NASA’s two Voyager probes are the longest-lasting research devices currently in outer space. They’re also the furthest manmade objects from Earth at 15 billion and 12 billion miles away, still hurtling further from our solar system each day. Despite collecting data since the 1970s, the probes aren’t stopping yet.
Thanks to a new energy-saving technique discovered by NASA engineers, the probes might be able to keep operating for a few more years. The latest modification is one in a long line of engineering marvels and shortcuts keeping the Voyager probes in operation this long. As a result of the latest efforts, Voyager 2 may be able to start collecting data alongside NASA’s upcoming Interstellar Mapping and Acceleration Probe (IMAP) in 2025.
Imagine the cold, bitter emptiness of space. Now imagine taking it a step further. This is the reality of the Voyager probes since they departed the heliosphere, a protective bubble of particles and magnetic waves created by the sun, in the 2010s. Given their distance from the sun, the probes can’t rely on solar power to keep their instruments running. So, NASA engineers outfitted them with a trio of radioisotope thermoelectric generators. These rely on plutonium-238 and the heat generated as it decays to produce electricity.
Even so, the Voyager batteries are fading each year, dropping in increments of four watts annually. So, to keep the instruments running, NASA needed to get creative.
The first move, happening in 2019, was to turn off the heating units used to keep the instruments warm. This has allowed the devices to keep operating—even though they’re now 50 degrees Celsius colder than the limit of their tested range.
After squeezing all they could from that change, the team had to act even more drastically. Now, NASA is shutting down a Voyager 2 system designed to protect the craft from voltage spikes. This allows the engineers to divert the reserve power the system uses to its instruments. According to Voyager project manager Suzanne Dodd of NASA’s Jet Propulsion Laboratory, the move could buy the Voyager probes a few more years. If successful, the team will implement the same change to Voyager 1 later this year.
“I continue to be amazed by these spacecraft and by the engineers who come up with clever ways to operate them,” she says.
Beyond the latest change, Dodd believes the team could extend the Voyage’s lifespan as far as 2035. To do so, though, will require turning off some scientific instruments one by one.
The craft are equipped with several instruments, including a plasma science experiment, a cosmic ray detector, a low energy charged particle detector, a plasma wave surveyor, and a magnetometer. The latter two require just two watts of energy, meaning they’ll likely be the final survivors. Meanwhile, the other three instruments need between three and five watts each, making them likely candidates to be sacrificed first. But, by turning off some instruments, the team will be able to gather data from the others for additional years.
After nearly half a century of work, the Voyager probes are still generating valuable scientific data. The universe beyond the heliosphere is mysterious and filled with particles and magnetic fields to explore.
NASA Voyager project scientist Linda Spilker says, “The further we get from the sun, the more interesting it gets because we really don’t know what we might find. And having two Voyager spacecraft is like seeing through binoculars.”
If the Voyager probes can hang on for a few more years, they’ll be joined in space by NASA’s IMAP craft. Also destined to map the heliosphere, IMAP will provide fresh data for scientists to compare to data collected by the Voyager probes.
The aging spacecraft are also working together with the New Horizons probe, which sailed past Pluto and is now five billion miles away from Earth. It’s equipped with better sensors than those onboard the Voyagers, but scientists still use data from its predecessors to guide the New Horizons mission. NASA hopes the probe will operate until 2050 thanks to the lessons it has learned from Voyager.
Meanwhile, teams are working on new spacecraft that will travel into interstellar space and continue the mission of the Voyagers.
For now, though, the original probes are still on a mission. Thanks to the creative thinking of the NASA team, they have a few more years to do what they do best.