Since September 5, 1977, NASA's Voyager 1 has been an iconic spacecraft, tirelessly roaming through the vastness of the cosmos. After successfully completing its primary mission of observing the gas giants, Voyager 1 has traveled farther than any other spacecraft in history. Although many of its original components have been switched off over the years, the spacecraft continues to provide invaluable data from beyond our solar system.
As Voyager 1 ventures further into interstellar space, some components are no longer necessary, such as its camera, which captured its iconic last picture. However, maintaining the functionality of its thrusters remains critical for keeping the spacecraft's antenna properly aligned with Earth. Recently, the mission team has successfully revived backup roll thrusters, which are essential since the primary active thrusters face potential failure this fall due to residue buildup.
Initially, to prevent buildup formation within the thruster tubes, the mission team would periodically activate all thrusters. However, in 2004, the main rolling thrusters encountered a significant issue: two small internal heaters lost power. The problem was deemed unfixable at that time. “I think at that time, the team was OK with accepting that the primary roll thrusters didn’t work, because they had a perfectly good backup,” stated Kareem Badaruddin, Voyager mission manager at NASA's Jet Propulsion Laboratory (JPL). “And, frankly, they probably didn’t think the Voyagers were going to keep going for another 20 years.”
With a communication pause approaching from May 4 this year to February 2026, necessitated by upgrades to Deep Space Station 43, NASA's team aimed to ensure all contingencies were planned. Deep Space Station 43, a powerful 70-meter (230 feet) antenna located in Canberra, Australia, is part of NASA's Deep Space Network (DSN). It is the only station capable of communicating with the Voyager probes now that they are in the realms of interstellar space.
Faced with the upcoming communication hiatus, the mission team reevaluated the main thruster malfunction. They speculated that a disturbance in the circuit might have “flipped a switch” in the system, potentially allowing them to reactivate the thrusters with a command. This procedure, however, was fraught with risk. The team had to carefully activate the dormant main thrusters and address the heater issue simultaneously. If the automatic system detected a drift and activated the thruster before the heaters were fixed, it could have resulted in an explosion.
To mitigate this risk, the team meticulously aligned the star tracker, which measures the spacecraft's position, as precisely as possible. This was no small feat, especially considering the distance from Earth, where it takes over 23 hours for a signal to travel. Despite the challenges, the team executed the maneuver and attempted to switch the heaters back on—and it worked! The main thrusters were successfully revived.
“It was such a glorious moment. Team morale was very high that day,” exclaimed Todd Barber, the mission’s propulsion lead at JPL. “These thrusters were considered dead. And that was a legitimate conclusion. It’s just that one of our engineers had this insight that maybe there was this other possible cause and it was fixable. It was yet another miracle save for Voyager.”
As Voyager 1 continues its extraordinary journey through the cosmos, this unexpected revival of its main thrusters not only extends its operational life but also reaffirms the ingenuity and perseverance of the teams working tirelessly to unlock the mysteries of our universe.
