Five large parabolic ("dish") antennas are located at the Goldstone site to handle the workload, since at any given time the DSN is responsible for maintaining communication with up to 30 spacecraft. The antennas function similarly to a home satellite dish. However, since the spacecraft they communicate with are much further away than the communication satellites which home satellite dishes use, the signals received are much weaker, requiring a larger aperture antenna to gather enough radio energy to make them intelligible. The largest, a 70-meter (230 ft) Cassegrain antenna, is used for communication with space missions to the outer planets, such as the Voyager spacecraft, at 20 billion kilometers the most distant manmade object from Earth. The radio frequencies used for spacecraft communication are in the microwave part of the radio spectrum; S band (2.29 - 2.30 GHz), X band (8.40 - 8.50 GHz) and the Ku band (31.8 - 32.3 GHz). In addition to receiving radio signals from the spacecraft (called downlink signals), the antennas transmit commands to the spacecraft (called uplink signals) with high power radio transmitters powered by klystron tubes.
A major goal in the design of the station is to reduce interference with the weak incoming downlink radio signals by natural and manmade radio noise. The remote Mojave Desert location was chosen because it is far from manmade sources of radio noise such as motor vehicles. The RF front ends of the radio receivers at the dishes use ruby masers, consisting of a bar of synthetic ruby cooled by liquid helium to 4.5°K to minimize the noise introduced by the electronics.
When not needed for spacecraft communication, the Goldstone antennas are used as sensitive radio telescopes for astronomical research, such as mapping quasars and other celestial radio sources; radar mapping planets, the Moon, comets and asteroids; spotting comets and asteroids with the potential to strike Earth; and the search for ultra-high energy neutrino interactions in the Moon by using large-aperture radio antennas.
Antennas at Goldstone Deep Space Communications Complex
It is commonly believed that the first American satellite, Explorer 1, was confirmed to be in orbit by the use of the phrase "Goldstone has the bird". However, Goldstone was not in operation at the time of Explorer 1, and like many oft-repeated quotations it is incorrect. Others claim that the actual phrase was "Gold has it!", incorrectly identifying "Gold" as a temporary tracking station at Earthquake Valley, east of Julian, California. In fact, Gold Station was located at the Air Force Missile
Test Center (AFMTC) in Florida and the temporary tracking station at Earthquake Valley was Red Station.