Jemison, 36, has long strived to go where few have gone before. Reared in Chicago, the youngest of three children of a teacher and a maintenance supervisor, she earned her chemical engineering degree at Stanford and her M.D. at Cornell. After 2½ years as a Peace Corps doctor in Africa and two years in private practice in L.A., she was accepted in NASA's training program in 1987, one of 15 chosen from nearly 2,000 applicants. Her mission now accomplished, Jemison quit NASA last March and plans to launch a company that will help bring advanced technology to underdeveloped countries. But even the full-blast, unmarried Houstonite needs to fire her retro-rockets occasionally. In late May she'll make a cameo appearance on Star Trek: The Next Generation, which is right in character. "Life is what your creator gave you for free," Jemison has said. "Style is what you do with it."