Knowra Extravehicular activity Extravehicular activity Extravehicular activity (EVA) is work performed by a crew member outside a spacecraft while protected by a spacesuit. It includes spacewalks in orbit and surface operations on celestial bodies.
Spacesuit : A wearable life-support system that protects a person from vacuum, temperature extremes, and other hazards. The suit supplies pressure, oxygen, cooling, and communications during an EVA.
Hubble Space Telescope servicing missions : Five Space Shuttle missions that repaired and upgraded the Hubble Space Telescope between 1993 and 2009. Astronauts used repeated EVAs to replace instruments and restore Hubble's capabilities.
Alexei Leonov : A Soviet cosmonaut who performed the first human spacewalk in 1965. His pioneering EVA exposed the practical difficulties of moving and working in a pressurized suit.
Intravehicular activity : Work performed by a crew member inside a spacecraft, whether in a pressurized or otherwise protected area. IVA takes place within the spacecraft rather than in the external environment.
Space adaptation syndrome : A form of motion sickness caused by the body's adjustment to weightlessness. Disorientation and nausea can affect an astronaut's readiness for demanding EVA work.
Airlock : A sealed chamber that allows passage between environments at different pressures without exposing either environment to the other. Crew members use an airlock to exit and re-enter a pressurized spacecraft.
International Space Station maintenance : The inspection, repair, and upgrading of the International Space Station and its external systems. Many station repairs and installations require astronauts to work outside the orbiting laboratory.
Voskhod 2 : A 1965 Soviet crewed mission during which Alexei Leonov made the first spacewalk. The mission demonstrated EVA in orbit, though suit expansion nearly prevented Leonov's return.
Lunar surface EVA : An extravehicular activity conducted on the Moon's surface in a spacesuit. Unlike orbital spacewalks, lunar EVAs involve gravity, terrain, and dust.
Spacesuit thermal control : Systems that regulate a spacesuit's internal temperature by removing or retaining heat. Sunlight and shadow create rapid temperature changes that EVA suits must manage.
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