Wet workshop

Did You Know?

• NASA contractor Brand Griffin proposed building a station from a spent Space Launch System hydrogen fuel tank at Earth-Moon L2, named Skylab II.
• NanoRacks is developing its concept Independence-1 (formerly Ixion) to turn spent rocket tanks into habitable living areas.

Apollo-derived concepts

Wernher von Braun proposed a wet workshop concept for launch on the Saturn V, modifying the S-II second stage to serve as living space once in orbit. Because the S-IC lower stage cannot reach orbit alone, the S-II would fire and then vent remaining propellant after reaching orbit. The station floors were designed as an open grid to allow propellant to pass through to piping at the tank bottom, and the structure provided convenient hand and footholds. Since all propellant was needed to reach orbit, life support equipment could not be stored inside the S-II during launch; instead, von Braun placed this equipment in a large cylindrical carrier mounted atop the S-II in place of the S-IVB. After reaching orbit and venting, a large access hatch in the top of the S-II's hydrogen tank would open, and the cargo module would be inserted hydraulically into the tank, sealed, and the tank repressurized to form a large living space. Solar cells lining the outside of the S-II would provide power. During the 1960s, as Apollo transitioned from development to launch, groups within NASA studied post-Apollo uses of Saturn hardware under the Apollo Applications Program. Saturn V production lines were planned to shut down after producing enough for Moon missions, but on-orbit testing of Apollo systems proceeded better than expected, freeing a small number of Saturn IB launchers for use.

Shuttle-derived concepts

Several conversions of the Space Shuttle's external tank (ET) were studied. During launch the ET reached about 98% of orbital speed before being dropped and deliberately spun to increase drag. Some proposals suggested keeping the ET attached to the Shuttle into orbit, bleeding off remaining propellant through the Space Shuttle Main Engines left open; one such test was scheduled but canceled after the 1986 Challenger disaster changed safety rules. The ET would have provided a huge working space—its oxygen tank alone was much larger than the entire Space Station Freedom—but access through inspection manholes raised questions about inserting realistic amounts of building materials. A related concept, the Aft Cargo Carrier, studied by Martin Marietta in 1984, consisted of a large cylindrical cargo container bolted to the bottom of the ET, offering the same volume as the orbiter's cargo bay for wider loads, and was also used as a basis for a short-duration station design.