NASA astronauts Michael Barratt and Nicole Stott participate in a training session in the shuttle mission simulator at NASA's Johnson Space Center.

NASA astronauts Michael Barratt and Nicole Stott, both STS-133 mission specialists, participate in a training session in the fixed-base shuttle mission simulator (SMS) and the Space Station Training Facility (SSTF) in the Jake Garn Simulation and Training Facility at NASA's Johnson Space Center. Photo credit: NASA or National Aeronautics and Space Administration