Voyager 1, the probe which became the first man-made object to leave the solar system in 2012, has been away from home for a long, long time—approximately 40 years. It’s still been beaming back reams of data and, in its off time, sending extremely ill-advised texts to distant alien civilizations that may or may not exist. (It’s so lonely.) Now it’s over 13 billion miles (nearly 21 billion kilometers) from Earth.
On Friday, NASA said it had successfully dusted off the spacecraft’s long-dormant backup thrusters for the first time in 37 years. In a blog post, the agency explained that Voyager 1's main attitude control thrusters had been degrading, making it difficult to reorient the spacecraft so that its antenna points back towards Earth. But the probe had a series of four backup trajectory correction maneuver thrusters which hadn’t been used since 1980, and through a series of tests NASA discovered that they remained functional and worked just as well as the main set.
“The Voyager flight team dug up decades-old data and examined the software that was coded in an outdated assembler language, to make sure we could safely test the thrusters,” Jet Propulsion Laboratory chief engineer Chris Jones wrote.
According to NASA, the TCM thrusters were located on the back side of the craft and previously were used in a more continuous firing mode during planetary flybys (the last such being Saturn in 1980). Ground control was able to reconfigure them to fire in a milliseconds-long pulse mode; the Verge noted the ability to use the TCM thrusters as a replacement for the main set “should extend [Voyager 1's] life by a couple of years.”
“The Voyager team got more excited each time with each milestone in the thruster test,” JPL propulsion engineer Todd Barber added in the blog post. “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.”
Voyager 1's sibling craft, Voyager 2, is 10.8 billion miles (over 17 billion kilometers) from Earth and will likely undergo a similar procedure, though per NASA, its main thruster set is in better condition.