NASA Extends Voyager 2 Mission by Swapping Heaters to Save Power

NASA has completed a delicate power-management maneuver on Voyager 2, currently more than 13 billion miles from Earth, that is expected to extend the spacecraft's scientific mission by two years or more. In July, the mission team turned off two heaters and a digital tape recorder that had been kept running for its residual heat, replacing them with two different heaters and a propulsion instrument that also produces waste heat.

The operation, internally dubbed the "big bang," required a year of planning and involved nearly every team member at the Jet Propulsion Laboratory. Because of the probe's distance, commands take roughly 20 hours to arrive and another 20 hours for confirmation, meaning engineers waited about 40 hours to learn whether each step succeeded.

Voyager 2 and its twin, Voyager 1, launched in 1977 to study the outer planets and are now the only human-made objects operating in interstellar space. Both are powered by radioisotope thermoelectric generators that convert heat from decaying plutonium into electricity, but output declines by about four watts per year.

As power margins have grown razor-thin, NASA has progressively shut down non-essential systems. Voyager 1 now operates with two science instruments; Voyager 2 retains three. The recent heater swap prevented the need to turn off one of Voyager 2's remaining instruments before the end of 2026.

Mission manager Kareem Badaruddin noted that although the spacecraft were built to the same design, they have behaved differently over decades of flight. The team plans to attempt a similar power-saving strategy on Voyager 1, but success with Voyager 2 does not guarantee the same outcome.

The Voyagers continue to return unique data on the boundary where the sun's influence gives way to the interstellar medium. NASA's New Horizons probe, currently about six billion miles from Earth, is also headed toward that region but has not yet reached interstellar space.