Voyager 1 Will Be One Light-Day From Earth on 18 November 2026, 49 Years After Its Launch, With Two of Its Ten Instruments Still Running

NASA says Voyager 1 will be 16.094 billion miles (25.902 billion kilometres) from Earth at 2:16:07 a.m. Pacific time on 18 November 2026. That is one light-day, the distance light travels in 24 hours, and NASA says Voyager 1 will be the first human-made object to reach that distance. The spacecraft left Cape Canaveral on 5 September 1977, and NASA’s instrument status table, dated 17 April 2026, shows two of its ten science instruments still switched on.

Voyager 2 went up first

Voyager 2 lifted off from Cape Canaveral, Florida, on 20 August 1977 and Voyager 1 followed on 5 September 1977. Voyager 2 rode a Titan IIIE-Centaur rocket. Until NASA Administrator James Fletcher announced the new names on 7 March 1977, JPL records, the pair were called Mariner Jupiter/Saturn 1977.

An alignment that comes round every 175 years

JPL says mission designers noted in the 1960s that the outer planets align only about every 175 years, and that the next alignment would fall in the late 1970s. Called the Grand Tour, the first plan was two pairs of spacecraft. JPL says it proved too costly and was cancelled in 1971. In 1972 NASA approved a smaller project: two Mariner-class spacecraft launched in 1977 to study Jupiter and Saturn only.

Scientists held out hope that one craft could go on to Uranus and Neptune, and Voyager 2 did. NASA’s mission pages give these closest approaches:

• Voyager 1 passed Jupiter on 5 March 1979 at about 280,000 km and Saturn on 12 November 1980 at about 126,000 km.
• Voyager 2 passed Jupiter on 9 July 1979 at about 645,000 km and Saturn in late August 1981 at about 101,000 km.
• Voyager 2 passed Uranus on 24 January 1986 at about 81,500 km and Neptune on 25 August 1989 at about 4,800 km.

NASA says Voyager 2 is still the only spacecraft to have visited Uranus and Neptune. Voyager 1’s cameras went off on 14 February 1990 to save power, according to NASA’s status table.

Two crossings of the heliopause

The Sun blows a bubble of charged particles and magnetic fields called the heliosphere, and the heliopause is the boundary where that solar wind meets the colder, denser material between the stars.

JPL’s 12 September 2013 release gives 25 August 2012 as the day Voyager 1 crossed, and the date is an inference. Voyager 1’s plasma sensor no longer works, so scientists could not measure the gas directly at the time. A solar eruption reached the spacecraft in April 2013 and made the surrounding plasma oscillate, and the pitch of those oscillations showed plasma about 40 times denser than in the outer heliosphere. Fainter oscillations from late 2012 were extrapolated back, and abrupt changes in energetic-particle density first seen on 25 August 2012 matched what a crossing should look like. Voyager project scientist Ed Stone said of the new data: “we believe this is mankind’s historic leap into interstellar space.”

Voyager 2 crossed on 5 November 2018, and its plasma instrument was working. JPL says that instrument recorded a steep drop in solar-wind speed that day and then no solar-wind flow at all, and three other instruments supported it. NASA announced the crossing on 10 December 2018, with the probe about 18 billion km from Earth and its signals taking about 16.5 hours one way. NASA’s Voyager 2 page lists a different date, 25 November 2018, in one table. The JPL announcement says 5 November, the date used here.

Five months of unreadable data from Voyager 1

On 14 November 2023 Voyager 1 stopped sending readable science and engineering data. JPL says it still accepted commands and otherwise behaved normally. In early March 2024 the team sent a command that made the spacecraft return a readout of the memory of its flight data subsystem, one of three onboard computers. About 3 percent of that memory was corrupted, NASA reported on 4 April 2024, traced to a single chip that stores part of it, including some of the computer’s software code.

Engineers cannot be sure why the chip failed. NASA names two possibilities: an energetic particle from space, or wear after 46 years. Nobody could repair the chip, and no single free spot in the memory was big enough for the lost code. So the team split it into pieces, stored them in different places and adjusted the references between them. It sent the first relocated code, which packages engineering data, on 18 April 2024. A signal on 20 April confirmed it worked, the first engineering data in five months, JPL wrote on 22 April.

Science data came back in stages. NASA’s 22 May post says commands sent on 17 May restored the plasma wave instrument and the magnetometer. Its 13 June post gives the date of that command as 19 May and says all four instruments were by then returning usable data. Each command takes about 23 hours to reach the spacecraft, and NASA’s May post says the team waited nearly two days to confirm that the commands had worked.

Four watts a year

Each Voyager carries three radioisotope generators, which JPL says turn the heat of decaying plutonium into electricity. At launch each produced about 158 watts, according to NASA’s Voyager 1 page. JPL’s 5 March 2025 release says each spacecraft now loses about 4 watts a year, and that without shutting instruments off the probes would have had “only a few more months of power” before the mission was declared over. That release adds that engineers believed at least one instrument on each could keep running into the 2030s, and that unforeseen problems could shorten that.

The switch-offs follow an order agreed years earlier. The dates, from NASA’s table: Voyager 2’s plasma science instrument on 26 September 2024, Voyager 1’s cosmic ray subsystem on 25 February 2025, Voyager 2’s low-energy charged particle instrument on 24 March 2025 and Voyager 1’s on 17 April 2026. Voyager 1’s power dipped unexpectedly during a routine roll manoeuvre on 27 February 2026, NASA says, which put the spacecraft at risk of an automatic shutdown that would be harder to recover from. A small motor that turns the sensor stays powered, drawing 0.5 watts, so the instrument could be restarted if power ever allowed it.

That leaves Voyager 1 with a plasma wave instrument and a magnetometer. Voyager 2 has those two plus the cosmic ray subsystem. On 4 August 2026 NASA described a procedure its engineers call the “Big Bang” for Voyager 2: turn off some power-hungry devices and switch to lower-power alternatives at once, while keeping the spacecraft warm enough to work. Without it, another Voyager 2 instrument would have had to go before the end of 2026. Three instruments should keep running for at least another year on the saving, the post says, and the team plans the same change on Voyager 1 in the coming months.

What the Golden Record carries

Each Voyager carries a 12-inch, gold-plated phonograph record in an aluminium jacket, with a cartridge and needle and symbols that explain how to play it. A committee led by Carl Sagan of Cornell University chose the contents, NASA says, and Sagan noted the record would only be played if advanced spacefaring civilisations exist in interstellar space.

The record holds 115 images, encoded in analog form. It also has spoken greetings in 55 languages, from Akkadian, spoken in Sumer about six thousand years ago, to Wu, a modern Chinese dialect. Among them are Bengali, Gujarati, Hindi, Kannada, Marathi, Oriya, Punjabi, Rajasthani, Telugu and Urdu. In English the greeting is “Hello from the children of planet Earth.”

The record also holds natural sounds (surf, wind, thunder, birds, whales), printed messages from President Carter and U.N. Secretary General Waldheim, and 27 pieces of music. They include Bach, Mozart and Beethoven, Chuck Berry’s “Johnny B. Goode”, Blind Willie Johnson’s “Dark Was the Night” and a raga of 3 minutes 30 seconds, “Jaat Kahan Ho”, sung by Surshri Kesar Bai Kerkar. NASA calls the music a 90-minute selection, and the durations in its table add up to 1 hour 27 minutes 16 seconds by our addition.

How far a light-day is

Light takes 8 minutes 20 seconds to reach the Sun from Earth, and NASA gives 3 to 22 minutes for Mars depending on where the planets are. India’s Mars Orbiter worked within that range until contact ended in 2022. Another NASA mission, the James Webb Space Telescope, sits about 1.5 million km out. Neptune, which Voyager 2 reached in 1989, is on average 4 light-hours 10 minutes away.

Divided out, NASA’s light-day figure of 25,902,068,356 km comes to about 173 astronomical units, where one AU is the Earth-Sun distance. NASA’s Voyager 1 mission page, read on 8 October 2026, still carries an older figure of 164.7 AU as of 21 August 2024. Neither it nor the light-day page, which was last updated on 2 October 2026, gives a live distance for either probe. The light-day page says Voyager 1 will have taken 49 years, 2 months and 11 days to reach one light-day, and that Voyager 2 is on pace to reach the same distance in November 2035.