"Hubble Repair Mission: STS-61," Spaceflight, January 1994, pp. 15-16; "STS-61 Mission Report," Roelof Schuiling, Spaceflight, March 1994, p. 78; STS-61 Space Shuttle Mission Report, NSTS-08288, February 1994, pp. 3, 5-6; interview, David S. F. Portree with Jeffrey Hoffman, June 18, 1996.
Each of HST's British Aerospace-built solar array wings was 12 m (39.4 ft) long and 2.8 m (9.2 ft) wide fully deployed, weighed 160 kg (352 lb), and generated 2.5kW of electricity. Array replacement was scheduled for HST SM-01 before the telescope was launched. Originally this was meant to compensate for solar array degradation so total electricity produced would remain above 4.5kW, but problems with "jitters" in the arrays caused by thermal expansion and contraction quickly overshadowed the original justification. The new arrays were modified to eliminate the vibration problem. The arrays were stowed rolled up in a special Solar Array Carrier (SAC) at the front of the payload bay. After the first EVA the arrays were commanded to close. The starboard array failed to close properly because of a bent bistem in its support framework. The array was closed only 30 percent to avoid bistem breakage, which might have created a sharp-edge hazard. Thornton was unable to receive radio from Endeavour or the ground until 3 hr, 15 min into the EVA; she lost radio again near EVA's end. Akers served as relay during the blackout. The astronauts detached and jettisoned the starboard array, then installed its jitter-proof replacement. The port array was then removed and stowed in the SAC for return to Earth and its replacement installed. The new arrays were left rolled up. The astronauts finished the EVA by installing a foot restraint for the next EVA.
"Hubble Repair Mission: STS-61," Spaceflight, January 1994, p. 16; "STS-61 Mission Report," Roelof Schuiling, Spaceflight, March 1994, p. 78; "Hubble Space Telescope Servicing Mission Report No. 5, Hubble gets new ESA-supplied solar arrays," December 6, 1993; STS-61 Space Shuttle Mission Report, NSTS-08288, February 1994, pp. 3, 6; interview, David S. F. Portree with Kathy Thornton, June 17, 1996.
December 6
1993 EVA 13 World EVA 119 U.S. EVA 63 Shuttle EVA 25
Duration: 6:47
Spacecraft/mission: STS-61
Crew: Richard Covey, Ken Bowersox, Story Musgrave, Thomas Akers, Jeffrey Hoffman, Kathy Thornton, Claude Nicollier (ESA) Spacewalkers: Story Musgrave, Jeffrey Hoffman
Purpose: Repair HST; replace WFPC with WFPC-2
The objective of the third HST servicing EVA was to replace the 281-kg (620-lb) Wide Field/Planetary Camera. WFPC-2, built from a WFPC spare after ground controllers determined that HST had faulty optics, was stowed in the Radial Scientific Instrument Protective Enclosure (RSIPE). Musgrave and Hoffman removed the original WFPC and placed it in the RSIPE. The IV crew then tipped HST forward on the Flight Support System to put the closed aperture door within RMS reach. Both Hoffman and Musgrave mounted the RMS and replaced two of four MSS magnetometers near HST's aperture. They discovered that the MSS covers are disintegrating, raising fears that foam fragments from the covers might infiltrate HST's optics. The team installed four more fuse plugs and performed some light tasks originally scheduled for the next EVA before closing out.
"Hubble Repair Mission: STS-61," Spaceflight, January 1994, p. 16; "STS-61 Mission Report," Roelof Schuiling, Spaceflight, March 1994, p. 78; STS-61 Space Shuttle Mission Report, NSTS-08288, February 1994, pp. 3, 6; interview, David S. F. Portree with Jeffrey Hoffman, June 18, 1996.
December 7
1993 EVA 14 World EVA 120 U.S. EVA 64 Shuttle EVA 26
Duration: 6:50
Spacecraft/mission: STS-61
Crew: Richard Covey, Ken Bowersox, Story Musgrave, Thomas Akers, Jeffrey Hoffman, Kathy Thornton, Claude Nicollier (ESA) Spacewalkers: Kathy Thornton, Thomas Akers
Purpose: Repair HST; install COSTAR unit
The GHSP had to be sacrificed to provide a place for the $50-million COSTAR device for correcting HST's faulty optics. Thornton mounted the RMS and opened the GHSP access door using a power ratchet tool. One of the two JSC-supplied power tools carried on Endeavour failed completely, while the other lost its variable speed setting. Akers then climbed inside, disconnected the 221-kg (487-lb) photometer, pulled it out, and handed it to Thornton. Nicollier then moved Thornton and GHSP to a holding device, where she temporarily stowed the instrument. Thornton pulled the 290-kg (640-lb) COSTAR from the Axial Scientific Instrument Protective Enclosure (ASIPE). Akers aligned the device on its rails, slid it in, engaged its latches, and connected its electrical cables. The astronauts then placed the GHSP in COSTAR's place in the ASIPE. The replacement task, scheduled to require 3 hr, 10 min, was completed in only 35 min. COSTAR could not be fully tested for 6 to 8 wk, but initial checks completed ahead of the final HST SM-01 EVA gave the device good marks. The astronauts then installed a new Goddard/Lockheed/Fairchild DF-224 co-processor to improve computer performance. Communications problems continued for Thornton. Following the EVA, Covey and Bowersox fired Endeavour's forward thrusters for 61 sec to boost HST into a 516-km (321-mi) circular orbit.
STS-61 Space Shuttle Mission Report, NSTS-08288, February 1994, pp. 3, 5-6; "Hubble Repair Mission: STS-61," Spaceflight, January 1994, p. 16; "STS-61 Mission Report," Roelof Schuiling, Spaceflight, March 1994, p. 81; "Hubble Vision Problems Clear Up After December Repair," William Harwood, Space News, January 17-23, 1994; Corrective Optics Space Telescope Axial Replacement, Ball Corporation, October 1993; interview, David S. F. Portree with Kathy Thornton, June 17, 1996.
December 8
1993 EVA 15 World EVA 121 U.S. EVA 65 Shuttle EVA 27
Duration: 7:21
Spacecraft/mission: STS-61
Crew: Richard Covey, Kenneth Bowersox, Story Musgrave, Thomas Akers, Jeffrey Hoffman, Kathy Thornton, Claude Nicollier (ESA) Spacewalkers: Story Musgrave, Jeffrey Hoffman
Purpose: Repair HST; replace solar array drive electronics
STS-61, 1993 - Kathy Thornton (top) maneuvers the COSTAR unit toward Tom Akers. (STS061-98-00Q)
Image
The astronauts replaced HST's SADE then put protective covers fabricated aboard Endeavour on MSS units 3 and 4 to prevent foam from getting into the telescope's optics. Controllers on the ground then commanded HST's solar arrays to unroll. They experienced trouble, so Hoffman and Musgrave aided deployment. Each array required 5 min to unroll. Communication problems meant no biomedical data during most of the EVA. The astronauts returned to the airlock, ending a record EVA total of 35 hr, 28 min for STS-61. According to Hoffman, by this EVA Nicollier could anticipate his needs. He would reach toward a tool or bolt and Nicollier would automatically move the RMS to put it within reach. Nicollier earned the nickname "the Magician" for his RMS acumen. On December 9 Nicollier used the RMS to grapple the telescope and lift it above Endeavour's payload bay. Ground controllers charged HST's batteries, deployed the high-gain antenna booms, and opened the aperture door. Nicollier then released the telescope. Covey and Bowersox moved Endeavour away, taking care not to strike HST with plumes from the orbiter's steering jets. On December 11 the crew performed space suit evaluations in the middeck and stowed the RMS. Endeavour landed in Florida on December 13.
STS-61 Space Shuttle Mission Report, NSTS-08288, February 1994, pp. 3, 5; "STS-61 Mission Report," Roelof Schuiling, Spaceflight, March 1994, p. 78; interview, David S. F. Portree with Jeffrey Hoffman, June 18, 1996.
December 13
STS-61/Endeavour landing
September 9
1994 EVA 1 World EVA 122 Russian EVA 57 Space Station EVA 65
Duration: 5:04
Spacecraft/mission: Mir PE-16
Crew: Yuri Malenchenko, Talgat Musabayev, Valeri Polyakov Spacewalkers: Yuri Malenchenko, Talgat Musabayev
Purpose: Inspect docking port struck by Progress-M 24; mend thermal blanket torn by Soyuz-TM 17
Soyuz-TM 17 and Progress-M 24 struck Mir in January 1993 and August 1994, respectively. Valeri Polyakov, a medical doctor, monitored Malenchenko and Musabayev from inside Mir during this inspection EVA, which was scheduled to last 3 hr, 40 min. The cosmonauts started by replacing space exposure cassettes outside Kvant 2, then moved to the front of the Mir base block. They inspected Kristall near where it joined the base block and found that the damage caused by Soyuz-TM 17 was light—a missing 30-cm-by-40-cm (11.8-in-by-15.8-in) thermal blanket and scratches on insulation nearby. They mended the damage, then inspected the Progress-M 24 impact area on the Mir transfer compartment, finding no appreciable damage.
MirNews 229, Chris Vandenberg, September 13, 1994; "Mir Undamaged by Progress Bump," Aviation Week & Space Technology, September 19, 1994, p. 71; "Space Station Cosmonauts," Neville Kidger, Spaceflight, January 1995, pp. 8-9.
September 14
1994 EVA 2 World EVA 123 Russian EVA 58 Space Station EVA 66
Duration: 6:01
Spacecraft/mission: Mir PE-16
Crew: Yuri Malenchenko, Talgat Musabayev, Valeri Polyakov Spacewalkers: Yuri Malenchenko, Talgat Musabayev
Purpose: Routine maintenance; prepare to move solar arrays from Kristall to Kvant; inspect Sofora
PE-16's second EVA, planned to last 4 hr, launched Mir's reconfiguration ahead of the scheduled arrival of the U.S. Shuttle Atlantis in June 1995. Malenchenko and Musabayev inspected the movable solar arrays on Kristall, which were scheduled to be retracted and moved to Kvant through a series of EVAs. They also inspected mounting brackets and drives on Kvant on which the arrays would be mounted. The cosmonauts took down space exposure cassettes from Rapana and inspected Sofora, then mounted a new amateur radio antenna. Valeri Polyakov tested the new antenna from inside Mir.
MirNews 229, September 13, 1994; "Mir Undamaged by Progress Bump," Aviation Week & Space Technology, September 19, 1994, p. 71; "Space Station Cosmonauts," Neville Kidger, Spaceflight, January 1995, p. 9.
September 16
1994 EVA 3 World EVA 124 U.S. EVA 66 Shuttle EVA 28
Duration: 6:51
Spacecraft/mission: STS-64
Crew: Richard Richards, L. Blaine Hammond, Carl Meade, Mark Lee, Susan Helms, Jerry Linenger Spacewalkers: Mark Lee, Carl Meade
Purpose: Test SAFER self-rescue device
Mark Lee and Carl Meade performed the first untethered EVA since the MMU flights in 1984 to test the Simplified Aid for EVA Rescue (SAFER) device. Lee and Meade participated in SAFER air-bearing floor tests, virtual reality training development, and reach-and-access design tests, as well as briefings to Shuttle Program management to secure development funding when funding from the Space Station program dried up for a time in 1993. SAFER is worn under the astronaut's PLSS backpack. The device weighs 37.7 kg (83 lb), more than 114 kg (250 lb) lighter than the MMU. SAFER attaches to the astronaut using the six existing PLSS hard points, including the two provided for the MMU, so no EMU modifications were required. "Towers" for thrusters extend up the sides of the PLSS. SAFER has no bulky hand controller arms in front. The hand controller is a small box—for this first test it was hard-secured to the astronaut's chest. In the ISS production model SAFER, the hand controller will be embedded in one of the thruster towers. The astronaut will pull a lanyard so the controller swings out on an arm, placing it within easy reach. SAFER has 24 fixed-position thrusters. Four compressed nitrogen tanks hold 60 sec of nitrogen if the device is used for translation, or 120 sec if it is used for rotation and stabilization. Jerry Linenger was IV crewman, while Susan Helms piloted the RMS. Commander Richard Richards and Pilot Blaine Hammond stood by to rescue the SAFER astronaut. The test had four parts—familiarization, a programmed jet test series to gather engineering data, tumbling tests, and precision maneuvering—and occurred within a 7.6-m-by-8.2-m (25-ft-by-27-ft) box of space at the front of Discovery's payload bay. The astronauts quickly determined that the device used less nitrogen than predicted. After completing the familiarization and engineering data portions of the test, Lee and Meade took turns standing in an MFR on the RMS and tumbling the other. The tumbled astronaut activated SAFER's automatic attitude hold system, stabilized, then maneuvered toward the RMS, which Helms pulled away to simulate a separation rate of 0.06 mps (0.2 fps). Meade rolled Lee at 2 rpm—faster than planned, but SAFER stabilized him without difficulty. Finally, the astronauts took turns flying SAFER precisely along the RMS to a point near the aft flight deck windows. During the tests the astronauts replenished SAFER's propellant supply from the nitrogen recharge unit at the front of Discovery's payload bay seven times. The Electronic Cuff Checklist (ECC), a planned replacement for paper checklists, performed poorly, and Meade's feet became very cold.