Neutral Buoyancy Simulator Photo courtesy of NASA

The Neutral Buoyancy Simulator is located in Building 4705 at the Marshall Space Flight Center in Huntsville, Alabama. It was designed by the Army in 1955 to provide a simulated zero-gravity environment in which engineers, designers and astronauts could perform for extended periods of time in simulated environment of outer space. The Neutral Buoyancy Simulator is a facility that is unique within the National Aeronautics and Space Administration (NASA) inventory of training facilities. Due to its capability to support research and testing of operational techniques and materials needed to successfully perform space-manned missions, the Neutral Buoyancy Simulator contributed significantly to the American manned space program. Projects Gemini, Apollo, Skylab and the Space Shuttle have all benefited from the Neutral Buoyancy Simulator. Until the mid-1970s, when an additional facility was constructed at the Johnson Space Flight Center to support the Space Shuttle Program, this facility was the only test facility that allowed astronauts to become familiar with the dynamics of body motion under weightless conditions.

Interior of simulator during test Photo courtesy of NASA

Within the heart of the simulator is a large water tank, 75 feet in diameter and 40 feet deep. The water within the simulator is temperature controlled, continuously recirculated and filtered. There are four observation levels with portholes to view activities within the simulator. An elevator serves all four observation levels and special systems are integrated into the tank for underwater audio and video, pressure-suit environmental control and emergency rescue and treatment. Life support is simultaneously provided by these systems for up to four pressure-suited subjects. Additional systems include date aquisition and recording, underwater lighting, special underwater pneumatic and electrical power operations of motor, valves, controls, and indicators that are required for high fidelity and functional engineering mockups and trainers. Adjacent to the Neutral Buoyancy Simulator is a completely equipped test control area for directing, controlling and monitoring simulation activities in the Neutral Buoyancy Simulator. An annex contains the operating crew dressing and shower area. For a complete copy of the National Historic Landmark registration form for the Neutral Buoyancy Simulator, click here.

The Neutral Buoyancy Simulator, a National Historic Landmark, is located inside the George C. Marshall Space Flight Center in Huntsville, Alabama. It is closed to the public. You can also download (in pdf) the Neutral Buoyancy National Historic Landmark nomination.