In the 1960's NASA investigated ways to gain further spaceflight experience after the Apollo Lunar missions. Some plans involved launching a space station, or orbital workshop as it became known, on two-stage, Saturn IB rockets.
The hydrogen tank of the Saturn S-IVB stage offered ample room for setting up an orbital workshop. Early plans involved what would be known as the "wet" workshop. Launched full of liquid oxygen and liquid hydrogen, the S-IVB would function normally as the rockets second stage during ascent. Most of the fuel would be consumed as the J-2 engine propelled the stage into orbit. Once safely in orbit, remaining fuel and oxidizer could be vented into space, allowing the hydrogen tank to later be pressurized with a breathable atmosphere and occupied by astronauts. Special fittings would be attached to the walls allowing equipment and experiments to be mounted when astronauts arrived. Floors and walls, formed by an aluminum grid structure, with ample openings so as not to interfere with fuel flow, could be pre-installed in the tank.
On top of the S-IVB stage would be a Multiple Docking Adaptor, or MDA. The MDA would have up to five docking ports for Apollo spacecraft or expansion modules. The MDA would contain many pieces of equipment that would be installed within the vented hydrogen tank when astronauts arrived.
Read Full Article »