STS-121 Mission Specialist Thomas Reiter checks the fitting of his launch suit in the Operations and Checkout Building.

STS-121 Mission Specialist Thomas Reiter checks the fitting of his launch suit in the Operations and Checkout Building. On the 12-day mission, the crew will test new equipment and procedures to improve shuttle safety, as well as deliver supplies and make repairs to the station. This mission is the 115th shuttle flight and the 18th U.S. flight to the station. Photo credit: NASA/Kim Shiflett