STS-51

Infobox Space mission
mission_name = STS-51
insignia = STS-51 patch.svg
shuttle = Discovery
launch_pad = 39-B
launch = September 12, 1993, 7:45 a.m. EDT
landing = September 22, 1993, 3:56 am EDT on KSC SLF runway 15
duration = 9 days, 20 hours, 11 minutes, 11 seconds
altitude = 160 nautical miles (296 km)
inclination = 28.45 degrees
orbits = 157
distance = 4,106,411 miles (6,608,628 km)
crew_photo = STS-51-crew.jpg
crew_caption =
previous = STS-57
next = STS-58

STS-51 was a Space Shuttle "Discovery" mission to insert the ACTS satellite into earth orbit. The mission launched from Kennedy Space Center, Florida, on September 12, 1993.

Crew

*Frank L. Culbertson, Jr.(2), Commander
*William F. Readdy (2), Pilot
*James H. Newman Ph.D.(1), Mission Specialist 1
*Daniel W. Bursch (1), Mission Specialist 2
*Carl E. Walz (1), Mission Specialist 3

Mission parameters

*Mass:
**"Orbiter landing with payload:" 92,371 kg
**"Payload:" 18,947 kg
*Perigee: 300 km
*Apogee: 308 km
*Inclination: 28.45°
*Period: 90.6 min

pace walks

*" Newman and Walz " - EVA 1
*EVA 1 Start: September 16, 1993 - 08:40 UTC
*EVA 1 End: September 16, - 15:45 UTC
*Duration: 7 hours, 05 minutes

Mission highlights

STS-51 was notable for having been scrubbed three times on the launchpad, each time after the crew had boarded the spacecraft [cite web |url=http://science.ksc.nasa.gov/shuttle/missions/sts-51/mission-sts-51.html |title=STS 51 (57) |publisher= NASA |accessdate=2008-03-29 ] :

*On July 17, 1993, the launch was scrubbed on the pad due to a flaw in the pyrotechnic initiator controller that triggers the release of the solid rocket boosters from the mobile launcher platform.

*On July 24, 1993, problems with a hydraulic power unit in one of the solid rocket boosters caused another scrub on the pad. Because of the Perseid meteor shower, the next launch window did not open until the second week of August.

*On August 12, 1993, the count reached the T-3 second mark, at which point the Space Shuttle Main Engines (SSMEs) had ignited. A shutdown was then triggered by faulty fuel flow sensors in one of the SSMEs.

*STS-51 successfully launched on September 12, 1993.

The Advanced Communications Technology Satellite (ACTS) was deployed. This satellite will serve as a test bed for advanced experimental communications satellite concepts and technology. Its Transfer Orbit Stage (TOS) upper stage fired on time 45 minutes later and boosted the satellite to geosynchronous altitude on the first day of the mission.

The first attempt to deploy ACTS was delayed by the crew when two-way communications were lost with Mission Control about 30 minutes before the deploy time. Flight controllers could receive telemetry and voice communications from "Discovery", however the crew could not receive communications from the ground. The crew waived off the 2:43 p.m. CDT deploy when they did not receive a "go" from Mission Control as called for in preflight plans made for just such an occurrence.

After the waive off of deploy, the crew changed the shuttle's S-Band communications system to a lower frequency and restored two-way communications with the ground. The two-way communications had been lost for a total of about 45 minutes. After consulting the crew, flight controllers began immediately planning for the second, and ultimately successful deploy.

Another payload on this mission was the Orbiting Retrievable Far and Extreme Ultraviolet Spectrometer (ORFEUS) telescope mounted on the Shuttle Pallet Satellite (SPAS) payload carrier. ORFEUS was designed to provide information on how stars are born and how they die, while studying gaseous interstellar clouds. SPAS also carried an IMAX camera which was used to film "Discovery" in orbit for the IMAX film Destiny in Space. Also in the cargo bay was the Limited Duration Space Environment Candidate Materials Exposure (LDCE) experiment.

During the deployment on September 12 of the Advanced Communications Technology Satellite (ACTS) and its Transfer Orbit Stage (TOS) booster, two Super*Zip explosive cords, one primary and the other a backup simultaneously detonated. This caused minor tears in two dozen insulation blankets mounted on the bulkhead between the payload bay and the AFT near the #3 APU.

On Thursday, September 16, 1993, spacewalkers Jim Newman and Carl Walz performed a spacewalk designed to evaluate tools, tethers and a foot restraint platform. Their findings reassured the designers and planners of the Hubble Space Telescope servicing flight that their preparations are sound. The new equipment designed for the extensive spacewalk work that will be required on the December telescope servicing mission was only part of the goal of today's spacewalk, and Newman and Walz fulfilled the other goals as they explained at length to Mission Control the differences they perceived between work in orbit and ground training. The two EVA crewmen were ahead of schedule much of the day, and completed more tasks than originally planned for the spacewalk.

However, as they were cleaning up, a balky tool box lid slowed them down when they had to pry it free and close it for "Discovery"'’s trip home. The toolbox lid stretched the spacewalk by about 45 minutes over what had been planned, with Newman and Walz logging a total seven hours, five minutes and 28 seconds of spacewalk time.

Other in-cabin payloads included the Air Force Maui Optical Site (AMOS) Auroral Photography Experiment-B (APE-B), Commercial Protein Crystal Growth (CPCG), Chromosome and Plant Cell Division in Space (CHROMEX), High Resolution Shuttle Glow Spectroscopy-A (HRSGS-A), IMAX, Investigations into Polymer Membrane Processing (IPMP) and the Radiation Monitoring Equipment-III (RME-III) experiment. The Investigation into Polymer Membrane Processing, or IPMP, is designed to research the mixing of various solvent systems in the absence of convection found on Earth in hopes of controlling the porosity of various polymer membranes. RME measures gamma ray, electron, neutron and proton radiation levels in the crew cabin throughout the flight.

Onboard, Mission Specialist Jim Newman donned a special visor to perform a medical experiment testing vision in weightlessness as part of investigations into how vision compensates for the inner ear's lack of balance in space. Newman also successfully tested a Global Positioning System receiver flying aboard "Discovery" as an evaluation of using such equipment to supplement the shuttle's navigation. Also, in a precursor of space station operations, one of "Discovery"’s fuel cells was turned off and restarted.

In another medical evaluation, Commander Frank Culbertson and Mission Specilaist Dan Bursch rode a stationary bike on "Discovery"’s lower deck as part of a continuing study of using exercise to counteract the effects of weightlessness on the body. The crew also powered up an experiment that looks at improving membrane filters in weightlessness and checked on another experiment that has been running well studying the effects of microgravity on plant cells.

Astronauts Carl Walz and Jim Newman operated the experiments designed to study the glowing effect, one a spectrometer that records the effect on film in fine detail and another that records the effect on still photographs. The experiments are hoped to provide information about just what types of gases — in addition to atomic oxygen — create the glow. The information on kinds of gases in the extreme reaches of the atmosphere may be coupled with the materials exposure experiment in the cargo bay to assist with the design and construction of future spacecraft.

Mission insignia

The five white stars and one yellow star of the insignia symbolize the flight's numerical designation in the Space Transportation System's mission sequence.

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-51/mission-sts-51.html NASA mission summary]
* [http://www.nss.org/resources/library/shuttlevideos/shuttle57.htm STS-51 Video Highlights]

References