NASA’s interstellar Voyager 2 spacecraft was launched back in 1977, and it is now more than 12 billion miles (20 billion kilometers) from Earth.
Despite its number designation, it is NASA’s oldest operational spacecraft, having lifted off from the space agency’s Cape Canaveral Space Launch Complex 41 two weeks before Voyager 1.
Voyager 2 features five science instruments that have allowed it to send a wealth of valuable data back to Earth during the decades since its launch.
Now, NASA has announced that it will use a small amount of backup power to help keep all of Voyager 2’s science instruments alive until 2026 instead of letting one die this year.
Voyager 1 and 2 are humanity’s only interstellar spacecraft
The Voyager probes are the only human-made spacecraft to have reached interstellar space. They have helped to alter our perception of our place in the universe, with Voyager 1 being responsible for the famous ‘pale blue dot’ image taken at the suggestion of famous astrophysicist and science popularizer Carl Sagan.
The two spacecraft are the only two to ever operate beyond our Sun’s heliosphere, the protective particles and magnetic fields generated by our Sun that mark the boundary between our solar system and interstellar space. Understandably, therefore, NASA wants to keep them operational for as long as possible so as to glean the maximum amount of data they can.
“The science data that the Voyagers are returning gets more valuable the farther away from the Sun they go, so we are definitely interested in keeping as many science instruments operating as long as possible,” Linda Spilker, Voyager’s project scientist at NASA’s Jet Propulsion Laboratory in Southern California, explained in a blog post.
Both Voyager probes are powered by radioisotope thermoelectric generators (RTGs), which convert heat from decaying plutonium into electricity. Though these systems have allowed the Voyager spacecraft to operate for more than 45 years, the decay process means that the generators produce slightly less power every year.
To date, mission specialists have been gradually turning systems off in order to keep scientific instruments alive. Now though, Voyager 2 has run out of options, meaning NASA officials have been deciding which instrument will be the first to discontinue this year.
Voyager 1, meanwhile, had one instrument fail early on in its mission, meaning operators won’t have to make a similar decision for the twin probe for another year or so.
NASA’s new method could prolong Voyager 1 and 2 missions
It turns out, though, that NASA seems to have found an alternative to turning off one of Voyager 2’s science instruments this year.
Voyager is equipped with a voltage regulator that triggers a backup circuit in the event of a voltage fluctuation. NASA has decided that it will now tap into this reserve energy to keep all five Voyager 2 science instruments alive for just a little longer — until 2026, to be precise.
Of course, this does mean that Voyager 2 will essentially get rid of its safety net in the case of a potentially damaging voltage fluctuation. The NASA team decided, though, that after 45 years of relative stability in Voyager 2’s electrical systems, it was willing to take the risk. If the new method works as intended, NASA may also apply it to Voyager 1 in a year’s time.
“Variable voltages pose a risk to the instruments, but we’ve determined that it’s a small risk, and the alternative offers a big reward of being able to keep the science instruments turned on longer,” said Suzanne Dodd, Voyager’s project manager at JPL. “We’ve been monitoring the spacecraft for a few weeks, and it seems like this new approach is working.”
