KENNEDY SPACE CENTER, Fla. -- STS-118 Commander Scott Kelly stands inside an M-113 armored personnel carrier before his driving session as part of emergency exit training. He and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Commander Scott Kelly practices driving an M-113 armored personnel carrier with fellow crew members Tracy Caldwell, Alvin Drew and Dave Williams, all mission specialists, as passengers. They are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Pilot Charlie Hobaugh stands inside an M-113 armored personnel carrier before his driving session as part of emergency exit training. He and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Alvin Drew stands inside an M-113 armored personnel carrier before his driving session, as part of emergency exit training. He and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Pilot Charlie Hobaugh practices driving an M-113 armored personnel carrier with passenger (at left) Tracy Caldwell, mission specialist. They and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Barbara R. Morgan practices driving an M-113 armored personnel carrier as part of emergency exit training. Seen in the back, at left, are Commander Scott Kelly and Mission Specialists Tracy Caldwell and Alvin Drew. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. She and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Alvin Drew practices driving an M-113 armored personnel carrier, with (at right) Mission Specialists Barbara R. Morgan and Dave Williams as passengers. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. Williams represents the Canadian Space Agency. They and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Tracy Caldwell is ready to take her turn at driving an M-113 armored personnel carrier as part of emergency exit training. Seen behind her at right is Mission Specialist Dave Williams, who represents the Canadian Space Agency. They and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Rick Mastracchio practices driving an M-113 armored personnel carrier as part of emergency exit training. The astronauts seen behind him are Mission Specialists Alvin Drew, Barbara R. Morgan, Dave Williams (standing) and Tracy Caldwell. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. Williams represents the Canadian Space Agency. The crew is at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Tracy Caldwell practices driving an M-113 armored personnel carrier as part of emergency exit training. Seen in the back are Mission Specialist Alvin Drew, Pilot Charlie Hobaugh and educator astronaut and Mission Specialist Barbara R. Morgan. They and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Dave Williams, who represents the Canadian Space Agency, signals success after driving an M-113 armored personnel carrier as part of emergency exit training. Behind him are, at left, Pilot Charlie Hobaugh and, right, Mission Specialist Tracy Caldwell. They and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Rick Mastracchio gets ready to practice driving an M-113 armored personnel carrier as part of emergency exit training. Behind him, at right, is Mission Specialist Tracy Caldwell. They and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Barbara R. Morgan is ready to practice driving an M-113 armored personnel carrier as part of emergency exit training. Behind her at the rear are Mission Specialists (left) Tracy Caldwell and Dave Williams. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. She and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Commander Scott Kelly practices driving an M-113 armored personnel carrier, as part of emergency exit training, with fellow crew members aboard. Behind Kelly is Mission Specialist Barbara R. Morgan. The crew is at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Dave Williams, who represents the Canadian Space Agency, gets ready to practice driving an M-113 armored personnel carrier as part of emergency exit training. Behind him is Mission Specialist Barbara R. Morgan. They and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- Inside an M-113 armored personnel carrier, the STS-118 crew gets instructions on its use for emergency exit procedures from Launch Pad 39A. At left is Mission Specialist Dave Williams, who represents the Canadian Space Agency. At right are (back to front) Pilot Charlie Hobaugh and Mission Specialists Alvin Drew and Tracy Caldwell. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- After completing their driving training on the M-113 armored personnel carrier (behind them), the STS-118 crew take a break. From left are Mission Specialists Dave Williams and Rick Mastracchio, Commander Scott Kelly, Mission Specialist Barbara R. Morgan, Pilot Charlie Hobaugh, and Mission Specialists Alvin Drew and Tracy Caldwell. Williams represents the Canadian Space Agency. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. The crew is at Kennedy for the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew arrives at Kennedy's Shuttle Landing Facility aboard a Shuttle Training Aircraft to take part in the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. From left are Mission Specialists Barbara R. Morgan, Dave Williams and Rick Mastracchio. Williams represents the Canadian Space Agency. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. TCDT activities include M-113 armored personnel carrier training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew arrives at Kennedy's Shuttle Landing Facility aboard a Shuttle Training Aircraft to take part in the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. From left are Mission Specialist Barbara R. Morgan, Commander Scott Kelly and Mission Specialist Alvin Drew. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. TCDT activities include M-113 armored personnel carrier training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew arrives at Kennedy's Shuttle Landing Facility aboard a Shuttle Training Aircraft to take part in the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. From left are Mission Specialists Alvin Drew; Barbara R. Morgan; Dave Williams, representing the Canadian Space Agency; Rick Mastracchio; Tracy Caldwell; Pilot Charlie Hobaugh and Commander Scott Kelly. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. TCDT activities include M-113 armored personnel carrier training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew arrives at Kennedy's Shuttle Landing Facility aboard a Shuttle Training Aircraft to take part in the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. Shuttle Launch Director Mike Leinbach (left) welcomes Mission Specialists Tracy Caldwell, Rick Mastracchio and Dave Williams of the Canadian Space Agency, as Commander Scott Kelly (back to camera) looks on. TCDT activities include M-113 armored personnel carrier training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew arrives at Kennedy's Shuttle Landing Facility aboard a Shuttle Training Aircraft to take part in the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. Mission Specialist Barbara R. Morgan, NASA's first educator astronaut, acknowledges those who have turned out to welcome them. TCDT activities include M-113 armored personnel carrier training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, FLA. -- The STS-118 crew arrives at Kennedy's Shuttle Landing Facility aboard a Shuttle Training Aircraft to take part in the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. Shuttle Launch Director Mike Leinbach (left) welcomes Commander Scott Kelly (right). TCDT activities include M-113 armored personnel carrier training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew gets instructions on emergency exit procedures from Launch Pad 39A. From left are Mission Specialist Rick Mastracchio, Pilot Charlie Hobaugh, Mission Specialist Alvin Drew, Commander Scott Kelly, and Mission Specialists Tracy Caldwell, Dave Williams and Barbara R. Morgan, whojoined NASA's Teacher in Space program in 1985. She was selected as an astronaut in 1998. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew arrives at Kennedy's Shuttle Landing Facility aboard a Shuttle Training Aircraft to take part in the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. From left are Mission Specialist Barbara R. Morgan, Commander Scott Kelly and Mission Specialist Alvin Drew. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. DT activities include M-113 armored personnel carrier training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew arrives at Kennedy's Shuttle Landing Facility aboard a Shuttle Training Aircraft to take part in the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. Commander Scott Kelly (at microphone) introduces his crew to media representatives on site to welcome them. From left are Mission Specialists Alvin Drew; Barbara R. Morgan; Dave Williams, representing the Canadian Space Agency; Rick Mastracchio; Tracy Caldwell; and Pilot Charlie Hobaugh. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. TCDT activities include M-113 armored personnel carrier training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Alvin Drew completes suitup for the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Tracy Caldwell fixes her helmet during suitup for the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Pilot Charlie Hobaugh suits up for the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Barbara R. Morgan finishes suitup for the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Tracy Caldwell suits up for the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Dave Williams, who represents the Canadian Space Agency, is eager to start the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Alvin Drew is eager to begin the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Pilot Charlie Hobaugh's launch and entry suit is monitored after his suitup for the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Rick Mastracchio gets help suiting up before the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Dave Williams, who represents the Canadian Space Agency, completes suitup before the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Commander Scott Kelly's launch and entry suit is monitored after his suitup for the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Rick Mastracchio adjusts his helmet during suitup before the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Commander Scott Kelly gets help suiting up before the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Barbara R. Morgan gets help with the fit of her launch and entry suit during Terminal Countdown Demonstration Test (TCDT) activities, a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Rick Mastracchio gets help with the fit of his launch and entry suit during Terminal Countdown Demonstration Test (TCDT) activities, a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Tracy Caldwell tests the fit of her helmet and launch and entry suit during Terminal Countdown Demonstration Test (TCDT) activities, a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- In the slidewire basket bunker area of Launch Pad 39A, STS-118 Mission Specialist Dave Williams is introduced to the press during a media interview before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. Williams represents the Canadian Space Agency. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- On the slidewire basket bunker area of Launch Pad 39A, STS-118 Commander Scott Kelly talks to the media before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Alvin Drew gets help with the fit of his launch and entry suit during Terminal Countdown Demonstration Test (TCDT) activities, a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Barbara R. Morgan checks the fit of her helmet during Terminal Countdown Demonstration Test (TCDT) activities, a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Dave Williams gets help with his boot during fit testing of his launch and entry suit. He and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT) activities, a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Dave Williams tests the fit of his launch and entry suit during Terminal Countdown Demonstration Test (TCDT) activities, a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Rick Mastracchio tests the fit of his helmet as well as the launch and entry suit. He and other crew members are at Kennedy for the Terminal Countdown Demonstration Test (TCDT) activities, a dress rehearsal for launch. TCDT activities include the M-113 training, payload familiarization, emergency egress training at the pad and a simulated launch countdown. The STS-118 payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew walks out of the Operations and Checkout Building, heading for Launch Pad 39A and a simulated launch countdown. On the left, Pilot Charlie Hobaugh leads one column, with Mission Specialist Rick Mastracchio behind him. On the right, Commander Scott Kelly leads, with Mission Specialists Tracy Caldwell and Dave Williams behind. Not pictured are Mission Specialists Alvin Drew and teacher-turned-astronaut Barbara R. Morgan. The countdown concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- The smiling STS-118 crew walks toward the Astrovan that will take them to Launch Pad 39A for a simulated launch countdown. From left are Mission Specialists Barbara R. Morgan and Rick Mastracchio, Pilot Charlie Hobaugh, Mission Specialists Dave Williams and Tracy Caldwell, and Commander Scott Kelly. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. The countdown concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew walks toward the Astrovan that will take them to Launch Pad 39A for a simulated launch countdown. From left are Mission Specialists Barbara R. Morgan and Rick Mastracchio, Pilot Charlie Hobaugh, Mission Specialists Dave Williams and Tracy Caldwell, and Commander Scott Kelly. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. The countdown concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew heads into the Astrovan that will take them to Launch Pad 39A for a simulated launch countdown. First in is Commander Scott Kelly. Following, right to left, are Pilot Charlie Hobaugh and Mission Specialists Tracy Caldwell, Dave Williams, Rick Mastracchio, teacher-turned-astronaut Barbara R. Morgan and Alvin Drew. The countdown concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Barbara R. Morgan is helped with her helmet during suitup for the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. Teacher-turn-astronaut Morgan is making her first space flight. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew walks toward the Astrovan that will take them to Launch Pad 39A for a simulated launch countdown. On the left are Pilot Charlie Hobaugh leading the way and Mission Specialist Rick Mastracchio. ON the right, Commander Scott Kelly leads with (front to back) Mission Specialists Tracy Caldwell, Dave Williams and Alvin Drew. Not visible is teacher-turned-astronaut Barbara R. Morgan, also a mission specialist. The countdown concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- On the slidewire basket bunker area of Launch Pad 39A, the STS-118 crew talks to the media before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. At right, Mission Specialist Tracy Caldwell has the microphone. The others, from left, are Commander Scott Kelly, Pilot Charlie Hobaugh and Mission Specialists Alvin Drew, Rick Mastracchio, Dave Williams and Barbara Morgan. Williams represents the Canadian Space Agency. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- In the slidewire basket bunker area of Launch Pad 39A, STS-118 Mission Specialist Barbara R. Morgan reacts to the waiting press during a media interview before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. Morgan is a teacher-turned-astronaut whose association with NASA began more than 20 years ago. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- In the slidewire basket bunker area of Launch Pad 39A, STS-118 Mission Specialist Barbara R. Morgan is introduced to the press during a media interview before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. Morgan is a teacher-turned-astronaut whose association with NASA began more than 20 years ago. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- On an upper level of the Pad 39A fixed service structure, the STS-118 crew get instructions from a trainer about using the emergency egress system. The crew members seen here are, from left, Commander Scott Kelly and Mission Specialists Barbara R. Morgan, Tracy Caldwell and Dave Williams. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. Williams represents the Canadian Space Agency. The crew is at Kennedy for training activities in the terminal countdown demonstration test, or TCDT. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- On the slidewire basket bunker area of Launch Pad 39A, the STS-118 crew greets the media before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. From left are Commander Scott Kelly, Pilot Charlie Hobaugh and Mission Specialists Alvin Drew, Rick Mastracchio, Dave Williams, Barbara R. Morgan and Tracy Caldwell. Williams represents the Canadian Space Agency. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- On the slidewire basket bunker area of Launch Pad 39A, the STS-118 crew talks to the media before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. At left is Commander Scott Kelly, with the microphone. The others, from left, are Pilot Charlie Hobaugh and Mission Specialists Alvin Drew, Rick Mastracchio, Dave Williams, Barbara R. Morgan and Tracy Caldwell. Williams represents the Canadian Space Agency. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- On an upper level of the Pad 39A fixed service structure, the STS-118 crew members look at the slidewire basket that is part of the emergency egress system. On the left are Commander Scott Kelly and Mission Specialists Barbara R. Morgan, Tracy Caldwell, Dave Williams and Alvin Drew. On the right is Mission Specialist Rick Mastracchio. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. Williams represents the Canadian Space Agency. The crew is at Kennedy for training activities in the terminal countdown demonstration test, or TCDT. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- On the slidewire basket bunker area of Launch Pad 39A, STS-118 educator astronaut and Mission Specialist Barbara R. Morgan responds to a question from the media before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- Members of the STS-118 crew enjoy breakfast together before the next event in their Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. Following the meal, the crew will don their flight suits and board Space Shuttle Endeavour for a simulated countdown. From left are Mission Specialists Alvin Drew and the Canadian Space Agency's Dave Williams, Pilot Charlie Hobaugh, Commander Scott Kelly, and Mission Specialists Tracy Caldwell, Rick Mastracchio and teacher-turned-astronaut Barbara R. Morgan. TCDT activities also include M-113 armored personnel carrier training, payload familiarization, and emergency egress training at the pad. The STS-118 payload includes the S5 truss, a SPACEHAB module and external stowage platform 3. The mission is the 22nd flight to the International Space Station and is targeted for launch on Aug.7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- In the slidewire basket bunker area of Launch Pad 39A, STS-118 Pilot Charlie Hobaugh waits to begin a media interview before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. Those activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- In the slidewire basket bunker area of Launch Pad 39A, STS-118 Mission Specialist Alvin Drew waits to begin a media interview before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. Those activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- In the slidewire basket bunker area of Launch Pad 39A, STS-118 Commander Scott Kelly waits to begin a media interview before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. Those activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- In the slidewire basket bunker area of Launch Pad 39A, STS-118 Mission Specialist Tracy Caldwell reacts to the waiting press during a media interview before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. Those activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. --In the White Room on Launch Pad 39A, STS-118 Mission Specialist Rick Mastracchio is eager to enter Space Shuttle Endeavour for a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- In the slidewire basket bunker area of Launch Pad 39A, STS-118 Mission Specialist Tracy Caldwell reacts to the waiting press during a media interview before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. Those activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- In the slidewire basket bunker area of Launch Pad 39A, STS-118 Mission Specialist Rick Mastracchio waits to begin a media interview before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. Those activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- In the slidewire basket bunker area of Launch Pad 39A, STS-118 Commander Scott Kelly talks to the media at a press conference before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. Those activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- In the White Room on Launch Pad 39A, the closeout crew prepares STS-118 Commander Scott Kelly's launch and entry suit before he enters Space Shuttle Endeavour. Kelly and the rest of the crew are taking part in a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- In the White Room on Launch Pad 39A, the closeout crew prepares the launch and entry suit on STS-118 Mission Specialist Dave Williams before he enters Space Shuttle Endeavour. Williams, who represents the Canadian Space Agency, and the rest of the crew are taking part in a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- STS-118 Commander Scott Kelly climbs aboard the shuttle training aircraft, known as an STA, for landing practice. The practice is part of Terminal Countdown Demonstration Test, or TCDT, activities that include a simulated launch countdown.The STA is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. The STS-118 mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. The mission payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- One of two shuttle training aircraft, or STA, taxis out to the runway at the Shuttle Landing Facility. STS-118 Commander Scott Kelly and Pilot Charlie Hobaugh are each piloting one of the STAs for landing practice. The practice is part of Terminal Countdown Demonstration Test, or TCDT, activities that include a simulated launch countdown. The STA is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. The STS-118 mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. The mission payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- In the White Room on Launch Pad 39A, the closeout crew prepares the launch and entry suit on STS-118 Mission Specialist Barbara R. Morgan before she enters Space Shuttle Endeavour. Morgan, the teacher-turned-astronaut, and the rest of the crew are taking part in a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- In the White Room on Launch Pad 39A, the closeout crew prepares the launch and entry suit on STS-118 Mission Specialist Rick Mastracchio before he enters Space Shuttle Endeavour. Mastracchio and the rest of the crew are taking part in a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- In the White Room on Launch Pad 39A, STS-118 Mission Specialist Alvin Drew adjusts his launch and entry suit before he enters Space Shuttle Endeavour. Drew and the rest of the crew are taking part in a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- STS-118 Commander Scott Kelly checks the fit of his launch and entry suit. The fitting is part of the Terminal Countdown Demonstration Test, or TCDT, activities that include a simulated launch countdown. Kelly is suiting up also for landing practice in the shuttle training aircraft, known as an STA. The STA is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. The STS-118 mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. The mission payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- STS-118 Commander Scott Kelly settles in his cockpit seat aboard the shuttle training aircraft, known as an STA, for landing practice. The practice is part of Terminal Countdown Demonstration Test, or TCDT, activities that include a simulated launch countdown. The STA is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. The STS-118 mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. The mission payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- Two shuttle training aircraft, or STAs, wait to taxi onto the runway at the Shuttle Landing Facility. STS-118 Commander Scott Kelly and Pilot Charlie Hobaugh are each piloting one of the STAs for landing practice. The practice is part of Terminal Countdown Demonstration Test, or TCDT, activities that include a simulated launch countdown. The STA is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. The STS-118 mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. The mission payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- On the top level of the Pad 39A fixed service structure, the STS-118 crew takes a break from training activities in the terminal countdown demonstration test, or TCDT. From left are Mission Specialists Dave Williams, Tracy Caldwell, Barbara R. Morgan and Alvin Drew, Pilot Charlie Hobaugh, Commander Scott Kelly and Mission Specialist Rick Mastracchio. Williams represents the Canadian Space Agency. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. Behind them is the top of the external tank. TCDTactivities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- On Launch Pad 39A, STS-118 Mission Specialist Tracy Caldwell makes her way to the White Room. There she will have her launch and entry suit prepared for liftoff by the closeout crew. Caldwell and the rest of the crew are taking part n a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew arrives on Launch Pad 39A for a media interview before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. From left are Mission Specialists Dave Williams and Rick Mastracchio, Pilot Charlie Hobaugh and Mission Specialist Alvin Drew. Williams represents the Canadian Space Agency. TCDTactivities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/Ken Thornsley

KENNEDY SPACE CENTER, Fla. -- In the White Room on Launch Pad 39A, the closeout crew prepares the launch and entry suit on STS-118 Pilot Charlie Hobaugh before he enters Space Shuttle Endeavour. Hobaugh and the rest of the crew are taking part in a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- In the White Room on Launch Pad 39A, STS-118 Mission Specialist Dave Williams waits for the closeout crew to finish checking his launch and entry suit before he enters Space Shuttle Endeavour. Behind Williams is Pilot Charlie Hobaugh. Williams, who represents the Canadian Space Agency, and the rest of the crew are taking part in a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- STS-118 Commander Scott Kelly, left, and Pilot Charlie Hobaugh check the fit of their launch and entry suits. The fitting is part of the Terminal Countdown Demonstration Test, or TCDT, activities that include a simulated launch countdown. Kelly and Hobaugh are suiting up also for landing practice in the shuttle training aircraft, known as an STA. The STA is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. The STS-118 mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. The mission payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- On an upper level of the Pad 39A fixed service structure, the STS-118 crew members get directions about using the slidewire basket that is part of the emergency egress system. At right, Mission Specialist Tracy Caldwell identifies the pull lever to release the basket. At far left is Mission Specialist Dave Williams, who represents the Canadian Space Agency. At center is Mission Specialist Alvin Drew. The crew is at Kennedy for terminal countdown demonstration test, or TCDT, training activities. Those activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- In the White Room on Launch Pad 39A, STS-118 Mission Specialist Alvin Drew adjusts his launch and entry suit before he enters Space Shuttle Endeavour. Drew and the rest of the crew are taking part in a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- In the White Room on Launch Pad 39A, STS-118 Pilot Charlie Hobaugh waits for the closeout crew to finish checking his launch and entry suit before he enters Space Shuttle Endeavour. Hobaugh and the rest of the crew are taking part in a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- Dressed in their launch and entry suits, STS-118 Pilot Charlie Hobaugh and Commander Scott Kelly (waving) are headed for the runway for landing practice in the shuttle training aircraft, known as an STA. The practice is part of Terminal Countdown Demonstration Test, or TCDT, activities that include a simulated launch countdown. The STA is a Grumman American Aviation-built Gulf Stream II jet that was modified to simulate an orbiter's cockpit, motion and visual cues, and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. The STS-118 mission is the 22nd flight to the International Space Station and is targeted for launch on Aug. 7. The mission payload aboard Space Shuttle Endeavour includes the S5 truss, a SPACEHAB module and external stowage platform 3. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- In the White Room on Launch Pad 39A, the closeout crew prepares the launch and entry suit on STS-118 Mission Specialist Tracy Caldwell before she enters Space Shuttle Endeavour. Caldwell and the rest of the crew are taking part in a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- In the White Room on Launch Pad 39A, STS-118 Commander Scott Kelly adjusts his launch and entry suit before he enters Space Shuttle Endeavour. Kelly and the rest of the crew are taking part in a simulated launch countdown, the culmination of terminal countdown demonstration test activities. The White Room is situated at the end of the orbiter access arm and provides entry into the orbiter. TCDT activities also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, Fla. -- Back on the slidewire landing area of Pad 39A, the STS-118 crew learns about landing in the baskets in the event of an emergency. From left are Mission Specialist Rick Mastracchio, Commander Scott Kelly, Mission Specialists Barbara R. Morgan, Alvin Drew, Dave Williams and Tracy Caldwell, and Pilot Charlie Hobaugh. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. Williams represents the Canadian Space Agency. The crew is at Kennedy for training activities in the terminal countdown demonstration test, or TCDT. TCDTactivities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- On an upper level of the Pad 39A fixed service structure, the STS-118 crew listen to a trainer, at left, about using the emergency egress system. The crew members are, from left, Commander Scott Kelly, Mission Specialists Tracy Caldwell, Barbara R. Morgan, Dave Williams and Alvin Drew, Pilot Charlie Hobaugh and Mission Specialist Rick Mastracchio. Williams represents the Canadian Space Agency. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. The crew is at Kennedy for training activities in the terminal countdown demonstration test, or TCDT. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- On an upper level of the Pad 39A fixed service structure, the STS-118 crew members get directions about using the slidewire basket that is part of the emergency egress system. At left is Mission Specialist Rick Mastracchio. At right are (from the left) Commander Scott Kelly, Mission Specialist Barbara R. Morgan, Pilot Charlie Hobaugh and Mission Specialists Dave Williams and Alvin Drew. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. Williams represents the Canadian Space Agency. The crew is at Kennedy for training activities in the terminal countdown demonstration test, or TCDT. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew poses in front of the hatch opening on Space Shuttle Endeavour before the crew's morning training activities in the terminal countdown demonstration test, or TCDT. Standing at left is Mission Specialist Dave Williams. Standing in the back are Commander Scott Kelly (left) and Mission Specialist Alvin Drew; seated in the middle are Mission Specialists Tracy Caldwell (left) and Barbara R. Morgan; kneeling in front are Pilot Charlie Hobaugh (left) and Mission Specialist Rick Mastracchio. Williams represents the Canadian Space Agency. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- The STS-118 crew poses for a photo on Launch Pad 39A during training activities in the terminal countdown demonstration test, or TCDT. From left are Mission Specialists Dave Williams and Barbara R. Morgan, Commander Scott Kelly, Mission Specialist Alvin Drew, Pilot Charlie Hobaugh, and Mission Specialists Rick Mastracchio and Tracy Caldwell. Williams represents the Canadian Space Agency. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. Behind them can be seen the solid rocket boosters and external tank of Space Shuttle Endeavour atop the mobile launcher platform. TCDT activities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton

KENNEDY SPACE CENTER, Fla. -- On the top level of the Pad 39A fixed service structure, the STS-118 crew takes a break from training activities in the terminal countdown demonstration test, or TCDT. From left are Mission Specialist Dave Williams, Pilot Charlie Hobaugh, Mission Specialist Alvin Drew, Commander Scott Kelly and Mission Specialists Tracy Caldwell, Barbara R. Morgan and Rick Mastracchio. Williams represents the Canadian Space Agency. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. Behind them is the top of the external tank and a solid rocket booster. TCDTactivities include M-113 training, payload familiarization, the emergency egress training at the pad and a simulated launch countdown. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton