Skylab, the Saturn V's final flight

Updated October 19, 2026 · 5 min read

Skylab, America's first space station, was launched on 14 May 1973 by the thirteenth and final Saturn V, SA-513, flying in a two-stage configuration. The station itself was a converted S-IVB third stage turned into a habitable workshop. Damaged during launch and repaired in orbit by its first crew, it hosted three crews for a total of 171 days before falling back to Earth in July 1979.

From rocket stage to space station

The idea dates from the mid-1960s: reuse an S-IVB, the smallest hydrogen stage in the Saturn family, as an orbital habitat. In the original "wet workshop" plan, a fueled S-IVB would have flown as the upper stage of a Saturn IB, after which astronauts would vent its tanks and fit out the interior in orbit. The cancellation of lunar missions from 1970 freed up Saturn Vs and changed everything: the station could be outfitted on the ground and launched ready to use. This was the "dry workshop."

Skylab's Orbital Workshop was built from an S-IVB originally meant for a Saturn IB. The large hydrogen tank became two-deck living quarters with crew sleep stations, a laboratory, a shower and a galley; the smaller oxygen tank served as a trash container. Attached were an airlock, a multiple docking adapter and the Apollo Telescope Mount, a solar observatory with its own windmill-shaped solar arrays.

The launch of 14 May 1973

SA-513 flew without a third stage: the station, under an aerodynamic shroud, took the place of the S-IVB and the Apollo spacecraft. The Saturn V performed normally, and the S-II, the last powered stage, reached orbit itself.

The trouble lay with the station. About one minute after liftoff, the micrometeoroid shield, which was also meant to shade the workshop from solar heating, was pulled open by airflow and torn away. It took one of the workshop's two large solar wings with it; the other stayed jammed by a strip of debris. In orbit, Skylab was short of power and its interior temperature climbed above 50 °C (120 °F).

The rescue in orbit

The first crew, scheduled to launch the next day, was held for ten days while NASA improvised repairs. Skylab 2 (Pete Conrad, Joseph Kerwin, Paul Weitz) launched on 25 May 1973 carrying a parasol sunshade, which they deployed from inside through a small scientific airlock. Temperatures fell to bearable levels. On 7 June, in a difficult spacewalk, Conrad and Kerwin cut the strap pinning the remaining solar wing and freed it, restoring most of the station's power.

Skylab 3 (Alan Bean, Owen Garriott, Jack Lousma) installed a second, more durable sunshade stretched between two poles in August 1973. These improvised fixes, with no precedent, laid the groundwork for the maintenance spacewalks later performed on the Hubble Space Telescope and the International Space Station.

Three crews, 171 days

The last crew came home on 8 February 1974. Skylab 4's 84 days remained the American spaceflight endurance record until 1995. The astronauts studied how the human body adapts to long-term weightlessness, photographed Earth, and took hundreds of thousands of images of the Sun with the Apollo Telescope Mount, including landmark observations of the corona and coronal mass ejections. The Skylab 4 crew also observed Comet Kohoutek.

The fall of Skylab

NASA planned to boost the station to a higher orbit using the Space Shuttle, expected to fly in the late 1970s. But the Shuttle slipped, and stronger-than-expected solar activity puffed up the upper atmosphere, increasing drag on Skylab. On 11 July 1979 the station reentered; debris fell into the Indian Ocean and across a sparsely populated area of Western Australia around Esperance, injuring no one. The local shire jokingly sent NASA a 400-dollar fine for littering.

What remains

A backup Orbital Workshop, built as a spare and never launched, is on display at the National Air and Space Museum in Washington, D.C., and is the best way to picture the inside of a converted S-IVB. The surviving Saturn Vs are covered on where to see a Saturn V. Skylab's launch closes the list of all 13 Saturn V launches; the Saturn family flew only once more, in 1975, for the Apollo-Soyuz mission.

Sources

• W. David Compton and Charles D. Benson, Living and Working in Space: A History of Skylab, NASA SP-4208, 1983.
• Roger E. Bilstein, Stages to Saturn, NASA SP-4206, 1980.
• National Air and Space Museum
• NASA History Office