Experts at the agency's Jet Propulsion Laboratory in California made a decision to turn to four backup thrusters that were last used on November 8, 1980.
Engineers wanted to see if these alternate thrusters could point Voyager 1's antenna toward Earth, a job normally handled by a different set that's now degrading. With that hardware in an unreliable state, they had to come up with a solution, and decided that attempting to wake up a set of older thrusters which hadn't been used since Voyager 1 was still making its way around some of our nearby planets.
Voyager 2 is also on course to enter interstellar space, likely within the next few years, and now, its attitude control thrusters are still functioning well.
Thanks to the successful test, Voyager will switch to the backup thrusters in January and will be able to beam data back to Earth a bit longer. Still, NASA had to at least try, and Voyager 1 was one indeed up for the challenge.
"With these thrusters that are still functional after 37 years without use, we will be able to extend the life of the Voyager 1 spacecraft by two to three years", Suzanne Dodd, Voyager project manager, said in the release.
All of Voyager's thrusters were developed by Aerojet Rocketdyne. It orients itself by firing several 10-millisecond puffs with its thrusters - problem is, the ones it regularly uses haven't been performing as well after four decades in space.
On Wednesday, the engineers "learned the TCM thrusters worked perfectly - and just as well as the attitude control thrusters", said NASA.
"The mood was one of relief, joy and incredulity after witnessing these well-rested thrusters pick up the baton as if no time had passed at all", he said in a statement. The "attitude control thrusters" have been in decline since 2014, and are now wasting more propellant than ever. The team was delighted when the results of their test were resoundingly positive. That won't happen anytime soon, though, because Voyager 2's original thrusters are still working fine. They will likely also conduct similar tests on the backup thrusters on Voyager 2. The Voyager missions are a part of the NASA Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate in Washington.