STS-127 Mission Specialist Julie Payette

In the Operations and Checkout Building at NASA's Kennedy Space Center in Florida, STS-127 Mission Specialist Julie Payette checks the communication system in her helmet. She and other crew members will be heading for Launch Pad 39A for a simulated launch countdown. The crew is at Kennedy for a launch dress rehearsal called the terminal countdown demonstration test, or TCDT, which includes emergency exit training and equipment familiarization. (Credit: NASA/Kim Shiflett)