NASA's Voyager 1 spacecraft is about to reach an extraordinary milestone! On Nov. 18, 2026, humanity's most distant spacecraft will become the first human-made object to reach a distance of one light-day from Earth — more than 16 billion miles (25.9 billion kilometers) away!
But what exactly is a light-day? It's the distance light travels in 24 hours, meaning a radio signal sent from Earth now takes an entire day to reach Voyager 1, with another 24 hours needed for a response to return. This video explains the remarkable scale of that distance and what it means for communicating with a spacecraft so far from home.
Launched in 1977, Voyager 1 revolutionized our understanding of the outer solar system before becoming the first spacecraft to enter interstellar space in 2012. Nearly 50 years into its journey, the legendary spacecraft continues exploring the unknown.
Still carrying its famous Golden Record, a message from humanity to the cosmos, Voyager 1 continues pushing the boundaries of space exploration farther than ever before.
Credit: NASA/JPL-Caltech
