(03/31/1998) --- Members of the STS-90 crew participate in Terminal Countdown Demonstration Test (TCDT) activities at KSC's Launch Pad 39B. The TCDT is held at KSC prior to each Space Shuttle flight to provide crews with the opportunity to participate in simulated countdown activities. The STS-90 crew members are, from left to right, Payload Specialist Jay Buckey, M.D., Pilot Scott Altman, Mission Specialist Kathryn (Kay) Hire, Commander Richard Searfoss, Payload Specialist James Pawelczyk, Ph.D., Mission Specialist Dafydd (Dave) Williams with the Canadian Space Agency, and Mission Specialist Richard Linnehan, D.V.M. 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