Since it left Earth 40 years ago, NASA’s Voyager 1 spacecraft has had an enviable adventure across the solar system — and beyond. Though it hasn’t made headlines in a while, the spacecraft delighted space nerds Friday night when news broke that it fired up its backup thrusters for the first time in 37 years.

The question is, why? Scientists from NASA and the University of Arkansas tell Inverse it’s actually a great new boost for the ol’ spacecraft, especially since the thrusters it’s been using since 2014 aren’t doing so well.

“The attitude control thrusters on Voyager 1 are showing degradation, meaning they appear to be reaching their end of life,” NASA’s Voyager project manager Suzanne Dodd tells Inverse. “We did a test of the [trajectory correction maneuver (TCM)] thrusters to see if they would operate, and could replace the attitude control thrusters. By using the TCM thrusters we will gain two to three additional years of lifetime for the mission.”

Jupiter's Great Red Spot
(March 1, 1979) As Voyager 1 flew by Jupiter, it captured this photo of the Great Red Spot.

Back in its heyday, Voyager 1 visited Jupiter and Saturn — and took exquisite photos of its journey. In fact, according to NASA, the spacecraft hasn’t needed to use its TCM thrusters since November 8, 1980. But even though the Voyager 1 is about 13.1 billion miles from Earth — and was half-asleep for a few decades — its TCM thrusters worked perfectly during this test. It took 19 hours and 35 minutes for the spacecraft’s signal to reach Earth, confirming the experiment worked.

“Having a signal and firing its thrusters? That’s incredible with 21 billion kilometers from Earth in ultra freezing temperatures in the vacuum of space!” Caitlin Ahrens, an astronomer at the University of Arkansas tells Inverse. “Voyager 1, in essence, has no limits to its travel!”

Since this recent test went over swimmingly, the space agency says it will switch Voyager 1 to the TCM thrusters sometime in January. It’ll likely perform a similar test on Voyager 2’s TCM thrusters down the line. In a few years, that spacecraft will join its twin, Voyager 1, in interstellar space. We love a happy ending!

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