Prior to the third launch attempt on mission STS-121, Mission Specialist Thomas Reiter is helped with his launch suit before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. The launch of Space Shuttle Discovery on mission STS-121 is the 115th shuttle flight and the 18th U.S. flight to the International Space Station. During the 12-day mission, the STS-121 crew will test new equipment and procedures to improve shuttle safety, as well as deliver supplies and make repairs to the International Space Station.