NASA’s Deep Space Network listened for Voyager 1 on October 18 and again on October 19, 2026, and detected no signal either time. The spacecraft, about 16 billion miles from Earth, came back on October 20, roughly 48 hours after the first missed contact, and communication has held since. NASA reported the episode on October 29.
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Engineers have determined that one group of thrusters went offline and its backups switched on. The change was an automatic fault-protection response, which puts the spacecraft in a safe configuration and pauses normal operations so the team can diagnose the problem. The cause is still under investigation.
A thruster swap and a safe-mode pause
The account comes from a NASA Voyager mission blog post. Kareem Badaruddin, the Voyager mission manager at the Jet Propulsion Laboratory, said the team was relieved to be back in contact and eager to understand what happened, and that the mission has reached a point where the unexpected has to be expected. NASA’s post does not say whether the thruster fault is connected to the power-saving work done a few weeks earlier, and it does not claim that it is.
Fault protection is a design feature, not a malfunction in itself. A spacecraft launched in 1977 carries software that, when it sees a problem it cannot resolve alone, stops and waits for instructions, and at this distance every instruction has a cost in time. Suzanne Dodd, the Voyager project manager, described the experience of sending a message, going home and waiting two days for the response.
The Deep Space Network is the system of large antennas that made the October attempts. Its two scheduled tries came 24 hours apart, and the signal was found again on the third day. NASA has said the team has kept contact since October 20, though the post lists no date for a finding on why the thrusters changed over.
The power budget behind the quiet
The same post describes a separate piece of engineering. In early September 2026, engineers turned off three Voyager 1 devices and replaced them with three lower-power alternatives, finishing about six weeks after the same swap on Voyager 2, which NASA covered in an August 4 post. That earlier effort carried the nickname the Big Bang. The six devices help keep the spacecraft warm, so the swaps had to happen together while heat stayed properly distributed.
The motive is arithmetic. Both probes lose about 4 watts of power per year as the plutonium in their radioisotope thermoelectric generators decays. Without the change, Voyager 1 would likely have had to turn off another science instrument as early as summer 2027.
The Voyager 2 post adds that the mission has turned off two science instruments on each spacecraft since 2024, that Voyager 2 keeps three instruments running, and that without the swap another would have had to shut down before the end of 2026. The savings should extend operation of those three by at least an extra year, NASA said, and the team planned the same swap on Voyager 1 in the coming months. The September work on Voyager 1 is that follow-through, and the headroom it bought is the difference between summer 2027 and sooner.
The mission launched with 10 dedicated science instruments, and two have been switched off in recent years. NASA’s post does not name which two.
One light-day on November 18
On November 18, 2026, Voyager 1 will be 16.09 billion miles, or 25.89 billion kilometers, from Earth, which is one light-day. The probe is traveling at about 38,000 miles per hour. The mission page puts the milestone at 2:16 a.m. Pacific time on that date. A radio message will take 24 hours to reach the spacecraft and another 24 hours for the reply to return, and NASA says nothing about the spacecraft or its environment is expected to change at that point. The mission’s distance tracker shows where both probes are now, and the main Voyager page covers the mission overall.
The mission page notes that Voyager 1 has been operating since 1977 and has reached interstellar space, so the spacecraft is now in its 49th year of flight. Every power-saving step is judged against that age: the plutonium that heats and runs it decays on a fixed schedule, and engineers can only choose which capabilities to give up first. Each swap trades one kind of margin for another, which is why the team treats an unexplained thruster change with such care.
The light-day figure explains why the October silence was so hard to read. At that distance a single command and its reply take 48 hours to complete, the same span as the gap between the first missed contact and the signal’s return. The open item is the thruster fault: NASA says the cause is still being investigated, and no date has been given for a finding.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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