Endeavour Mission STS-126

Space shuttle Endeavour crew members, from left, commander Chris Ferguson, pilot Eric Boe and mission specialists Steve Bowen, Sandra Mangnus, Shane Kimbrough, Donald Petit and Heidemarie Stefanyshyn-Piper, attend a news conference at Kennedy Space Center in Cape Canaveral, Fla., Oct. 28, 2008. Endeavour, in background, is scheduled for launch on Nov. 14.

The crew of Space Shuttle Endeavour leave the operations and checkout building for their final day of the Terminal Countdown Demonstration Test Oct. 29, 2008, a dress rehearsal for the Nov. 14 launch, at Kennedy Space Center in Cape Canaveral, Fla.

Embryology researcher Justin Matthew examines a portion of a device that will carry three samples of just-fertilized bovine embryos into space aboard the space shuttle Endeavour, at the University of Florida in Gainesville, Fla., Thursday, Nov. 6, 2008. Matthew and fellow researcher Luciano Bonilla will prepare the embryos so that space's effects on early-stage mammalian life can be studied.

Space shuttle Endeavour stands ready for launch on pad 39A at Kennedy Space Center in Cape Canaveral, Fla., Wednesday, Nov. 12, 2008.

Space shuttle Endeavour stands ready on launch pad 39A at Kennedy Space Center in Cape Canaveral, Fla., Wednesday, Nov. 12, 2008.

An electrician replaces bulbs near the Vehicle Assembly Building at the Kennedy Space Center, Fla., Thursday, Nov. 13, 2008. Space shuttle Endeavour is scheduled to lift-off Friday evening on a mission to the International Space Station.

Space shuttle Endeavour stands ready for launch at pad 39A at Kennedy Space Center in Cape Canaveral, Fla., Friday, Nov. 14, 2008.

Space shuttle Endeavour is seen on pad 39A as the moon rises at the Kennedy Space Center, Friday, Nov. 14, 2008, in Cape Canaveral, Fla.

Space shuttle Endeavour lifts off from pad 39A at the Kennedy Space Center, Friday Nov. 14, 2008, in Cape Canaveral, Fla. Endeavour's seven member crew is on a mission to the International Space Station.

Space shuttle Endeavour's lift off is seen from the rocket garden at the Kennedy Space Center, Friday Nov. 14, 2008, in Cape Canaveral, Fla.

The Space Shuttle Endeavour, backdropped by a colorful Earth and the blackness of space, carries the Leonardo Multi-Purpose Logistics Module visible in its payload bay, in this image photographed by a STS-126 crewmember Saturday, Nov. 15, 2008.

The crew of the space shuttle Endeavour is welcomed aboard the International Space Station after docking, Sunday, Nov. 16, 2008.

NASA astronaut Shane Kimbrough pushes equipment into the International Space Station from a cargo canister that was delivered by the shuttle Endeavour, Monday, Nov. 17, 2008. The canister carried almost 15,000 pounds of equipment that will allow the space station to expand from three to six crew members next year.

An interior view of the Leonardo Multi-Purpose Logistics Module. Leonardo was moved from Endeavour's cargo bay and linked to the International Space Station Monday, Nov. 17, 2008, carrying two water recovery systems racks for recycling urine into potable water, a second toilet system, new galley components, combustion science experiment rack, two separate sleeping quarters and a resistance exercise device for the crew.

Astronaut Steve Bowen participates in the mission's first session of extravehicular activity Tuesday, Nov. 18, 2008, as construction and maintenance continues on the International Space Station.

Astronaut Heidemarie Stefanyshyn-Piper anchored to a Canadarm2 mobile foot restraint as she participates in the mission's first session of extravehicular activity Tuesday Nov. 18, 2008, as construction and maintenance continues on the International Space Station.

Mission specialist Shane Kimbrough is seen in the lower part of the photo during a space walk on the International Space Station, Thursday, Nov. 20, 2008.

Astronaut Stephen Bowen is seen during a space walk outside the International Space Station, Monday, Nov. 24, 2008. The spacewalk marks the fourth and final spacewalk of space shuttle Endeavour's nearly two-week visit to the orbiting outpost.