NASA buys another year of science from its 48-year-old Voyager 2 probe

Voyager 2, launched in 1977 and now roughly 142 astronomical units from the Sun, runs on a radioisotope thermoelectric generator whose plutonium decay yields about four fewer watts of usable power each year. That steady decline has already forced the mission to power down instruments — each Voyager has shut off two since 2024 — and Voyager 2 was on track to lose another of its three remaining instruments later this year.

JPL engineers avoided that cut by reworking the spacecraft’s power budget: switching off non-essential systems and swapping in lower-power alternatives that still keep the probe warm in deep space. The change preserves all three of Voyager 2’s active instruments for at least another year. NASA plans to apply the same reconfiguration to Voyager 1, currently the most distant human-made object at about 171 AU, in the coming months.

The adjustment is a reminder of how thin the margins have become on both probes, where a one-way command now takes nearly a full day to arrive. Managing the dwindling nuclear supply watt by watt is what keeps the only two operating spacecraft in interstellar space returning data nearly half a century after launch.