KENNEDY SPACE CENTER, FLA. - From the west side of Launch Pad 39B, Space Shuttle Discovery is viewed moments after liftoff on mission STS-121. The fiery display fit the day: Fourth of July. The launch made history as it was the first ever to take place on Independence Day. 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/Sandy Joseph, Robert Murray

KENNEDY SPACE CENTER, FLA. - Shooting like a roman candle into Florida's blue sky from Launch Pad 39B, Space Shuttle Discovery kicks off the Fourth of July fireworks with its own fiery display, reflected as well in the nearby water. History was made with the first ever launch on Independence Day. It was the third launch attempt in four days; the others were scrubbed due to weather concerns. Liftoff on mission STS-121 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 courtesy of Nikon/Scott Andrews

KENNEDY SPACE CENTER, FLA. - Framed by palm trees, Space Shuttle Discovery lifts off Launch Pad 39B at 2:38 p.m. EDT. The fiery display fit the day: Fourth of July. The launch made history as it was the first ever launch on Independence Day. 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/Sandy Joseph, Robert Murray

KENNEDY SPACE CENTER, FLA. - As the ground fills with smoke and steam, Space Shuttle Discovery creates its own fireworks display, fitting for the first ever launch to be made on Independence Day. It was the third launch attempt in four days; the others were scrubbed due to weather concerns. Liftoff on mission STS-121 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 courtesy of Nikon/Scott Andrews

KENNEDY SPACE CENTER, FLA. - Space Shuttle Discovery shoots into Florida's blue sky over the blue Atlantic Ocean, kicking off Fourth of July fireworks with its own fiery display. History was made with the first ever launch on Independence Day. It was the third launch attempt in four days; the others were scrubbed due to weather concerns. Liftoff on mission STS-121 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 courtesy of Nikon/Scott Andrews

KENNEDY SPACE CENTER, FLA. - As smoke and steam billows across the ground, Space Shuttle Discovery leaps free and rockets into the clear blue sky, creating its own fireworks display. History was made with the first ever launch on Independence Day. It was the third launch attempt in four days; the others were scrubbed due to weather concerns. 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 courtesy of Nikon/Scott Andrews

KENNEDY SPACE CENTER, FLA. - Framed by palm trees, Space Shuttle Discovery lifts off Launch Pad 39B at 2:38 p.m. EDT. The fiery display fit the day: Fourth of July. The launch made history as it was the first ever launch on Independence Day. 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/Sandy Joseph, Robert Murray

KENNEDY SPACE CENTER, FLA. - Framed by palm trees, Space Shuttle Discovery lifts off Launch Pad 39B at 2:38 p.m. EDT. The fiery display fit the day: Fourth of July. The launch made history as it was the first ever launch on Independence Day. 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/Sandy Joseph, Robert Murray

KENNEDY SPACE CENTER, FLA. - STS-121 Commander Steven Lindsey is helped with his boot during suitup before heading to Launch Pad 39B and the third attempt at liftoff on mission STS-121. 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. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - STS-121 Mission Specialist Piers Sellers is eager for launch as he suits up before heading to Launch Pad 39B and liftoff. The launch 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. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Mission Specialist Piers Sellers adjusts his glove while donning his launch suit before heading to Launch Pad 39B and liftoff on mission STS-121. 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. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Smoke and steam billow across Launch Pad 39B as the launch of Space Shuttle Discovery on mission STS-121 kicks off the fireworks for the U.S. holiday and makes history as the first time a shuttle has launched 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/Tony Gray & Tim Powers

KENNEDY SPACE CENTER, FLA. - Cameras are the accessory of the day at the Kennedy Space Center's Banana River viewing site. All eyes and lenses are focused on Launch Pad 39B and the successful launch of Space Shuttle Discovery on mission STS-121. It was the third launch attempt in four days; the others were scrubbed due to weather concerns. 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/Louie Roguevert

KENNEDY SPACE CENTER, FLA. - 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

KENNEDY SPACE CENTER, FLA. - Under clear blue skies, the launch of Space Shuttle Discovery on mission STS-121 kicks off the fireworks for the U.S. holiday in its third launch attempt in four days. Liftoff from Launch Pad 39B 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/Sandy Joseph & Robert Murrary

KENNEDY SPACE CENTER, FLA. - As smoke and team billow across Launch Pad 39B, Space Shuttle Discovery on mission STS-121 kicks off the fireworks for the U.S. holiday and makes history as the first time a shuttle has launched 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/Tony Gray

KENNEDY SPACE CENTER, FLA. - Making history with the first-ever launch on Independence Day, Space Shuttle Discovery rockets into the blue sky on mission STS-121, trailing fiery exhaust and blue mach diamonds from the main engine nozzles. Liftoff from Launch Pad 39B (seen below) 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 credit: NASA/Tony Gray & Tim Powers

KENNEDY SPACE CENTER, FLA. - Framed by trees in nearby woods, Space Shuttle Discovery rockets into the blue sky from Launch Pad 39B on mission STS-121, kicking off the fiery festivities of 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/Sandy Joseph & Robert Murray

KENNEDY SPACE CENTER, FLA. - Space Shuttle Discovery appears to leap from the midst of palms as it rockets into the blue sky from Launch Pad 39B on mission STS-121, kicking off the fiery festivities of 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/Sandy Joseph & Robert Murray

KENNEDY SPACE CENTER, FLA. - Clearing the lighting rod on Launch Pad 39B, Space Shuttle Discovery makes history as the first to launch on Independence Day as it rockets into the clear blue sky. 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/Sandy Joseph & Robert Murray