The crew members of mission STS-120 arrive to take part in terminal countdown demonstration test activities.

The crew members of mission STS-120 arrive at NASA's Kennedy Space Center Shuttle Landing Facility aboard T-38 jet aircraft to take part in terminal countdown demonstration test activities. The T-38 jet aircraft on which Mission Specialist Doug Wheelock arrived is shown here. Wheelock will be making his first shuttle flight and will perform three spacewalks during the STS-120 mission. The terminal countdown demonstration test 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 to the International Space Station. Photo credit: NASA/Kim Shiflett