Ed Stone has been project scientist for the Voyager program for over 40 years. Alexandra Witze, profiling Stone, now 77, for Nature:
To many, the Voyagers are synonymous with the unflappable Stone. The man and the mission are bound together, even as the probes enter yet another phase in their storied lifetime. Almost 19 billion kilometres from Earth, Voyager 1 is flirting with the edge of interstellar space, the medium between the stars. Last July, it saw the flood of charged particles from the Sun subside to a mere trickle — a sign that the spacecraft may soon break out of the Solar System.
Stone has had—and continues to have—a remarkable career. Voyager 1 and Voyager 2 have returned reams of data, and they are currently poised to leave the solar system, the first manmade objects to do so. They have plenty of time to continue exploring, too—their plutonium-based generators are projected to last another 12 years before they peter out.
In the meantime, scientists are eagerly awaiting the day when they confirm that one of the two spacecraft have entered interstellar space. Discover what scientists think that will look like when it happens.