The United States military space program began at the end of World War II when a few people realized that space flight was now achievable and could be employed to military advantage. Science and technology in the form of advanced radar, jet propulsion, ballistic rockets such as the V-2, and nuclear energy had dramatically altered the nature of war. Army Air Forces Commanding General Henry H. "Hap" Arnold wrote in November 1945 that a space ship "is all but practicable today" and could be built "within the foreseeable future." The following month the Air Force Scientific Advisory Group concluded that long-range rockets were technically feasible and that satellites were a "definite possibility." The U.S. Navy also expressed interest in space flight. In November 1945 the Navy Bureau of Aeronautics produced a satellite report, and, on March 7, 1946 proposed an interservice space program. The idea was presented to the joint Army-Navy Aeronautical Board on April 9. Major General Curtis E. LeMay, the Director of Research and Development for the Army Air Forces, however, viewed space operations as an exclusive Air Force domain, and he ordered an independent study.