"In this century, I have bounced sensitive whispers off the moon, and guided manmade moons in orbit around our earth. For the first time ever, I have cupped my ears and listened to satellites. My far reaching voice can now reach across the vast expanse of space. I can guide rockets and missiles ... I can do that and more. I am the Signal Corps..." Sgt. 1st Class Samuel A. Barnes , 1976This year, the United States celebrates the 50th anniversary of the Apollo 11 Mission, which expanded our exploration of space by bringing men to the moon for the first time. The foundations of this achievement are closely linked to the history of Army communications and the developments of the Signal Corps.The first "contact" with the moon occurred in 1946 with Project Diana, a Signal Corps project which bounced radio signals off the moon from its Diana radar. The experiment consisted of transmitting quarter-second pulses of radio-frequency energy every four seconds in the direction of the moon. The first detected echo signals returned approximately 2.5 seconds after transmission at moonrise on 10 January 1945.In the late 1950s and early 1960s the Signal Corps Research and Development Laboratory contributed special components or subsystems to the U.S. satellite program, such as solar power devices, high-frequency control crystals, special batteries and high efficiency, low voltage to high voltage transistor power converters to the payloads developed by other organizations. They also tracked satellites at the Deal Laboratory. The responsibility for carrying out the Army's portion of what would become the Initial Defense Communications Satellite Program belonged to the Army SATCOM Agency.The Army SATCOM Agency played a prominent role in communications for Apollo 11 as the lead in the joint venture by Army, Navy, Air Force and Marines to support recovery efforts, using the Tactical Satellite Communications (TACSATCOM) terminals as the first line of communications during those operations. TACSAT I, an experimental synchronous satellite launched in February 1969, was used in conjunction with Army-developed Satellite Communications Terminal AN/TRC-156, providing voice communications for Apollo 11 spacecraft re-entry and splashdown, and Satellite Communications Terminal AN/TRC-157, used for voice and teletype communications in recovery operations.