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.

Thursday, April 19, 2012

Skylab 1 press release from Martin Marietta

This week I wanted to post something from Skylab 1 — the mission that launched the space station itself.

This March 1973 press release from the Martin Marietta corporation (today, part of Lockheed Martin) shows the station’s multiple docking adapter (MDA) nearing completion. This component provided two ports at which an Apollo spacecraft could dock. Generally, the capsule would use the port located along the axis of the station—visible at the top of this image—and transfer crew and supplies. It would then remain docked there to provide the crew with a vehicle for their return to earth at the end of the mission. The second port, projecting out from the side of the module, provided a place to dock a rescue craft if necessary (thankfully, it never was).

The MDA was 5.1 metres (17 ft) long, 3 metres (10 ft) in diameter, and weighed 6,210 kg (13,800 lb). The press release also points out that it contained 7,000 electrical connections and 6 miles (9.6 km) of wiring!

Massive though it was, the MDA was a relatively small piece of Skylab, and an even tinier part of the launch vehicle that carried the station to orbit. It’s the third item from the top of the stack in this diagram released by NASA’s Marshall Space Flight Center in connection with the launch:

Note that in addition to building the MDA, Martin Marietta  was responsible for the overall integration of the station components produced by other contractors.

Image copyrights:  Although issued by Martin Marietta, I believe the photo in the press release is actually a cropped version of a NASA image (72-H-1393). As a work of the US federal government, that would place it in the public domain. The diagram of the launch vehicle is from a NASA publication and therefore also in the public domain.

Thursday, April 12, 2012

Skylab program brochure from McDonnell Douglas

Today I’m sharing a brochure from 1972 put out by McDonnell Douglas about Skylab— America’s first space station. The company (today, absorbed into Boeing) was one of the major contractors for its construction.

It’s a lovely piece, printed on glossy, thick stock, 30 cm × 22.5 cm, and it shows up every smudge and bit of dirt on my scanner.

Skylab is perhaps best remembered today for its uncontrolled re-entry over Western Australia in 1979. In retrospect, this makes the timeline on page 7 look incredibly short-sighted: a 110-ton space station in orbit with no evidence of any plan for its future further than eight months.

Copyright information: There’s no copyright notice on the brochure, so as a work first published in the United States before 1989 without any such notice, it seems to be in the public domain.