JSC2007-E-27769 (6 June 2007) --- Astronauts Michael J. Massimino (left), Andrew J. Feustel (right, partially obscured) and John M. Grunsfeld (foreground), STS-125 mission specialists, participate in a training session with a Hubble Space Telescope mockup in the Neutral Buoyancy Laboratory (NBL) near Johnson Space Center.
Photographer Robert Markowitz