During the all too fleeting peace between World War II and the Korean Conflict, the Signal Corps shrank from a high of 350,000 to some 50,000 personnel. But, this did not curtail the Corps' scientific studies. On 10 January 1946, Signal Corps scientists, using a modified SCR-271 long range radar antenna (the Diana Tower), succeeded in bouncing radar signals off the moon. The experiment demonstrated that very high frequency radio waves could penetrate the ionosphere encircling the earth and evidenced the feasibility of space communications. Following Project Diana, the Signal Corps broadened its space-related activities and participated in postwar atomic bomb tests. In 1949, the Signal Corps provided electronic support for guided missiles, an effort which grew into the United States Army Signal Missile Support Agency. With the development of Army missiles the Signal Corps mission of providing combat surveillance and target acquisition.
Find out more in "Getting the Message Through" at http://www.history.army.mil/books/30-17/Front.htm#toc