US astronaut. His five space shuttle flights include the Discovery mission in April 1990 to deploy the Hubble Space Telescope. He also flew with the Columbia mission in July 1999 to deploy the Chandra X-Ray Observatory. He went on to be associate director for Astromaterials Research and Exploration Science at the Johnson Space Center. He was selected as an astronaut in 1978.
Subjects: Astronomy and Astrophysics.