Voyager 2 is nearly 50 years old, losing about 4 watts of power every year as its plutonium power source fades — and NASA just bought it at least another year of science with an all-at-once power-syst

A 49-year-old spacecraft gets a new lease on life

Nearly 49 years after its launch on August 20, 1977, Voyager 2 continues its journey through interstellar space, but its power supply is steadily fading. The spacecraft loses about four watts of electrical power every year, a consequence of the natural radioactive decay of plutonium-238 inside its radioisotope thermoelectric generators (RTGs). That decay reduces the heat that is converted into electricity, and the aging thermoelectric converters have also become less efficient over time.

To manage this decline, NASA engineers have spent years shutting down non-essential systems. Cameras and other instruments used only for planetary encounters were switched off after Voyager 2's flyby of Neptune in 1989. More recently, heaters and other components have been turned off to stretch the remaining power budget.

The 'Big Bang' procedure

In July 2026, engineers at NASA's Jet Propulsion Laboratory carried out a coordinated power and thermal procedure on Voyager 2, nicknamed the "Big Bang." The operation freed almost 10 watts of power by switching off a digital tape recorder and two heaters, while switching on two different heaters and a propulsion instrument. The reconfiguration was tested in May and June 2026, with the final setup completed by mid-July.

According to NASA, the saving should keep all three of Voyager 2's remaining science instruments — the magnetometer, plasma wave subsystem, and cosmic ray subsystem — operating for at least an extra year. The agency described the procedure in a mission update released on August 4, 2026.

Space Daily notes that the "Big Bang" could delay the need to shut down another instrument by at least a year and possibly two, as reported by Scientific American. The publication also highlights that the power decline is only one variable; other faults could still end the mission earlier.

The challenge of distance and age

Voyager 2 is currently about 20 billion kilometers from Earth, with a one-way communication time of about 19 hours. That means every command takes hours to reach the spacecraft, and engineers must wait almost two days to learn whether it was accepted. The spacecraft is approximately 143 AU from Earth, and its attitude-control thrusters, which use hydrazine, must stay warm to keep the high-gain antenna pointed toward our planet.

Engineers rely on models and old documentation because some critical temperatures on the spacecraft are not directly measured. The 70-meter dish at Canberra was unavailable for upgrades during testing, adding another layer of complexity.

NASA has said the Voyagers may continue to operate at least one science instrument into the 2030s if the spacecraft remain healthy. Space Daily notes that the Voyager 1 2024 thruster swap was a similar balancing act, borrowing power from a main heater to warm a dormant thruster branch.

A storied mission

The Voyager probes were originally designed for a four-year mission to tour the solar system, but they have far exceeded expectations, becoming NASA's longest-lived mission at a cost of more than $865 million. Voyager 2 is the only spacecraft to have visited all four gas giants — Jupiter, Saturn, Uranus, and Neptune — and it crossed the heliopause in 2018, entering interstellar space. Voyager 1 crossed that boundary in 2012.

The probes made numerous discoveries: at Jupiter in 1979, they found two new moons, Thebe and Metis, and a ring around the planet; Voyager 1 also spotted volcanoes on Jupiter's moon Io. At Saturn in 1980 and 1981, they returned detailed images of the rings and moons. Voyager 2 at Uranus in 1986 discovered two extra rings and ten new moons, and at Neptune in 1989 it found four rings and captured detailed images of Triton. In 1990, Voyager 1 took the famous "pale blue dot" photo from 4 billion miles away.

Both probes carry a golden record with information about humanity, and they continue to transmit data even as their power dwindles.

Next steps

NASA plans to apply the same reconfiguration to Voyager 1 in the coming months. Voyager 1, which launched on September 5, 1977, is the most distant human-made object. By November 2026, it will be about 16 billion miles from Earth, while Voyager 2 will be more than 13.2 billion miles away, traveling at 34,000 mph relative to the Sun.

The "Big Bang" procedure is another chapter in the ongoing story of managing these aging spacecraft, a series of delicate interventions that have kept the Voyagers exploring decades longer than anyone expected.