Each Deep Space Network, or DSN, site has one huge, 70-meter (230-foot) diameter antenna. The 70-meter antennas are the largest and most sensitive DSN antennas, capable of tracking a spacecraft traveling tens of billions of miles (kilometers) from Earth.
Weighing in at nearly 2,970 U.S. tons (2.7 million kilograms), the surface of this giant, dish-shaped reflector is maintained to a precision of within half an inch (one centimeter) across its entire 41,400 square foot (3,850-square-meter) surface. This precision is crucial – even minor deformations would interfere with the antenna’s operations.
A hydrostatic bearing assembly supports the antenna’s tremendous weight on three pads, which glide around a large steel ring on a film of oil the thickness of a sheet of paper.
NASA built the 70-meter antenna when ambitious missions began venturing beyond Earth orbit and needed more powerful communications tools to track them. The 70-meter antenna in Goldstone, dubbed the "Mars antenna," was the first of the giant antennas designed to receive weak signals and transmit very strong ones far out into space, featuring a 64-meter-wide (210-foot) dish when it became operational in 1966. The dish was upgraded from 64 meters to 70 meters in 1988 to enable the antenna to track NASA's Voyager 2 spacecraft as it encountered Neptune.
While officially dubbed Deep Space Station 14, or DSS 14, the antenna picked up the Mars name from its first task: tracking the Mariner 4 spacecraft, which had been lost by smaller antennas after its historic flyby of Mars in 1965.
The Mars antenna has supported missions that include Pioneer, Cassini and the Mars Exploration Rovers. It received Neil Armstrong's famous communiqué from Apollo 11: "That's one small step for a man. One giant leap for mankind." It has also helped with imaging nearby planets, asteroids and comets by bouncing its powerful radar signal off the objects of study.