After Explorer I, the first US satellite, was launched in January 1958, the Jet Propulsion Laboratory (JPL) in California looked for a location to build more efficient, high-performance antennas. These antennas would provide tracking services for the upcoming lunar mission, Pioneer. Goldstone Dry Lake on the Fort Irwin military reservation with its small, established community located in a naturally bowl-shaped depression with surrounding hills was the ideal location. Locations in valleys were desired because they provided natural shielding from Radio Frequency (RF) interference. The Deep Space Network (DSN) has three complexes separated by about 120 degrees of longitude. The other two facilities are located in Madrid, Spain and Canberra, Australia.