Spacewalk Cancelled

None of it happened; at least, not on STS-5. In fact, no astronaut would leave Columbia's airlock for a spacewalk until STS-87 in November 1997! The excursion was postponed by 24 hours until 15 November - the day before the Shuttle was due to return home - when both Lenoir and Overmyer suffered a particularly severe dose of space sickness. More trouble was afoot, however, when they tried again. When the men finally donned their suits and ran through the pre-spacewalk checks, a problem was noted with Allen's ventilation fan: it sounded, said the crew, ''like a motorboat''.

In effect, the fan was starting up, running unexpectedly slowly, surging, struggling and finally shutting itself down. Nor was Allen's suit the only one causing headaches. The primary oxygen regulator in Lenoir's suit - which would have been used during his 'pre-breathing' exercises and throughout the spacewalk itself - failed to produce enough pressure; regulating to 3.8 psi instead of the required 4.3 psi. Some of the astronauts' helmet-mounted floodlights also refused to work properly. After several fruitless attempts to troubleshoot the problems, the spacewalk was cancelled and deferred to STS-6.

This proved disappointing to Columbia's crew, particularly Lenoir. According to Brand: ''I guess I was the bad guy. As much as I hated to, I recommended to the ground that we [cancel] the EVA, because we had a unit in each spacesuit fail in the same way. It was a little pump [and] one of its [functions] was to be a cooling pump. So it looked like we had a generic failure there. It was the first time out of the ship. We didn't want to get two guys or even one guy outside and then have [another failure]. We could have taken a chance and could have done it, but we didn't. I'm not sure Bill Lenoir was ever very happy about that, because he and Joe, of course, wanted to go out and have that first EVA.''

Fortunately for Joe Allen, he would perform not one, but two spacewalks on a later satellite-rescue mission, but Lenoir would not fly again and would depart the astronaut corps for a NASA management job in 1984.

Immediately after Columbia's landing on 16 November, a task force, headed by Richard Colonna, was set up by NASA to investigate the problems. The fault in Lenoir's suit was traced to two missing 'locking' devices - each the size of a grain of rice - in the primary oxygen regulator. According to paperwork provided by the suit's manufacturer, Hamilton Standard of Hartford, Connecticut, the devices were fitted in August 1982, but actually had not been fitted at all and were not checked. Their absence allowed the pressure in Lenoir's suit to drop back half a pound from 4.3 to 3.8 psi.

The problem in Allen's suit, on the other hand, was a faulty magnetic sensor in the fan electronics. Colonna's report, released in December 1982, pointed out that ''even with no improvements, if the regulator were fabricated properly, the PLSS [Portable Life Support System - the suit's backpack] would function properly''. It also listed ways to test and inspect regulators and motors and recommended testing inside the Shuttle's airlock on the day before launch. Additional plans were set out, though not in time for STS-6, to provide sensors with better moisture-resistant coatings for future motors and new tests to pick up defects.

0 0

Post a comment