The moment of ignition is captured in this photo of Space Shuttle Discovery being launched on mission STS-121 from Launch Pad 39B.

The moment of ignition is captured in this photo of Space Shuttle Discovery being launched on mission STS-121 from Launch Pad 39B. The launch was the first ever made 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 17 at Kennedy's Shuttle Landing Facility. Photo courtesy of Nikon/Scott Andrews