Neutral Buoyancy Simulator - Origins and First Tank

Origins and First Tank

See also: Neutral buoyancy simulation as a training aid

NASA has flown zero-g flights on various aircraft for many years. In 1959, Project Mercury astronauts trained in a C-131 Samaritan aircraft, which was dubbed the "Vomit Comet". Airplane weightlessness is limited to 25 seconds at a time, which hampers efforts to practice EVAs which might last hours.

Prior to May 1960, NASA recognized the possibility of underwater neutral buoyancy simulations and began testing its efficacy. NASA engaged Environmental Research Associates of Baltimore to try neutral buoyancy simulations first in a pool near Langley Research Center. Visitors and other issues disturbed those efforts, and they moved the operation to McDonogh School where Scott Carpenter was the first astronaut to participate suited. Then, after difficult EVAs through Gemini 11 in mid-September 1966, the Manned Spacecraft Center fully understood the importance of testing procedures underwater and sent the Gemini 12 crew to train at McDonogh.

Meanwhile, MSFC was looking ahead to the Apollo Applications Program which would involve EVAs to convert a mostly-empty S-IVB rocket stage into a space station, and the people designing the hardware needed a thorough understanding of the challenges of weightlessness. Charlie Cooper at MSFC theorized that neutral buoyancy exercises could help with EVA planning while he was reviewing film of the Gemini 4 EVA. He and Charles D. Stocks pursued the idea with a couple of NASA scuba suits and an 8 feet (2.4 m) diameter, 8 feet (2.4 m) deep pool which had been previously used for forming metal parts explosively. November 1965 tests included removal of the ST-124 and a J-2 engine propellant utilization valve - early steps in a nascent Skylab mission, then called S-IVB orbital workshop.