Extra-Vehicular Activity

From OCE Space Simulation
(Redirected from EVA)
Jump to: navigation, search

Extra-Vehicular Activity (or EVA) is the term for any activity that involves astronauts venturing outside the Habitat, for any reason, during the mission. EVAs typically involve two astronauts, and last for no more than fifteen minutes.

Reasons for EVAs

Damage to Habitat

If the Habitat is damaged in such a way that requires outside access (i.e., holes from meteoroid impacts, engine malfunctions, etc.), astronauts may embark on EVA to repair said damage.


Once the Habitat has landed, it is customary to embark on an Exploratory EVA. This involves two astronauts going outside of the Habitat to perform a preliminary survey of the planetary surface.

Sample Collection

Sample collection is one of the most important aspects towards the science which is done on the mission. Astronauts will embark on an EVA with appropriate sample collection equipment, leaving the collected samples in containers in the hotbox when done.

EVA Protocol

Prior to deciding to embark on any EVA, the Habitat crew must inform Mission Control of their intentions, their choice of astronauts for the EVA, and obtain Mission Control's approval. After said approval is obtained, two astronauts not going on the EVA assist the two EVA astronauts in getting into their EVA suits. Once the EVA astronauts are prepared to embark, they enter the airlock. The other astronauts obtain permission from MC to depressurize the airlock, and then depressurize it. Once it has been completely depressurized, the EVA astronauts are given permission by the Mission Commander (or Subcommander, if the Mission Commander is incapacitated) to embark.

Once the EVA objectives have been completed, the EVA astronauts return to the airlock door and request permission to enter. The astronauts aboard the Habitat ensure that the airlock is still at equal pressure to the outside environment, and then grant the requested permission. The EVA astronauts then enter the airlock, and inform the other astronauts when they have sealed the outer door behind them. The other astronauts acknowledge that the EVA astronauts are inside, and repressurize the airlock. When it is repressurized, the astronauts activate the Decontamination Cycle and inform the EVA astronauts that said cycle is in progress. When the cycle is complete and all EVA astronauts are detected as clean of any contaminants, the astronauts aboard the Habitat inform the EVA astronauts that it is safe to open the inner door.

Once successfully returned to the Habitat, the two astronauts who helped suit-up the EVA astronauts help remove the suits. The suits are folded and stored properly on the racks in the airlock.

EVA Suits

Main article: EVA Suits

The EVA Suit design has changed over the years of Spacesim, as can be seen in the following pictures.

Lyra Evans demonstrates the old EVA suit helmets in 2006-07.
Kenneth Lindsay demonstrates the new helmet design with the old suit design in 2006-07.
Max Jeffcott and Clarisse demonstrate the new helmet combined with the new suit design during a Training Mission in 2009-10.

See Also