From 1984–1987, Kerwin served as Director of Space and Life Sciences at the Johnson Space Center. There, he was responsible for direction and coordination of medical support to operational crewed spacecraft programs, including health care and maintenance of the astronauts and their families; for direction of life services, supporting research and light experiment project; and for managing JSC earth sciences and scientific efforts in lunar and planetary research. In 1986, he issued a report on the deaths of the crew killed in the "Challenger" disaster to Associate Administrator for Space Flight, Richard H. Truly.