Bob Behnken
Colonel Behnken trained as an international space station crew member following the loss of Columbia and as a mission specialist for STS-400 the launch-on-need rescue flight for the last Hubble servicing mission.  He flew STS-123 in March 2008 and STS-130 in February 2010, logging more than 708 hours in space, and performing more than 37 hours in six spacewalks.  Colonel Behnken is currently assigned to the cadre of astronauts that will train and fly the initial test flights of the Boeing CST-100 or Space X Dragon commercially built spacecraft.