(04/17/1998) --- STS-90 Mission Commander Richard Searfoss sits in a chair during suitup activities in the Operations and Checkout Building. Searfoss and the rest of his flight crew will shortly depart for Launch Pad 39B, where the Space Shuttle Columbia awaits a second liftoff attempt at 2:19 p.m. EDT. His third trip into space, Searfoss commands this life sciences research flight that will focus on the most complex and least understood part of the human body the nervous system. Neurolab will examine the effects of spaceflight on the brain, spinal cord, peripheral nerves and sensory organs in the human body