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8. The Next Steps With each mission, the Space Transportation System continued to expand its operational functionality. The first four flights had demonstrated the system’s basic capabilities, and the next four had revealed its capabilities as a launch vehicle. After a brief change of pace on sts-9, during which the orbiter served as a space-based science laboratory, the shuttle resumed the expansion of its capabilities as a payload launch system. sts-41b Crew: Commander Vance Brand, Pilot Robert “Hoot” Gibson, Mission Specialists Bruce McCandless, Ron McNair, and Bob Stewart Orbiter: Challenger Launched: 3 February 1984 Landed: 11 February 1984 Mission: Launch of two communication satellites, first flight of the Manned Maneuvering Unit The first nine Space Shuttle missions received relatively straightforward designations. Each was given a number, and that number was the order in which they flew. But beginning with sts-10 (which was cancelled and later flew as sts-51c) and sts-13, the agency decided there were problems with naming missions this way. Bob Crippen was commander of the mission that would have been sts-13. “My friend Jim Beggs, who was the administrator of nasa, had triskaidekaphobia (fear of the number 13), and he said, ‘There’s not going to be [another disaster like] Apollo 13, or a Shuttle 13, so come up with a new numbering system.’” Astronaut Rick Hauck had a similar recollection, though he remembered the decision also being partly inspired by a desire to avoid confusion down the road. “It’s my sense that there was someone that decided, ‘We are not going to fly a mission called sts-13.’ Thirteen-phobic. So at some point, 170 | the next steps they said, ‘Okay, we’re going to rename these missions.’ And [it was] also because you’d plan a mission, you’d get everybody started on it, and then something would cause that mission to slip past another mission, so that, in itself, was causing confusion. ‘We’re going to fly sts-12 before we fly sts11 .’ So it’s easier if you don’t number them sequentially.” The new system combined the last number of the fiscal year in which the mission was scheduled plus either a 1 or a 2 for the launch location—1 for Kennedy Space Center and 2 for the planned launch facilities at Vandenberg Air Force Base—plus a letter to designate the planned order. This meant that the tenth Space Shuttle mission became 41b: 4 for 1984, 1 because it was launching from Kennedy, and B because it would be the second mission that year. Continuing the series of incremental firsts in the early shuttle program, 41b would mark the first use of the Manned Maneuvering Unit (mmu) “backpack” developed by the Martin Marietta Corporation. “It was supposed to be an early-day Buck Rogers flying belt, if you know what I mean, except it didn’t have the person zooming real fast,” recalled 41b commander Vance Brand. “It was a huge device on your back that was very well designed and redundant so that it was very safe, but it moved along at about one to two or three miles per hour. It used cold nitrogen gas coming out in spurts to thrust you around. The trick was not to let the eva crewmen get too far out such that orbital mechanics would take over and separate us. We didn’t want them lost in space. We didn’t want to come back and face their wives if we lost either one of them up there.” When McCandless first began using the mmu, he encountered a couple of problems. First was a slight offset in his center of mass. For the mmu to work properly, the thrust had to be delivered based on the center of mass of the mmu, its wearer, and the spacesuit. As long as those were properly aligned, it would move properly. However, after McCandless found the mmu was not maneuvering quite the way he expected, it was discovered that in the microgravity environment a small offset, such as additional equipment being worn on one side that wasn’t factored in, could cause the mmu to move in unanticipated ways. The other problem McCandless ran into was that the internal thermal control system for the spacesuit was configured assuming that the astronaut would be exerting effort that would cause him or her to generate heat. The idea was that an astronaut would be working up a sweat and...

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