2009 Private tour of NASA neutral buoyancy lab at Johnson Space Center in Houston, Texas on Monday, August 31, 2009. Astronauts are trained for EVA (extra vehicular activities) or space walks in the pool is the largest pool in the world, it measures 200 ft by 120 ft by 40 ft deep. Met astronauts Shayne Kimbrough, Dorothy Metcalf-Lindenburger and Commander Mike Mossimoso. Dorothy is headed up on the space shuttle in March of 2010, which is one of the last shuttle missions.