Overview
The Deep Space Network (DSN) is a collection of deep-space communication facilities operated by NASA's Jet Propulsion Laboratory (JPL). Large parabolic antennas (34 to 70 meters in diameter) are located at three sites: Goldstone in California, near Madrid in Spain, and near Canberra in Australia. Together they maintain uninterrupted 24-hour contact with spacecraft traveling far beyond Earth orbit.
Timekeeping Role
Precise timing is critical for DSN operations. Communication with a Mars probe involves a one-way light-time delay of 4 to 24 minutes, and the exact send and receive timestamps are used to determine the spacecraft's position and velocity. Each facility is equipped with hydrogen maser atomic clocks providing nanosecond-level accuracy. Relativistic time dilation corrections are applied routinely.
Why Three Stations at 120-Degree Intervals
The three facilities are spaced roughly 120 degrees apart in longitude so that, as Earth rotates, at least one station always has line of sight to any given direction in space. This arrangement allows seamless handovers as a spacecraft drops below the horizon at one site and rises at the next, preventing communication blackouts. Even Voyager 1, now about 24 billion km from Earth, remains in contact thanks to this relay of stations.
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