Space shuttle Atlantis STS-122 Commander Steve Frick watch a slidewire basket descend to the landing zone.

During a training session on emergency exit from the fixed service structure on Launch Pad 39A, space shuttle Atlantis STS-122 Commander Steve Frick, left, and Mission Specialist Leland Melvin watch a slidewire basket descend to the landing zone. Seven slidewire baskets are available to carry the crew from the level of the pad's Orbiter Access Arm to a safe landing site below, if needed. Each basket can hold up to three people. A braking system catch net and drag chain slow, and then halt, the baskets as they travel down the wire at approximately 55 miles per hour. The journey takes about half a minute. A bunker is located in the landing zone 1,200 feet west of the pad, with an M-113 armored personnel carrier stationed nearby. The STS-122 crew is at NASA's Kennedy Space Center to take part in terminal countdown demonstration test, or TCDT, activities, a standard part of launch preparations. The TCDT provides astronauts and ground crews with equipment familiarization and a simulated launch countdown before launch. On mission STS-122, Atlantis will deliver the European Space Agency's Columbus module to the International Space Station. Columbus is a multifunctional, pressurized laboratory that will be permanently attached to U.S. Node 2, called Harmony, and will expand the research facilities aboard the station. Launch is targeted for Dec. 6. Photo credit: NASA/Kim Shiflett