Institute for Telecommunication Sciences / January 1958

January 1958: Explorer I Launched

On the 31st of January 1958, the U.S. launched the Explorer I into space. The first American satellite was a joint project between the Army's Redstone Arsenal and the Jet Propulsion Laboratory of the National Advisory Committee for Aeronautics (the predecessor to NASA). Explorer's primary instruments were radiation detectors, developed by James Van Allen, which were intended to measure cosmic rays outside the Earth's atmosphere. Instead, the instruments detected rings of radiation in the Earth’s upper atmosphere which were named in honor of Van Allen. In Boulder, Central Radio Propagation Laboratory scientists celebrated, and used the data from Explorer along with that from the previously launched Soviet Sputniks to help understand the ionosphere, a layer of the atmosphere that reflects radio waves and allows for radio communication over long distances. For the first time, the ionosphere could be studied by looking at radio waves that had passed through it instead of reflecting off it. Soon CRPL and NASA began work on the TOPSI, or “topside sounder," project which equipped satellites with radio equipment to probe the ionosphere in order to better understand it. CRPL published ionospheric propagation predictions from January 1946 to October 1976 to assist broadcasters by providing “useful tools for effective frequency allocation, for efficient use of assigned frequencies, and for developing specifications for engineering design of high frequency communications equipment and circuits.” These prediction services and the improved understanding of the atmosphere gained through satellite sounding helped advance both commercial radio and television and public safety and military communication in the United States. Today, ITS employees continue to work to improve and safeguard satellite communications through interagency agreements with NASA, NOAA, and the Department of Defense.