Langley's Otto Trout suggested as early as 1963 that zero-gravity activities could be simulated by immersing astronauts in a large tank of water. Years later, Marshall Space Flight Center turned Trout's abortive idea into a major component of NASA's astronaut training program." Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, (Washington: NASA, 1995), p. 303.
