Voyager 1 leaves the Sun's bubble; no craft has gone farther
By the summer of 2012, Voyager 1 had been flying outward for thirty-five years, well past its original mission to Jupiter and Saturn. On August 25, 2012, at a distance of about 121 astronomical units from the Sun, Voyager 1 is understood to have crossed the heliopause on that date, though NASA did not announce confirmation via plasma data until September 2013. No human-made object had ever traveled through the thin, cold plasma of interstellar space before. JPL scientists spent roughly a year confirming the plasma data before announcing the crossing.
A NASA spacecraft built in the 1970s, launched from Cape Canaveral, became the first object of any nation to leave the Sun's domain entirely. The achievement rests on the Jet Propulsion Laboratory's engineering and on decades of American deep-space tracking through the Deep Space Network, a program no other country has matched at this range.
QHow far has Voyager 1 traveled since the 2012 heliopause crossing?
The probe has pushed roughly 50 astronomical units farther into interstellar space since 2012. As of August 2026, Voyager 1 sits at 171.19 AU from Earth, about 25.6 billion kilometers, making it the most distant human-made object ever built, still farther out than its twin, Voyager 2. It covers that distance at a steady clip of about 61,000 kilometers per hour relative to the Sun, a speed set by the gravity assists it picked up decades earlier at Jupiter and Saturn. No thrusters accelerate it now. The distance simply keeps compounding year after year, driven by momentum alone, with no thrusters left to slow or steer it.
QWhat actually detected the heliopause before scientists announced the crossing?
Not a camera or a compass, but the plasma wave experiment aboard Voyager 1, an instrument built to listen to charged particles rather than see anything. In June 2012, NASA reported the spacecraft was registering a sharp uptick in high-energy particles arriving from interstellar space, a signal that solar wind was thinning out and losing its grip. Scientists cross-checked this against data from Voyager 2, still inside the heliosphere, to confirm the difference was real and not instrument drift. The plasma wave subsystem is one of only two instruments still functioning on the spacecraft today, alongside its magnetometer, the last two of the original instrument suite still returning data.
QHow long can Voyager 1 keep talking to Earth before it goes silent for good?
NASA engineers estimate the plutonium-fueled radioisotope thermoelectric generators powering Voyager 1 will keep producing enough electricity to transmit engineering data only until around 2036. The RTGs lose about four watts of output every year as their plutonium-238 decays, which is why mission controllers have been shutting down onboard systems one at a time for years just to keep the transmitter alive. By the time power runs out, Voyager 1 will have operated for nearly 59 years, over 500 times longer than its original two-planet mission to Jupiter and Saturn ever called for. After that, the spacecraft will keep flying but will no longer be able to transmit data.
