What Is the Skylab Space Station? Learn About Skylab’s Operational History and Skylab’s Impact on Space Exploration

Skylab was the first (and, as of 2019, only) space station built and operated exclusively by NASA. Launched in 1973, it was occupied for approximately eight months, during which time it completed nearly a hundred experiments across a number of fields.

The Soviets built the first space station, Salyut 1, in the early 1970s, and launched steadily improved versions of it through Salyut 7 in 1982. Skylab was in orbit from 1973–79. It was built using the heavy lift capabilities of the Saturn V rocket.

The origins of Skylab go back to the beginnings of the U.S. space program. Aerospace Engineer Wernher von Braun and science-fiction novelist Arthur C. Clarke both advocated for crewed space stations as early as the 1950s.

• Various plans for a manned space station were developed throughout the 1960s, ranging from large, rotating stations crewed by 24 astronauts to small, two-man canisters. During this period, however, NASA and the public were more focused on moon-based missions, and the development of a habitable space station was put on the back burner until the end of the decade, when NASA developed the Apollo Applications Program to find ways to use hardware that had been developed for the moon landing.
• Getting a large, habitable station into space was a major logistical challenge. Early proposals for what was then known as the Orbital Workshop called for re-using sections of the Saturn V rockets that would carry the station into orbit. In these proposals, the crew would live and work in a reconfigured fuel tank. As more powerful rockets became available, this design was shelved in favor of a pre-assembled “dry workshop” that would be ready as soon as it reached orbit.
• The aerospace firm McDonnell Douglas began work on the station, renamed Skylab, in early 1970. The station itself was launched aboard a modified Saturn V in May of 1973.

Skylab consisted of five distinct modules.

1. 1. The Orbital Workshop was the largest segment, and comprised the main living and working areas of the space station. It contained the crew’s sleeping cabins, shower, galley, and wardroom, as well as many of the station’s life science experiments.
2. 2. The Airlock Module allowed crew to conduct spacewalks.
3. 3. The Apollo Telescope Mount consisted of a number of telescopes and solar arrays.
4. 4. The Multiple Docking Adapter enabled a second spacecraft to dock with the station (say in the event of an emergency rescue) and also contained additional experiments.
5. 5. Whenever the station was inhabited, the crew’s Apollo Command and Service Module remained docked.

During its lifetime, Skylab was crewed three separate times, beginning in May 1973 with Skylab 2 and lasting until the crew of Skylab 4 departed in February 1974. The Skylab program was marked by challenges and a number of successes.

• During the initial launch of the station, a piece of the station’s micrometeoroid shield was ripped off and damaged one of the station’s main solar arrays. The loss of the solar array deprived the station of a major source of power, and the loss of the micrometeoroid shield (which was also meant to act as a thermal blanket) exposed the station to extraordinary levels of heat.
• The initial crew launch (Skylab 2) was delayed as NASA scrambled to find a way to save the station. Rather than conducting scientific experiments, the crew of Skylab 2 was dispatched to make the station habitable. Under strenuous conditions, they managed to deploy the remaining solar array and a solar shade to replace the micrometeoroid shield.
• The crew of Skylab 3 experienced much more success. During their stay, they completed their assigned experiments ahead of schedule and requested additional assignments. Experiments included physiological experiments to study the long-term effects of microgravity on humans, a number of solar observations, as well as experiments related to earth and materials science.
• Skylab’s third crew, Skylab 4, remained in space a record 84 days. During this time, they conducted a number of experiments but also experienced a number of difficulties related to the workload mission control had assigned them. Despite these challenges, the crew of Skylab 4 completed all of their assignments and made a number of important solar observations.

After the return of SL-4, a fourth crewed mission was cancelled, leaving Skylab’s future in limbo. NASA estimated that the station would remain in orbit until the early 1980s, by which time it was thought that a shuttle-based crew could boost the station into a higher orbit and prolong its operational life. However, delays in the space shuttle program meant that this plan was never carried out.

More importantly, NASA scientists based their initial projections of Skylab’s orbital decay on an inaccurate model of solar activity. When solar activity increased, Earth’s atmosphere heated, increasing the drag on Skylab. By late 1977, it became clear that Skylab would re-enter the atmosphere sometime in 1979. What would happen to the approximately 25 tons of debris expected to survive re-entry became a major logistical and even diplomatic problem.

Despite fears that the station’s debris could strike a major population center, NASA’s ground control managed to direct the station toward the south Indian Ocean, though much of the debris still wound up striking parts of Western Australia.

Though Skylab may have something of a mixed history, it still represents an important step in the history of space exploration. The experiences of the Skylab crews led to the development of new protocols to manage crew psychology on long-term space missions, as well as new exercise regimens to deal with some of the physiological problems experienced by crews in microgravity. Skylab 2 also demonstrated the feasibility of conducting large-scale repairs in orbit.

Learn more about space exploration in Chris Hadfield’s MasterClass.