Voyager 1 Endures at the Edge of Space on Tiny Nuclear Power
Voyager 1, launched in 1977, is now about 25 billion kilometres from Earth, so far that radio signals take more than 22 hours to reach it; it continues to send back data from interstellar space using a nuclear power source the size of a car battery. Its plutonium generators now deliver ~230 watts (down from ~470 W at launch), fading about 4 watts per year, leading NASA to progressively shut down nonessential systems to extend the mission into the 2030s. Two instruments remain active as it drifts beyond the heliopause, with signals traveling via NASA’s Deep Space Network, a faint whisper from humanity's farthest probe.