On January 28, the Voyager 1 probe crossed a symbolic milestone, reaching a distance of 25 billion kilometers from Earth. This was confirmed by tracker data on NASA’s website, which monitors the spacecraft’s position and velocity.
The Farthest Spacecraft in History
Launched in 1977, Voyager 1 was designed to explore the Solar System’s giant planets. It completed a flyby of Jupiter in 1979 and later passed Saturn in 1981. The gravitational pull of these massive planets propelled the probe to a high enough speed to escape the Solar System permanently.
Still Going Strong After 47 Years
More than 47 years after its launch, Voyager 1 remains operational, continuing to transmit data back to Earth using its four functioning scientific instruments. However, the probe’s advanced age has led to increasing technical challenges. In recent years, it has experienced multiple issues, including a temporary loss of contact with NASA.
Despite these difficulties, Voyager 1 has achieved yet another historic milestone. On January 28, it became the first spacecraft to reach a distance of 25 billion kilometers from Earth. At this vast distance, a signal from Earth takes 23 hours and 9 minutes to reach the probe—and just as long for a response to return.
Interestingly, because Earth orbits the Sun, there are times when the distance between our planet and Voyager 1 temporarily decreases rather than increases. However, relative to the Sun, the probe is currently 24.84 billion kilometers away and is expected to surpass the 25-billion-kilometer mark in mid-May 2025.
The Next Milestone: One Light Day from the Sun
The next significant milestone for Voyager 1 will be reaching a distance of one light day—25.9 billion kilometers from the Sun. This will occur in January 2027, coinciding with the 50th anniversary of its launch. While the spacecraft is expected to remain operational at that time, engineers will likely have to shut down some of its remaining scientific instruments due to the gradual depletion of its radioisotope generators.
Although one light day is an immense distance from a human perspective, it is relatively small in astronomical terms. For comparison, the closest star to the Sun, Proxima Centauri, is 4.24 light-years away. At its current speed, it would take Voyager 1 approximately 74,000 years to reach it.
