To any astronaut, what is an EVA?

To an astronaut, EVA means Extravehicular Activity. It is a spaceflight operation in which a suited crew member performs work outside a spacecraft or space station, often in the vacuum of space.

An EVA can involve tasks such as installing equipment, repairing a satellite, connecting external station components or carrying out experiments. Astronauts usually leave through an airlock while wearing a spacesuit that supplies oxygen, removes carbon dioxide, regulates temperature and protects against the vacuum and extreme environment.

The phrase is broader than “spacewalk.” A spacewalk is the familiar public term for an EVA in orbit, but space agencies also use EVA for other work outside a vehicle or habitat, including certain surface operations. The abbreviation is not the name of the suit: NASA commonly calls its spacewalking suit the Extravehicular Mobility Unit, or EMU. “Extravehicular” simply means occurring outside the vehicle, so the full expansion of EVA is the canonical answer.