Spacewalk

NASA "spacewalkers" during the space shuttle program were designated as EV-1, EV-2, EV-3 and EV-4 (assiged to mission specialists for each mission, if applicable).
Camp-out procedure
For EVAs from the International Space Station, NASA now routinely employs a camp out procedure to reduce the risk of decompression sickness. This was first tested by the Expedition 12 crew. During a camp out, astronauts sleep overnight prior to an EVA in the airlock, and lower the air pressure to 10.2 psi (70 kPa), compared to the normal station pressure of 14.7 psi (101 kPa). Spending a night at the lower air pressure helps flush nitrogen from the body, thereby preventing "the bends".