Scientists first noticed the spacecraft's main thrusters were degrading in 2014.
NASA made the decision to activate the disused thrusters because the thrusters they had been using to adjust the spacecraft's antenna weren't functioning well anymore. It relies on small devices called thrusters to orient itself so it can communicate with Earth. It did. After almost four decades of dormancy, the Aerojet Rocketdyne manufactured thrusters fired perfectly.
And there's a lot we don't know about interstellar space - like, how does material from other stars interact with our solar system? But this past Tuesday, engineers fired them up anyway, and after 19 hours of waiting for the results to transmit from Voyager's antenna to Earth, they learned that it actually worked.
The Voyager missions discovered the first active volcanoes beyond Earth, at Jupiter's moon Io, and hints of a subsurface ocean on Jupiter's moon Europa. On Nov. 29, it was found that the TCM thrusters were working as good as the attitude control thrusters. These are located on the back of the spacecraft and are identical to the thrusters that they've used so far. "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", said Todd Barber, a NASA propulsion engineer.More news: Microsoft is building a massive new headquarters that looks nothing like Apple's
By switching to the spacecraft's "trajectory correction maneuver" thrusters, last used during the spacecraft's encounter with Saturn in 1980, engineers say they will be able to extend the lifetime of Voyager by two or three more years before its waning power reserves expire. The experts will turn back to the attitude control thrusters once there's insufficient power to operate the heaters.
Although the Voyager 1's twin spacecraft-Voyager 2-launched just 16 days after Voyager 1, its standard thrusters appear to be in much better shape, NASA officials wrote.
Until now special control thrusters were used to alter its direction, but the 1970s-made technology has been wearing out. The attitude control thrusters now used for Voyager 2 are not yet as degraded as Voyager 1's, however.
The spacecraft are powered by radioisotope thermal generators (RTGs) that generate heat from the decay of plutonium-238.
Voyager 2 is also on course to enter interstellar space, likely within the next few years. The Voyager missions are a part of the NASA Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate in Washington.