SCORE

On 18 December 1958, the United States launched SCORE (Signal Communicating by Orbiting Relay Experiment) ^1,2,3,4 the world’s first artificial communications satellite capable of relaying terrestrial transmissions. SCORE, launched under the newly formed Advanced Research Projects Agency (ARPA), was based on equipment modified by the US Army Signal Corps and launched by the US Air Force Ballistic Missile Division on an Atlas rocket. It was a 68-kg conical satellite placed in an elliptical LEO (between 182 km and 1,048 km), at an inclination 32.3°, with an orbital period of 101 minutes. SCORE was a store-and-forward, or delayed-repeater system: signals from Earth stations were recorded on magnetic tape and later rebroadcast by the satellite during subsequent passes. The satellite could carry a single voice channel or up to seventy 60-words-per-minute teletype channels, with a maximum recorded message length of four minutes. Its most famous transmission was President Dwight D. Eisenhower’s Christmas message of 1958, the first human voice to be broadcast from space.

SCORE’s simple VHF transponder was quickly assembled from modified commercial components by the US Army Signal Corps to include a pager-type FM receiver paired with a VHF FM transmitter and an external power amplifier to ~8 W (uplink 150 MHz, downlink 132 MHz; 108 MHz beacon). Contrary to popular belief, it was not a direct derivative of the WWII SCR-536 ‘Handie-Talkie,’ which was an HF AM set at 3.5–6 MHz.

Although SCORE’s batteries failed after 12 days and the spacecraft re-entered Earth’s atmosphere after only 34 days, the mission was an experimental success. It demonstrated the feasibility of satellite relay communications and validated the Atlas B rocket as a space launch vehicle.