KENNEDY SPACE CENTER, FLA. -- A suit technician helps Space shuttle Atlantis STS-122 Mission Specialist Rex Walheim put on his launch and entry suit, preparing for launch. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT provides astronauts and ground crews with equipment familiarization, emergency egress training and a simulated launch countdown. On mission STS-122, Atlantis will deliver the Columbus module to the International Space Station. The European Space Agency's largest single contribution to the station, Columbus is a multifunctional, pressurized laboratory that will be permanently attached to U.S. Node 2, called Harmony. The laboratory will expand the research facilities aboard the station, providing crew members and scientists from around the world the ability to conduct a variety of experiments in the physical, materials and life sciences. Launch is targeted for Dec. 6. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Space shuttle Atlantis STS-122 Mission Specialist Stanley Love has his helmet fitted on his launch and entry suit, preparing for launch. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT provides astronauts and ground crews with equipment familiarization, emergency egress training and a simulated launch countdown. On mission STS-122, Atlantis will deliver the Columbus module to the International Space Station. The European Space Agency's largest single contribution to the station, Columbus is a multifunctional, pressurized laboratory that will be permanently attached to U.S. Node 2, called Harmony. The laboratory will expand the research facilities aboard the station, providing crew members and scientists from around the world the ability to conduct a variety of experiments in the physical, materials and life sciences. Launch is targeted for Dec. 6. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Space shuttle Atlantis STS-122 Mission Specialist Stanley Love tries on his launch and entry suit, preparing for launch. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT provides astronauts and ground crews with equipment familiarization, emergency egress training and a simulated launch countdown. On mission STS-122, Atlantis will deliver the Columbus module to the International Space Station. The European Space Agency's largest single contribution to the station, Columbus is a multifunctional, pressurized laboratory that will be permanently attached to U.S. Node 2, called Harmony. The laboratory will expand the research facilities aboard the station, providing crew members and scientists from around the world the ability to conduct a variety of experiments in the physical, materials and life sciences. Launch is targeted for Dec. 6. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Space shuttle Atlantis STS-122 Mission Specialist Rex Walheim has his helmet fitted on his launch and entry suit, preparing for launch. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT provides astronauts and ground crews with equipment familiarization, emergency egress training and a simulated launch countdown. On mission STS-122, Atlantis will deliver the Columbus module to the International Space Station. The European Space Agency's largest single contribution to the station, Columbus is a multifunctional, pressurized laboratory that will be permanently attached to U.S. Node 2, called Harmony. The laboratory will expand the research facilities aboard the station, providing crew members and scientists from around the world the ability to conduct a variety of experiments in the physical, materials and life sciences. Launch is targeted for Dec. 6. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Space shuttle Atlantis STS-122 Mission Specialist Leland Melvin tries on his launch and entry suit, preparing for launch. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT provides astronauts and ground crews with equipment familiarization, emergency egress training and a simulated launch countdown. On mission STS-122, Atlantis will deliver the Columbus module to the International Space Station. The European Space Agency's largest single contribution to the station, Columbus is a multifunctional, pressurized laboratory that will be permanently attached to U.S. Node 2, called Harmony. The laboratory will expand the research facilities aboard the station, providing crew members and scientists from around the world the ability to conduct a variety of experiments in the physical, materials and life sciences. Launch is targeted for Dec. 6. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Space shuttle Atlantis STS-122 Mission Specialist Leland Melvin tries on the gloves of his launch and entry suit, preparing for launch. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT provides astronauts and ground crews with equipment familiarization, emergency egress training and a simulated launch countdown. On mission STS-122, Atlantis will deliver the Columbus module to the International Space Station. The European Space Agency's largest single contribution to the station, Columbus is a multifunctional, pressurized laboratory that will be permanently attached to U.S. Node 2, called Harmony. The laboratory will expand the research facilities aboard the station, providing crew members and scientists from around the world the ability to conduct a variety of experiments in the physical, materials and life sciences. Launch is targeted for Dec. 6. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. - STS-125 Mission Specialist Andrew Feustel is helped by suit technicians to don a harness over his launch and entry suit before entering space shuttle Atlantis for a simulated launch countdown. The countdown is the culmination of terminal countdown demonstration test, or TCDT, activities as preparation before launch. TCDT provides astronauts and ground crews with an opportunity to participate in various launch activities, including equipment familiarization, emergency training and the countdown. Atlantis’ STS-125 mission to service NASA’s Hubble Space Telescope is targeted for launch Oct. 14. Photo credit: NASA/Amanda Diller

CAPE CANAVERAL, Fla. - STS-125 Mission Specialist Michael Good is helped by suit technicians to don a harness over his launch and entry suit before entering space shuttle Atlantis for a simulated launch countdown. The countdown is the culmination of terminal countdown demonstration test, or TCDT, activities as preparation before launch. TCDT provides astronauts and ground crews with an opportunity to participate in various launch activities, including equipment familiarization, emergency training and the countdown. Atlantis’ STS-125 mission to service NASA’s Hubble Space Telescope is targeted for launch Oct. 14. Photo credit: NASA/Amanda Diller

CAPE CANAVERAL, Fla. - STS-125 Mission Specialist Mike Massimino s helped by a suit technician to don a harness over his launch and entry suit before entering space shuttle Atlantis for a simulated launch countdown. The countdown is the culmination of terminal countdown demonstration test, or TCDT, activities as preparation before launch. TCDT provides astronauts and ground crews with an opportunity to participate in various launch activities, including equipment familiarization, emergency training and the countdown. Atlantis’ STS-125 mission to service NASA’s Hubble Space Telescope is targeted for launch Oct. 14. Photo credit: NASA/Amanda Diller

CAPE CANAVERAL, Fla. - STS-125 Commander Scott Altman is helped by a suit technician to don a harness over his launch and entry suit before entering space shuttle Atlantis for a simulated launch countdown. The countdown is the culmination of terminal countdown demonstration test, or TCDT, activities as preparation before launch. TCDT provides astronauts and ground crews with an opportunity to participate in various launch activities, including equipment familiarization, emergency training and the countdown. Atlantis’ STS-125 mission to service NASA’s Hubble Space Telescope is targeted for launch Oct. 14. Photo credit: NASA/Amanda Diller

The crew of STS-90 participate in Terminal Countdown Demonstration Test (TCDT) activities at KSC's Launch Pad 39B. The TCDT is held at KSC prior to each Space Shuttle flight to provide crews with the opportunity to participate in simulated countdown activities. Here, STS-90 Pilot Scott Altman gives a "thumbs-up" after being suited up in his orange launch and re-entry suit. Columbia is targeted for launch of STS-90 on April 16 at 2:19 p.m. EDT and will be the second mission of 1998. The mission is scheduled to last nearly 17 days

The crew of STS-90 participate in Terminal Countdown Demonstration Test (TCDT) activities at KSC's Launch Pad 39B. The TCDT is held at KSC prior to each Space Shuttle flight to provide crews with the opportunity to participate in simulated countdown activities. Here, Mission Specialist Kathryn (Kay) Hire gives a "thumbs-up" to the mission after being suited up in her orange launch and re-entry suit. Columbia is targeted for launch of STS-90 on April 16 at 2:19 p.m. EDT and will be the second mission of 1998. The mission is scheduled to last nearly 17 days

KENNEDY SPACE CENTER, FLA. -- STS-120 Mission Specialist Doug Wheelock tries on his launch and entry suit to prepare for launch. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT also includes emergency egress procedures, equipment familiarization and a simulated launch countdown. Mission STS-120, which will carry the Italian-built U.S. Node 2 to the International Space Station, is targeted for launch on Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-120 Mission Specialist Stephanie Wilson tries on her launch and entry suit, preparing for launch. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT also includes emergency egress procedures, equipment familiarization and a simulated launch countdown. Mission STS-120, which will carry the Italian-built U.S. Node 2 to the International Space Station, is targeted for launch on Oct. 23. Photo credit: NASA/Kim Shiflett

The crew of STS-90 participate in Terminal Countdown Demonstration Test (TCDT) activities at KSC's Launch Pad 39B. The TCDT is held at KSC prior to each Space Shuttle flight to provide crews with the opportunity to participate in simulated countdown activities. Here, Payload Specialist Jay Buckey, M.D., is assisted with his orange launch and re-entry suit by a USA technician. Columbia is targeted for launch of STS-90 on April 16 at 2:19 p.m. EDT and will be the second mission of 1998. The mission is scheduled to last nearly 17 days

CAPE CANAVERAL, Fla. - At Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-131 Commander Alan Poindexter, at right in the orange suit, prepares to enter space shuttle Discovery from the pad's White Room. The members of space shuttle Discovery's STS-131 crew, dressed in their launch-and-entry suits, are participating in the Terminal Countdown Demonstration Test, or TCDT, a dress rehearsal for launch. TCDT includes training on the emergency exit systems at the launch pad, driving practice of the M-113 armored personnel carrier and a simulated launch countdown. The crew will deliver the multi-purpose logistics module Leonard, filled with resupply stowage platforms and science racks, to the International Space Station. STS-131, targeted for launch on April 5, will be the 33rd shuttle mission to the station and the 131st shuttle mission overall. For information on the STS-131 mission and crew, visit http:__www.nasa.gov_mission_pages_shuttle_shuttlemissions_sts131_index.htm. Photo credit: NASA_Regina Mitchell-Ryall

CAPE CANAVERAL, Fla. - At Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-131 Commander Alan Poindexter, in the orange suit, prepares to enter space shuttle Discovery from the pad's White Room. The members of space shuttle Discovery's STS-131 crew, dressed in their launch-and-entry suits, are participating in the Terminal Countdown Demonstration Test, or TCDT, a dress rehearsal for launch. TCDT includes training on the emergency exit systems at the launch pad, driving practice of the M-113 armored personnel carrier and a simulated launch countdown. The crew will deliver the multi-purpose logistics module Leonardo, filled with resupply stowage platforms and science racks, to the International Space Station. STS-131, targeted for launch on April 5, will be the 33rd shuttle mission to the station and the 131st shuttle mission overall. For information on the STS-131 mission and crew, visit http:__www.nasa.gov_mission_pages_shuttle_shuttlemissions_sts131_index.htm. Photo courtesy of Scott Andrews

CAPE CANAVERAL, Fla. - In the Operations and Checkout Building at NASA's Kennedy Space Center in Florida, STS-131 Pilot James P. Dutton Jr. suits up for his first practice countdown. The members of space shuttle Discovery's STS-131 crew put on their launch-and-entry suits before heading to the Astrovan for the ride to Launch Pad 39A. The crew is participating in the Terminal Countdown Demonstration Test, or TCDT, a dress rehearsal for launch. TCDT includes training on the emergency egress systems at the launch pad, driving practice of the M-113 armored personnel carrier and a simulated launch countdown. The crew will deliver the multi-purpose logistics module Leonard, filled with resupply stowage platforms and science racks, to the International Space Station. STS-131, targeted for launch on April 5, will be the 33rd shuttle mission to the station and the 131st shuttle mission overall. For information on the STS-131 mission and crew, visit http:__www.nasa.gov_mission_pages_shuttle_shuttlemissions_sts131_index.htm. Photo credit: NASA_Kim Shiflett

CAPE CANAVERAL, Fla. - In the Operations and Checkout Building at NASA's Kennedy Space Center in Florida, STS-131 Mission Specialist Rick Mastracchio suits up for his third practice countdown. The members of space shuttle Discovery's STS-131 crew put on their launch-and-entry suits before heading to the Astrovan for the ride to Launch Pad 39A. The crew is participating in the Terminal Countdown Demonstration Test, or TCDT, a dress rehearsal for launch. TCDT includes training on the emergency egress systems at the launch pad, driving practice of the M-113 armored personnel carrier and a simulated launch countdown. The crew will deliver the multi-purpose logistics module Leonard, filled with resupply stowage platforms and science racks, to the International Space Station. STS-131, targeted for launch on April 5, will be the 33rd shuttle mission to the station and the 131st shuttle mission overall. For information on the STS-131 mission and crew, visit http:__www.nasa.gov_mission_pages_shuttle_shuttlemissions_sts131_index.htm. Photo credit: NASA_Kim Shiflett

KENNEDY SPACE CENTER, FLA. - The STS-115 crew members are suiting up for their simulated launch countdown. Shown here is Mission Specialist Steven MacLean, who is with the Canadian Space Agency. The mission crew is at KSC for Terminal Countdown Demonstration Test (TCDT) activities that are preparation for launch on Space Shuttle Atlantis, scheduled to take place in a window that opens Aug. 27. The TCDT has included emergency egress training as well as the simulation. During their 11-day mission to the International Space Station, the STS-115 crew will continue construction of the station and attach the payload elements, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Cory Huston

KENNEDY SPACE CENTER, FLA. -- STS-123 Mission Specialist Rick Linnehan is fully suited for the launch dress rehearsal, culmination of the terminal countdown demonstration test, or TCDT. The TCDT provides astronauts and ground crews with an opportunity to participate in various simulated countdown activities, including equipment familiarization and emergency training. Space shuttle Endeavour is targeted to launch March 11 at 2:28 a.m. EDT on the 16-day STS-123 mission to the International Space Station. Endeavour and its crew will deliver the first section of the Japan Aerospace Exploration Agency's Kibo laboratory and the Canadian Space Agency's two-armed robotic system, Dextre. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-123 Mission Specialist Mike Foreman is ready to finish suiting up for the launch dress rehearsal, culmination of the terminal countdown demonstration test, or TCDT. The TCDT provides astronauts and ground crews with an opportunity to participate in various simulated countdown activities, including equipment familiarization and emergency training. Space shuttle Endeavour is targeted to launch March 11 at 2:28 a.m. EDT on the 16-day STS-123 mission to the International Space Station. Endeavour and its crew will deliver the first section of the Japan Aerospace Exploration Agency's Kibo laboratory and the Canadian Space Agency's two-armed robotic system, Dextre. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-123 Pilot Gregory H. Johnson is ready to finish suiting up for the launch dress rehearsal, culmination of the terminal countdown demonstration test, or TCDT. The TCDT provides astronauts and ground crews with an opportunity to participate in various simulated countdown activities, including equipment familiarization and emergency training. Space shuttle Endeavour is targeted to launch March 11 at 2:28 a.m. EDT on the 16-day STS-123 mission to the International Space Station. Endeavour and its crew will deliver the first section of the Japan Aerospace Exploration Agency's Kibo laboratory and the Canadian Space Agency's two-armed robotic system, Dextre. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-123 Mission Specialist Robert L. Behnken is fully suited for the launch dress rehearsal, culmination of the terminal countdown demonstration test, or TCDT. The TCDT provides astronauts and ground crews with an opportunity to participate in various simulated countdown activities, including equipment familiarization and emergency training. Space shuttle Endeavour is targeted to launch March 11 at 2:28 a.m. EDT on the 16-day STS-123 mission to the International Space Station. Endeavour and its crew will deliver the first section of the Japan Aerospace Exploration Agency's Kibo laboratory and the Canadian Space Agency's two-armed robotic system, Dextre. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-120 Mission Specialist Doug Wheelock has his helmet fitted on his launch and entry suit, preparing for launch. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT also includes emergency egress procedures, equipment familiarization and a simulated launch countdown. Mission STS-120, which will carry the Italian-built U.S. Node 2 to the International Space Station, is targeted for launch on Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-116 Mission Specialist Christer Fuglesang checks his helmet during suit fit-check, part of the prelaunch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. Fuglesang represents the European Space Agency. The STS-116 mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - As part of pre-pack and fit check for Terminal Countdown Demonstration Test (TCDT) activities, STS-114 Mission Specialist Stephen Robinson signals okay for his launch suit check. The TCDT is held at KSC prior to each Space Shuttle flight. It provides the crew of each mission an opportunity to participate in simulated countdown activities. The test ends with a mock launch countdown culminating in a simulated main engine cutoff. The crew also spends time undergoing emergency egress training exercises at the launch pad. STS-114 is the first Return to Flight mission to the International Space Station. The launch window extends July 13 through July 31.

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. - The STS-115 crew members are suiting up for their simulated launch countdown. Shown Shown here is Mission Specialist Daniel Burbank. The mission crew is at KSC for Terminal Countdown Demonstration Test (TCDT) activities that are preparation for launch on Space Shuttle Atlantis, scheduled to take place in a window that opens Aug. 27. The TCDT has included emergency egress training as well as the simulation. During their 11-day mission to the International Space Station, the STS-115 crew will continue construction of the station and attach the payload elements, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Cory Huston

KENNEDY SPACE CENTER, FLA. - The STS-115 crew members are suiting up for their simulated launch countdown. Shown here is Commander Brent Jett. The mission crew is at KSC for Terminal Countdown Demonstration Test (TCDT) activities that are preparation for launch on Space Shuttle Atlantis, scheduled to take place in a window that opens Aug. 27. The TCDT has included emergency egress training as well as the simulation. During their 11-day mission to the International Space Station, the STS-115 crew will continue construction of the station and attach the payload elements, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Cory Huston

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. -- 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 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 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. - The STS-115 crew members are suiting up for their simulated launch countdown. Shown here is Mission Specialist Heidemarie Stefanyshyn-Piper. The mission crew is at KSC for Terminal Countdown Demonstration Test (TCDT) activities that are preparation for launch on Space Shuttle Atlantis, scheduled to take place in a window that opens Aug. 27. The TCDT has included emergency egress training as well as the simulation. During their 11-day mission to the International Space Station, the STS-115 crew will continue construction of the station and attach the payload elements, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Cory Huston

KENNEDY SPACE CENTER, FLA. -- STS-120 Mission Specialist Paolo Nespoli has his helmet fitted on his launch and entry suit, preparing for launch. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT also includes emergency egress procedures, equipment familiarization and a simulated launch countdown. Mission STS-120, which will carry the Italian-built U.S. Node 2 to the International Space Station, is targeted for launch on Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - The STS-115 crew members are suiting up for their simulated launch countdown. Shown here being helped with his helmet is Pilot Christopher Ferguson. The mission crew is at KSC for Terminal Countdown Demonstration Test (TCDT) activities that are preparation for launch on Space Shuttle Atlantis, scheduled to take place in a window that opens Aug. 27. The TCDT has included emergency egress training as well as the simulation. During their 11-day mission to the International Space Station, the STS-115 crew will continue construction of the station and attach the payload elements, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Cory Huston

KENNEDY SPACE CENTER, FLA. - As part of pre-pack and fit check for Terminal Countdown Demonstration Test (TCDT) activities, STS-114 Mission Specialist Charles Camarda has his launch suit checked for fit. The TCDT is held at KSC prior to each Space Shuttle flight. It provides the crew of each mission an opportunity to participate in simulated countdown activities. The test ends with a mock launch countdown culminating in a simulated main engine cutoff. The crew also spends time undergoing emergency egress training exercises at the launch pad. STS-114 is the first Return to Flight mission to the International Space Station. The launch window extends July 13 through July 31.

KENNEDY SPACE CENTER, FLA. -- STS-116 Mission Specialist Christer Fuglesang checks the fit of his helmet during suit fit-check, part of the prelaunch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. Fuglesang represents the European Space Agency. The STS-116 mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-120 Mission Specialist Daniel Tani has his helmet adjusted during fitting of his launch and entry suit. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT also includes emergency egress procedures, equipment familiarization and a simulated launch countdown. Mission STS-120, which will carry the Italian-built U.S. Node 2 to the International Space Station, is targeted for launch on Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - The STS-115 crew members are suiting up for their simulated launch countdown. Shown here is Mission Specialist Joseph Tanner. The mission crew is at KSC for Terminal Countdown Demonstration Test (TCDT) activities that are preparation for launch on Space Shuttle Atlantis, scheduled to take place in a window that opens Aug. 27. The TCDT has included emergency egress training as well as the simulation. During their 11-day mission to the International Space Station, the STS-115 crew will continue construction of the station and attach the payload elements, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Cory Huston

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-120 Mission Specialist Stephanie Wilson has her helmet adjusted during fitting of her launch and entry suit. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT also includes emergency egress procedures, equipment familiarization and a simulated launch countdown. Mission STS-120, which will carry the Italian-built U.S. Node 2 to the International Space Station, is targeted for launch on Oct. 23. Photo credit: NASA/Kim Shiflett

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 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. - The STS-115 crew members are suiting up for their simulated launch countdown. Shown here being helped with his glove is Pilot Christopher Ferguson. The mission crew is at KSC for Terminal Countdown Demonstration Test (TCDT) activities that are preparation for launch on Space Shuttle Atlantis, scheduled to take place in a window that opens Aug. 27. The TCDT has included emergency egress training as well as the simulation. During their 11-day mission to the International Space Station, the STS-115 crew will continue construction of the station and attach the payload elements, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Cory Huston

KENNEDY SPACE CENTER, FLA. -- STS-120 Mission Specialist Daniel Tani tries on his helmet with his launch and entry suit, preparing for launch. The fitting is part of terminal countdown demonstration test, or TCDT, activities the crew is undertaking at NASA's Kennedy Space Center. The TCDT also includes emergency egress procedures, equipment familiarization and a simulated launch countdown. Mission STS-120, which will carry the Italian-built U.S. Node 2 to the International Space Station, is targeted for launch on Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - As part of pre-pack and fit check for Terminal Countdown Demonstration Test (TCDT) activities, STS-114 Mission Specialist Andrew Thomas has his launch suit checked for fit. The TCDT is held at KSC prior to each Space Shuttle flight. It provides the crew of each mission an opportunity to participate in simulated countdown activities. The test ends with a mock launch countdown culminating in a simulated main engine cutoff. The crew also spends time undergoing emergency egress training exercises at the launch pad. STS-114 is the first Return to Flight mission to the International Space Station. The launch window extends July 13 through July 31.

KENNEDY SPACE CENTER, FLA. - The STS-115 crew members are suiting up for their simulated launch countdown. Shown here is Commander Brent Jett. The mission crew is at KSC for Terminal Countdown Demonstration Test (TCDT) activities that are preparation for launch on Space Shuttle Atlantis, scheduled to take place in a window that opens Aug. 27. The TCDT has included emergency egress training as well as the simulation. During their 11-day mission to the International Space Station, the STS-115 crew will continue construction of the station and attach the payload elements, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Cory Huston

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. - The STS-115 crew members are suiting up for their simulated launch countdown. Shown here adjusting his glove is Mission Specialist Joseph Tanner. The mission crew is at KSC for Terminal Countdown Demonstration Test (TCDT) activities that are preparation for launch on Space Shuttle Atlantis, scheduled to take place in a window that opens Aug. 27. The TCDT has included emergency egress training as well as the simulation. During their 11-day mission to the International Space Station, the STS-115 crew will continue construction of the station and attach the payload elements, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Cory Huston

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. - As part of pre-pack and fit check for Terminal Countdown Demonstration Test (TCDT) activities, STS-114 Mission Specialist Stephen Robinson has his launch suit checked for fit. The TCDT is held at KSC prior to each Space Shuttle flight. It provides the crew of each mission an opportunity to participate in simulated countdown activities. The test ends with a mock launch countdown culminating in a simulated main engine cutoff. The crew also spends time undergoing emergency egress training exercises at the launch pad. STS-114 is the first Return to Flight mission to the International Space Station. The launch window extends July 13 through July 31.

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. - As part of pre-pack and fit check for Terminal Countdown Demonstration Test (TCDT) activities, STS-114 Mission Specialist Soichi Noguchi tries on his launch suit. The TCDT is held at KSC prior to each Space Shuttle flight. It provides the crew of each mission an opportunity to participate in simulated countdown activities. The test ends with a mock launch countdown culminating in a simulated main engine cutoff. The crew also spends time undergoing emergency egress training exercises at the launch pad. STS-114 is the first Return to Flight mission to the International Space Station. The launch window extends July 13 through July 31.

KENNEDY SPACE CENTER, FLA. - The STS-115 crew members are suiting up for their simulated launch countdown. Shown here is Mission Specialist Daniel Burbank. The mission crew is at KSC for Terminal Countdown Demonstration Test (TCDT) activities that are preparation for launch on Space Shuttle Atlantis, scheduled to take place in a window that opens Aug. 27. The TCDT has included emergency egress training as well as the simulation. During their 11-day mission to the International Space Station, the STS-115 crew will continue construction of the station and attach the payload elements, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Cory Huston

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. -- Mission STS-117 Commander Rick Sturckow checks the fit of his launch suit and helmet, part of pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

KENNEDY SPACE CENTER, FLA. -- Mission STS-117 Pilot Lee Archambault checks the fit of his launch suit and helmet, part of pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

KENNEDY SPACE CENTER, FLA. -- Mission STS-117 Mission Specialist Danny Olivas has donned his launch suit for a fit check, part of the pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

KENNEDY SPACE CENTER, FLA. -- Mission STS-117 Mission Specialist Danny Olivas has donned his launch suit for a fit check, part of the pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

KENNEDY SPACE CENTER, FLA. -- Mission STS-117 Mission Specialist Steven Swanson checks the fit of his launch suit and helmet, part of pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

CAPE CANAVERAL, Fla. - STS-125 Mission Specialist John Grunsfeld is helped donning a harness over his launch and entry suit before entering space shuttle Atlantis for a simulated launch countdown. The countdown is the culmination of terminal countdown demonstration test, or TCDT, activities as preparation before launch. TCDT provides astronauts and ground crews with an opportunity to participate in various launch activities, including equipment familiarization, emergency training and the countdown. Atlantis’ STS-125 mission to service NASA’s Hubble Space Telescope is targeted for launch Oct. 14. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, FLA. -- Mission STS-117 Mission Specialist Patrick Forrester has donned his launch suit for a fit check, part of the pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

KENNEDY SPACE CENTER, FLA. -- STS-116 Mission Specialist Nicholas Patrick is helped putting on his helmet during suit fit-check, part of the prelaunch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-116 mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Mission STS-117 Mission Specialist James Reilly has donned his launch suit and helmet for a fit check, part of the pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

Members of the STS-90 crew participate in Terminal Countdown Demonstration Test (TCDT) activities at KSC's Launch Pad 39B. The TCDT is held at KSC prior to each Space Shuttle flight to provide crews with the opportunity to participate in simulated countdown activities. Here, STS-90 Payload Specialist Dafydd (Dave) Williams with the Canadian Space Agency is assisted into his orange launch and re-entry suit. Columbia is targeted for launch of STS-90 on April 16 at 2:19 p.m. EDT and will be the second mission of 1998. The mission is scheduled to last nearly 17 days

KENNEDY SPACE CENTER, FLA. -- STS-116 Mission Specialist Joan Higginbotham has donned her complete launch suit to check the fit, part of the prelaunch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-116 mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - In the White Room on Launch Pad 39B, STS-121 Mission Specialist Stephanie Wilson waits for final adjustments to her launch suit before entering Space Shuttle Discovery. The crew is taking part in a full dress rehearsal for launch, including countdown and culminating in main engine cutoff. The rehearsal is the final part of Terminal Countdown Demonstration Test (TCDT) activities that the crew has been involved in for two days. TCDT provides the crew of each mission an opportunity to participate in various simulated countdown activities, including equipment familiarization and emergency egress training. Mission STS-121 is scheduled to be launched July 1. Photo credit: NASA/Amanda Diller

KENNEDY SPACE CENTER, FLA. -- Mission STS-117 Pilot Lee Archambault checks the fit of his launch suit and helmet, part of pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

KENNEDY SPACE CENTER, FLA. -- Mission STS-117 Mission Specialist Patrick Forrester has donned his launch suit and helmet for a fit check, part of the pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

KENNEDY SPACE CENTER, FLA. -- Mission STS-117 Commander Rick Sturckow checks the fit of his launch suit and helmet, part of pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

KENNEDY SPACE CENTER, FLA. -- STS-116 Mission Specialist Joan Higginbotham has donned her complete launch suit to check the fit, part of the prelaunch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-116 mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-116 Mission Specialist Robert Curbeam checks the fit of his helmet during suit fit-check, part of the prelaunch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-116 mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-116 Mission Specialist Robert Curbeam checks the fit of his helmet during suit fit-check, part of the prelaunch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-116 mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-116 Mission Specialist Nicholas Patrick checks the fit of his gloves during suit fit-check, part of the prelaunch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-116 mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Mission STS-117 Mission Specialist Steven Swanson has donned his launch suit for a fit check, part of the pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

KENNEDY SPACE CENTER, FLA. -- Mission STS-117 Mission Specialist James Reilly has donned his launch suit for a fit check, part of the pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown.The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

KENNEDY SPACE CENTER, FLA. -- Mission STS-117 Commander Rick Sturckow checks the fit of his launch suit and helmet, part of pre-launch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-117 mission is No. 21 to the International Space Station. Mission payloads aboard Atlantis include the S3/S4 integrated truss structure, a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the station. Launch is scheduled for no earlier than March 15. Photo credit: NASA/Kim Shiflett.

KENNEDY SPACE CENTER, FLA. -- STS-116 Mission Specialist Sunita Williams is enthusiastic about donning her launch suit to check the fit, including the helmet, which is part of the prelaunch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-116 mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-116 Mission Specialist Sunita Williams checks the fit of her launch suit, part of the prelaunch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-116 mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-116 Mission Specialist Nicholas Patrick has donned his launch suit for a fit-check, part of the prelaunch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-116 mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-116 Mission Specialist Christer Fuglesang checks the fit of his launch suit, part of the prelaunch preparations during terminal countdown demonstration test (TCDT) activities. The mission crew is at KSC for the TCDT, which includes a simulated launch countdown. The STS-116 mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Kim Shiflett

STS-87 Payload Specialist Leonid Kadenyuk of the National Space Agency of Ukraine (NSAU) is assisted with his orange launch and entry spacesuit by NASA suit technicians at Launch Pad 39B during Terminal Countdown Demonstration Test (TCDT) activities. The crew of the STS-87 mission is scheduled for launch Nov. 19 aboard the Space Shuttle Columbia. The TCDT is held at KSC prior to each Space Shuttle flight providing the crew of each mission opportunities to participate in simulated countdown activities. The TCDT ends with a mock launch countdown culminating in a simulated main engine cut-off. The crew also spends time undergoing emergency egress training exercises at the pad and has an opportunity to view and inspect the payloads in the orbiter's payload bay

STS-87 Payload Specialist Leonid Kadenyuk, at right, of the National Space Agency of Ukraine (NSAU) is assisted into his orange launch and entry spacesuit ensemble by NASA Suit Technician Al Rochford, at left, before participating in Terminal Countdown Demonstration Test (TCDT) activities. The crew of the STS-87 mission is scheduled for launch Nov. 19 aboard the Space Shuttle Columbia. The TCDT is held at KSC prior to each Space Shuttle flight providing the crew of each mission opportunities to participate in simulated countdown activities. The TCDT ends with a mock launch countdown culminating in a simulated main engine cut-off. The crew also spends time undergoing emergency egress training exercises at the pad and has an opportunity to view and inspect the payloads in the orbiter's payload bay

STS-87 Mission Specialist Winston Scott poses in his orange launch and entry spacesuit with NASA suit technicians at Launch Pad 39B during Terminal Countdown Demonstration Test (TCDT) activities. The crew of the STS-87 mission is scheduled for launch Nov. 19 aboard the Space Shuttle Columbia. Scott will be performing an extravehicular activity (EVA) spacewalk during the mission. The TCDT is held at KSC prior to each Space Shuttle flight providing the crew of each mission opportunities to participate in simulated countdown activities. The TCDT ends with a mock launch countdown culminating in a simulated main engine cut-off. The crew also spends time undergoing emergency egress training exercises at the pad and has an opportunity to view and inspect the payloads in the orbiter's payload bay

STS-87 Mission Specialist Kalpana Chawla, Ph.D., is assisted with her orange launch and entry spacesuit by NASA suit technicians at Launch Pad 39B during Terminal Countdown Demonstration Test (TCDT) activities. The crew of the STS-87 mission is scheduled for launch Nov. 19 aboard the Space Shuttle Columbia. The TCDT is held at KSC prior to each Space Shuttle flight providing the crew of each mission opportunities to participate in simulated countdown activities. The TCDT ends with a mock launch countdown culminating in a simulated main engine cut-off. The crew also spends time undergoing emergency egress training exercises at the pad and has an opportunity to view and inspect the payloads in the orbiter's payload bay

S90-40670 (13 June 1990) --- STS-35 crewmembers take a ride in the M113 tracked vehicle during emergency training conducted during the Terminal Countdown Demonstration Test (TCDT) at the Kennedy Space Center (KSC). From left, wearing launch and entry suits (LES), are pilot Guy S. Gardner, payload specialist Ronald A. Parise, commander Vance D. Brand, mission specialists Robert A. R. Parker, Jeffrey A. Hoffman and John M. Lounge. The two-day TCDT, which began 04-27-90, is a dress rehearsal for launch. STS-35 is set to lift off in May. View provided by KSC with alternate number KSC-90PC-838.

KENNEDY SPACE CENTER, FLA. - A suit technician helps STS-114 Mission Specialist Soichi Noguchi suit up in the Operations and Checkout Building for the trip to Launch Pad 39B for a mock launch countdown culminating in a simulated main engine cutoff. Noguchi is with the Japan Aerospace Exploration Agency. The dress rehearsal is part of Terminal Countdown Demonstration Test (TCDT) activities held prior to each Space Shuttle flight. It provides the crew of each mission an opportunity to participate in various simulated countdown activities, including equipment familiarization and emergency egress training. STS-114 is the first Return to Flight mission to the International Space Station. The launch window extends July 13 through July 31.

KENNEDY SPACE CENTER, FLA. - A suit technician helps STS-114 Commander Eileen Collins with a boot as she suits up in the Operations and Checkout Building for the trip to Launch Pad 39B for a mock launch countdown culminating in a simulated main engine cutoff. The dress rehearsal is part of Terminal Countdown Demonstration Test (TCDT) activities held prior to each Space Shuttle flight. It provides the crew of each mission an opportunity to participate in various simulated countdown activities, including equipment familiarization and emergency egress training. STS-114 is the first Return to Flight mission to the International Space Station. The launch window extends July 13 through July 31.

KENNEDY SPACE CENTER, FLA. - A suit technician helps STS-114 Pilot James Kelly suit up in the Operations and Checkout Building for the trip to Launch Pad 39B for a mock launch countdown culminating in a simulated main engine cutoff. The dress rehearsal is part of Terminal Countdown Demonstration Test (TCDT) activities held prior to each Space Shuttle flight. It provides the crew of each mission an opportunity to participate in various simulated countdown activities, including equipment familiarization and emergency egress training. STS-114 is the first Return to Flight mission to the International Space Station. The launch window extends July 13 through July 31.

KENNEDY SPACE CENTER, FLA. - A suit technician helps STS-114 Mission Specialist Stephen Robinson suit up in the Operations and Checkout Building for the trip to Launch Pad 39B for a mock launch countdown culminating in a simulated main engine cutoff. The dress rehearsal is part of Terminal Countdown Demonstration Test (TCDT) activities held prior to each Space Shuttle flight. It provides the crew of each mission an opportunity to participate in various simulated countdown activities, including equipment familiarization and emergency egress training. STS-114 is the first Return to Flight mission to the International Space Station. The launch window extends July 13 through July 31.

STS-88 Mission Commander Robert D. Cabana suits up in the Operations and Checkout Building prior, as part of flight crew equipment fit check, to his trip to Launch Pad 39A. He is helped by suit tech (right) Lloyd Armintor and an unidentified KSC worker. The crew are at KSC to participate in the Terminal Countdown Demonstration Test (TCDT) which includes mission familiarization activities, emergency egress training, and the simulated main engine cut-off exercise. This is Cabana's fourth space flight. Mission STS-88 is targeted for launch on Dec. 3, 1998. It is the first U.S. flight for the assembly of the International Space Station and will carry the Unity connecting module

STS-88 Mission Specialist James H. Newman (left) suits up in the Operations and Checkout Building, as part of flight crew equipment fit check, prior to his trip to Launch Pad 39A. He is helped by suit tech Terri McKinney. The crew are at KSC to participate in the Terminal Countdown Demonstration Test (TCDT) which includes mission familiarization activities, emergency egress training, and the simulated main engine cut-off exercise. This is Newman's third space flight. Mission STS-88 is targeted for launch on Dec. 3, 1998. It is the first U.S. flight for the assembly of the International Space Station and will carry the Unity connecting module

STS-88 Pilot Frederick W. "Rick" Sturckow suits up in the Operations and Checkout Building, as part of flight crew equipment fit check, prior to his trip to Launch Pad 39A. He is helped by suit tech Terri McKinney. The crew are at KSC to participate in the Terminal Countdown Demonstration Test (TCDT) which includes mission familiarization activities, emergency egress training, and the simulated main engine cut-off exercise. This is Sturckow's first space flight. Mission STS-88 is targeted for launch on Dec. 3, 1998. It is the first U.S. flight for the assembly of the International Space Station and will carry the Unity connecting module

STS-88 Mission Specialist Jerry L. Ross (right) suits up in the Operations and Checkout Building, as part of a flight crew equipment fit check, prior to his trip to Launch Pad 39A. He is helped by suit tech Leonard Groce II. The STS-88 crew is at KSC to participate in the Terminal Countdown Demonstration Test (TCDT) which includes mission familiarization activities, emergency egress training, and a simulated launch countdown. This is Ross' sixth space flight. Mission STS-88 is targeted for launch on Dec. 3, 1998. It is the first U.S. flight for the assembly of the International Space Station and will carry the Unity connecting module

STS-88 Mission Specialist Nancy J. Currie suits up in the Operations and Checkout Building, as part of flight crew equipment fit check, prior to her trip to Launch Pad 39A. She is helped by suit tech Drew Billingsley. The crew are at KSC to participate in the Terminal Countdown Demonstration Test (TCDT) which includes mission familiarization activities, emergency egress training, and the simulated main engine cut-off exercise. This is Currie's third space flight. Mission STS-88 is targeted for launch on Dec. 3, 1998. It is the first U.S. flight for the assembly of the International Space Station and will carry the Unity connecting module

STS-88 Mission Specialist Sergei Konstantinovich Krikalev, a Russian cosmonaut, suits up in the Operations and Checkout Building, as part of a flight crew equipment fit check, prior to his trip to Launch Pad 39A. He is helped by suit tech George Brittingham. The STS-88 crew is at KSC to participate in the Terminal Countdown Demonstration Test (TCDT) which includes mission familiarization activities, emergency egress training, and a simulated launch countdown. This is Krikalev's second flight on the Space Shuttle. Mission STS-88 is targeted for launch on Dec. 3, 1998. It is the first U.S. flight for the assembly of the International Space Station and will carry the Unity connecting module

STS-82 Mission Specialist Steven L. Smith adjusts the glove of his launch and entry space suit during a practice countdown at KSC. Smith and the other six STS-82 crew members are at KSC to participate in the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. STS-82 will be the second Hubble Space Telescope servicing mission. Liftoff is targeted for Feb. 11