A younger brother of renowned physicist J. Robert Oppenheimer, Frank Oppenheimer conducted research on aspects of nuclear physics during the time of the Manhattan Project, and made contributions to uranium enrichment. After the war, Oppenheimer's earlier involvement with the American Communist Party placed him under scrutiny, and he resigned from his physics position at the University of Minnesota. Oppenheimer was a target of McCarthyism and was blacklisted from finding any physics teaching position in the United States until 1957, when he was allowed to teach science at a high school in Colorado. This rehabilitation allowed him to gain a position at the University of Colorado teaching physics. In 1969, Oppenheimer founded the Exploratorium in San Francisco, and he served as its first director until his death in 1985.