Thursday, April 26, 2012

Skylab 2 parasol sample from NASA MFA office

Here’s a tiny snippet of material used to solve a serious engineering problem in space. 

The Skylab 1 mission1 was the launch of America’s first space station. It was carried into orbit—without a crew—by a Saturn V rocket that the cancellation of the last few Apollo moon missions had left surplus. Skylab 2 was to launch one day later and carry the first astronauts to the station for a 28-day visit.

However, during the launch of the station on 14 May 1973, it became apparent that something had gone badly wrong. Engineers deduced that during launch, Skylab had lost its meteroid shield—the tube-like structure that encircled the main body of the station to protect it from debris and from the Sun’s heat. Without this protection, the temperature inside Skylab soon reached 38° C and was expected to go as high as 77° C.

The launch of Skylab 2 was postponed while equipment and procedures were developed to repair the station. A key feature of these repair efforts was a “parasol” that the astronauts could deploy through one of Skylab's airlocks and which would provide the station with protection from the Sun. The parasol fabric was orange nylon laminated to aluminized Mylar, manufactured for NASA by the G. T. Schjeldahl Company2 (today simply Sheldal) of Northfield, Minnesota.

The Skylab 2 crew launched on 25 May and successfully deployed the parasol the following day. Within a few days, the interior temperature stabilised at 26° C, making the station habitable and ensuring the safety of the supplies and experiments aboard.

To celebrate the success of the efforts, NASA’s Manned Flight Awareness Office issued laminated cards to employees that contained a small swatch of the parasol material (roughly 1 cm, or ½”, along each edge). The swatch was mounted on an image of Skylab taken by the Skylab 2 crew as they departed the station (NASA image 73-H-580), and clearly shows the parasol deployed. The card also bore the employee’s name (which I've blurred out here for their privacy), a message of congratulations, and facsimiles of the autographs of the nine Skylab astronauts.

The back of the card features another view of Skylab with the parasol in place (NASA image 73-H-578)—also taken by the departing Skylab 2 crew—overlaid with small portraits of all nine astronauts.

1 Skylab mission numbering is a little problematic. In this post, I’m following the scheme preferred by NASA headquarters—Skylab 1 was the launch of the station, followed by Skylab 2, 3, and 4, each of which took a crew of three astronauts up to it. Skylab Program management used a different scheme: they didn’t number the station launch, and used Skylab 1, 2, and 3 to refer to the three flights with a crew. Note that the front of this card uses this latter scheme.
2 Wikipedia informs me that company founder Gilmore T. Schjeldahl (1 June 1912 – 10 March 2002) ‘may be best known for inventing the plastic-lined airsickness bag’.

Copyright information: the Skylab photos, astronaut portraits, and card design and text are all works of NASA. As works of the US federal government, all are in the public domain.

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