On loan from
MIT to
NASA Headquarters as the Senior Scientist for the
International Space Station since 2000; prior to that, on loan from MIT as the Senior Scientist for the
Office of Life and Microgravity Sciences, NASA-HQ, 1998–2000; crew training, flight and post-flight activities 1996–1998; Lead Scientist of the
Microgravity Space and Applications Division since 1985–1996. He served as Program Scientist on five different
Spacelab flights. In addition, he helped organize and has served as co-chair for
Microgravity Science Working Groups between NASA and
space agencies from the
European Union, France, Germany, Japan, and Russia. He was the founding co-chair of the
International Microgravity Science Strategic Planning Group consisting of these space agencies plus Canada. He was principal investigator on an experiment that flew in the
Materials Experiment Apparatus on the
D-1 mission in 1985. Group leader and researcher, NASA
Langley Research Center, 1962–1985. Leader of a research group investigating the effects of
convection on
semiconductor materials' properties. He was a principal investigator in the
MSAD flight program from 1986 to 1997. He has done research in various techniques and types of
semiconductor crystal growth,
electric and
optical properties of materials, electronic devices for remote sensing and
flat panel displays, and
heat shield protection for
atmospheric reentry of space vehicles. This research resulted in the publication of over 40 technical paper and over 50 technical conference reports. He trained as the Alternate Payload Specialist for
STS-42 (
First International Microgravity Laboratory) which flew in January 1992. ==Spaceflight experience==