The farthest human-made object is now so distant that even light takes nearly 24 hours to reach it; exactly 49 years after NASA launched Voyager 1 to explore Jupiter and Saturn, the spacecraft is still in interstellar space and sending data back to Earth

Voyager 1 probe has been traveling away from Earth since 1977, crossing the edge of the Sun’s influence and venturing into interstellar space. Today, the NASA spacecraft is more than 15.9 billion miles away, so distant that even light takes nearly 24 hours to bring its signals back to Earth. Yet, after almost five decades in space, Voyager 1 is still sending data home.

So if the spacecraft sends a message right now, we cannot receive it immediately. The signal has to cross nearly a full day of empty space before NASA can hear it.

A spacecraft from 1977 is still sending data

Voyager 1 was never originally designed to spend decades traveling through interstellar space. Its initial mission was to explore the outer planets, particularly Jupiter and Saturn.

It launched exactly 49 years ago on September 5, 1977, 16 days after Voyager 2 was launched into space. But a carefully chosen trajectory gave Voyager 1 a faster route outward, allowing it to overtake its twin later that year.

At Jupiter, it discovered a previously unknown ring system and two new moons, Thebe and Metis. At Saturn, it found new moons and another ring, while its observations of Titan revealed a thick atmosphere dominated by nitrogen.

Then its mission changed. After completing its planetary encounters, Voyager 1 continued outward, eventually reaching the boundary where the Sun's influence gives way to the interstellar environment.

On August 25, 2012, NASA determined that Voyager 1 had crossed the heliosphere, the enormous bubble created by the Sun's particles and magnetic field, becoming the first spacecraft to enter interstellar space. It has been traveling through that environment ever since.

Nearly 16 billion miles away, it is still doing science

The remarkable part is not simply that Voyager 1 has survived the journey. It is that the spacecraft can still measure and transmit information from such a great distance.

Its instruments have been used to study the particles, magnetic fields and other conditions beyond the heliosphere. As the spacecraft moves farther from the Sun, its measurements provide scientists with a rare opportunity to study an environment that no other spacecraft has previously reached.

But keeping a spacecraft alive for almost five decades at such a distance is becoming difficult.

Voyager 1 has been running on a steadily declining supply of electrical power generated by radioactive material. NASA has therefore been gradually switching off systems and instruments that are no longer essential, trying to preserve enough power to keep the remaining scientific equipment and communications systems operating.

In April 2026, NASA shut down another instrument to conserve power and extend the spacecraft's remaining operational life.

The longest conversation in human history

There is something almost strange about the scale of the mission. Voyager 1 is not simply far away. It is so far away that Earth and the spacecraft are separated by almost an entire light-day.

NASA’s live Voyager position page indicates that Voyager 1 will reach a distance of one light-day from Earth in November 2026.

That means if you could somehow travel at the speed of light, it would still take a day to reach where Voyager 1 is now. But Voyager 1 itself is nowhere near that speed. It is moving away from the Sun at roughly 37,800 mph.

The delay becomes even more striking when NASA needs to communicate with the spacecraft. A command sent from Earth takes more than 23 hours to reach Voyager 1. If the spacecraft responds immediately, its reply takes another 23 hours or so to travel back. In other words, a simple exchange between NASA and Voyager 1 can take almost two days.

And every piece of data arriving from Voyager 1 is therefore already almost a day old by the time scientists receive it. The spacecraft is effectively calling home from a place that is nearly a day away, even for light.

A message for whoever comes after us

Voyager 1 also carries something more permanent than its scientific instruments. Attached to the spacecraft is the Voyager Golden Record, a gold-plated copper disc containing sounds, music, images and greetings from Earth. It was designed as a message to any intelligent life that might someday encounter the spacecraft.

The record includes greetings in dozens of languages, sounds from Earth and music ranging from classical compositions to Chuck Berry.