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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, 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
ground-based persons as well as its three separate crews 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 micro-gravity conditions exceeded the combined
totals of all of the world's previous space flights up to that time.
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 technical skills for scientific,
operational, and maintenance functions. Their manual control of the space station, their fine pointing of experiments, and their reasoning
and judgment 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.
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 helped 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 was expected that Skylab would remain in orbit eight to ten years. However, in the fall
of 1977, it was determined that Skylab was no longer in a stable attitude as a result of greater than predicted solar activity.
On July 11, 1979, Skylab impacted the Earth surface. The debris dispersion area stretched from the Southeastern Indian Ocean across a
sparsely populated section of Western Australia.
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