NASA’s Voyager 1 is set to reach a historic milestone in November 2026, when it will be one light-day away from Earth, marking a significant moment in humanity’s exploration of deep space.
Launched in 1977, the spacecraft has travelled for more than 48 years and is currently over 25 billion kilometres from Earth, moving at an average speed of about 16.99 kilometres per second.
At a distance of one light-day, a signal sent from Earth will take a full 24 hours to reach Voyager 1, underscoring the vast scale of the universe. One light-day equals roughly 26 billion kilometres.
Voyager 1 carries two radio transmitters, though it has relied on only one, the X-band, for several years. The second, the S-band, has not been used since 1981. The probe currently transmits data at just 160 bits per second, comparable to early dial-up internet speeds.
Although Voyager 1 was launched after Voyager 2, it took a faster route and overtook its twin on December 15, 1977. It later became the first human-made object to enter interstellar space.
Originally designed for a four-year mission, Voyager 1 continued far beyond its planned lifespan. It crossed the heliosphere, the boundary where the Sun’s influence gives way to interstellar space, and made several key discoveries, including a thin ring around Jupiter and two of its moons, Thebe and Metis. At Saturn, it identified five additional moons and a new ring known as the G-Ring.
The spacecraft now runs on a radioisotope thermoelectric generator that loses about four watts of power each year. Scientists hope Voyager 1 will continue operating long enough to mark its 50th anniversary in 2027.