The Space Shuttle Columbia surges skyward from Launch Pad 39B at 2:19 p.m. EDT Apr. 17 to begin the nearly 17-day STS-90 Neurolab mission. The launch was delayed 24 hours due to difficulty with a network signal processor, which was replaced Apr. 16, on the orbiter. The crew members on-board include Commander Richard Searfoss, Pilot Scott Altman, Mission Specialists Richard Linnehan, D.V.M., Dafydd (Dave) Williams, M.D., with the Canadian Space Agency, and Kathryn (Kay) Hire; and Payload Specialists Jay Buckey, M.D., and James Pawelczyk, Ph.D. Investigations during the Neurolab mission will focus on the effects of microgravity on the nervous system