Bringing satellite communications almost to reality has required more than putting a man-made satellite into orbit around the earth. Just as important have been the invention and development of many remarkable new devices: the transistor, the solar cell, the traveling wave tube, the horn-reflector antenna, the waveguide, the solid-state maser, and the electronic computer—to mention only some of the more important. Without them it would still be impossible to find a tiny speeding object miles out in space, send signals to it, amplify them billions of times, and then return them to distant points on the earth. Some of the new devices that help make satellite communications possible [Illustration: horn-reflector antenna] [Illustration: traveling-wave tube] [Illustration: transistor] [Illustration: solar cell] [Illustration: solid-state maser] _When you look back at it, we have seen remarkable progress in satellite communications—and work is still continuing at a fast pace. Some of the milestones have been these:_ OCTOBER 1945 Arthur C. Clarke publishes “Extra-Terrestrial Relays—Can Rocket Stations Give World-Wide Radio Coverage?” in _Wireless World_, suggesting the use of satellites for communications. JANUARY 11, 1946 Project Diana of the U. S. Army Signal Corps bounces microwave radar signals off the moon and back to the earth, proving that relatively low power can transmit signals over very long distances. APRIL 1955 John R. Pierce publishes “Orbital Radio Relays” in _Jet Propulsion_, pointing out the requirements for a satellite communications system. JULY 29, 1958 Congress passes the National Aeronautics and Space Act, setting up the National Aeronautics and Space Administration (NASA), with satellite communications experimentation as one of its interests. DECEMBER 18, 1958 Score, the first communications satellite, is launched by the U. S. Air Force. It is equipped with tape recorder units that transmit prerecorded messages back to the earth upon receipt of signals. On December 19 a Christmas greeting to the world recorded by President Eisenhower—the first message from a satellite to the earth—is transmitted. Score continues to transmit for 12 days before its batteries become too weak for further use. [Illustration: {uncaptioned}] NOVEMBER 23, 1959 Live voice transmission is accomplished from Bell Telephone Laboratories in Holmdel, New Jersey, via the moon to Jet Propulsion Laboratories in Goldstone, California. This is the first of 17 tests in Project Moonbounce, all using the moon as a reflector. JULY 8, 1960 The Bell System proposes to the Federal Communications Commission a detailed plan for a world-wide communications system using active repeater satellites to provide telephone circuits and facilities for transmitting television to various parts of the world.