The STS-120 crew, including ESA astronaut Paolo Nespoli, walks out of the Operations and Checkout Building to board a bus that will transport them to the launch pad for the practice countdown - part of the Terminal Countdown Demonstration Test (TCDT) at NASA's Kennedy Space Center, Florida. The TCDT provides the astronauts and ground crew with an opportunity to participate in various launch preparation activities, including equipment familiarisation, emergency training and the simulated countdown.