The objective of the STS-5 EVA was to have Lenoir (EV-1) and Allen (EV-2) verify the operational status of the end-to-end Shuttle EVA system. This included preparing and using the Extravehicular Mobility Unit (EMU), the airlock and payload bay provisions, and demonstrating procedures, timelines and training. The EVA was scheduled for three-and-a-half hours and included a range of major tasks; specifically, evaluating communications, translation rates, Shuttle EVA tools, restraints and torque measurements at a work station. The latter involved working at a mock-up Main Electronic Box (which was to be replaced on the Solar Max satellite during STS-13, or 41-C), during which thermal blankets would be removed, fasteners mounted, connecters uncoupled, a ground strap severed and the connectors re-coupled (all demonstrations of manipulative tasks). They would also be operating the winch to simulate contingency modes for closing the payload bay doors and conducting translations down the payload bay door hinge line with a bag of EVA tools (with an approximate mass of 27 kg) to demonstrate techniques for moving mass across the payload bay.14
Lenoir's illness led to the EVA being delayed, to avoid the risk of the astronaut vomiting inside the helmet and potentially choking himself. The following day, after waking up to music from The Stroll, the two astronauts prepared their equipment and began their pre-breathing period. After troubleshooting some minor problems as the spacecraft came back into communications range of Houston, the first signs of a more serious problem were reported by the crew as they prepared the suits. The fan on Allen's suit developed a fault and, despite some troubleshooting efforts, refused to work correctly.
It soon became apparent that Allen's suit would not support an EVA so, while repair activities continued in an attempt to fix the problem, the crew suggested to Mission Control that a solo EVA demonstration should be undertaken to try to salvage something from the EVA objective. Joe Allen put forward his thoughts on the idea to the ground: "I would sure like to make a strong suggestion that ... Bill proceeds with this [solo EVA]. He is well trained and ought to go to it.'' Lenoir also tried to influence the decision himself: "In looking at our flight plan here for the EVA, I would suggest that ... we just do a bare bones [demonstration] to verify the
EVA, which in essence would be the aft translation and some of the little tasks. I would not be very inclined to want to put my foot into any foot restraints, being the only guy out there.''
Mission Control came back with an amended plan to have Lenoir to check out the EMU while remaining in the airlock. The crew, though disappointed, was not about to knock the idea - an "almost EVA'' was better than no EVA at all. For Lenoir, this would have been a frustrating activity, being so close to the exit but not being able to even put his head outside. However, the crew would conform to the rules from Mission Control and prepare for their experiment, the rationale being that their work would help later crews with their EVA preparations and post-EVA activities. But while Lenoir was beginning to pressurise his suit and the crew and ground were discussing the problem with Allen's suit, a new glitch surfaced. Lenoir was unable to raise the pressure in his suit from 3.8 psi to the required 4.3 psi. After receiving the "go" from Houston to reattempt the pressurisation, the same problem occurred. It was decided to perform a leak check and press on with the pre-breathing stage before Lenoir pressurised the suit and let it stabilise for three minutes. This was completed successfully, but still not at the mandatory 4.3 psi.
Mission Control broke the bad news to the crew that the EVA had to be terminated as Lenoir's suit was regulating too low to continue. However, they did request that Allen's suit (without the astronaut inside as it would have been too hot to wear comfortably) should be pressurised to see if its regulator operated
correctly. During the re-pressurisation of Allen's suit, further problems were encountered, with the regulator logging just 4.1 psi. It was expected that full pressurisation would take longer as there was no astronaut inside the suit, which meant that there was a greater internal volume to pressurise, but after installing a new LiHO canister the regulator recorded 4.3 psi, underlining the fact that the problem was in Lenoir's suit alone. There would be no EVA for the astronauts this time, but with most of their objectives accomplished, the crew observed that only a safe entry and landing remained. As Allen commented, "Out of these two [the EVA and a safe landing], if we had to make a choice, let's choose the safe landing.''15
In hindsight, Lenoir thought that - from an engineering standpoint - far more was learned from the failures and abandoning the EVA than by completing the task, as those failures would likely have occurred at some point in the future. It was far better to have experienced them when an EVA was not necessary than when it was essential. This perspective was not picked up by the media to the same degree, the failures highlighted as a setback rather than simply part of the learning curve in the development of the systems and procedures.
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