Goldstone: Fifty Years of Listening to Voyager

Somewhere in the Mojave Desert northeast of Barstow, a dish antenna seventy meters across is pointed at the sky. Built in nineteen sixty-six and enlarged to its current size in nineteen eighty-eight, it has been pointed at some part of the sky, without interruption, ever since. Most of what it is listening for is unremarkable by any ordinary standard: telemetry from distant spacecraft, calibration signals, the routine traffic of solar system exploration. But some of what it listens for is the furthest sound a human machine has ever made.

Voyager One was launched on September fifth, nineteen seventy-seven, on a trajectory calculated to take it past Jupiter and Saturn and then out of the solar system entirely. It has been traveling ever since. As of twenty twenty-six, it is more than twenty-three billion kilometers from Earth, which is a number that does not fit comfortably into the human scale of distance. The signal from Voyager, traveling at the speed of light, takes more than twenty-one hours to arrive. When engineers at the Goldstone Deep Space Communications Complex send a command to Voyager One, they are sending a message that will not arrive for nearly a day, and the confirmation of its receipt will not return for another day after that.

The dish that handles much of this communication is the largest steerable radio antenna in the Western Hemisphere. Pointing it at Voyager One requires aiming at a spot the size of a school bus at a distance of twenty-three billion kilometers, then holding that aim precisely enough to catch a signal measured in trillionths of a watt. The engineering that makes this possible is not exotic or classified. It is the cumulative product of sixty years of refinement in the Mojave Desert, at a facility the federal government established in nineteen fifty-eight to track Pioneer One.

The complex is not visible from Interstate Fifteen. Most people who drive the Mojave never know it is there. But at this moment, while you are on this road, somewhere in the scrub desert to the east, that dish is listening to the most distant object humanity has ever sent into the universe. The conversation has been going on for nearly fifty years, and no one is planning to stop.