CAPE CANAVERAL, Fla. – In the White Room on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-119 Pilot Tony Antonelli (center) and Mission Specialist Richard Arnold are getting ready to enter the open hatch into space shuttle Discovery. The White Room is at the end of the orbiter access arm on the fixed service structure and provides access into the shuttle. The STS-119 mission is the 28th to the International Space Station and the 125th space shuttle flight. Discovery will deliver the final pair of power-generating solar array wings and the S6 truss segment. Installation of S6 will signal the station's readiness to house a six-member crew for conducting increased science. Liftoff is scheduled for 7:43 p.m. EDT. Photo credit: NASA/Tony Gray, Tom Farrar

CAPE CANAVERAL, Fla. – In the White Room on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-119 Mission Specialist Joseph Acaba is helped by the closeout crew putting on his harness, which includes a parachute pack, before crawling through the open hatch into space shuttle Discovery. The White Room is at the end of the orbiter access arm on the fixed service structure and provides access into the shuttle. The STS-119 mission is the 28th to the International Space Station and the 125th space shuttle flight. Discovery will deliver the final pair of power-generating solar array wings and the S6 truss segment. Installation of S6 will signal the station's readiness to house a six-member crew for conducting increased science. Liftoff is scheduled for 7:43 p.m. EDT. Photo credit: NASA/Tony Gray, Tom Farrar

CAPE CANAVERAL, Fla. – In the White Room on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-119 Mission Specialists Joseph Acaba (left), Koichi Wakata (center) and Steve Swanson (right) talk to the closeout crew as they prepare to go through the open hatch into space shuttle Discovery. The White Room is at the end of the orbiter access arm on the fixed service structure and provides access into the shuttle. The STS-119 mission is the 28th to the International Space Station and the 125th space shuttle flight. Discovery will deliver the final pair of power-generating solar array wings and the S6 truss segment. Installation of S6 will signal the station's readiness to house a six-member crew for conducting increased science. Liftoff is scheduled for 7:43 p.m. EDT. Photo credit: NASA/Tony Gray, Tom Farrar

CAPE CANAVERAL, Fla. – Space shuttle Discovery roars off Launch Pad 39A on the STS-119 mission atop twin towers of fire that light up the sky after sunset at NASA's Kennedy Space Center in Florida. Liftoff was on time at 7:43 p.m. EDT. The STS-119 mission is the 28th to the International Space Station and the 125th space shuttle flight. Discovery will deliver the final pair of power-generating solar array wings and the S6 truss segment. Installation of S6 will signal the station's readiness to house a six-member crew for conducting increased science. Photo courtesy of Scott Andrews

CAPE CANAVERAL, Fla. – In the White Room on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-119 Mission Specialist Steve Swanson is helped by the closeout crew putting on his harness, which includes a parachute pack, before crawling through the open hatch into space shuttle Discovery. The White Room is at the end of the orbiter access arm on the fixed service structure and provides access into the shuttle. The STS-119 mission is the 28th to the International Space Station and the 125th space shuttle flight. Discovery will deliver the final pair of power-generating solar array wings and the S6 truss segment. Installation of S6 will signal the station's readiness to house a six-member crew for conducting increased science. Liftoff is scheduled for 7:43 p.m. EDT. Photo credit: NASA/Tony Gray, Tom Farrar

CAPE CANAVERAL, Fla. – In the White Room on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-119 Mission Specialist John Phillips is helped by the closeout crew putting on his harness, which includes a parachute pack, before crawling through the open hatch into space shuttle Discovery. The White Room is at the end of the orbiter access arm on the fixed service structure and provides access into the shuttle. The STS-119 mission is the 28th to the International Space Station and the 125th space shuttle flight. Discovery will deliver the final pair of power-generating solar array wings and the S6 truss segment. Installation of S6 will signal the station's readiness to house a six-member crew for conducting increased science. Liftoff is scheduled for 7:43 p.m. EDT. Photo credit: NASA/Tony Gray, Tom Farrar

CAPE CANAVERAL, Fla. – In the White Room on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-119 Pilot Tony Antonelli is getting into his harness, which includes a parachute pack, before crawling through the open hatch into space shuttle Discovery. The White Room is at the end of the orbiter access arm on the fixed service structure and provides access into the shuttle. The STS-119 mission is the 28th to the International Space Station and the 125th space shuttle flight. Discovery will deliver the final pair of power-generating solar array wings and the S6 truss segment. Installation of S6 will signal the station's readiness to house a six-member crew for conducting increased science. Liftoff is scheduled for 7:43 p.m. EDT. Photo credit: NASA/Tony Gray, Tom Farrar

CAPE CANAVERAL, Fla. – In the White Room on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-119 Mission Specialists Koichi Wakata (center) and Steve Swanson are getting into their harnesses, which include a parachute pack, before crawling through the open hatch into space shuttle Discovery. The White Room is at the end of the orbiter access arm on the fixed service structure and provides access into the shuttle. The STS-119 mission is the 28th to the International Space Station and the 125th space shuttle flight. Discovery will deliver the final pair of power-generating solar array wings and the S6 truss segment. Installation of S6 will signal the station's readiness to house a six-member crew for conducting increased science. Liftoff is scheduled for 7:43 p.m. EDT. Photo credit: NASA/Tony Gray, Tom Farrar

CAPE CANAVERAL, Fla. – In the White Room on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-119 Commander Lee Archambault talks to the closeout crew who will put on his harness, which includes a parachute pack, before crawling through the open hatch into the shuttle. The White Room is at the end of the orbiter access arm on the fixed service structure and provides access into space shuttle Discovery. The STS-119 mission is the 28th to the International Space Station and the 125th space shuttle flight. Discovery will deliver the final pair of power-generating solar array wings and the S6 truss segment. Installation of S6 will signal the station's readiness to house a six-member crew for conducting increased science. Liftoff is scheduled for 7:43 p.m. EDT. Photo credit: Photo credit: NASA/Tony Gray, Tom Farrar