Dormant thrusters awaken: Voyager 1’s 37-year silence ends to keep Earth in touch

NASA’s Jet Propulsion Laboratory revived four attitude-control hydrazine thrusters on Voyager 1 in 2017 after they had been idle since 1980, firing 10-millisecond pulses at a distance of about 21 billion kilometers to keep the spacecraft’s dish pointed at Earth. The 19-hour-35-minute signal lag meant there was no real-time control, so engineers reconstructed the dormant branch’s behavior from old records and code and used a spare trajectory-correction thruster set. The test, enabled by hardware redundancy, extended the probe’s life by a few years as power and aging continue to challenge the mission, underscoring how careful engineering and cross-generational knowledge keep deep-space hardware operational.