In a dramatic engineering feat, NASA has managed to bring back to life a set of long-dormant thrusters aboard Voyager 1, the most distant spacecraft from Earth, just ahead of an extended communications blackout. The successful fix could help keep the legendary probe on course and communicating with home until at least next year.
Voyager 1, which launched in September 1977, is currently traveling more than 15.5 billion miles (25 billion kilometers) away from Earth, far outside the heliosphere — the bubble of magnetic fields and particles created by the Sun. The spacecraft relies on multiple thruster sets to keep its antenna accurately pointed toward Earth, ensuring a steady stream of data from the edge of interstellar space.
Within the primary thruster system are roll thrusters, which maintain the spacecraft’s orientation by keeping it pointed at a guide star. Voyager 1’s original roll thrusters ceased functioning in 2004 after internal heaters lost power. Since then, the spacecraft has relied on backup roll thrusters for orientation. But over time, tiny amounts of propellant residue threatened to clog these backup units, risking the mission’s future.
With the threat of both thruster failure and an upcoming months-long pause in communications due to upgrades on the key Deep Space Network antenna in Canberra, Australia, engineers had to act fast. If both sets of roll thrusters failed, Voyager 1 could lose its ability to point toward Earth, ending a mission that has lasted nearly five decades.
NASA’s Jet Propulsion Laboratory team took a bold approach: they theorized that a disturbance in the circuitry might have simply flipped a switch in the wrong direction, cutting off power to the heaters. If they could reset the switch, it might restart the heaters and revive the original roll thrusters — units thought to be ‘dead’ for 20 years. But the maneuver was risky, since any malfunction could send the probe spinning out of alignment or even cause minor explosions if fuel lines froze.
The team sent a command to Voyager 1 on March 19 to activate both the heaters and thrusters. Then, they waited — more than 23 hours for data to travel back across the vast distance. When the telemetry finally arrived on March 20, it showed a dramatic rise in heater temperature, confirming that the thrusters were back online and operational. The fix was a relief for the mission team and marked yet another remarkable chapter in Voyager’s journey.
With this successful revival, Voyager 1 remains on track to continue sending invaluable data from the frontier of interstellar space, even as NASA temporarily loses direct command capabilities during the Deep Space Network upgrades. The mission’s resilience stands as a testament to the ingenuity and creativity of the engineers behind one of humanity’s greatest scientific adventures.
