Voyager 1: The 1977 Spacecraft in Interstellar Space — Still Sending Signals From Nearly 25 Billion Kilometres Away

The signal left Earth 22 hours and 48 minutes ago.

It's still traveling.

When it arrives, the spacecraft on the other end will have already moved another 1.4 million kilometres further away. And if that spacecraft replies, you'll have to wait another 22 hours and 48 minutes to hear back.

This is what talking to Voyager 1 feels like in September 2026. The longest-distance phone call in human history. And the phone is a 46-year-old machine built with 1970s microchips, running on plutonium, tumbling through interstellar space at 17 kilometres per second.

It still works.

Where is Voyager 1 right now?

Voyager 1 is approximately 165 AU from Earth — that's 165 times the distance from Earth to the Sun. In raw numbers: nearly 24.7 billion kilometres. A signal traveling at the speed of light takes close to 23 hours to cross that gap.

No human-made object has ever been further from Earth.

For context: Pluto at its furthest sits about 49 AU from the Sun. Voyager 1 is more than three times beyond that — and Pluto is already so remote that sunlight takes 5.5 hours to reach it. Voyager 1 is in a completely different neighbourhood. A darker, colder place where the Sun has shrunk to just another pinprick star.

Has Voyager 1 actually left the solar system?

On August 25, 2012, Voyager 1 crossed the heliopause — the boundary where the Sun's stream of charged particles finally loses its battle against the gas and dust of interstellar space. After 35 years of travel, it became the first human-made object confirmed in interstellar space.

Scientists knew it had crossed because the particle environment changed abruptly. High-energy cosmic rays from outside the solar system spiked. Solar wind particles dropped to near-zero. It was like walking through a door.

A door 18.8 billion kilometres from home.

How is Voyager 1 still working after 46 years?

Voyager 1 doesn't run on solar panels. This far from the Sun, sunlight is too faint to power a night-light. Instead, it runs on three radioisotope thermoelectric generators — RTGs — that convert heat from decaying plutonium-238 into electricity.

At launch in 1977, those RTGs produced about 470 watts. Each year, they decay. By 2026, they generate roughly 250–260 watts. That's less than a standard kitchen lightbulb left on for an hour.

NASA engineers have been powering down instruments one by one as the electricity fades. By the late 2020s, there may not be enough power to run a single heater — and Voyager 1 needs heaters to stop critical electronics from freezing in the –270°C void. After that, it goes quiet.

What happened when Voyager 1 went silent in 2023?

In late 2023, something went wrong.

Voyager 1 started sending gibberish. Its science transmissions became unreadable — corrupted in a way engineers had never encountered before. For months, the spacecraft appeared physically fine (power normal, trajectory stable) but it couldn't tell Earth what it was sensing.

The diagnosis: a single chip in the Flight Data System had failed, and all data was being routed through it, scrambled beyond recognition.

The fix? Write a software patch. For a 46-year-old spacecraft 24 billion kilometres away, with a 45-hour round-trip communication delay.

Engineers couldn't reboot or restart. They had to work around the broken chip by carefully splitting the corrupted code across three other memory locations in the FDS — memory never designed to hold it. Every command had to be planned precisely, because a mistake meant waiting 45 hours just to find out how badly you'd failed.

In April 2024, they sent the fix. They waited.

Forty-five hours later, Voyager 1 replied with clean, coherent data for the first time in months.

What is on the Voyager Golden Record?

Every Voyager spacecraft carries a 12-inch gold-plated copper disc — the Golden Record. Designed by a committee that included astronomer Carl Sagan, it is a message to whoever, or whatever, might eventually find it.

On it: 116 images of Earth and humanity. Greetings in 55 languages. Sounds — rain, surf, wind, a heartbeat, a baby crying, a dog barking. Music from 27 cultures, including Bach, Beethoven, Chuck Berry, and a Peruvian wedding song. And a brain-wave recording of Sagan's collaborator Ann Druyan — made the night she was falling in love with him — while she thought about, as she later described it, "the history of ideas and human suffering and human joy."

That's what we launched into the dark.

The instructions for playing the record are engraved on its cover in binary and diagram form — a message designed to be decoded by an intelligence with no knowledge of humanity whatsoever. Whether that intelligence exists is the open question. You can dig deeper into the science behind missions like this in the SkyLens learn section, or track live satellites passing overhead right now on the live tracker.

Is Voyager 1 heading toward another star?

Not in any meaningful human timescale.

In approximately 40,000 years, Voyager 1 will pass within 1.7 light-years of a star called Gliese 445, in the constellation Camelopardalis. (Gliese 445 is itself moving toward our solar system, so they're drifting toward each other — their closest approach in roughly 40 millennia, about 800 times longer than all of recorded human history.)

The nearest star to Earth is Proxima Centauri at 4.24 light-years. At 17 km/s, Voyager 1 would need around 73,000 years to reach it — and it isn't even pointed that direction.

When will Voyager 1 stop working?

NASA estimates RTG power will fall below the minimum needed to operate any science instrument sometime in the late 2020s. Engineers will make every watt count until then. After that, the spacecraft will continue drifting — but in silence.

It will never stop. There is nothing to slow it down.

In a million years, Voyager 1 will still be out there, intact. The Golden Record will still be playable. The brain-wave recording will still be on the disc. No atmosphere. No weather. No erosion. Just cold and dark and silence, and the last artefact humanity ever launched into the night between stars.

That thought either comforts you or it doesn't.

Voyager launched 49 years ago on a 5-year mission — and it's still sending data from beyond the solar system. Read more stories like this on SkyLens.