NASA astronaut Rex Walheim is lowered into the water to train for spacewalk in the Neutral Buoyancy Laboratory (NBL) on Tuesday, March 22, 2011, in Houston. ( NASA Photo / Houston Chronicle, Smiley N. Pool )
NASA astronaut Rex Walheim is lowered into the water to train for spacewalk in the Neutral Buoyancy Laboratory (NBL) on Tuesday, March 22, 2011, in Houston. ( NASA Photo / Houston Chronicle, Smiley N. Pool )