page_title: MISTRAM
hierarchical_section_title: MISTRAM
caption_attribution_description: English: Air Force Eastern Test Range of 1957 In October 1952, the Air Research and Development Command approved a plan to extend the Eastern Range's length to 5,000 miles to meet SNARK and NAVAHO missile testing requirements. Antigua, St. Lucia, Fernando de Noronha and Ascension were tentatively selected as host sites, and agree-ments were negotiated with the governments of Britain, St. Lucia, Brazil and Ascension to authorize construction. The St. Lucia and Ascension agree-ments were signed on 26 June 1956, and the Brazilian Agreement was signed on 21 January 1957. Following an exchange of notes with the State Department, Britain granted the U.S. access to Antigua on 15 January 1957. The St. Lucia site was activated on 5 December 1956, and Antigua and Ascension were ready for operations in October 1957. The Fernando de Noronha station was activated off the coast of Brazil on 18 September 1958. Twelve small telemetry ships were positioned downrange to fill in the gaps between Antigua and Ascension in 1957 and 1958.** The Eastern Range supported its first 5,000-mile-long mission (a SNARK test flight) on 31 October 1957.
context_page_description: MISTRAM was a high-resolution tracking system used by the United States Air Force to provide highly detailed trajectory analysis of rocket launches.
  A "classic" ranging system used since the 1960s uses radar to time a radio signal's travel to a target and back. This technique is accurate to approximately 1%. The accuracy of this technique is limited by the need to create a sharp "pulse" of radio so that the start of the signal can be accurately defined. There are both practical and theoretical limits to the sharpness of the pulse. In addition, the timing of the signals often introduced inaccuracies of its own until the introduction of high precision clocks.
  In MISTRAM, this was avoided by broadcasting a continuous signal. The basic system used a ground station located down range from the launch site and a transponder on the vehicle. The tracking station transmitted an X-band carrier signal which the transponder responded to by re-broadcasting it on another frequency. By slowly changing the frequency of the carrier broadcast from the station and comparing this with the phase of the signal being returned, ground control could measure the distance to the vehicle very accurately.
context_section_description: MISTRAM (MISsile TRAjectory Measurement) was a high-resolution tracking system used by the United States Air Force (and later NASA) to provide highly detailed trajectory analysis of rocket launches.
  A "classic" ranging system used since the 1960s uses radar to time a radio signal's travel to a target (in this case, the rocket) and back. This technique is accurate to approximately 1%. The accuracy of this technique is limited by the need to create a sharp "pulse" of radio so that the start of the signal can be accurately defined. There are both practical and theoretical limits to the sharpness of the pulse. In addition, the timing of the signals often introduced inaccuracies of its own until the introduction of high precision clocks.
  In MISTRAM, this was avoided by broadcasting a continuous signal. The basic system used a ground station located down range from the launch site (at Valkaria, Florida and Eleuthera Island, Bahamas) and a transponder on the vehicle. The tracking station transmitted an X-band carrier signal which the transponder responded to by re-broadcasting it on another (shifted) frequency. By slowly changing the frequency of the carrier broadcast from the station and comparing this with the phase of the signal being returned, ground control could measure the distance to the vehicle very accurately. Even with the analog circuitry used, MISTRAM was accurate to less than 1 km at the distance of the moon.
  To meet more stringent ballistic missile test requirements, several systems were designed, procured and added to the US Air Force Eastern Range's instrumentation in the 1950s and 1960s. The AZUSA continuous wave tracking system was added to the Cape in the mid-1950s and Grand Bahama in the early 1960s. The AN/FPS-16 radar system was introduced at the Cape, Grand Bahama, San Salvador, Ascension and East Grand Bahama Island between 1958 and 1961. In the early 1960s, the MISTRAM (Missile Trajectory Measurement) system was installed at Valkaria, Florida and Eleuthera island in the Bahamas to support Minuteman missile flights.
caption: US Air Force Eastern Test Range (Historical Map).
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