Space Shuttle Discovery rockets off the mobile launcher platform on Launch Pad 39B on mission STS-121.

Making history with the first-ever launch on Independence Day, Space Shuttle Discovery rockets off the mobile launcher platform on Launch Pad 39B on mission STS-121. Despite the billowing clouds of smoke and steam, the tail masts can still be seen. To the left is the White Room at the end of the orbiter access arm, which is moved away from the orbiter 7 minutes, 24 seconds before launch. 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/Regina Mitchell-Ryall & Don Kight