The Voyager probes are not fully powering down ... yet

The Voyager spacecraft have been flying through space for nearly 45 years, so seeing recent headlines that these interstellar pioneers are powering down understandably caused some waves. 

But are the Voyager spacecraft really about to be shut down?

To clarify the situation, Astronomy reached out to the mission press officer Calla Cofield who was quick to correct the impression, saying, “nothing new is starting now.” She went on to explain that NASA is following a strategic plan to keep their oldest explorers going for as long as possible.

Keeping the lights on

The twin Voyager spacecraft left Earth nearly five decades ago; Voyager 2 left our planet Aug. 20, 1977, with Voyager 1 following shortly after on Sept. 5. Both spacecraft are powered by three radioisotope thermoelectric generators (RTGs) and have a host of instruments collecting and sending scientific data back to Earth. (In Voyager 1’s case it takes about 20 hours and 33 minutes for that data to reach us!) 

Now, the RTGs aboard the Voyager spacecraft turn heat into electricity in order to power the probes. That heat comes from the decay of plutonium-238 radioisotopes. However, at this point in their lifetimes, the generators are producing about 40 percent less electricity than when they were first launched.

To keep them running for as long as possible, NASA began aggressively planning which systems to shut off in 2019. But the agency has been tackling the problem of diminishing power for decades now. “After 45 years in flight,” says Cofield, “the power budget is getting to the point where the team has to turn off whatever they can to keep the spacecraft running and doing science.”

Over the last three years, this has involved turning off the heaters to five of the probes' scientific instruments."Amazingly, all five have continued to operate well below the temperatures they were tested at!” says Cofield.

The Voyager Science Steering Group will make further decisions on maintaining the power budget for the Voyager mission this August. According to Cofield, the creativity and innovation of the engineering team means that, in theory, the plans could stretch the Voyager missions into the 2030s — half a century longer than the probes were originally expected to last. However, that would require the team to turn off even more scientific instruments at some point. 

So, at least as it stands now, the Voyager spacecraft aren’t going anywhere (other than interstellar space) any time soon!