KENNEDY SPACE CENTER, FLA. -- The sun is setting as Space Shuttle Discovery nears its place on Launch Pad 39B at NASA's Kennedy Space Center. At right are the fixed and rotating service structures. First motion was at 12:45 p.m. EDT. The shuttle rests on a mobile launcher platform and made the 4.2-mile journey from the Vehicle Assembly Building via the crawler-transporter beneath the platform. The rollout is an important step before launch of Discovery on mission STS-121 to the International Space Station. Discovery's launch is targeted for July 1 in a launch window that extends to July 19. During the 12-day mission, Discovery's crew will test new hardware and techniques to improve shuttle safety, as well as deliver supplies and make repairs to the station. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- Space Shuttle Discovery nears its destination on its rollout to Launch Pad 39B. Discovery rests on top of the mobile launcher platform, which is carried by the crawler-transporter underneath. First motion of the shuttle leaving NASA's Vehicle Assembly Building was at 12:45 p.m. EDT. The 4.2-mile journey from the VAB to the pad takes approximately 8 hours. The rollout is an important step before launch of Discovery on mission STS-121 to the International Space Station. Discovery's launch is targeted for July 1 in a launch window that extends to July 19. During the 12-day mission, Discovery's crew will test new hardware and techniques to improve shuttle safety, as well as deliver supplies and make repairs to the station. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- Space Shuttle Discovery, seen behind the orange external tank and white solid rocket boosters, moves into place on the hardstand of Launch Pad 39B. The shuttle rests on a mobile launcher platform and made the 4.2-mile journey from the Vehicle Assembly Building via the crawler-transporter beneath the platform. The rollout is an important step before launch of Discovery on mission STS-121 to the International Space Station. Discovery's launch is targeted for July 1 in a launch window that extends to July 19. During the 12-day mission, Discovery's crew will test new hardware and techniques to improve shuttle safety, as well as deliver supplies and make repairs to the station. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- The lights from the fixed and rotating service structures bathe Space Shuttle Discovery in a warm glow as it rests on the hardstand of Launch Pad 39B at NASA's Kennedy Space Center after completing the 4.2-mile journey from the Vehicle Assembly Building. First motion was at 12:45 p.m. EDT. The shuttle rests on a mobile launcher platform. The rollout is an important step before launch of Discovery on mission STS-121 to the International Space Station. Discovery's launch is targeted for July 1 in a launch window that extends to July 19. During the 12-day mission, Discovery's crew will test new hardware and techniques to improve shuttle safety, as well as deliver supplies and make repairs to the station. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- Space Shuttle Discovery approaches the ramp on its rollout to Launch Pad 39B. Discovery rests on top of the mobile launcher platform, which is carried by the crawler-transporter underneath. First motion of the shuttle leaving NASA's Vehicle Assembly Building was at 12:45 p.m. EDT. The 4.2-mile journey from the VAB to the pad takes approximately 8 hours. The rollout is an important step before launch of Discovery on mission STS-121 to the International Space Station. Discovery's launch is targeted for July 1 in a launch window that extends to July 19. During the 12-day mission, Discovery's crew will test new hardware and techniques to improve shuttle safety, as well as deliver supplies and make repairs to the station. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- Amid the glow of lights from the fixed and rotating service structures, Space Shuttle Discovery rests on the hardstand of Launch Pad 39B at NASA's Kennedy Space Center after completing the 4.2-mile journey from the Vehicle Assembly Building. First motion was at 12:45 p.m. EDT. The shuttle rests on a mobile launcher platform. The rollout is an important step before launch of Discovery on mission STS-121 to the International Space Station. First motion of the shuttle leaving NASA's Vehicle Assembly Building was at 12:45 p.m. EDT. Discovery's launch is targeted for July 1 in a launch window that extends to July 19. During the 12-day mission, Discovery's crew will test new hardware and techniques to improve shuttle safety, as well as deliver supplies and make repairs to the station. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. -- Amid the glow of lights from the fixed and rotating service structures, Space Shuttle Discovery rests on the hardstand of Launch Pad 39B at NASA's Kennedy Space Center after completing the 4.2-mile journey from the Vehicle Assembly Building. First motion was at 12:45 p.m. EDT. The shuttle rests on a mobile launcher platform. The rollout is an important step before launch of Discovery on mission STS-121 to the International Space Station. First motion of the shuttle leaving NASA's Vehicle Assembly Building was at 12:45 p.m. EDT. Discovery's launch is targeted for July 1 in a launch window that extends to July 19. During the 12-day mission, Discovery's crew will test new hardware and techniques to improve shuttle safety, as well as deliver supplies and make repairs to the station. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. -- This side view taken from the upper level of the fixed service structure shows Space Shuttle Discovery, mated with the orange external tank, as it has come to rest on the hardstand of Launch Pad 39B. The shuttle rests on a mobile launcher platform and made the 4.2-mile journey from the Vehicle Assembly Building via the crawler-transporter beneath the platform. The rollout is an important step before launch of Discovery on mission STS-121 to the International Space Station. Discovery's launch is targeted for July 1 in a launch window that extends to July 19. During the 12-day mission, Discovery's crew will test new hardware and techniques to improve shuttle safety, as well as deliver supplies and make repairs to the station. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- The sun is setting as Space Shuttle Discovery arrives on the hardstand of Launch Pad 39B at NASA's Kennedy Space Center. At right are the fixed and rotating service structures. First motion was at 12:45 p.m. EDT. The shuttle rests on a mobile launcher platform and made the 4.2-mile journey from the Vehicle Assembly Building via the crawler-transporter beneath the platform. The rollout is an important step before launch of Discovery on mission STS-121 to the International Space Station. First motion of the shuttle leaving NASA's Vehicle Assembly Building was at 12:45 p.m. EDT. Discovery's launch is targeted for July 1 in a launch window that extends to July 19. During the 12-day mission, Discovery's crew will test new hardware and techniques to improve shuttle safety, as well as deliver supplies and make repairs to the station. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. -- Amid the glow of lights from the fixed and rotating service structures, Space Shuttle Discovery rests on the hardstand of Launch Pad 39B at NASA's Kennedy Space Center after completing the 4.2-mile journey from the Vehicle Assembly Building. First motion was at 12:45 p.m. EDT. The shuttle rests on a mobile launcher platform. The rollout is an important step before launch of Discovery on mission STS-121 to the International Space Station. Discovery's launch is targeted for July 1 in a launch window that extends to July 19. During the 12-day mission, Discovery's crew will test new hardware and techniques to improve shuttle safety, as well as deliver supplies and make repairs to the station. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- Near Launch Pad 39B, wild pigs (at right) root for food near a stand of trees while Space Shuttle Discovery rolls out to the pad. The 4.2-mile journey from the Vehicle Assembly Building began at 12:45 p.m. EDT. The rollout is an important step before launch of Discovery on mission STS-121 to the International Space Station. Discovery's launch is targeted for July 1 in a launch window that extends to July 19. During the 12-day mission, Discovery's crew will test new hardware and techniques to improve shuttle safety, as well as deliver supplies and make repairs to the station. Photo credit: NASA/Ken Thornsley