The Voyager 1 Spacecraft Is Still Sending Data from 15 Billion Miles Away

The faint whisper from humanity's farthest messenger takes over 22 hours to cross the void. This signal, originating from the Voyager 1 spacecraft, is broadcast with the power of a refrigerator light bulb—a testament to the incredible engineering behind its nearly five-decade journey. Originally designed for a five-year tour of Jupiter and Saturn, the resilient probe took advantage of a rare planetary alignment to slingshot its way through the outer solar system, far exceeding its initial mission goals and continuing to explore the cosmos.

Its remarkable longevity is owed to a radioisotope thermoelectric generator, which converts heat from decaying plutonium into electricity. This is a vital power source in the darkness of deep space, where sunlight is far too weak for solar panels. In 2012, Voyager 1 achieved a monumental milestone by crossing the heliopause—the boundary of our sun's magnetic influence—officially entering the space between the stars. Its faint data, captured by the massive antennas of the Deep Space Network, continues to provide scientists with the first direct measurements of this unexplored interstellar (Review) region.