STS-46

Int. Designation	1992-049A
Launched	31 July 1992
Launch Site	Pad 39B, Kennedy Space Center, Florida
Landed	8 August 1992
Landing Site	Runway 33, Kennedy Space Center, Florida
Launch Vehicle	OV-104 Atlantis/ET-48/SRB-BI052/SSME #1 2032; #2 2033; #3 2027
Duration	7 days 23 hrs 15 min 3 sec
Call sign	Atlantis
Objective	Deployment of ESA’s European Retrievable Carrier (EURECA) and operation of joint NASA/ISA Tethered Satellite System (TSS)

Flight Crew

SHRIVER, Loren James, 48, USAF, commander, 3rd mission Previous missions: STS 51-C (1985); STS-31 (1990)

ALLEN, Andrew Michael, 36, USMC, pilot NICOLLIER, Claude, 47, civilian, ESA mission specialist 1 IVINS, Marsha Sue, 41, civilian, mission specialist 2, 2nd mission Previous mission: STS-32 (1990)

HOFFMAN, Jeffrey Alan, 47, civilian, mission specialist 3, payload commander, 3rd mission

Previous missions: STS 51-D (1985); STS-35 (1990)

CHANG-DIAZ, Franklin Raymond de Los Angeles, 42, civilian, mission specialist 4, 3rd mission

Previous missions: STS 61-C (1986); STS-34 (1989)

MALERBA, Franco, 46, civilian, Italian Space Agency payload specialist

Flight Log

The launch of STS-46 was delayed just 45 seconds at T — 5 minutes, to verify that the APUs were ready to start. The deployment of the European Space Agency’s European Retrievable Carrier (EURECA) was delayed by one day due to a problem with its data-handling system. Following deployment from Atlantis using the RMS, EUR – ECA’s thrusters were fired to boost the platform to its planned operating altitude of about 500 km. The firing was planned to last 24 minutes, but lasted only six minutes due to unexpected altitude data from EURECA. The problem was resolved and the engines were restarted to place the payload in its operational orbit during the sixth day of the mission. EURECA was subsequently retrieved and returned to Earth during the STS-57 mission in 1993.

The EURECA satellite is hoisted above Atlantis’s payload bay by the RMS prior to deploy­ment. The 16-mm lens gives this 35-mm frame a “fish eye’’ effect. The Tethered Satellite System in centre frame is stowed in the payload bay prior to its planned operations later in the mission

The delay to the EURECA deployment also delayed the Tethered Satellite System experiment for a day. The objective of TSS was to demonstrate the technology of long – tethered systems in space and to demonstrate that such systems were useful for research. The investigations planned for the system on this mission included a variety of space plasma physics and electrodynamics investigations. TSS could operate in the upper reaches of the atmosphere at an altitude higher than the operating range of balloons but below that of orbiting satellites, providing prolonged data gathering far beyond that of sounding rockets. The experiment, if successful, would probably lead to follow-on research into the use of tether systems for generating electrical power, spacecraft propulsion, broadcasting from space, studying the atmosphere, using the atmosphere as a wind tunnel and controlled microgravity experiments.

The 518 kg satellite featured a 1.6-meter sphere mounted on both a pallet in the cargo bay and on the Spacelab Mission Peculiar Equipment Support Structure (MPESS) that supports TSS orbiter-based science instruments. The sphere had an electrically conductive surface and carried its science instruments mounted on extend­able booms. The extended boom satellite support structure measured twelve metres when fully extended above the payload bay and the motorised reel used to deploy the satellite could hold up to 108 km of tether (on STS-46, this was limited to 20 km). A data acquisition system would acquire data from the satellite and control it when

deployed. The programme envisaged 30 hours of deployed activity, with twelve experiments gathering data on the satellite, the support structure and the environment in which it was flying.

During this mission, the system suffered several failures. The No. 2 umbilical failed to retract from the tethered satellite and the satellite itself failed to deploy on the first “flyaway” attempt. The deployment was also punctuated by an unplanned stop at 179 metres, a second at 256 metres, and the inability to either deploy or retrieve the satellite at 224 metres. During STS-46, the satellite reached a maximum distance of 256 metres, instead of the planned 20 kilometres on the initial deployment, due to a jammed tether line. Despite numerous attempts over several days to free the tether, TSS operations were curtailed and the satellite successfully stowed for return to Earth. Post-flight investigations revealed that a protruding 4-inch bolt had hampered deploy­ment operations. Slack tether during the deployment operations was also likely to have resulted in the cable snagging in the Upper Tether Control Mechanism.

Frustrated by their setbacks with TSS, the crew nevertheless completed a range of secondary experiments and payloads, working on a two-shift system. Allen, Nicollier and Malerba formed the Blue Team, while Ivins, Hoffman and Chang-Diaz were the Red Team. Mission commander Shriver worked with either team. There were six NASA experiments located in the payload bay. These were designed to study the effects of the space environment on materials and equipment that were planned for future use on Space Station Freedom. The 70 mm IMAX Cargo Bay Camera was also in the payload bay and was remotely controlled by the crew from the aft flight deck to film scenes from the mission for use in future IMAX films. There were also three secondary payloads located in the mid-deck area, which the crew worked on during their flight.

The mission was extended by one day in order to complete science activities. This would be the last flight of Atlantis prior to a scheduled inspection and modification period. This was later extended to include additional modifications that would allow Atlantis to dock with the Mir space station. Atlantis was shipped to Rockwell in October 1992. Its next mission would be STS-66 in 1994.

Milestones

153rd manned space flight

79th US manned space flight

49th Shuttle mission

12th flight of Atlantis

6th flight of Shuttle pallet mission

1st European mission specialist (Nicollier)

1st European RMS operator (Nicollier)

1st Italian in space (Malerba)

TSS-1 was the longest structure ever flown in space (256 metres) Allen celebrates his 37th birthday in space (4 Aug)