The STS-120 crew is at NASA's Kennedy Space Center for the pre-launch terminal countdown demonstration test.

The STS-120 crew is at NASA's Kennedy Space Center for the pre-launch terminal countdown demonstration test, or TCDT. Here, during emergency egress training, Pilot George Zamka touches the handle that releases the slidewire basket that can carry the crew safely to a landing site away from the shuttle. The TCDT provides astronauts and ground crews an opportunity to participate in various simulated countdown activities, including equipment familiarization and emergency training. The STS-120 mission will deliver the U.S. Node 2 module, named Harmony, aboard space shuttle Discovery to the International Space Station. Launch of Discovery on mission STS-120 is targeted for Oct. 23 at 11:38 a.m. EDT on a 14-day mission. Photo credit: NASA/Kim Shiflett