NASA launch team members cheer and wave American flags at the launch of Space Shuttle Discovery on mission STS-121.

In Firing Room 4 of the Launch Control Center, NASA launch team members cheer and wave American flags at the successful launch of Space Shuttle Discovery on mission STS-121. The launch made history as the first to occur on Independence Day. Liftoff was on-time at 2:38 p.m. EDT. During the 12-day mission, the STS-121 crew of seven will test new equipment and procedures to improve shuttle safety, as well as deliver supplies and make repairs to the International Space Station. Landing is scheduled for July 16 or 17 at Kennedy's Shuttle Landing Facility. Photo credit: NASA/Bill Ingalls