(04/04/1997) --- STS-83 Mission Specialist Donald A. Thomas is assisted into his launch/entry suit in the Operations and Checkout (O&C) Building. He has flown on both STS-70 and STS-65. He holds a doctorate in materials science and has been the Principal Investigator for a Space Shuttle crystal growth experiment. Because of his background in materials science, Thomas will be concentrating his efforts during the Red shift on the five experiments in this discipline in the large Isothermal Furnace. He also will work on the ten materials science investigations in the Electromagnetic Containerless Processing Facility and four that will be measuring the effects of microgravity and motion in the orbiter on the experiments. Thomas and six fellow crew members will shortly depart the O&C and head for Launch Pad 39A, where the Space Shuttle Columbia will lift off during a launch window that opens at 2:00 pm EST, April 4