Skylab and the Space Shuttles were a platform for practicing EVA work needed for more extended periods of living in space.
As spacecraft and their missions became more complex, so did EVAs. Performing EVA work from the payload bay of the nation's "space truck," Space Shuttle astronauts serviced satellites and tested methods later used in building the International Space Station.
Today, space station astronauts go outside to replace equipment, retrieve scientific experiments, and make repairs when damage occurs. They continue to require specialized tools and equipment to work efficiently.
Even before Gene Cernan's nearly fatal EVA, NASA contracted with Environmental Research Associates in Randallstown, Maryland, to provide underwater neutral buoyancy training in the swimming pool of a local private school. Astronaut Scott Carpenter became the first to test this method. Cernan followed him for post-mission evaluation and Buzz Aldrin for pre-mission training for Gemini XII.
Later astronauts used a pool at the Marshall Space Flight Center in Alabama, but astronauts now use the Neutral Buoyancy Laboratory (NBL) at the Johnson Space Center in Texas to train for EVAs. Underwater training gives astronauts a realistic sense of weightlessness, and those pools are large enough to contain mockups of payloads and space station modules on which astronauts can practice their EVA procedures.
Extensive training in classrooms and simulators prepares astronauts for nearly every possible EVA scenario. They rely on printed reminders of their training in the form of checklists. Following these checklists, completely and in order, helps ensure a successful mission. Checklists have also become a place for in-flight notes or jokes to lighten the mood.
