KENNEDY SPACE CENTER, FLA. - The STS-115 mission crew happily heads to the Astrovan for the ride to Launch Pad 39B and another attempt at liftoff. From the left, in the back row are Mission Specialists Heidemarie Stefanyshyn-Piper and Joseph Tanner; in the center row are Mission Specialists Steven MacLean and Daniel Burbank; in the front row leading the way are Pilot Christopher Ferguson and Commander Brent Jett. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Just before dawn, Atlantis touches down on Runway 33 at NASA's Kennedy Space Center, concluding mission STS-115. Aboard are Commander Brent Jett, Pilot Christopher Ferguson, and Mission Specialists Joseph Tanner, David Burbank, Heidemarie Stefanyshyn-Piper and Steven MacLean, who represents the Canadian Space Agency. During the mission, Tanner, McLean, Burbank and Piper completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, FLA. - KSC Deputy Director Bill Parsons (left) talks with STS-115 Mission Specialist Daniel Burbank, who just returned from space. During the mission, astronauts completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - After their return from space, the STS-115 crew is welcomed by NASA and KSC officials. The crew members, from left, are Mission Specialists Joseph Tanner and Heidemarie Stefanyshyn-Piper; Pilot Christopher Ferguson; Mission Specialist Steven MacLean; Commander Brent Jett; and Mission Specialist Daniel Burbank. At right are NASA Administrator Michael Griffin, Deputy Associate Administrator for Space Operations Lynn Cline, and a representative of the Canadian Space Agency. During the mission, astronauts completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - After a safe landing aboard Atlantis on Runway 33 of the Shuttle Landing Facility, the STS-115 crew greets the media. At the microphone is Commander Brent Jett. Behind him, left to right, are Mission Specialist Daniel Burbank, Pilot Christopher Ferguson and Mission Specialists Steven MacLean, Joseph Tanner and Heidemarie Stefanyshyn-Piper. During the mission, astronauts completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - The STS-115 mission crew respond to well-wishers as they head to the Astrovan for the ride to Launch Pad 39B. From left are Pilot Christopher Ferguson, Mission Specialists Steven MacLean, Heidemarie Stefanyshyn-Piper, Daniel Burbank and Joseph Tanner (hidden), and Commander Brent Jett. The crew is eager for another attempt at liftoff after the Sept. 8 scrub. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Before welcoming the STS-115 crew on their return from space, NASA officials look at the underside of the orbiter Atlantis on the Shuttle Landing Facility. From right are NASA Administrator Michael Griffin, KSC Deputy Director Bill Parsons and Shuttle Launch Director Mike Leinbach. During the mission, astronauts completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Storm clouds fill the sky from Launch Pad 39B, at right, west beyond the Vehicle Assembly Building. Space Shuttle Atlantis still sits on the pad after a scrub was called Aug. 27 due to a concern with fuel cell 1. Towering above the shuttle is the 80-foot lightning mast. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. - Concluding mission STS-115, Atlantis and her crew return to Kennedy Space Center and approach a landing before sunrise on Runway 33. Aboard are Commander Brent Jett, Pilot Christopher Ferguson, and Mission Specialists Joseph Tanner, David Burbank, Heidemarie Stefanyshyn-Piper and Steven MacLean, who represents the Canadian Space Agency. During the mission, Tanner, McLean, Burbank and Piper completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the White Room on Launch Pad 39B, STS-115 Pilot Christopher Ferguson talks with the closeout crew before entering Space Shuttle Atlantis. Ferguson is making his first shuttle flight. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC.

KENNEDY SPACE CENTER, FLA. - Space Shuttle Atlantis roars off the launch pad for a rendezvous with the International Space Station on mission STS-115. In the foreground are only a few of the hundreds of photographers capturing the historic scene from the grounds of the NASA News Center. Just beyond them is the countdown clock, marking launch and mission-elapsed time. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Jim Grossmann

KENNEDY SPACE CENTER, FLA. - With umbilicals still attached, the orbiter Atlantis is being towed from the Shuttle Landing Facility to the Orbiter Processing Facility. Atlantis landed on Runway 33 at 6:21:30 a.m. EDT after the 11-day, 19-hour, 6-minute mission STS-115 to the International Space Station. Atlantis traveled 4.9 million miles, landing on orbit 187. During the mission, astronauts delivered and installed the massive P3/P4 truss, an integral part of the station's backbone, and two sets of solar arrays that will eventually provide one quarter of the station's power. In the OPF, the process flow will begin to ready the vehicle for its next flight. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, FLA. - In the White Room on Launch Pad 39B, STS-115 Mission Specialist Heidemarie Stefanyshyn-Piper gets help with her launch suit from the closeout crew before entering Space Shuttle Atlantis. Piper is making her first shuttle flight. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC

KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Pilot Christopher Ferguson adjusts his glove during suitup before heading to the launch pad for another attempt at liftoff. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Lit from behind, Atlantis is close to touchdown on Runway 33 at NASA's Kennedy Space Center, concluding mission STS-115. Aboard are Commander Brent Jett, Pilot Christopher Ferguson, and Mission Specialists Joseph Tanner, David Burbank, Heidemarie Stefanyshyn-Piper and Steven MacLean, who represents the Canadian Space Agency. During the mission, Tanner, McLean, Burbank and Piper completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Mike Kerley

KENNEDY SPACE CENTER, FLA. - After a week's delay of launching due to weather and technical issues, the crew of mission STS-115 have had the traditional breakfast before their third attempt to launch on Space Shuttle Atlantis. Seated left to right are Mission Specialists Heidemarie Stefanyshyn-Piper and Joseph Tanner, Commander Brent Jett, Pilot Christopher Ferguson and Mission Specialists Steven MacLean and Daniel Burbank. MacLean is with the Canadian Space Agency. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. Following the breakfast, the crew will don their launch suits before heading to Launch Pad 39B. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Before welcoming the STS-115 crew on their return from space, NASA officials look at the underside of the orbiter Atlantis on the Shuttle Landing Facility. From left are Mission Launch Integration Director LeRoy Cain, NASA Administrator Michael Griffin and Shuttle Launch Director Mike Leinbach. During the mission, astronauts completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - At the traditional post-landing inspection, STS-115 Mission Specialists Steven MacLean and Daniel Burbank examine the underside of the orbiter Atlantis. During the mission, astronauts completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Mission Specialist Daniel Burbank dons his launch and re-entry suit before heading to the launch pad for another attempt at liftoff. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Mission Commander Brent Jett signals a "go" for another attempt at liftoff. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - At a post-landing press conference at NASA's Kennedy Space Center, the STS-115 crew answer questions from the media about their mission. Seated from left are Commander Brent Jett, Pilot Christopher Ferguson, and Mission Specialists Joseph Tanner, Daniel Burbank, Heidemarie Stefanyshyn-Piper and Steven MacLean, who represents the Canadian Space Agency. During the mission to the International Space Station, astronauts delivered and installed the massive P3/P4 truss, an integral part of the station's backbone, and two sets of solar arrays that will eventually provide one quarter of the station's power. After 11 days, 19 hours and 6 minutes in space, the crew returned to Earth aboard Atlantis at 6:21:30 a.m. EDT. Photo credit: NASA/Cory Huston

KENNEDY SPACE CENTER, FLA. - After landing safely aboard Atlantis on Runway 33 of the Shuttle Landing Facility, STS-115 Commander Brent Jett is happy to touch Earth again. He and other crew members are examining the underside of the orbiter Atlantis during the traditional post-landing inspection.During the mission, astronauts completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - At the traditional post-landing inspection, STS-115 Mission Specialists Steven MacLean and Daniel Burbank look over Atlantis. During the mission, astronauts completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Just before dawn, Atlantis nears touchdown on Runway 33 at NASA's Kennedy Space Center, concluding mission STS-115. Aboard are Commander Brent Jett, Pilot Christopher Ferguson, and Mission Specialists Joseph Tanner, David Burbank, Heidemarie Stefanyshyn-Piper and Steven MacLean, who represents the Canadian Space Agency. During the mission, Tanner, McLean, Burbank and Piper completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/John Kechele

KENNEDY SPACE CENTER, FLA. - At a post-landing press conference at NASA's Kennedy Space Center, the STS-115 crew members smile at a question from the media. Seated from left are Commander Brent Jett, Pilot Christopher Ferguson, and Mission Specialists Joseph Tanner, Daniel Burbank, Heidemarie Stefanyshyn-Piper and Steven MacLean, who represents the Canadian Space Agency. During the mission to the International Space Station, astronauts delivered and installed the massive P3/P4 truss, an integral part of the station's backbone, and two sets of solar arrays that will eventually provide one quarter of the station's power. After 11 days, 19 hours and 6 minutes in space, the crew returned to Earth aboard Atlantis at 6:21:30 a.m. EDT. Photo credit: NASA/Cory Huston

KENNEDY SPACE CENTER, FLA. - The drag chute glows in the lights illuminating Atlantis as it touches down on Runway 33 at NASA's Kennedy Space Center, concluding mission STS-115. Aboard are Commander Brent Jett, Pilot Christopher Ferguson, and Mission Specialists Joseph Tanner, David Burbank, Heidemarie Stefanyshyn-Piper and Steven MacLean, who represents the Canadian Space Agency. During the mission, Tanner, McLean, Burbank and Piper completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Mike Kerley

KENNEDY SPACE CENTER, FLA. - In the White Room on Launch Pad 39B, STS-115 Mission Specialist Joseph Tanner gets help with his launch suit from the closeout crew before entering Space Shuttle Atlantis. Tanner is making his fourth shuttle flight. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC.

KENNEDY SPACE CENTER, FLA. - After returning from the International Space Station, STS-115 Commander Brent Jett (right) gets a close look at the underside of the orbiter Atlantis at the traditional post-landing inspection. During the mission, astronauts completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Mission Specialist Joseph Tanner dons his launch and re-entry suit before heading to the launch pad for another attempt at liftoff. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. Liftoff today is scheduled for 11:15 a.m. EDT. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Mission Commander Brent Jett finishes suiting up for another attempt at liftoff. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - NASA Administrator Michael Griffin, right, talks to the STS-115 crew after its return from space. The crew members shown are Mission Specialists Joseph Tanner, Heidemarie Stefanyshyn-Piper and Daniel Burbank. During the mission, astronauts completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Just before dawn, Atlantis nears touchdown on Runway 33 at NASA's Kennedy Space Center, concluding mission STS-115. Aboard are Commander Brent Jett, Pilot Christopher Ferguson, and Mission Specialists Joseph Tanner, David Burbank, Heidemarie Stefanyshyn-Piper and Steven MacLean, who represents the Canadian Space Agency. During the mission, Tanner, McLean, Burbank and Piper completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, FLA. - Atlantis is moved into the Orbiter Processing Facility after being towed from the Shuttle Landing Facility. Atlantis landed on Runway 33 at 6:21:30 a.m. EDT after the 11-day, 19-hour, 6-minute mission STS-115 to the International Space Station. Atlantis traveled 4.9 million miles, landing on orbit 187. During the mission, astronauts delivered and installed the massive P3/P4 truss, an integral part of the station's backbone, and two sets of solar arrays that will eventually provide one quarter of the station's power. In the OPF, the process flow will begin to ready the vehicle for its next flight. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Space Shuttle Atlantis roars off the launch pad for a rendezvous with the International Space Station on mission STS-115. In the foreground is the countdown clock, marking launch and mission-elapsed time, on the grounds of the NASA News Center. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Webb Dillard

KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Pilot Christopher Ferguson finishes suiting up for another attempt at liftoff. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - With umbilicals still attached, the orbiter Atlantis is being towed from the Shuttle Landing Facility to the Orbiter Processing Facility. Atlantis landed on Runway 33 at 6:21:30 a.m. EDT after the 11-day, 19-hour, 6-minute mission STS-115 to the International Space Station. Atlantis traveled 4.9 million miles, landing on orbit 187. During the mission, astronauts delivered and installed the massive P3/P4 truss, an integral part of the station's backbone, and two sets of solar arrays that will eventually provide one quarter of the station's power. In the OPF, the process flow will begin to ready the vehicle for its next flight. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the White Room on Launch Pad 39B, STS-115 Commander Brent Jett gets help with his launch suit from the closeout crew before entering Space Shuttle Atlantis. Jett is making his fourth shuttle flight. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC.

KENNEDY SPACE CENTER, FLA. - The STS-115 crew poses in front of the orbiter Atlantis, which brought them safely back from space to NASA's Kennedy Space Center. From left are Mission Specialists Daniel Burbank, Heidemarie Stefanyshyn-Piper and Steven MacLean; Pilot Christopher Ferguson; Commander Brent Jett; and Mission Specialist Joseph Tanner. During the mission, Tanner, McLean, Burbank and Piper completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Mission Specialist Steven MacLean dons his helmet to complete suiting up for another attempt at liftoff. MacLean is with the Canadian Space Agency. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - After their return from space, the STS-115 crew members are welcomed by NASA and KSC officials. The crew, from left, are Mission Specialists Joseph Tanner, Heidemarie Stefanyshyn-Piper and Daniel Burbank; Pilot Christopher Ferguson; and Mission Specialist Steven MacLean. On the right are At right are NASA Administrator Michael Griffin, Deputy Associate Administrator for Space Operations Lynn Cline, a representative of the Canadian Space Agency, KSC Director Jim Kennedy and Deputy Director Bill Parsons. During the mission, astronauts completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Atlantis is towed to the Orbiter Processing Facility along the tow-way from the Shuttle Landing Facility. Atlantis landed on Runway 33 at 6:21:30 a.m. EDT after the 11-day, 19-hour, 6-minute mission STS-115 to the International Space Station. Atlantis traveled 4.9 million miles, landing on orbit 187. During the mission, astronauts delivered and installed the massive P3/P4 truss, an integral part of the station's backbone, and two sets of solar arrays that will eventually provide one quarter of the station's power. In the OPF, the process flow will begin to ready the vehicle for its next flight. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Mission Specialists Joseph Tanner and Heidemarie Stefanyshyn-Piper pose while suiting up for the ride to Launch Pad 39B and another attempt at liftoff. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - After suiting up, the STS-115 mission crew exits the Operations and Checkout Building to board the Astrovan to Launch Pad 39B. On the left, front to back, are Pilot Christopher Ferguson and Mission Specialists Steven MacLean and Heidemarie Stefanyshyn-Piper. On the right, front to back, are Commander Brent Jett and Mission Specialists Daniel Burbank and Joseph Tanner. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Mission Specialist Daniel Burbank gets a final adjustment on his helmet before heading to the launch pad for another attempt at liftoff. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Storm clouds gather behind Space Shuttle Atlantis on Launch Pad 39B. Atlantis was originally scheduled to launch on Aug. 27, but a scrub was called by mission managers due to a concern with fuel cell 1. Towering above the shuttle is the 80-foot lightning mast. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. - During suitup in the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Mission Specialist Joseph Tanner signals a "go" for another attempt at liftoff. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - After their return from space, the STS-115 crew members are exiting the crew transport vehicle on the Shuttle Landing Facility. First out is Commander Brent Jett. Behind him, still inside, are Mission Specialists Heidemarie Stefanyshyn-Piper and Joseph Tanner. During the mission, astronauts completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Mission Specialist Steven MacLean signals "go" for another attempt at liftoff. MacLean is with the Canadian Space Agency. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Mission Specialist Heidemarie Stefanyshyn-Piper is eager for another attempt at liftoff. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building at NASA Kennedy Space Center, STS-115 Mission Specialist Heidemarie Stefanyshyn-Piper is donning her launch and re-entry suit before heading to the launch pad for another attempt at liftoff. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - STS-115 Mission Specialists Daniel Burbank (left) and Steven MacLean get help with their launch suits from the closeout crew before entering Space Shuttle Atlantis. Both astronauts are making their second shuttle flights. MacLean is with the Canadian Space Agency. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC

KENNEDY SPACE CENTER, FLA. - The movement of Atlantis is reflected in the water next to the tow-way as the orbiter is towed from the Shuttle Landing Facility to the Orbiter Processing Facility. Umbilical lines are still attached to the orbiter. Atlantis landed on Runway 33 at 6:21:30 a.m. EDT after the 11-day, 19-hour, 6-minute mission STS-115 to the International Space Station. Atlantis traveled 4.9 million miles, landing on orbit 187. During the mission, astronauts delivered and installed the massive P3/P4 truss, an integral part of the station's backbone, and two sets of solar arrays that will eventually provide one quarter of the station's power. In the OPF, the process flow will begin to ready the vehicle for its next flight. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the White Room on Launch Pad 39B, STS-115 Mission Specialist Steven MacLean adjusts his launch suit while talking with the closeout crew. MacLean, who represents the Canadian Space Agency, is making his second shuttle flight. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC

KENNEDY SPACE CENTER, FLA. - Atlantis is moved into the Orbiter Processing Facility after being towed from the Shuttle Landing Facility. Atlantis landed on Runway 33 at 6:21:30 a.m. EDT after the 11-day, 19-hour, 6-minute mission STS-115 to the International Space Station. Atlantis traveled 4.9 million miles, landing on orbit 187. During the mission, astronauts delivered and installed the massive P3/P4 truss, an integral part of the station's backbone, and two sets of solar arrays that will eventually provide one quarter of the station's power. In the OPF, the process flow will begin to ready the vehicle for its next flight. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - A heavy bank of storm clouds gather behind Space Shuttle Atlantis on Launch Pad 39B. Atlantis was originally scheduled to launch Aug. 27, but a scrub was called by mission managers due to a concern with fuel cell 1. Towering above the shuttle is the 80-foot lightning mast. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. - Concluding mission STS-115, Atlantis and her crew return to Kennedy Space Center and approach a landing before sunrise on Runway 33. Aboard are Commander Brent Jett, Pilot Christopher Ferguson, and Mission Specialists Joseph Tanner, David Burbank, Heidemarie Stefanyshyn-Piper and Steven MacLean, who represents the Canadian Space Agency. During the mission, Tanner, McLean, Burbank and Piper completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - After suiting up, the STS-115 mission crew enthusiastically greet the onlookers as they head to the Astrovan for the ride to Launch Pad 39B. From left are Mission Specialist Heidemarie Stefanyshyn-Piper, Steven MacLean, Joseph Tanner, Pilot Christopher Ferguson and Daniel Burbank. Not seen is Commander Brent Jett. The crew is eager for another attempt at liftoff after the Sept. 8 scrub. The launch attempt on Sept. 8 was scrubbed due to an issue with a fuel cut-off sensor system inside the external fuel tank. This is one of several systems that protect the shuttle's main engines by triggering their shutdown if fuel runs unexpectedly low. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Storm clouds roll across Launch Pad 39B where Space Shuttle Atlantis still sits on the pad. Atlantis was originally scheduled to launch Aug. 27, but a scrub was called by mission managers due to a concern with fuel cell 1. Towering above the shuttle is the 80-foot lightning mast. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. - Atlantis releases its drag chute to assist in landing on Runway 33 at NASA's Kennedy Space Center, concluding mission STS-115. Aboard are Commander Brent Jett, Pilot Christopher Ferguson, and Mission Specialists Joseph Tanner, David Burbank, Heidemarie Stefanyshyn-Piper and Steven MacLean, who represents the Canadian Space Agency. During the mission, Tanner, McLean, Burbank and Piper completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Chuck Tintera

KENNEDY SPACE CENTER, FLA. - Just before dawn, Atlantis approaches touchdown on Runway 33 at NASA's Kennedy Space Center, concluding mission STS-115. Aboard are Commander Brent Jett, Pilot Christopher Ferguson, and Mission Specialists Joseph Tanner, David Burbank, Heidemarie Stefanyshyn-Piper and Steven MacLean, who represents the Canadian Space Agency. During the mission, Tanner, McLean, Burbank and Piper completed three spacewalks to attach the P3/P4 integrated truss structure to the International Space Station. Main gear touchdown was at 6:21:30 a.m. EDT. Nose gear touchdown was at 6:21:36 a.m. and wheel stop was at 6:22:16 a.m. At touchdown -- nominally about 2,500 ft. beyond the runway threshold -- the orbiter is traveling at a speed ranging from 213 to 226 mph. Atlantis traveled 4.9 million miles, landing on orbit 187. Mission elapsed time was 11 days, 19 hours, six minutes. This is the 15th night landing at KSC and the 23rd night landing overall. Photo credit: NASA/Mike Kerley

KENNEDY SPACE CENTER, FLA. - With umbilicals still attached, the orbiter Atlantis is being towed from the Shuttle Landing Facility to the Orbiter Processing Facility. Atlantis landed on Runway 33 at 6:21:30 a.m. EDT after the 11-day, 19-hour, 6-minute mission STS-115 to the International Space Station. Atlantis traveled 4.9 million miles, landing on orbit 187. During the mission, astronauts delivered and installed the massive P3/P4 truss, an integral part of the station's backbone, and two sets of solar arrays that will eventually provide one quarter of the station's power. In the OPF, the process flow will begin to ready the vehicle for its next flight. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, FLA. - Led by the Convoy Command Center, Atlantis is towed from the Shuttle Landing Facility to the Orbiter Processing Facility. The command center is the prime vehicle to control critical communications between the orbiter, the crew and the Launch Control Center after a shuttle landing, to monitor the health of the shuttle orbiter systems and to direct convoy operations at the Shuttle Landing Facility. Atlantis landed on Runway 33 at 6:21:30 a.m. EDT after the 11-day, 19-hour, 6-minute mission STS-115 to the International Space Station. Atlantis traveled 4.9 million miles, landing on orbit 187. During the mission, astronauts delivered and installed the massive P3/P4 truss, an integral part of the station's backbone, and two sets of solar arrays that will eventually provide one quarter of the station's power. In the OPF, the process flow will begin to ready the vehicle for its next flight. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Inside the Launch Control Center, Shuttle Launch Director Mike Leinbach (center, standing) watches the computer screen as cameras document Space Shuttle Atlantis' climb toward space on mission STS-115. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. sts-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Inside the Launch Control Center, NASA and KSC officials turn from their computers to watch through the broad windows the launch of Space Shuttle Atlantis on mission STS-115. Second from left is Kennedy Space Center Director Jim Kennedy. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Nearly obscured by its own contrail, Space Shuttle Atlantis hurtles toward space for a rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. - The primitiveness of the dunes (foreground) clash with the technology exhibited in the launch of Space Shuttle Atlantis for its rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Sandra Joseph & Robert Murray

KENNEDY SPACE CENTER, FLA. - Inside the Launch Control Center, KSC officials turn from their computers to watch through the broad windows the launch of Space Shuttle Atlantis on mission STS-115. Second from left is NASA Test Director Pete Nickolenko. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. sts-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Flaming rockets propel Space Shuttle Atlantis into the sky for a rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo courtesy of Nikon/Scott Andrews

KENNEDY SPACE CENTER, FLA. - Inside the Launch Control Center, Associate Administrator for Space Operations Mission William Gerstenmaier congratulates the launch team after the liftoff of Space Shuttle Atlantis on mission STS-115. Behind him, at right, are Pat Leslie and Robbie Ashley, STS-115 payload manager. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. Mission STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Following the successful launch of Space Shuttle Atlantis on mission STS-115, NASA Administrator Michael Griffin, Associate Administrator for Space Operations Mission William Gerstenmaier, Launch Integration Director LeRoy Cain and Shuttle Launch Director Mike Leinbach respond to questions from the media during a post-launch press conference. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Through a slight haze of clouds, Space Shuttle Atlantis hurtles toward space for a rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. - Inside the Launch Control Center, NASA Administrator Michael Griffin congratulates the launch team after the liftoff of Space Shuttle Atlantis on mission STS-115. Behind him are (left to right) Shuttle Launch Director Mike Leinbach, Pat Leslie and Robbie Ashley, STS-115 payload manager. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. Mission STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - The morning sky lightens behind Space Shuttle Atlantis while lights on the fixed service structure (FSS) still illuminate the orbiter on Launch Pad 39B. Atlantis was originally scheduled to launch at 12:29 p.m. EDT on this date, but a 24-hour scrub was called by mission managers due to a concern with Fuel Cell 1. Seen poised above the orange external tank is the vent hood (known as the "beanie cap") at the end of the gaseous oxygen vent arm. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. Extending from the FSS to Atlantis is the orbiter access arm with the White Room at the end. The White Room provides entry into the orbiter through the hatch. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Troy Cryder

KENNEDY SPACE CENTER, FLA. - Although it appears to be standing on twin columns of fire, Space Shuttle Atlantis leaps off the launch pad, heading toward space for a rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Sandra Joseph & Robert Murray

KENNEDY SPACE CENTER, FLA. - Inside the Launch Control Center, NASA and KSC officials applaud the successful launch of Space Shuttle Atlantis on mission STS-115. From right are NASA Administrator Michael Griffin, Associate Administrator for Space Operations Mission William Gerstenmaier, Shuttle Launch Director Mike Leinbach, NASA Flow Director Angie Brewer, and Public Affairs Officer George Diller, who provided commentary leading up to the launch. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Space Shuttle Atlantis appears enveloped in the smoke and steam created at liftoff from Launch Pad 39B. Liftoff was on-time at 11:14:55 a.m. EDT. Atlantis is heading for space and its rendezvous with the International Space Station on mission STS-115. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Sandra Joseph & Robert Murray

KENNEDY SPACE CENTER, FLA. - Space Shuttle Atlantis leaps off the launch pad past the lightning mast on top of the fixed service structure at left. Atlantis is heading for space and its rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After several earlier launch attempts were scrubbed due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo courtesy of Nikon/Scott Andrews

KENNEDY SPACE CENTER, FLA. - The morning sky lightens behind Space Shuttle Atlantis while lights on the fixed service structure (FSS) still illuminate the orbiter on Launch Pad 39B. Atlantis was originally scheduled to launch at 12:29 p.m. EDT on this date, but a 24-hour scrub was called by mission managers due to a concern with Fuel Cell 1. Seen poised above the orange external tank is the vent hood (known as the "beanie cap") at the end of the gaseous oxygen vent arm. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. Extending from the FSS to Atlantis is the orbiter access arm with the White Room at the end. The White Room provides entry into the orbiter through the hatch. At right is the 300,000-gallon water tank that releases its contents onto the mobile launcher platform during liftoff to aid sound suppression. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Troy Cryder

KENNEDY SPACE CENTER, FLA. - Tree limbs frame the brilliant launch of Space Shuttle Atlantis as it flees the smoke and steam below, heading for a rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo courtesy of Nikon/Scott Andrews

KENNEDY SPACE CENTER, FLA. - Flaming rockets propel Space Shuttle Atlantis away from the smoke and steam below and into the sky for a rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Sandra Joseph & Robert Murray

KENNEDY SPACE CENTER, FLA. - Space Shuttle Atlantis is in the spotlight on Launch Pad 39B. Atlantis was originally scheduled to launch at 12:29 p.m. EDT on this date, but a 24-hour scrub was called by mission managers due to a concern with Fuel Cell 1. Seen poised above the orange external tank is the vent hood (known as the "beanie cap") at the end of the gaseous oxygen vent arm. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Jim Grossmann

KENNEDY SPACE CENTER, FLA. - Inside the Launch Control Center, Robbie Ashley, STS-115 payload manager, and Pat Lesley, with United Space Alliance, receive a special award from (at left) Shuttle Launch Director Mike Leinbach and (at right) NASA Flow Director Angie Brewer. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Clouds spread throughout the sky behind Launch Pad 39B where Space Shuttle Atlantis still sits after the scrub of its launch on mission STS-115. Atlantis was originally scheduled to launch at 12:29 p.m. EDT on this date, but a 24-hour scrub was called by mission managers due to a concern with fuel cell 1. Towering above the shuttle is the 80-foot lightning mast. At right is the 300,000-gallon water tank that releases its contents onto the mobile launcher platform during liftoff to aid sound suppression. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. - Huge clouds roll over Launch Pad 39B where Space Shuttle Atlantis still sits after the scrub of its launch on mission STS-115. Atlantis was originally scheduled to launch at 12:29 p.m. EDT on this date, but a 24-hour scrub was called by mission managers due to a concern with fuel cell 1. Towering above the shuttle is the 80-foot lightning mast. At right is the 300,000-gallon water tank that releases its contents onto the mobile launcher platform during liftoff to aid sound suppression. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. - Space Shuttle Atlantis roars into the sky above the primitive sand dunes in the foreground. Heading for its rendezvous with the International Space Station on mission STS-115, liftoff was on-time at 11:14:55 a.m. EDT. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Sandra Joseph & Robert Murray

KENNEDY SPACE CENTER, FLA. - Smoke and steam billow across Launch Pad 39B as Space Shuttle Atlantis hurtles into the sky for its rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After several earlier launch attempts were scrubbed due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo courtesy of Nikon/Scott Andrews

KENNEDY SPACE CENTER, FLA. - The sky is finally clear behind Launch Pad 39B where Space Shuttle Atlantis still sits after the scrub of its launch on mission STS-115. Atlantis was originally scheduled to launch at 12:29 p.m. EDT on this date, but a 24-hour scrub was called by mission managers due to a concern with fuel cell 1. Just above the orange external tank is the vent hood (known as the "beanie cap") at the end of the gaseous oxygen vent arm. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. Below, the orbiter access arm extends toward the cockpit of Atlantis with the White Room at the end. The White Room provides access into the cockpit of the vehicle. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. - Space Shuttle Atlantis leaps off the launch pad as smoke and steam billow behind it. Atlantis is heading for space and its rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After several earlier launch attempts were scrubbed due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo courtesy of Nikon/Scott Andrews

KENNEDY SPACE CENTER, FLA. - With applause and cheers from the onlookers, Space Shuttle Atlantis roars off the launch pad for a rendezvous with the International Space Station on mission STS-115. In the foreground is the countdown clock, marking launch and mission-elapsed time, on the grounds of the NASA News Center. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Debbie Odom

KENNEDY SPACE CENTER, FLA. - Space Shuttle Atlantis is bathed in light on Launch Pad 39B. Atlantis was originally scheduled to launch at 12:29 p.m. EDT on this date, but a 24-hour scrub was called by mission managers due to a concern with Fuel Cell 1. Seen poised above the orange external tank is the vent hood (known as the "beanie cap") at the end of the gaseous oxygen vent arm. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Jim Grossmann

KENNEDY SPACE CENTER, FLA. - NASA and KSC officials discuss the successful launch of Space Shuttle Atlantis on mission STS-115 at a press conference at NASA's Kennedy Space Center. From left are NASA Administrator Michael Griffin, Associate Administrator for Space Operations Mission William Gerstenmaier, Launch Integration Director LeRoy Cain and Shuttle Launch Director Mike Leinbach.Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -As if leaping out from amidst the woods, Space Shuttle Atlantis roars off Launch Pad 39B for a rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. - The morning sky lightens behind Space Shuttle Atlantis while lights on the fixed service structure (FSS) still illuminate the orbiter on Launch Pad 39B. Atlantis was originally scheduled to launch at 12:29 p.m. EDT on this date, but a 24-hour scrub was called by mission managers due to a concern with Fuel Cell 1. Seen poised above the orange external tank is the vent hood (known as the "beanie cap") at the end of the gaseous oxygen vent arm. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. Extending from the FSS to Atlantis is the orbiter access arm with the White Room at the end. The White Room provides entry into the orbiter through the hatch. At right is the 300,000-gallon water tank that releases its contents onto the mobile launcher platform during liftoff to aid sound suppression. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Troy Cryder

KENNEDY SPACE CENTER, FLA. - From the top of the Vehicle Assembly Building, the fiery launch of Space Shuttle Atlantis is seen against the background of the Atlantic Ocean to the east while billows of smoke and steam roll across the launch pad. Atlantis is heading for a rendezvous with the International Space Station on mission STS-115. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, FLA. - Looking like a work of art, Space Shuttle Atlantis roars into the blue Florida sky atop a column of fire for a rendezvous with the International Space Station on mission STS-115. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Dennis Sabo

KENNEDY SPACE CENTER, FLA. - Space Shuttle Atlantis is bathed in light on Launch Pad 39B. Atlantis was originally scheduled to launch at 12:29 p.m. EDT on this date, but a 24-hour scrub was called by mission managers due to a concern with Fuel Cell 1. Seen poised above the orange external tank is the vent hood (known as the "beanie cap") at the end of the gaseous oxygen vent arm. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Jim Grossmann

KENNEDY SPACE CENTER, FLA. - Inside the Launch Control Center, NASA and KSC officials turn from their computers to watch through the broad windows the launch of Space Shuttle Atlantis on mission STS-115. Second from left is Kennedy Space Center Director Jim Kennedy. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - Flaming rockets propel Space Shuttle Atlantis away from the smoke and steam below and into the sky for a rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. - The morning sky lightens behind Space Shuttle Atlantis while lights on the fixed service structure (FSS) still illuminate the orbiter on Launch Pad 39B. Atlantis was originally scheduled to launch at 12:29 p.m. EDT on this date, but a 24-hour scrub was called by mission managers due to a concern with Fuel Cell 1. Seen poised above the orange external tank is the vent hood (known as the "beanie cap") at the end of the gaseous oxygen vent arm. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. Extending from the FSS to Atlantis is the orbiter access arm with the White Room at the end. The White Room provides entry into the orbiter through the hatch. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Troy Cryder

KENNEDY SPACE CENTER, FLA. -Through a haze of clouds, Space Shuttle Atlantis hurtles toward space for a rendezvous with the International Space Station on mission STS-115. Liftoff was on-time at 11:14:55 a.m. EDT. After launch attempts were scrubbed Aug. 27 and 29 and Sept. 3 and 8 due to weather and technical concerns, this launch was executed perfectly. Mission STS-115 is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. During the mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo courtesy of Nikon/Scott Andrews