Skylab is Falling!

Posted on Fri, July 11 2014

Thirty-five years ago, on July 11, 1979, the first US space station fell out of orbit. It wasn’t a surprise or an error, nor was it a calamity. It was more like an intense meteor shower—sparkling and momentary—as Skylab entered the atmosphere. Very little of this spacecraft as large as a house was ever found on the ground.

Skylab had a brief but distinguished history between the last Apollo missions and the beginning of the Space Shuttle era. NASA repurposed some remaining Saturn hardware into an “orbital workshop” where three men at a time could live and work. It was the first US foray into spaceflight lasting longer than two weeks.

Skylab Orbital Workshop in Orbit An overhead view of the Skylab Orbital Workshop in Earth orbit as photographed from the Skylab 4 Command and Service Modules (CSM) during the final fly-around by the CSM before returning home. Credit: NASA.

Three crews occupied Skylab in 1973-1974, staying 28, 59, and 84 days and setting US long-duration records that lasted until Americans stayed on the Russian space station Mir in the 1990s. They operated an attached solar observatory (the Apollo Telescope Mount), did Earth and astronomical observations, conducted microgravity and biomedical experiments, did EVA maintenance and repair tasks, and proved how productively they could work in space.

When the third crew left, NASA powered down Skylab and abandoned it, committing resources to the next big program, the Space Shuttle. Skylab drifted silently in a parking orbit for the next five years, circling about 269-283 miles (433-455 km) overhead. Expecting it to remain in orbit for about 10 years, NASA gave some thought to its possible eventual reuse.

However, Skylab’s orbit deteriorated more quickly as a more active than expected sunspot cycle affected the atmosphere and increased drag on the space station. By 1978, it was clear that Skylab was losing altitude and would fall out of orbit unless boosted higher. Had the Space Shuttle been ready to fly, it might have been used to reboost Skylab to prolong its existence, but with the first shuttle launch not expected until 1981, NASA had to work on a controlled descent instead.

Of course, the forecast for a huge falling spacecraft caused a great deal of concern and public interest. In 1978, a Soviet satellite crashed in Canada and spread radioactive debris, which raised awareness of potential hazards from above. Skylab had no radioactive materials onboard, but it was a massive 85-ton structure. The prospect of huge chunks of metal raining from the sky was scary.

Cover of The New York Times from July 11, 1979.

NASA calculated a descent trajectory for minimal risk to human life and property that would bring Skylab down over remote areas of the southern Pacific Ocean. Remotely operating the spacecraft’s onboard thrusters, ground controllers oriented Skylab properly to begin its descent.

Meanwhile, the media had stoked interest in the descent and a Chicken Little “the sky is falling” alarmism—both serious and humorous—arose. The Washington Post alone ran some 30 stories about Skylab’s demise from April through July 1979. People worried where the debris would land as Skylab disintegrated and burned during its high-speed passage through the atmosphere, and some joked about being doomsday targets or placed bets on its point of impact. The political and diplomatic consequences would not be trivial if death or destruction occurred.

As it happened, the calculated path of descent was a few degrees off. Some of Australia’s population heard the sonic booms and saw the bright streaks of Skylab debris, some of which fell in the vicinity of Esperance and the desert beyond. No one was hurt, no significant property damage occurred, and some pieces of recovered debris made their way back to NASA for analysis and on to museums. Others bits were doubtless kept as souvenirs of the night when a home in space fell to Earth.

*The backup Skylab orbital workshop has been on display in the Museum’s building on the National Mall since 1976. A few small fragments of charred Skylab debris are in the Museum’s collection.

Backup Skylab Orbital Workshop at the Museum in Washington, DC Backup model of Skylab's orbital workshop on display at the Museum in Washington, DC.

Valerie Neal is a curator in the National Air and Space Museum’s Space History Department.

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