The STS-125 crew is taking part in a simulated launch countdown aboard space shuttle Atlantis at NASA's Kennedy Space Center in Florida. Seen in his seat in the mid-deck is Mission Specialist John Grunsfeld. The countdown is the culmination of terminal countdown demonstration test, or TCDT, activities as preparation before launch. TCDT provides astronauts and ground crews with an opportunity to participate in various launch activities, including equipment familiarization, emergency training and the countdown. Atlantis’ STS-125 mission to service NASA’s Hubble Space Telescope is targeted for launch Oct. 14. Photo credit: NASA/Kim Shiflett