Voyager 1 nearing a historic distance

A probe the size of a small car, launched in 1977, is about to reach a distance no human-made object has ever achieved before. Voyager 1 will soon be so far from Earth that a single radio command will take an entire day to reach it, and the same time for the confirmation to return.

Reaching the light-day milestone

In mid-November 2026, Voyager 1 will cross a distance known as a light-day, approximately 25.9 billion kilometers from Earth. This milestone will mark exactly 49 years, 2 months, and 13 days since its launch on September 5, 1977.

The scale of the distance

A light-day corresponds to about 25.9 billion kilometers, or 173.14 astronomical units. To put this in perspective, Voyager 1 will be 5.6 times farther than Neptune at that point, though it will still be only 0.0027% of the way to Proxima Centauri, our nearest neighboring star.

Communication challenges

Only the DSS-43 antenna in Canberra can communicate with Voyager 1, and a round trip for a command now requires 48 hours. This delay means that commands must be planned well in advance, as real-time adjustments are impossible.

Limited power and instruments

Due to insufficient energy, only two scientific instruments remain active aboard Voyager 1. Engineers have had to shut down other instruments over the years to conserve power, with the last one, the LECP instrument, turned off in April 2026.

Future of the mission

The radioisotope thermoelectric generators on Voyager 1 lose about 4 watts of power each year, and all communication with Earth is expected to cease around 2036. Despite this, the probe continues its journey, silent and unbreakable, far beyond what its designers could have imagined.