During World War II (1939–45), women undertook many roles that were previously exclusively male, including roles as scientific researchers. American crystallographer Isabella L. Karle developed processes to isolate plutonium chloride from impure plutonium oxide while working on the Manhattan Project. American mathematician Grace Murray Hopper worked for the U.S. Navy as one of the first computer programmers, and American biologist Rachel Carson worked for the U.S. Bureau of Fisheries (from 1940 the U.S. Fish and Wildlife Service) as an aquatic biologist. In the postwar years many female wartime workers returned to the domestic sphere, unlike Hopper and Carson, who maintained