Skylab

• 1. Introduction

  ›

  Skylab, America's first space station, was not built from scratch. It was built from a leftover rocket stage, a repurposed piece of a Saturn V that once existed to hurl men toward the Moon. When that enormous machine was no longer needed for lunar missions, engineers hollowed out its upper section and turned it into a place where human beings could live in orbit for months at a time. The pressurized volume inside exceeded 350 cubic meters, a figure that would not be matched by any space station until Mir was completed in 1996. Three crews would call it home between May 1973 and February 1974, conducting hundreds of experiments and repeatedly extending the record for human time spent in space. But Skylab's story begins well before any of that, with a rocket engineer's dream of a wheel spinning in the void, and it ends with debris raining down on Western Australia and an Australian shire issuing NASA a fine for littering.

• 2. Von Braun's Wheel and the Shrinking Dream

  ›

  Wernher von Braun laid out his vision in Collier's magazine between 1952 and 1954, in a series of articles titled "Man Will Conquer Space Soon!". His station was a circle 250 feet across, rotating to produce artificial gravity, requiring a fleet of 7,000 space shuttles just to haul its components into orbit. The 80 crew members would include astronomers, meteorologists, and soldiers conducting surveillance. Moon and Mars expeditions would depart from it. The transistor, the solar cell, and telemetry changed the calculation. Uncrewed satellites could photograph weather and enemy missiles and send the pictures home without any astronaut leaning out a window. A massive rotating city in orbit lost its justification. What survived was a smaller proposition: a single rocket could carry a station useful for science, even if it could carry nothing more ambitious.

  Von Braun returned to the idea in 1959, when he was head of the Development Operations Division at the Army Ballistic Missile Agency. Submitting his final Project Horizon plans to the U.S. Army, he included a note about an orbiting laboratory built from a Horizon upper stage. That sketch of an idea, almost an afterthought in a document about Moon missions, became the conceptual seed of Skylab. By 1962, the Douglas Aircraft Company had formally documented a proposal to use the Saturn S-IVB stage as a crewed space laboratory. The ambition had compressed from a 250-foot spinning wheel to a salvaged fuel tank, but the destination was the same.

• 3. Wet Workshop, Dry Workshop

  ›

  In November 1964, von Braun proposed converting the S-II second stage of a Saturn V into a station, a design that would have produced a living area 33 by 45 feet. The problem was that it required a dedicated Saturn V launch at a time when no one knew how many of those rockets would be needed to get men to the Moon. The fallback became a "wet workshop": a smaller station built inside an S-IVB third stage, which would be launched as the second stage of a Saturn IB, its fuel tank vented in orbit and then fitted out by astronauts. Astronauts raised safety concerns in May 1966 about purging a hydrogen tank in space, but the plan moved forward anyway.

  Everything changed when Apollo 8 succeeded in December 1968 and when NASA subsequently cancelled Apollo missions 18, 19, and 20. Canceling three Moon missions freed three Saturn V rockets. With that extra power available, engineers no longer needed to launch a station that would be assembled in orbit from a live fuel tank. The S-IC and S-II lower stages of a Saturn V could send up a station whose interior was already prepared on the ground. The wet workshop became a dry workshop. NASA sought US$450 million for the Apollo Applications Program in fiscal year 1967 but received only US$42 million. That constraint had shaped every compromise. The cancellation of lunar missions paradoxically gave the program the rocket it needed to build something larger.

• 4. Building a Place to Live

  ›

  Industrial design firm Raymond Loewy/William Snaith pushed NASA on a question that had never mattered for a one-week Moon mission: what is it like to actually live up there? They recommended a wardroom for meals, a window for watching Earth, and attention to color schemes. Astronauts were skeptical about the color discussions, but they agreed that books and individual music choices mattered. Early Apollo crews had complained bitterly about food that came in cubes and squeeze tubes; a NASA volunteer found the Apollo diet intolerable after just four days on Earth. Skylab food was designed around palatability instead.

  Each astronaut got a private sleeping area the size of a small walk-in closet, with a curtain, a sleeping bag, and a locker. There was a shower, designed for about 6 pints of water per use, with a cylindrical curtain running floor to ceiling and a vacuum system to capture stray droplets before they could float into electronics. The first astronaut to use it was Paul J. Weitz on Skylab 2. He reported that it took longer than expected but that you "come out smelling good". A full shower took about two and a half hours including setup and cleanup. The station also had a toilet, whose waste samples were considered so scientifically valuable that they would have been priorities in any rescue mission. To store all the trash and wastewater, engineers repurposed the S-IVB's 73,280-liter liquid oxygen tank below the Orbital Workshop, accessed through an airlock.

• 5. Launch Damage and Rescue

  ›

  Skylab launched on the 14th of May 1973, carried aloft by Saturn V serial number SA-513, the rocket originally built for Apollo 18. Sixty-three seconds after liftoff, the micrometeoroid shield tore away from the workshop. It took one of the two main solar panel arrays with it and jammed the other, leaving the station with a severe power deficit and no protection from solar heating. Temperatures inside rose to dangerous levels. NASA had assembled a rescue Apollo CSM and Saturn IB for standby use, but the immediate problem was not crew rescue; it was saving the station itself.

  Jack Kinzler, who would receive the NASA Distinguished Service Medal for the solution, designed a parasol-like sunshade that the first crew could deploy from inside through a small instrument port. On the 25th of May 1973, the Skylab 2 crew launched, moved into orbit, and got to work. They pushed the sunshade through the port and temperatures dropped to acceptable levels. During two subsequent spacewalks they freed the jammed solar panel. It was the first repair of that magnitude ever performed in space. One item was reportedly fixed by hitting it with a hammer. Skylab 3 launched on the 28th of July 1973 and Skylab 4 on the 16th of November 1973, with missions lasting 59 and 84 days respectively. All three missions successively broke the human endurance record in space, which had previously stood at 23 days, set by the Soviet Soyuz 11 crew aboard Salyut 1.

• 6. Science in Orbit

  ›

  About 80 named experiments were conducted aboard Skylab, though they are also described in some accounts as "almost 300 separate investigations". Astronauts logged about 2,000 hours of scientific and medical work, photographed the Sun 127,000 times, and captured 46,000 images of Earth. The Apollo Telescope Mount yielded photographs of eight solar flares, and scientists stated the resulting data would have been impossible to obtain with uncrewed spacecraft. One consequence was the confirmed existence of the Sun's coronal holes. Riccardo Giacconi's study of X-ray emissions from the Sun aboard Skylab contributed to his receiving the 2002 Nobel Prize in Physics.

  Student research accounted for 19 separate proposals, and several were praised by the crew, including a dexterity experiment and a test of whether spiders could spin webs in low gravity. Skylab 4 observed Comet Kohoutek. Ten spacewalks totaling 42 hours and 16 minutes were performed across all three missions. The Earth Resources Experiment Package gathered data in visible, infrared, and microwave bands. Protecting all the film from radiation required five separate vaults: four smaller ones in the Multiple Docking Adapter and a single large vault in the Orbital Workshop weighing 2,398 pounds empty. The heaviest film canisters weighed 40 kilograms and could hold up to 16,000 frames of film. Retrieving them required crewed spacewalks to the instruments during each mission.

• 7. Falling and the Fall

  ›

  British mathematician Desmond King-Hele of the Royal Aircraft Establishment predicted in 1973 that Skylab would fall to Earth by 1979, ahead of NASA's own estimates, because solar activity was heating the upper atmosphere and increasing drag on the station. By late 1977, NORAD had reached the same conclusion. A National Oceanic and Atmospheric Administration scientist criticized NASA publicly for using an inaccurate atmospheric model during what was shaping up to be the second most intense sunspot cycle in a century.

  Plans to boost Skylab using the Space Shuttle collapsed when it became clear the shuttle's first flight, STS-1, would not happen until April 1981, far too late. A Teleoperator Retrieval System, the robotic booster that Martin Marietta had built for US$26 million, was nearly complete, but NASA abandoned reboost plans in December 1978. Batelle Memorial Institute had estimated that up to 25 tons of debris could land in 500 pieces over an area 4,000 miles long and 1,000 miles wide. The lead-lined film vault, for example, was expected to hit the ground intact at 400 feet per second. In the Philippines, the concern was severe enough that President Ferdinand Marcos appeared on national television to reassure the public. The San Francisco Examiner offered US$10,000 for the first piece of Skylab delivered to its offices; the rival San Francisco Chronicle countered with US$200,000 if a subscriber suffered personal or property damage.

  Reentry began at approximately 16:37 UTC on the 11th of July 1979. Ground controllers had aimed for a point 810 miles south-southeast of Cape Town, South Africa, but a four-percent calculation error sent debris about 300 miles east of Perth. Pieces landed between Esperance and Rawlinna, roughly 130-150 kilometers around Balladonia. The station had broken apart about 10 miles above Earth, lower than expected. Stan Thornton found 24 pieces at his home in Esperance, flew to San Francisco after obtaining his first passport, waited a week for Marshall Space Flight Center to authenticate the wreckage, and collected the Examiner prize. The Shire of Esperance fined NASA A$400 for littering. The fine was paid on behalf of NASA in April 2009, after Scott Barley of Highway Radio raised the money from his morning show listeners.