Alexander with two divers

ESA astronaut Alexander Gerst, from Germany, during EVA pre-familiarisation training at ESA's Neutral Buoyancy Facility at the Astronaut Centre, in Cologne, Germany, 8 June 2010.
This course teaches ESA astronauts basic spacewalk (or extravehicular activity, EVA) concepts and skills, such as tethering to the Station, the use of special EVA tools, communicating with an EVA crewmate and with the control room and how to keep full situational awareness in a complex and challenging environment.