The Skylab space station was launched May 14, 1973, from the NASA Kennedy Space Center by a huge Saturn V launch vehicle, the Moon rocket of the Apollo Space Program. Sixty-three seconds after lift-off the meteoroid shield-designed also to shade Skylab's workshop-deployed inadvertently. It was torn from the space station by atmospheric drag. This event and its effects started a ten-day period in which Skylab was beset with problems that had to be conquered before the space station would be safe and habitable for the three manned periods of its planned eight-month mission.
When the meteoroid shield ripped loose it disturbed the mounting of workshop solar array 'wing' two and caused it to partially deploy. The exhaust plume of the second stage retro-rockets impacted the partially deployed solar array and literally blew it into space. Also, a strap of debris from the meteoroid shield overlapped solar array 'wing' number one such that when the programmed deployment signal occurred, wing number one was held in a slightly opened position where it was able to generate virtually no power. In the meantime, the space station had achieved a near-circular orbit at the desired altitude of 435 kilometers.
All other major functions including payload shroud jettison, deployment of the Apollo Telescope Mount ( Skylab's solar observatory) and its solar arrays, and pressurization of the space station occurred as planned. Scientists, engineers, astronauts and management personnel at the NASA Marshall Space Flight Center and elsewhere worked throughout the first ten-day period of Skylab's flight to devise the means for its rescue. Simultaneously, Skylab-seriously overheating-was maneuvered through varying nose-up attitudes that would best maintain an acceptable 'holding' condition. During that ten-day period and for some time thereafter, the space station operated on less than half of its designed electrical system which, in the partially nose-up attitudes, was generating power at reduced efficiency. The optimum condition that maintained the most favorable balance between Skylab temperatures and its power generation capability occurred at approximately 50 degrees nose-up.
Skylab's achievements are a summary of the accomplishments of many groundbased persons as well as its three separate crew-e who were launched in Apollo-type command modules by Saturn IB vehicles on May 25, July 28 and November 16, 1973. In Skylab, both the man-hours in space and the man-hours spent in performance of extravehicular activities (EVA) under zero-gravity conditions exceeded the combined totals of all the world's previous space flights.
By deploying the parasol-type sun shield through Skylab's solar scientific airlock and later releasing workshop solar array wing number one during EVA, the first crew made the remainder of the mission possible. The second crew, also during EVA, erected another sun shield, a twin-pole device.
The effectiveness of Skylab crews exceeded expectations, especially in their ability to perform complex repair tasks. They demonstrated excellent mobility, both internal and external to the space station, showing man to be a positive asset in conducting research from space. By selecting and photographing targets of opportunity on the Sun, and by evaluating weather conditions on Earth and recommending Earth Resources opportunities, crewmen were instrumental in attaining extremely high quality solar and Earth oriented data.
All three crews demonstrated their technical skills for scientific, operational and maintenance functions. Their manual control of the space station, their fine pointing of experiments and their reasoning and judgments throughout the manned periods were highly effective.
The capability to conduct longer manned missions was conclusively demonstrated in Skylab, first by the crew returning from the 28 day mission and, more forcefully, by the good health and physical condition of the second and third Skylab crews, who stayed in weightless space for 59 and 84 days respectively. Also, resupply of space vehicles was attempted for the first time in Skylab and was proven to be effective.
During their time in space all three crews exceeded the operational and experimental requirements placed upon them by the pre-mission flight plan and schedule. In addition, the third crew performed a number of sightings of Comet Kohoutek which were not initially scheduled.
Prior to departure, the third crew gathered samples of hardware, food and other general items which they placed in a bag and left in the Multiple Docking Adapter. In the event of a Skylab revisit, the bag will be retrieved to determine the effects on the samples of long term storage in the space environment.
Following the final manned phase of the Skylab mission, ground controllers performed some engineering tests of certain Skylab systems-tests that ground personnel were reluctant to do while men were aboard. Results from these tests will help to determine causes of failures during the mission and to obtain data on long term degradation of space systems. Upon completion of the engineering tests, Skylab was positioned into a stable attitude and systems were shut down. It is expected that Skylab will remain in orbit about eight years before entering the atmosphere and burning up.