"Above the Planet: Salyut EVA Operations," Neville Kidger, Spaceflight, March 1989, pp. 105; "Salyut 7 Our Commentary - Space Installers," V. Vladimirov, Pravda, November 4, 1983, p. 3 (translated in USSR Report: Space, JPRS-USP-84-002, March 16, 1984, pp. 16-18); "The Experience in Operation and Improving the Orlan-type Space Suits," I. P. Abramov, Acta Astronautica, Vol. 36, No. 1, July 1995, pp. 1-12.
November 3
1983 EVA 3
World EVA 47
Russian EVA 8
Space Station EVA 16
Duration: 2:55 Spacecraft/mission: Salyut 7 PE-2 Crew: Vladimir Lyakhov, Alexandr Alexandrov Spacewalkers: Vladimir Lyakhov, Alexandr Alexandrov Purpose: Augment Salyut 7 solar array
During this EVA, Lyakhov and Alexandrov followed the same procedure they used to install the first add-on solar array two days earlier. This marked the first time the Soviets performed two EVAs in one mission. The EVA was planned so that the principal activities occurred when the station was in daylight and in radio contact with the TsUP. The two add-on arrays installed by Lyakhov and Alexandrov increased Salyut 7's electrical capacity by 800W. According to Viktor Blagov, Deputy Flight Director at the TsUP, the EVAs were
...important for two reasons... solar battery elements gradually lose their productivity when they are operated in space for a very long time... [while at the same time] instruments which require more and more energy are being sent into orbit. In the future we will... attach special scientific modules which also require a great deal of energy. And today's installation operations are the very first steps in solving the orbital energy problems facing us... in the second place, although all kinds of maintenance work has been carried out in open space before, up to now such major installation operations have not been conducted. After all, the time is not far off when brigades of installation workers will fly into orbit and build large orbital complexes in space. [Lyakhov and Alexandrov] have already proved that all this is completely feasible.
Leonid Kizim and Vladimir Solovyov simultaneously simulated the work in the Hydrolaboratory neutral buoyancy facility in Star City. In a 1984 article, Alexandrov and Lyakhov described them as "the test pilots who trained us" and said that "in the event of difficulties the duplicating team on the ground could give us assistance with their recommendations."
"Above the Planet: Salyut EVA Operations," Neville Kidger, Spaceflight, March 1989, pp. 105; "Above the Abyss Once Again - Report from the Flight Control Center," A. Ivanokhov, Izvestia, November 4, 1983, p. 2 (translated in USSR Report: Space, JPRS-USP-84-002, March 16, 1984, pp. 13-15); Zemlya i Vselennaya, Vladimir Lyakhov and Alexandr Alexandrov, May-June 1984, pp. 5-11 (translated in USSR Report: Space, JPRS-USP-85-001, February 4, 1985, pp. 16-17).
1984
February 3
STS-41B/Challenger launch
February 7
1984 EVA 1
World EVA 48
U.S. EVA 40
Shuttle EVA 2
MMU EVA 1
Duration: 5:55 Spacecraft/mission: STS 41-B Crew: Vance Brand, Robert Gibson, Bruce McCandless, Robert Stewart, Ronald McNair Spacewalkers: Bruce McCandless, Robert Stewart Purpose: Test MMU; test MFR
"It may have been one small step for Neil but it's a heck of a big leap for me," quipped astronaut Bruce McCandless, MMU co-designer—with Charles Whitsett of NASA's Johnson Space Center (JSC)—as he took the Martin-Marietta Manned Maneuvering Unit (MMU) on its first test flight. The twin flight MMUs were delivered to JSC in Houston for acceptance testing in September 1983. The first MMU EVA began on mission day 5 of STS 41-B. For the EVA, Challenger's CDR Vance Brand provided intravehicular support during suit-up, monitored MMU speed and distance using Challenger's radar, and flew the orbiter, while Ronald McNair operated the Remote Manipulator System (RMS) mechanical arm. Jerry Ross was EVA CapCom in Houston for this and all subsequent MMU EVAs. In addition to testing the MMU in flight, McCandless and fellow MMU flyer Robert Stewart performed a dress rehearsal for the Solar Maximum Mission (Solar Max) satellite retrieval, scheduled for the next flight (STS 41-C). Both flight MMUs were carried in the forward part of Challenger's payload bay. To help relieve the thrashing and banging which occurred during airlock depressurization on STS-6, McCandless pointed his head toward the airlock floor while Stewart pointed toward the ceiling. McCandless spent 90 min checking and donning the port MMU, then tested it in the payload bay by maneuvering precisely around equipment. He found that the backpack shuddered and shook when forward movement was initiated in attitude hold. McCandless then moved 45 m (150 ft) out from Challenger, returned to the payload bay, flew out to 96 m (315 ft) and returned, then moved out again to about 99 m (325 ft). MMU nitrogen propellant use was higher than in simulations. Brand noted that the MMU's tracking lights were inadequate for finding the astronaut if he strayed away during orbital night, so ordered McCandless to hurry back to the payload bay before Challenger passed into darkness. Meanwhile, Stewart installed a Manipulator Foot Restraint (MFR) on the RMS, but had to postpone a test ride because the EVA was behind schedule. When McCandless returned to the payload bay, Stewart attached between the MMU arms the Trunnion Pin Attachment Device (TPAD) to be used to snare Solar Max. McCandless practiced docking with a trunnion pin mounted next to a mockup of the Solar Max main electronics box in the payload bay. McCandless reported later that he was chilled when out away from the payload bay. Stewart then flew the MMU 93 ft from Challenger. Brand noted that Stewart was traveling at 0.6 mps (2 fps) about 90 ft from Challenger, so warned him to slow down. Stewart tested the MMU for 65 min. Meanwhile, McCandless became the first astronaut to ride the MFR at end of RMS. The arm proved more stable for EVA work than expected.
STS 41-B, 1984—Bruce McCandless (pictured here) and Robert Stewart tested the MMU outside Challenger. (S84-27562)
Image
STS 41-B Pilot's Report, June 1984; "Astronauts Evaluate Maneuvering Backpacks," Craig Covault, Aviation Week & Space Technology, February 13, 1984, pp. 16-19; "Steppin' Out with Flash and Buck," Space News Roundup, NASA JSC, February 24, 1984, pp. 1-2.
February 9
1984 EVA 2
World EVA 49
U.S. EVA 41
Shuttle EVA 3
MMU EVA 2
Duration: 6:17 Spacecraft/mission: STS 41-B Crew: Vance Brand, Robert Gibson, Bruce McCandless, Robert Stewart, Ronald McNair Spacewalkers: Bruce McCandless, Robert Stewart Purpose: Test MMU; rehearse Solar Max repair
On mission day 7 Stewart and McCandless ventured outside again, this time with Pilot Robert Gibson operating the RMS. The manipulator arm suffered wrist joint and elbow TV camera malfunctions prior to this EVA. The camera problem meant that engineering film coverage of the EVA was not as comprehensive as planned. The joint failure was much more serious—it meant that the RMS could not release a rotating Shuttle Pallet Satellite above Challenger's payload bay, depriving the MMU astronauts of a spinning target for practice docking using the TPAD. The ability to dock with a rotating target was considered crucial to the Solar Max repair scheduled for STS 41-C. The astronauts practiced docking with fixed targets instead. Stewart performed a hydrazine transfer experiment to help validate the orbiter's proposed role as a satellite tanker. Freon dyed red for visibility filled in for poisonous hydrazine. A foot restraint worked itself loose; Brand maneuvered Challenger and McCandless moved down the starboard sill to retrieve the errant hardware. NASA called this an unplanned test of the Shuttle's ability to rescue an astronaut stranded by MMU failure.
STS 41-B Pilot's Report, June 1984; "Astronauts Evaluate Maneuvering Backpacks," Craig Covault, Aviation Week & Space Technology, February 13, 1984, pp. 16-19; "Steppin' Out with Flash and Buck," Space News Roundup, NASA JSC, February 24, 1984, pp. 1-2.
February 11
STS-41B/Challenger landing
April 3
Salyut 7/Soyuz-T 11 VE-3 launch
April 6
STS-41C/Challenger launch
April 8
1984 EVA 3
World EVA 50
U.S. EVA 42
Shuttle EVA 4
MMU EVA 3
Duration: 2:38 Spacecraft/mission: STS 41-C Crew: Robert Crippen, Francis Scobee, Terry Hart, James van Hoften, George Nelson Spacewalkers: George Nelson, James van Hoften Purpose: Retrieve Solar Max satellite
Challenger launched within a tight window to rendezvous with Solar Max. NASA considered the mission a critical demonstration of the Shuttle's ability to service satellites. As the orbiter approached the science satellite, the crew reduced cabin pressure to 70.3 kpascal (10.2 psi) to minimize EVA prebreathe time. On this date Pilot Dick Scobee helped Nelson and Van Hoften don their EMUs. After entering Challenger's payload bay, the spacewalkers discovered that the payload bay door slidewires were looser than expected. Nelson donned the MMU, then attempted to dock with Solar Max using the TPAD mounted between the hand controller arms. He bounced off Solar Max after the TPAD jaws failed to close on one of the satellite's berthing docking pins. Solar Max began to spin. Twice more he attempted to latch onto the satellite with the TPAD, each time adding to the slow spin. His difficulties were later traced to an obstructing grommet on Solar Max which did not appear in its blueprints. Nelson then tried to stabilize the satellite by gripping one of its two solar arrays and activating the MMU's automatic attitude hold feature, but this reversed the spin and started an unpredictable tumble about two axes. Solar Max lost its lock on the Sun and began draining its batteries. Nelson was forced to return to Challenger when his MMU nitrogen propellant supply ran low. MMU co-designer Charles Whitsett said later that the MMU's operating temperature was low, reducing nitrogen pressure, so there was probably more nitrogen available than Nelson thought—perhaps enough for another stabilization attempt. The astronauts and Mission Control considered changing MMUs and TPADs and trying again, but Challenger's rendezvous fuel was running low, threatening the orbiter's ability to recover a stranded MMU astronaut. A subsequent attempt by Terry Hart to capture the satellite using the RMS failed because of the tumble. The astronauts returned to the airlock. According to an Aviation Week editorial, the evening of April 8 "seemed like ebb tide for shuttle credibility. It had failed to live up to one of its development justifications: payload retrieval and refurbishment. A prospective Palapa communications satellite rescue attempt was beginning to seem like a grim joke. A Landsat 4 rescue in 1986, which needs money and work to start now, looked no better."
STS 41-C, 1984—George Nelson (left) and James van Hoften service the Solar Maximum Mission satellite (top right) in Challenger's payload bay. (41C-38-1853)
Image
STS 41-C Flight Crew Report, (no date); "Black Sunday... Fat Tuesday," William Gregory, Aviation Week & Space Technology, April 16, 1984, p. 13; "Orbiter Crew Restores Solar Max," Craig Covault, Aviation Week & Space Technology, April 16, 1984, pp. 18-20; "NASA Believes EVAs Valid Despite Recovery Problem," Aviation Week & Space Technology, April 1984, pp. 21-24; "Repair Mission Became High Drama," Space News Roundup, NASA JSC, April 27, 1984, pp. 1-2.
NASA Goddard Space Flight Center (GSFC), which operated Solar Max, stopped its tumble on April 9 before its batteries became depleted. On April 10, Terry Hart grappled the satellite with the RMS on the first try while Crippen piloted Challenger. Hart placed the satellite in its servicing cradle in the payload bay. Van Hoften and Nelson entered the bay on this date for an EVA scheduled to last 6 hr. They completed replacement of the satellite's 227-kg (500-lb) attitude control and main electronics box 1 hr ahead of schedule. Solar Max was a NASA GSFC-developed Multimission Modular Spacecraft (MMS) designed for routine servicing. Van Hoften reported that the EVA "tools are working great—haven't had one glitch yet." They praised the Module Servicing Tool, which was developed specifically for MMS servicing. The failed attitude control module and main electronics box of the satellite were stowed for return to Earth, where they would be analyzed to determine the cost-effectiveness of satellite refurbishment in orbit. If only certain satellite components wore out, then it would be cost-effective to make occasional repairs and change out instruments; if the entire satellite degraded at the same rate, it would be less costly to launch a new satellite. They also stowed thermal blankets and various aluminum parts for analysis by orbital debris researchers on Earth. The salvaged components acted as impromptu debris catchers during their 4 yr in space. Nelson experienced a minor urine containment problem; the liquid cooling garment absorbed most of the leakage, so the largest impact was on post-EVA cleanup. He noted some helmet fogging, though postflight inspection showed that no urine migrated to his helmet through the air circulation system. The fogging occurred when Nelson turned down the flow of cooling water to his Liquid Cooling Ventilation Garment (LCVG) after he became too cold. This reduced ventilation and allowed condensation to build up on the inside of his faceplate. Before returning to the airlock, Nelson stepped into an MFR and rode the RMS above Solar Max to examine and photograph the satellite from all angles. Van Hoften...