Neutral buoyancy simulation as a training aid

[4] Quickly, Environmental Research Associates' submerged testing evolved into proper neutral buoyancy simulation, featuring weighted subjects and numerous safety divers on hand during given sessions.

Carpenter's evaluation of the simulation was favorable and NASA quickly provided mockups of Gemini vehicles and docking components to facilitate further development of EVA capabilities via neutral buoyancy training.

Astronaut Gene Cernan first visited the McDonogh School indoor pool facility for post-mission evaluation of problems that he encountered during his Gemini IX-A EVA.

The post-mission evaluation verified the value of using neutral buoyancy simulation training before attempting all of the EVA tasks while wearing a pressure suit and working in the hostile environment of space.

Aldrin himself recognized some minor flaws of neutral buoyancy training, but described the method to have a "considerable advantage" over Keplerian trajectory aircraft.

[6] In September 2011, the Gemini XLV Symposium included a review of these accomplishments by G. Samuel Mattingly and featured remarks by astronauts Richard Gordon, Tom Jones, and Buzz Aldrin.

However, due to differences between the design of the mock-up used for training and what they found at Skylab, the astronauts used makeshift tools and redesigned how they would accomplish the task while they were in outer space.

[8] The main purpose for an astronaut to egress the vehicle and go EVA is often to provide a force to push, pull, crank, squeeze or transport an object.

However the astronaut-spacesuit combination, when properly balanced in neutral buoyancy as when in EVA, is weightless so the astronaut is, similar to standing on ice, unable to use weight to provide a force in any vector.

Early in the history of neutral buoyancy simulation there was consideration of providing the immersed astronaut with small motors to compensate for water drag, but this was soon dismissed as an unnecessary complication.

In EVA, most work is done slowly, carefully and methodically not because of the neutral buoyancy training but because that is how a task must be performed by a pressurized astronaut in weightlessness.

There are other less obvious but important features that must be considered in underwater EVA training, such as the visual differences due to refraction at the air-water interface at the helmet's visor and position or attitude in the suit relative to the task.

Neutral buoyancy, properly planned and conducted, works because it is a realistic simulation of the physical requirements of performing a task in EVA.