Voyager 1 will reach a distance of one light-day from Earth on November 18, marking a historic milestone for the farthest human-made object in history. The event is set to occur at 5:16:07 a.m.
A Half-Century of Interstellar Exploration
Launched in 1977, Voyager 1 and its twin, Voyager 2, were sent to conduct a grand tour of the outer planets. During its journey, Voyager 1 discovered two new moons and a thin ring around Jupiter. The probe eventually crossed into interstellar space in 2012, a region where the sun’s solar wind—a stream of charged particles—pushes against the surrounding gas and interstellar material to form the heliosphere.
“I just never imagined [the mission] would last that long,” Voyager project scientist at NASA's Jet Propulsion Laboratory (JPL) Linda Spilker told Science News.
Today, the spacecraft operates in the local interstellar medium, which Jamie Rankin, Voyager deputy project scientist at Princeton University, describes as the “suburb of space” surrounding our solar system. There, the probe detects changes in plasma and magnetic fields.
“In my mind the fun is receiving a signal back from the Voyager, a light-day away,” Voyager deputy project scientist at Princeton University Jamie Rankin said. These signals are transmitted via a 23-watt radio transmitter, which has an output comparable to a small refrigerator lightbulb.
Managing Dwindling Power Reserves
Voyager 1 is powered by three radioisotope thermoelectric generators, which function as nuclear-powered batteries converting heat from decaying plutonium-238. As these power sources degrade, mission scientists at NASA’s Jet Propulsion Laboratory (JPL) have had to implement creative measures to extend the craft’s life.
This includes troubleshooting, maintenance, and the systematic shutdown of non-essential instruments. In 2026, the team performed an initiative internally called “The Big Bang,” which involved shutting down three devices and activating three low-power alternatives to reduce energy consumption. Currently, Voyager 1 has only two instruments remaining in operation.
Unexpected Operational Challenges
The mission’s operational margins remain thin. In late October, NASA briefly lost contact with the spacecraft, an issue that may have been related to a group of thrusters going offline. “This is the first time we've seen the spacecraft do something like this, but we are also at a point in the mission where we have to expect the unexpected,” Voyager mission manager at NASA's Jet Propulsion Laboratory (JPL) Kareem Badaruddin said in a news release, highlighting the fragility of the aging hardware.
NASA estimates that the Deep Space Network will likely lose contact with Voyager 1 around 2036, when power levels become insufficient to transmit signals. The probe may also eventually freeze if it becomes unable to point its antenna toward Earth.
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Beyond its scientific mission, Voyager 1 carries a Golden Record curated by astronomer Carl Sagan and his colleagues. The disc contains an eclectic collection of music, ranging from Bach, Mozart, and Beethoven to blues artists like Blind Willie Johnson, as well as Aboriginal songs from Australia and percussion from Peru and Senegal.
It also includes Chuck Berry’s “Johnny B. Goode” and various natural sounds from Earth, serving as a time capsule for any intelligent life that might one day discover it.
Commemorating the Milestone
To mark the light-day milestone, NASA will host a moderated discussion on November 19 at 12 p.m. EST in the von Kármán Auditorium at JPL.
Participants will include Nicky Fox, associate administrator of the Science Mission Directorate; Jonathan Lunine, chief scientist at JPL; Suzanne Dodd, Voyager project manager; Linda Spilker, Voyager project scientist; Kareem Badaruddin, Voyager mission manager; and Jamie Rankin. The event will cover the status of both probes and include a preview of a documentary planned for the mission’s 50th anniversary in 2027.
The public is encouraged to participate in a “Shine Bright” event on November 17, where people can signal the spacecraft by flashing “V-G-R” in Morse code using a torch or the agency’s automated flasher. As Voyager 1 continues its journey, the distance ensures that any future conversation with the craft would be a slow, multi-day process, cementing its status as an enduring testament to human ingenuity.