Wednesday, May 27, 2009

Pete Conrad and crew to the rescue!

Skylab, America's first space station, was launched on May 14, 1973. It rode the last Saturn V in NASA's inventory, one which was originally intended for a canceled Moon landing. Less than a minute after launch, as the vehicle broke through the sound barrier and the zone of maximum dynamic pressure, the meteoroid shielding on the lab tore off, taking with it one of the station's two primary solar panels and jamming the other one.

As soon as Skylab reached orbit, controllers knew that something was seriously wrong. Temperatures inside the lab began to rise far outside normal ranges, eventually getting as high as 140 degrees F. There was also no power to the lab other than what was coming via the solar panels on the Apollo Telescope Mount.

I watched the launch on TV and I remember clearly the "oh no" reaction when we heard that Skylab might never be occupied because of the power and temperature problems. Pete Conrad, Commander of the first Skylab mission, and his crew of Paul Weitz and Joe Kerwin, were to have launched the next day. Their launch was scrubbed while NASA determined how to repair the station. Timing was of the essence - if NASA waited too long, the intense heat inside the lab would eventually melt the plastic and render the station uninhabitable.

In what had to be the most intensive spacecraft rescue mission ever undertaken, in less than 10 days NASA designed and built -- and trained the crew to use -- a "parasol" that could be deployed via a small airlock on the side of the station and which would bring the station's temperature back to livable levels. NASA also loaded the Apollo spacecraft with several tools that the crew could use to try to free the stuck solar panel.

The daring tactics of Conrad and crew are almost unthinkable in today's environment. Before docking with the station, Conrad maneuvered the CM close to the stuck solar panel so that Weitz, standing in the CM's open hatch, could try to cut loose the debris that held down the panel. When that didn't work, Conrad then tried to dock with Skylab. The docking mechanism refused to latch on several docking attempts. Conrad backed away and then tried again several times. Maneuvering fuel was running low, and Conrad was given one final chance to try to dock. This time he was told to continue pushing forward for 10 seconds with the CM after the probe had entered the drogue, in hopes that the pressure would cause the latches to fire. This final attempt worked; otherwise, the mission - and Skylab - would have been abandoned. Listening to this on the TV was sheer knuckle-biting tension!

Conrad and crew deployed the parasol successfully, which eventually brought the temperature inside the station down into the mid-80's. Prior to that, the crew were only able to enter the lab for a few minutes at a time without risking dehydration and heat prostration.

Finally, on June 7, 1973, Conrad and Kerwin undertook one of the most dangerous spacewalks ever attempted, to free the stuck solar panel. They worked in an area outside the station that was never meant to be serviced by astronauts, so it had no handholds or railings. They used tethers and their adapted limb pruning tool to get close to the stuck solar panel and eventually snip the metal debris that was holding it in place.

Because of the determination and skill of Conrad and his crew, the Skylab program was a complete success. The lab was occupied by three crews on and off over the next year, and America gained substantial experience in living for extended periods in space.

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