NASA Engineers Reactivate Voyager 1’s Long-Idle Thrusters Just in Time
NASA engineers have accomplished an extraordinary task by reactivating a set of long-dormant thrusters on the Voyager 1 spacecraft—just as they needed to sustain communication with the aging probe as it races through interstellar space.
Launched in 1977, Voyager 1 has been traveling at an approximate speed of 38,000 mph and is currently the farthest human-made object, situated about 15.5 billion miles away from Earth. For the last two decades, the spacecraft has depended on backup thrusters to manage its roll, ensuring it stays oriented toward Earth. Unfortunately, these backup thrusters have started to deteriorate, becoming clogged and unreliable, with engineers cautioning that they might only function for a few more months.
Complicating the situation, the sole antenna capable of transmitting commands to Voyager 1—a large dish located in Canberra, Australia—was set to go offline for significant upgrades. With the potential of losing contact during the extended maintenance window, NASA engineers opted to take a daring approach: reactivating the spacecraft’s original roll thrusters, which had been deemed unusable since 2004.
“At that point, the team was willing to accept that the main roll thrusters were nonfunctional because they had a perfectly good backup,” stated Kareem Badaruddin, Voyager mission manager. “And, to be honest, they probably didn’t think the Voyagers would continue operating for another two decades.”
A Bold Solution
The primary roll thrusters ceased operational capability more than twenty years ago due to failed internal heaters. Engineers had presumed the thrusters were irreparable. However, Todd Barber, the mission’s propulsion lead, mentioned that one team member proposed a new hypothesis: perhaps a malfunction in the heaters’ circuitry had merely switched them off. If that were the case, they could potentially be restarted.
The strategy was fraught with risk. Engineers planned to power up the inactive thrusters and try to restart the heaters. If the spacecraft deviated from its course during this process, the thrusters were programmed to engage automatically—potentially triggering a catastrophic malfunction if the heaters remained nonfunctional.
Yet, within 20 minutes of commencing the test, the team observed the heaters’ temperature increase—confirmation that the remedy had been successful.
“It was an exhilarating moment. Team morale was exceptionally high that day,” Barber remarked. “It was yet another miraculous rescue for Voyager.”
A Timely Challenge
Timing was crucial. As of May 4, the Canberra antenna—part of NASA’s Deep Space Network—has become inactive for upgrades expected to last until February 2026, with only limited availability in August and December. These enhancements are vital for supporting future missions, including plans for the Artemis program’s lunar landings, and will improve NASA’s ability to communicate with deep space missions.
Voyager 1 is positioned so far away that it takes 23 hours for a signal to reach it and another 23 hours for a response to arrive. With the spacecraft losing approximately four watts of power annually, engineers have had to power down nonessential systems to conserve energy. NASA aims to maintain operational functionality for both Voyager 1 and its twin, Voyager 2, beyond 2025.
A Legacy Surpassing Expectations
Initially intended for a five-year mission to investigate Jupiter and Saturn, both Voyager 1 and Voyager 2 have greatly surpassed anticipated outcomes. After achieving their initial objectives, the mission was prolonged to encompass Uranus and Neptune. Together, the spacecraft have explored four planets, 48 moons, and numerous magnetic fields and planetary rings.
In 2012, Voyager 1 became the first spacecraft to achieve interstellar space, crossing beyond the heliosphere—the bubble of particles and magnetic fields shaped by the sun. It now travels through a domain filled with remnants from ancient stars that exploded millions of years ago.
Despite their age and the severe conditions of deep space, the Voyager spacecraft continue to provide invaluable data. Thanks to the creativity and tenacity of NASA engineers, Voyager 1 remains on course—continuing its exploration, maintaining communication, and making history.