25/10/2026
🚀 On November 18, Voyager 1 will cross a boundary no human-made object has ever reached: it will be one full light-day from Earth.
NASA calculates that at 10:16:07 UTC, Voyager 1 will be 25.902 billion kilometers, or about 16.095 billion miles, away from our planet.
A light-day is simply the distance light travels in 24 hours.
That means a radio command transmitted from Earth will take an entire day to reach Voyager 1. If the spacecraft immediately responds, another 24 hours will pass before that reply reaches us.
A simple conversation with humanity’s most distant spacecraft will therefore require roughly two days.
Voyager 1 launched on September 5, 1977. It flew past Jupiter in 1979 and Saturn in 1980 before heading outward on a trajectory that eventually carried it beyond the heliosphere.
In August 2012, it became the first spacecraft to enter interstellar space, crossing the heliopause where the Sun’s solar wind gives way to the interstellar environment.
Nearly five decades after launch, Voyager 1 is still operating and returning measurements from a region no spacecraft had explored before.
It is moving through space at roughly 56,000 kilometers per hour, yet reaching this milestone has taken 49 years.
One important clarification: being one light-day away does not mean Voyager 1 has travelled for a light-day or reached another star. It describes its straight-line distance from Earth at that moment.
Earth’s own orbit causes Voyager’s distance from us to fluctuate slightly during the year. But calculations show that after November 18, it will remain beyond the one-light-day boundary permanently.
Voyager 2 is following behind and is expected to reach the same milestone around November 2035.
For the first time, something built by humans will be so distant that even light needs a full day to reach it.
📃 SOURCE REPORT
📌 NASA/JPL-Caltech