Williams with the Canadian Space Agency poses after arriving to begin Terminal Countdown Demonstration Test TCDT activities.

STS-90 Mission Specialist Dafydd (Dave) Williams with the Canadian Space Agency poses in the cockpit of his T-38 jet trainer aircraft after arriving at the KSC Shuttle Landing Facility along with other members of the crew from NASA’s Johnson Space Center to begin Terminal Countdown Demonstration Test (TCDT) activities. The TCDT is held at KSC prior to each Space Shuttle flight to provide crews with the opportunity to participate in simulated countdown activities. Columbia is targeted for launch of STS-90 on April 16 at 2:19 p.m. EDT and will be the second mission of 1998. The mission is scheduled to last nearly 17 days