After landing at NASA's Kennedy Space Center aboard a Grumman G2 aircraft gathers at a microphone.

After landing at NASA's Kennedy Space Center aboard a Grumman G2 aircraft, the STS-121 crew gathers at a microphone for the media. Seen here at center is Pilot Mark Kelly. Other crew members are Mission Commander Steven Lindsey and Mission Specialists Michael Fossum, Lisa Nowak, Stephanie Wilson, Piers Sellers and Thomas Reiter, who represents the European Space Agency. The crew is at the space center to take part in a Terminal Countdown Demonstration Test, or TCDT. Over several days, the crew will practice emergency egress from the pad and suit up in their orange flight suits for the simulated countdown to launch. Space Shuttle Discovery is designated to launch July 1 on mission STS-121. It will carry supplies to the International Space Station. Photo credit: NASA/Kim Shiflett