Voyager 1 Reaches 1 Light-Day From Earth on Nov. 18 at 16.094 Billion Miles
Updated
Updated · Smithsonian Magazine · Nov 9
Voyager 1 Reaches 1 Light-Day From Earth on Nov. 18 at 16.094 Billion Miles
3 articles · Updated · Smithsonian Magazine · Nov 9
Summary
November 18 at 5:16:07 a.m. Eastern will mark Voyager 1’s symbolic one-light-day milestone, when the probe sits 16.094 billion miles from Earth as the farthest human-made object.
24 hours is how long a one-way radio message will then take to reach the spacecraft, stretching a full exchange with NASA’s Deep Space Network to about two days.
2 instruments remain active on Voyager 1 after engineers shut down other systems to save power from its steadily weakening plutonium source, which could leave the signal too faint to detect around 2035.
October 18 and 19 brought a fresh reminder of the mission’s fragility when Voyager 1 missed two expected signals before contact resumed on October 20 for still-unknown reasons.
1977 launches sent both Voyager probes toward the outer planets, but Voyager 1 has been in interstellar space since 2012 and NASA plans a public Morse-code tribute on November 17.
It took nearly 50 years to travel one light-day; what does Voyager's milestone reveal about the daunting reality of interstellar travel?
How did engineers fix a 1977 computer from a light-day away, and what secrets will Voyager 1 uncover before going silent?
Voyager 1 Reaches One Light-Day: Engineering, Discovery, and the Meaning of Our Pale Blue Dot
Overview
On November 18, 2026, Voyager 1 will become the first human-made object to reach one light-day from Earth, after traveling nearly 50 years through space at 38,000 mph. This milestone means radio signals now take 24 hours each way, creating a 48-hour round-trip delay for communication. Despite aging hardware and power loss, NASA engineers have kept the probe running by shutting down non-essential systems, allowing at least one science instrument to operate into the 2030s. Voyager 1’s journey, including its iconic Pale Blue Dot photo, inspires global celebration and deep reflection on humanity’s place in the universe.