<p>Skylab space station and unfurled solar wing panel on display in the Smithsonian Air and Space Museum in Washington, D.C.  This is an engineering back-up of the space station, which was never used.
</p><p>Skylab was a space station launched and operated by NASA. It consisted of the second stage of a Saturn IV-B rocket.  Inside this stage was a second compartment, which formed a two-story area for work.  The lower level contained the "Saturn workshop," while the upper area was a wardroom where eating, sleeping, physical exercise, and recreation could occur.  Two huge solar panel arrays provided power to the station.  A multi-section docking ring was attached to the station's nose, which allowed a traditional Command and Service Module unit to dock.  Above the docking ring was the Apollo Telescope, a solar observatory.
</p><p>Disaster struck on launch day.  Just 63 seconds into the flight, the micrometeoroid shield around Skylab ripped free from the space station.  Just three seconds earlier, the rocket had passed Mach 1, and was passing through the "Max Q" -- the period of maximum atmospheric dynamic stress on the spacecraft.
</p><p>Rivets that didn't quite fit and seals which had not been totally completed allowed air to flow behind the shield at hypersonic speed.  This caused the shield to partially deploy -- moving a few inches outward from the space station.
</p><p>The shield ripped almost completely free from the space station, unpeeling like the skin of a fruit.  As the shield ripped away, it caused one of the solar panels to partially deploy -- and it ripped almost completely free of the space station.
</p><p>When the second stage separated from the space station at 9 minutes, 52 seconds into the flight, it fired retrorockets that allowed Skylab to move forward and away.  These retrorockets, however, caused the damaged solar panel to rip completely free from Skylab.
</p><p>At about 21 minutes into the flight, the Apollo Telescope Mount successfully deployed.  At 26 minutes into the flight, the solar panels were supposed to deploy.  But the micrometeoroid shield was wrapped around the only remaining solar panel arm, and the deployment pyrotechnics shorted out trying to move too much weight.
</p><p>The micrometeoroid shield was designed to also function as a thermal shield.  With this thermal shield gone, temperatures inside Skylab shot up to 225 degrees F.  This weakened the skin of the space station, and NASA engineers refused to pressurize the station for fear that it would simply implode in orbit.
</p><p>The first manned mission to Skylab, known as Skylab-2, was due to launch for the space station on May 5, but this was pushed back to May 20 in order to give NASA time to figure out what to do.
</p><p>NASA engineers devised an umbrella-like device.  This could be thrust out of the scientified airlock (an 8 inch by 8 inch opening designed to allow scientific instruments to be exposed to space but manipulated from inside the space station).  By inserting a pole into the interior of the device, the "parasol" extended a 22 foot by 24 foot canopy made of gold nylon backed by metallized mylar.  The astronauts had tried to free the trapped solar panel before docking, but failed.  Three days later, after Skylab's batteries began to fail, another attempt was made -- this time via spacewalk.  It nearly failed, but at the last moment the panel sprang free and fulled extended.  (Skylab-3 would later deploy another parasol -- this one extended via two long arms -- on top of the first to help cool the station even further.)
</p><p>Skylab astronauts flew to the space station using the same command and service modules first developed for the lunar landings.  The service modules were used to carry all the supplies the astronauts would need.  At the end of the mission, the capsule (command module) would detach from the service module.  The serivce module would burn up on re-entry, while the command module would splash down and return everyone to Earth safely.
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Only three manned missions were made to Skylab.  The final mission ended in February 1974.  Heating of the earth's atmosphere causes it to expand.  This put added drag on Skylab.  Without being boosted into a higher orbit, it would eventually crash back to earth.  Although plans were made to do so, they did not get done in time.  Skylab re-entered the earth's atmosphere over the Indian Ocean and Australia on July 11, 1979.  Many pieces of the space station made it to the ground, some of them quite large!
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/23165290@N00">Tim Evanson</a> from Cleveland Heights, Ohio, USA
CC BY-SA 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/timevanson/7275762722/">Skylab with unfurled solar panel - Smithsonian Air and Space Museum - 2012-05-15</a>