NASA’s Voyager probes have traveled through space for nearly 50 years. See the remarkable photos from their journeys.

Voyager 2, a pioneer in outer solar system exploration, left Earth for interstellar space 49 years ago, on August 20, 1977.

The twin of Voyager 1, which left Earth only a few weeks after, is the only spacecraft to visit all four of the solar system’s outer gas giants — Jupiter, Saturn, Uranus, and Neptune.

The Voyager probes were originally sent on a four-year mission to tour the solar system, but they exceeded expectations and are still going nearly half a century later.

That makes them NASA’s longest-lived mission, costing the agency more than $865 million.

The two probes have had their fair share of interstellar road bumps, which have only been exacerbated as the probes age.

In 2022, Voyager 1 started sending garbled data from outside the solar system.

NASA ultimately figured out that one of its computers had gone dead years earlier.

Voyager 2 fell into limbo in 2023, losing contact with NASA after someone sent a wrong command.

The agency detected a faint signal from Voyager days later after blasting a “shout” across the cosmos to get the probe to point its antennae back to Earth and resume communication.

Come November 2026, Voyager 1 will be 16 billion miles — or one light-day — away from Earth.

Voyager 2, meanwhile, will be more than 13.2 billion miles from Earth, traveling through interstellar space — the space between stars — at 34,000 mph relative to the Sun.

While both probes are losing about 4 watts of power each year, NASA continues to make efforts to keep them exploring.

In August, the agency announced it substituted some devices on Voyager 2 with “lower-power alternatives while ensuring the spacecraft remains warm enough to operate.” This, it said, should keep the probe’s instruments running for at least another year.

NASA plans to make the same change for Voyager 1.

To celebrate Voyager 2’s 49th birthday, here are 23 photos that show its history and what both probes have seen among the cosmos.