KENNEDY SPACE CENTER, FLA. -- With the payload successfully installed inside, the payload bay doors on Space Shuttle Discovery are closing. Seen here are the SPACEHAB module at left and the orbiter docking system at right. The shuttle is on Launch Pad 39B, ready for launch on mission STS-116 scheduled no earlier than Dec. 7. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 39B, technicians check the clearance under the payload door on Space Shuttle Discovery as the door closes. The payload includes the SPACEHAB module, the P5 integrated truss structure and other key components. Launch of Space Shuttle Discovery on mission STS-116 is scheduled no earlier than Dec. 7. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 39B, workers inside the payload changeout room monitor the closing of the payload bay doors on Space Shuttle Discovery. The payload includes the SPACEHAB module, the P5 integrated truss structure and other key components. Launch of Space Shuttle Discovery on mission STS-116 is scheduled no earlier than Dec. 7. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 39B, Space Shuttle Discovery's payload bay doors are fully closed and ready for launch. The payload includes the SPACEHAB module, the P5 integrated truss structure and other key components. Launch of Space Shuttle Discovery on mission STS-116 is scheduled no earlier than Dec. 7. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 39B, a worker inside the payload changeout room monitors the clearance during closing of one payload bay door on Space Shuttle Discovery. The payload visible is the P5 integrated truss structure. Launch of Space Shuttle Discovery on mission STS-116 is scheduled no earlier than Dec. 7. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- With the payload successfully installed inside, the payload bay doors on Space Shuttle Discovery are closing. Seen here are the SPACEHAB module at left, the P5 truss in the center, service module debris panels and the Space Test Program experiment canister on the integrated cargo carrier at right. The shuttle is on Launch Pad 39B, ready for launch on mission STS-116 scheduled no earlier than Dec. 7. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- With the payload successfully installed inside, the payload bay doors on Space Shuttle Discovery are closing. Seen here are the SPACEHAB module on top and the P5 truss below. Launch of Space Shuttle Discovery on mission STS-116 is scheduled no earlier than Dec. 7. Photo credit: NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, FLA. -- One of Space Shuttle Discovery's payload bay doors is nearly closed. Still visible are two major payload components, the SPACEHAB module on top and the P5 truss below. Launch of Space Shuttle Discovery on mission STS-116 is scheduled no earlier than Dec. 7. Photo credit: NASA/Dimitri Gerondidakis