The Deep Space Network (DSN) is a sophisticateddata communications system used by the U.S. National Aeronautics and Space Administration (NASA) in conjunction with manned and unmanned space missions. The DSN is also used by radio astronomers.
The main terminal of the DSN is located at JPL (Jet PropulsionLaboratory) headquarters in Pasadena, California. There are three primary antennas, spaced equally on a great circle that slants around the world. All three are large paraboloid (dish) antennasthat can be used for transmitting and receiving signals over a wide range of radio frequencies. One antenna is located in California, another is in Spain, and another is in Australia. Theantennas are located in such a way that all existing operational spacecraft can be monitored and controlled, and communications maintained with them, almost 100 percent of the time. This is true of both earth-orbiting satellites and interplanetary space vehicles.
Signals transmitted and received by DSN equipmentinclude satellite control and telemetry, e-mail (including text,graphics, video, programs, and sound attachments), communicationswith the Space Shuttles, and radio-frequency emanations fromdistant celestial objects.