(CNN) — Voyager 1, NASA’s deep-space probe, could soon become the first spacecraft to reach a historic milestone. In November 2026, the probe will be one light-day from Earth.

Launched in 1977, Voyager 1 is the farthest spacecraft from our planet, currently exploring interstellar space 15.8 billion miles away.

The term light-day refers to the distance at which it will take 24 hours for a signal or command traveling at the speed of light to reach the spacecraft from Earth, said Suzy Dodd, Voyager project manager at NASA’s Jet Propulsion Laboratory. One light-day is equivalent to 16 billion miles (26 billion kilometers).

So if Voyager’s team is asking the spacecraft to do something once it reaches that point, it will take another day for Voyager to respond.

“If I send a command and say,

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