infrared Background Signature Survey (IBSS) with Critical Ionization Velocity (CIV), Chemical Release Observation (CRO) and Shuttle Pallet Satellite-II (SPAS-II) experiments; and Space Test Payload-1 (STP-1). Classified payload consisted of Multi-Purpose Release Canister (MPEC). Also on board was Radiation Monitoring Equipment III (RME III) and Cloud Logic to Optimize Use of Defense Systems-IA (CLOUDS-I).

STS-39 was the first unclassified Department of Defense (DoD)-dedicated Space Shuttle mission. There had previously been seven Shuttle missions dedicated to the DoD, but those wereconsidered classified and information about the operation or success of the payloads or experiments was not released. For STS-39, only the payload in the Multi-Purpose Experiment Canister (MPEC) was listed as classified.

The crew was divided into two teams for around-the-clock operations. Among other activities, the crew made observations of the atmosphere and gas releases, "Discovery"’s orbital environment,and firings of the orbiter's engines, in wavelengths ranging from infrared to far ultraviolet. As part of the sophisticated experiments, five spacecraft or satellites were deployed from thepayload bay, and one was retrieved later during the mission.

Carried in the orbiter's cargo bay were: Air Force Program-675 (AFP-675); Infrared Background Signature Survey (IBSS); Space Test Program-01 (STP-01); and the MPEC. Inside thecrew cabin were the Cloud Logic to Optimize the Use of Defense Systems-1A (CLOUDS 1-A) experiment and the Radiation Monitoring Equipment-III (RME-III).

The Remote Manipulator System arm in the payload bay wasused to deploy the Shuttle Pallet Satellite-II (SPAS-II) on whichthe IBSS was mounted. Among other observations, the SPAS-II/IBSSwatched Discovery as it performed some orbital maneuvers includingthe "Malarkey Milkshake."The "Malarkey Milkshake" was an orbital maneuver wherein Discovery rotated out-of-plane, fired one OMS engine to move to a different orbital track, rapidly turned around 180° using RCS thrusters and returned to its original orbital track. This rapid sequence of maneuvers was named after the leader of the JSC guidance team which developed it (see Press Kit p. 26).] . The deployment of IBSS was delayed aday, until Flight Day Four, to give priority to the completion ofthe CIRRIS (Cryogenic Infrared Radiance Instrumentation forShuttle) experiment which was depleting its liquid helium coolantsupply faster than expected while making observations of auroraland airglow emissions.

As usual, crew members faced some unexpected challengesduring the mission. After working only about four hours, two taperecorders could not be reactivated. The tape recorders weredesigned to record observations made by three instruments onAFP-675. In a complicated two-hour bypass repair operation, theastronauts had to route wires and attach a splice wire to aKu-band antenna system so the data could be sent directly to aground station.

The high orbital inclination of the mission, 57 degrees withrespect to the equator, allowed the crew to fly over most ofEarth's large land masses and observe and record environmentalresources and problem areas.

May 6, 1991, 2:55:35 p.m. EDT, Runway 15, Kennedy Space Center, FL. Rollout distance: 9,235 ft, rollout time: 56 s. Landing diverted to KSC because of unacceptably high winds at planned landing site, Edwards. Landing weight: 211,512 lb (95,940 kg).

ee also

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

Notes

External links

* [http://science.ksc.nasa.gov/shuttle/missions/sts-39/mission-sts-39.html NASA mission summary]
* [http://www.jsc.nasa.gov/history/shuttle_pk/mrk/FLIGHT_040-STS-039_MRK.pdf NASA Press Kit]
* [http://www.nss.org/resources/library/shuttlevideos/shuttle40.htm STS-39 Video Highlights]