Minitrack - Development

Development

The original proposal had only a single pair of stations. However, this was soon realized to be insufficient. From the NASA history:

Before the end of 1955, ideas changed drastically. First, it was realized that a single pair of stations would provide very limited geographical coverage, rendering data acquisition difficult and the accumulation of orbital data very slow. Four pairs of stations across the southern U.S. were next proposed. The idea of a "radio fence" was implicit in this suggestion; i.e., the creation of a long chain of overlapping antenna patterns that the satellite must intersect frequently. The trouble was that the planned orbital inclination of the Vanguard satellite would keep it away from the southern U.S. too much of the time. The next logical step was the construction of a long north-south fence that the satellite would pass through on almost every orbit. But the Vanguard program could not financially support a long chain of paired stations; besides, further thought soon showed that complete orbital data could be computed from angular (interferometric) tracking alone. These changes in thinking manifested themselves in a report describing a chain of nine single Minitrack stations strewn along the 75th meridian. To the regret of some engineers, ranging and velocity-measuring capabilities were dropped.

The technical desirability of Minitrack stations on foreign soil was one thing; more formidable were site negotiation, site preparation, and logistics. The situation was particularly acute in South American countries that were sensitive about U.S. bases and where transportation and communication facilities were primitive. Unfortunately, Minitrack stations required radio-quiet spots which are usually not coexistent with the also-desired communication links and supply facilities.

The Site Selection Team had picked six South American locations: Havana, Panama, Quito, Lima, Antofagasta, and Santiago; but who would undertake the imposing task of setting up stations outside the United States proper? The U.S. Army, by virtue of its IAGS experience, was the logical choice. In September 1956, the Army Chief of Engineers initiated construction at the six sites at the request of NRL. More specifically, the task fell to the specially created Project Vanguard Task Force of the Army Map Service. It should be mentioned here that the South American sites, though near large cities, were generally some distance from modern facilities and their associated radio noise. The isolation and primitive conditions caused logistics and operator morale problems in early days.

The Minitrack sites in the continental U.S. were established with greater ease. The Navy set up and operated the Blossom Point and San Diego stations; the latter being at the Brown Naval Auxiliary Air Station, near Chula Vista, California, and operated by the Naval Electronics Laboratory. The stations downrange from Cape Canaveral were set up in cooperation with Great Britain and operated by the U.S. Navy and Air Force. After deliberation over tracking requirements, logistics, and support facilities, Antigua and Grand Turk were finally chosen for downrange stations instead of the initially planned Barbuda and Mayaguana.

The Blossom Point station, just 56 km southeast of Washington, went into operation in July 1956, and was soon employed as a training headquarters for Minitrack operators and as a test facility for Minitrack equipment. During the IGY and after, many foreign nationals took the Minitrack course at Blossom Point. In fact, the willingness of NRL and NASA to employ and train foreign nationals at the Minitrack and STADAN stations greatly eased the task of placing U.S. facilities on foreign soil. Minitrack stations have "earned their keep" many times over as non-political, nostrings- attached representatives of the United States. 28

The full Minitrack network of ten stations was placed in operation during October 1957, with the eleventh, at Woomera, Australia, added a month later. It should already be evident that the Minitrack network was not a static thing. Stations were added and subtracted as the space program required. Bigger satellites with more transmitter power made stations such as Antofagasta redundant. Political harassment in Cuba made it apparent as early as September 1957 that the Havana station would probably have to be moved.