NASA scientists use this plexiglass space station airlock test model to train astronauts for operations in space in 1966.
In this historical photo from the U.S. space agency, National Aeronautics and Space Adminstration's Langley Research Center scientists use this plexiglass space station airlock test model to determine astronauts' ability to move in and out through an airlock with the restraint of a pressurized suit.
Operations in space that call for crew transfer between spacecraft require airlocks of some kind. Mobility and performance in airlock systems must be determined to establish geometry and associated hardware for equipment suitable for manned space vehicle use. The airlock prevents artificial atmosphere loss when an astronaut transfers from one spacecraft to another or from the interior to the exterior in the performance of duties.
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