KENNEDY SPACE CENTER, FLA. - Prior to the third launch attempt on mission STS-121, Mission Specialist Piers Sellers fixes one of his gloves during suitup before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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. - Prior to the third launch attempt on mission STS-121, Pilot Mark Kelly fixes his glove during suitup before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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. - Prior to the third launch attempt on mission STS-121, Mission Specialist Stephanie Wilson gets help with her helmet during suitup before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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 Lisa Nowak is helped with her boots during suitup before heading to Launch Pad 39B and a third launch attempt. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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. - Prior to the third launch attempt on mission STS-121, Pilot Mark Kelly is helped with his boots during suitup before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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. - Mission Specialist Piers Sellers is happy to be making a third launch attempt on mission STS-121. Here, he fixes one of his gloves during suitup before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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. - Getting ready for a third launch attempt on mission STS-121, Mission Specialist Stephanie Wilson is suiting up before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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. - Prior to the third launch attempt on mission STS-121, Mission Specialist Thomas Reiter is suiting up before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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. - The STS-121 crew displays the spirit of the Fourth of July holiday with their flags and their eagerness to launch as they stride out of the Operations and Checkout Building. Leading the way are Pilot Mark Kelly (left) and Commander Steven Lindsey (right). Behind them are Mission Specialists (second row) Lisa Nowak and Michael Fossum; (third row) Stephanie Wilson and Piers Sellers; and (at the rear) Thomas Reiter, who represents the European Space Agency. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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. - Prior to the third launch attempt on mission STS-121, Commander Steven Lindsey looks thoughtful as he completes suiting up before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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. - After suiting up in his launch suit, Mission Specialist Michael Fossum gives a thumbs up for a third launch attempt on mission STS-121. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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 Commander Steven Lindsey is eager for a third launch attempt on the mission. Here, he is donning his launch suit before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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. - Mission Specialist Thomas Reiter, happy to be making a third launch attempt on mission STS-121, is suited up before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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. - Prior to the third launch attempt on mission STS-121, Mission Specialist Thomas Reiter is helped with his launch suit before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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 Commander Steven Lindsey is eager for a third launch attempt on the mission. Here, he is donning his launch suit before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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 Lisa Nowak is happy to be making a third launch attempt on the mission. She is suiting up before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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. - Prior to the third launch attempt on mission STS-121, Mission Specialist Michael Fossum is helped with his launch suit before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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 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 Lisa Nowak is helped with her launch suit during suitup for launch today on Space Shuttle Discovery. 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. - During suitup for launch today on Space Shuttle Discovery, STS-121 Mission Specialist Piers Sellers adjusts the communication device worn under his helmet. 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. - STS-121 Mission Specialist Stephanie Wilson is helped with her helmet during suitup for launch today on Space Shuttle Discovery. 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. - STS-121 Mission Specialist Michael Fossum is helped with the communication device he wears under his helmet during suitup for launch today on Space Shuttle Discovery. 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. - STS-121 Mission Specialist Michael Fossum is helped with his boot during suitup for launch today on Space Shuttle Discovery. 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. - STS-121 Mission Specialist Lisa Nowak is helped with her boot during suitup for a second launch attempt on Space Shuttle Discovery. The first launch attempt July 1 was scrubbed due to weather concerns and postponed 24 hours. 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. - Prior to the third launch attempt on mission STS-121, Mission Specialist Thomas Reiter is helped with his helmet during suitup before heading to Launch Pad 39B. The July 2 launch attempt was scrubbed due to the presence of showers and thunderstorms within the surrounding area of the launch site. 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 Pilot Mark Kelly is helped with his boot during suitup for a second launch attempt on Space Shuttle Discovery. The first launch attempt July 1 was scrubbed due to weather concerns and postponed 24 hours. 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 Commander Steven Lindsey is helped with his helmet during suitup for a second launch attempt on Space Shuttle Discovery. The first launch attempt July 1 was scrubbed due to weather concerns and postponed 24 hours. 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 Pilot Mark Kelly adjusts his helmet during suitup for a second launch attempt on Space Shuttle Discovery. The first launch attempt July 1 was scrubbed due to weather concerns and postponed 24 hours. 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. - STS-121 Mission Specialist Lisa Nowak is still eager for launch after suitup for a second launch attempt on Space Shuttle Discovery. The first launch attempt July 1 was scrubbed due to weather concerns and postponed 24 hours. 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. - STS-121 Pilot Mark Kelly gets help with his helmet fitting during suitup for a second launch attempt on Space Shuttle Discovery. The first launch attempt July 1 was scrubbed due to weather concerns and postponed 24 hours. 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. - STS-121 Mission Specialist Lisa Nowak is still eager for launch during suitup for a second launch attempt on Space Shuttle Discovery. The first launch attempt July 1 was scrubbed due to weather concerns and postponed 24 hours. 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. - STS-121 Commander Steven Lindsey adjusts a glove during suitup for a second launch attempt on Space Shuttle Discovery. The first launch attempt July 1 was scrubbed due to weather concerns and postponed 24 hours. 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. - STS-121 Commander Steven Lindsey pulls on his glove during suitup for a second launch attempt on Space Shuttle Discovery. The first launch attempt July 1 was scrubbed due to weather concerns and postponed 24 hours. 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