Thursday, May 16, 2013

NASA Celebrates Skylab at 40, Looks to the Future

This sketch of Skylab was drawn by George E. Mueller, NASA associate administrator for Manned Space Flight. This concept drawing was created at a meeting at the Marshall Space Flight Center on Aug. 19, 1966. The image details the station's major elements. In 1970, the station became known as Skylab. Three crewed Skylab missions (Skylab 2 in May 1973; Skylab 3 in July 1973; and Skylab 4 in November 1973) were flown, on which experiments were conducted in space science, Earth resources, life sciences, space technology and student projects. 
Image Credit: NASA


























Launched aboard the last of the Apollo-era Saturn V rockets on May 14, 1973, the uncrewed 
Skylab became America's first space station. The station almost immediately developed technical problems due to vibrations during liftoff when a critical meteoroid shield ripped off, taking one of the craft's two primary solar panels with it. Engineers in mission control maneuvered Skylab's secondary solar panels to face the sun to provide as much electricity as possible. Because of the loss of the meteoroid shield, however, this positioning caused workshop temperatures to rise to 126 F. Meanwhile, in an intensive 10-day period, NASA engineers developed procedures and trained the crew to make the workshop habitable. At the same time, engineers "rolled" Skylab to lower the temperature of the workshop. 

On May 25, the first crewed mission, launched to rendezvous with the station, bringing with it the first crew to inhabit America's space station. And, after the crew made substantial repairs, including deployment of a parasol sunshade that cooled the inside temperatures to 75 F, the workshop was made fully operational by June 4. 


The first crew consisted of Commander Pete Conrad, who also commanded Gemini XI and Apollo 12, and piloted Gemini V; Pilot Paul Weitz, who later commanded the maiden voyage of space shuttle Challenger in 1983 and became deputy director of NASA's Johnson Space Center in Houston; and, scientist and naval flight surgeon Joe Kerwin. 

Skylab 1 commander Pete Conrad undergoes a dental examination by medical officer Joseph Kerwin 
Credit: NASA


In all, the three Skylab crews conducted 16 biomedical experiments, obtaining information on humans' adaptation to microgravity for the first time. Kerwin stated: "It was a continuous and pleasant surprise to me to find out how easy it was to live in zero g, and how good we felt."


Skylab's achievements are a summary of the accomplishments of many ground-based teams, as well as its three separate crews. By deploying the parasol-type sun shield through Skylab's solar scientific airlock and later releasing workshop solar array wing No. 1 during a spacewalk, the first crew made the remainder of the mission possible. During another spacewalk, the second crew deployed another sun shield.


Alan Bean commanded the second Skylab crew, which launched on July 28, with Jack Lousma as pilot and Owen Garriott as scientist. Bean was the lunar module command pilot for Apollo 12 and served as backup spacecraft commander of the U.S. flight crew for the joint American-Soviet Apollo-Soyuz Test Project. Lousma joined the astronaut corps in 1966 and later commanded space shuttle Columbia's STS-3 mission in 1982. Garriott later served as director of Science and Applications at Johnson. 


The third and final Skylab mission, which launched on Nov. 16, 1973, was commanded by Gerald Carr. William Pogue served as the mission's pilot and Edward Gibson as the resident scientist. The Skylab crew successfully completed 56 experiments, 26 science demonstrations, 15 subsystem-detailed objectives, and 13 student investigations during their 1,214 revolutions of the earth. They also acquired extensive Earth resources observation data using hand-held cameras and Skylab's Earth Resources Experiment Package camera and sensor array. The crew logged 338 hours of operations of the Apollo Telescope Mount, which made extensive observations of the sun's solar processes. 


The use of the unique environment and vantage point of space, represented a major step in human spaceflight, serving as a bridge between the Apollo flights and long-duration spaceflights aboard the International Space Station. The three Skylab crews who inhabited the station during its 8-month lifespan, not only set successive new records for long-duration spaceflight, but also conducted an array of physical science, biomedical science, Earth applications and space applications experiments. 


Skylab also was instrumental in providing high school students an opportunity to participate in a major national space project. Designed and administered by the National Science Teachers Association, the Skylab student project invited students in U.S. high schools to submit proposals for experiments that could be performed aboard the station. When the student project was conceived, it was expected that five or six experiments could be accommodated. As the concept developed, 25 students were able to participate in 19 experiments. 


The neutron experiment of student Terry Quist provoked enough interest in the scientific community to influence planning for a similar, but more sensitive, experiment on the Apollo-Soyuz Test Project in 1975. The interest in, and failure of, Roger Johnston's capillary studies also prompted planning for a similar experiment on the same joint Soviet-American spaceflight.

Owen Garriott performs a spacewalk during Skylab 2
Credit: NASA

Following the final crewed phase of the Skylab mission, ground controllers performed engineering tests of certain Skylab systems -- tests that ground personnel were reluctant to do while the crews 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, where it was expected to remain for eight to 10 years. It had been hoped that one of the early Space Shuttle missions could be used to reboost Skylab and save it for future use. However, in fall 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 made a partially controlled re-entry intended to scatter the debris across the Indian Ocean. Much of the station burned up during reentry, but not as quickly as expected. The debris dispersion area stretched from the southeastern Indian Ocean across a sparsely populated section of Western Australia.

This view of the Kennedy Space Center and the Florida Atlantic coast area was taken as part of the Skylab 3 Earth Resources Experiments
Credit: NASA

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