STS-52

Flight Crew

WETHERBEE, James D., 39, USN, commander, 2nd mission Previous mission: STS-32 (1990)

BAKER, Michael A., 38, USN, pilot, 2nd mission Previous mission: STS-43 (1991)

VEACH, Lacy, 49, civilian, mission specialist 1, 2nd mission Previous mission: STS-39 (1991)

SHEPHERD, William Michael, 43, USN, mission specialist 2, 3rd mission Previous missions: STS-27 (1988); STS-41 (1990)

JERNIGAN, Tamara E., 32, civilian, mission specialist 3, 2nd mission Previous mission: STS-40 (1991)

MACLEAN, Steven Glenwood, 37, civilian, Canadian payload specialist 1

Flight Log

The original mid-October launch date for STS-52 slipped when it was decided to exchange No. 3 SSME over concerns about possible cracks in the LH coolant manifold on the engine nozzle. The revised launch on 22 October was delayed by two hours due to crosswinds at the Shuttle Landing Facility, violating the Return-To – Launch-Site criteria. There were also heavy clouds at the Banjul trans-oceanic abort landing site. Despite concerns about the weather, the decision was made to proceed with the launch, in spite of higher than permitted wind speeds at launch. This caused some controversy at the time, but NASA stated that they felt the launch was safe and was performed within the intent of the rule.

Once in orbit, the crew activated the USMP-1 payload, which contained three experiments mounted on two MPESS structures in the payload bay. The Lambda Point Experiment studied the properties of liquid helium in microgravity, while the

The Space Vision System (SVS) experiment is seen in the grasp of the RMS above the payload bay. Target spots placed on the Canadian Target Assembly (CTA) satellite were photographed and monitored as the arm moved around the payload bay holding the satellite. Computers measured the changing position of the dot pattern and provided real-time TV display of location and orientation of the CTA. This was an evaluation to aide future RMS operations in guiding the RMS more precisely during berthing and deployment activities

French Space Agency (CNES) and French Atomic Energy Commission (CEA)- sponsored Material pour L’Etude des Phenomenes Interessant la Solidification sur Terre et en Orbite (MEPHISTO) included crystal growth experiments. The Space Acceleration Measurement System (SAMS) had flown on previous Shuttle missions to measure and record accelerations which could affect onboard experiments. Located in the payload bay of the orbiter and operated by ground-based science teams indepen­dently of the flight crew, these experiments were a “dress rehearsal” for telescience operations on space station and other free-flying satellites.

The LAGEOS II satellite was successfully deployed at the end of FD 1 by spin stabilisation. Two subsequent firings of the solid rocket stages placed the geodynamics satellite in its 5,900 km orbit inclined at 52° to the equator. The previous satellite, LAGEOS I, which had been launched on a Delta expendable launch vehicle in 1976, was located at 110° inclination. The 426 laser reflectors on LAGEOS II provided accurate mapping of the Earth’s surface by using ground-based laser ranging systems and ground-based tracking stations worldwide. The possible applications for data collected by LAGEOS included calculations of the shifting of crustal plates, as well as rotation rates, tides and polar motion of the Earth. This data was also beneficial for global monitoring of regional fault movements in earthquake-prone areas of the Earth. By having two satellites in orbit, the data could be cross-referenced for confirmation and greater accuracy. The satellite was a joint project between NASA and the Agenzia Spaziale Italiana (ASI), the Italian Space Agency. The upper stage used for deployment of the satellite was the Italian Research Interim Stage (IRIS), also built by ASI and being evaluated on this flight for the first time for potential use on future Shuttle missions as an operational upper stage.

Canadian PS MacLean was responsible for the Canadian Experiments-2 (CANEX-2) programme of seven experiments, located both in the cargo bay and on the mid-deck of Columbia. His programme continued and expanded upon the work begun by Canadian astronauts aboard STS 41-G (Garneau) and STS-42 (Bondar), as part of Canadian involvement in Shuttle and Space Station operations. The primary experiment in the CANEX-2 package was the Space Vision System (SVS), in which a computerised “eye’’ would assist an astronaut in operating the RMS in situations where light or field of vision was restricted. The remaining CANEX-2 experiments included research into materials exposure (sample plates attached to the Canadian-built RMS), liquid-metal diffusion, phase partitioning in liquids, measure­ments of the Sun, photo-spectrometer in the atmosphere, the orbiter glow phenomena and space adaptation tests and observations.

The crew also worked with a number of mid-deck and payload bay secondary experiments, including the ESA-supplied ASP, a three-independent-sensor package that was designed to determine spacecraft orientation. There was also an experiment to control pressure in cryogenic fuel tanks in low gravity (which would have applica­tion to Space Station and long-duration space systems operations), protein crystal growth experiments, fluid mixing in microgravity, heat pipe performance in space, an experiment to study the proprietary protein molecule on twelve rodents, and an investigation into Shuttle RCS plume burn contamination.

One of the more challenging aspects of this mission regarding the payload was whether the capability of the Shuttle was being fully utilised on this flight. Commander Wetherbee commented from space that the experiment package his crew were dealing with was imposing time and power constraints on the mission, and that the crew were having a tough time staying out of each other’s way while performing the mid-deck experiments. That the mission was so successful was made possible by very good pre-flight planning of both crew and experiment time.

Milestones

155th manned space flight

81st US manned space flight

51st Shuttle mission

13th flight of Columbia

1st flight of USMP payload

1st flight of Italian IRIS upper stage on Shuttle

Baker celebrates his 39th birthday in space (27 Oct)