KENNEDY SPACE CENTER, FLA. -- In the payload changeout room on Launch Pad 39B, STS-116 crew members look over the mission payload one more time before launch. Mission Specialist Joan Higginbotham is at left. The crew is at KSC to take part in Terminal Countdown Demonstration Test activities, which include emergency egress training, a simulated launch countdown and payload familiarization. The TCDT is part of prelaunch preparations for the mission that is scheduled to lift off in a window opening no earlier than Dec. 7. 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. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- In the payload changeout room on Launch Pad 39B, Expedition 14 Flight Engineer Sunita Williams looks over the STS-116 mission payload one more time before launch. Williams will be traveling aboard Discovery with the STS-116 crew and staying on the International Space Station. The crew is at KSC to take part in Terminal Countdown Demonstration Test activities, which include emergency egress training, a simulated launch countdown and payload familiarization. The TCDT is part of prelaunch preparations for the mission that is scheduled to lift off in a window opening no earlier than Dec. 7. 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. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- In the payload changeout room on Launch Pad 39B, STS-116 crew members look over the mission payload with payload managers one more time before launch. Mission Specialist Christer Fuglesang is in the center.The crew is at KSC to take part in Terminal Countdown Demonstration Test activities, which include emergency egress training, a simulated launch countdown and payload familiarization. The TCDT is part of prelaunch preparations for the mission that is scheduled to lift off in a window opening no earlier than Dec. 7. 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. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- In the payload changeout room on Launch Pad 39B, STS-116 crew members look over the mission payload with payload managers one more time before launch. At left is Pilot William Oefelein. Second from right is Mission Specialist Robert Curbeam. The crew is at KSC to take part in Terminal Countdown Demonstration Test activities, which include emergency egress training, a simulated launch countdown and payload familiarization. The TCDT is part of prelaunch preparations for the mission that is scheduled to lift off in a window opening no earlier than Dec. 7. 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. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- In the payload changeout room on Launch Pad 39B, STS-116 crew members look over the mission payload one more time before launch. Pilot William Oefelein is at left and Mission Specialist Robert Curbeam is at right. The crew is at KSC to take part in Terminal Countdown Demonstration Test activities, which include emergency egress training, a simulated launch countdown and payload familiarization. The TCDT is part of prelaunch preparations for the mission that is scheduled to lift off in a window opening no earlier than Dec. 7. 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. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- In the payload changeout room on Launch Pad 39B, STS-116 Commander Mark Polansky looks over the mission payload one more time before launch. The crew is at KSC to take part in Terminal Countdown Demonstration Test activities, which include emergency egress training, a simulated launch countdown and payload familiarization. The TCDT is part of prelaunch preparations for the mission that is scheduled to lift off in a window opening no earlier than Dec. 7. 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. Photo credit: NASA/Kim Shiflett