Bill retired from NASA after 20 years as a flight surgeon in 2026. He has worked directly with NASA and international partner astronauts/cosmonauts preparing and caring for them for long duration space missions on the ISS. He has worked in the commercial LEO development program, developed astronaut selection medical standards, been director of the JSC Medical Clinic as well as the JSC Flight Medicine Clinic. His specialty is space medicine with US board certifications in aerospace medicine and occupational medicine.

