Voyager 1 probe, launched in 1977, transmits data from interstellar space

Launched in 1977, NASA's Voyager 1 spacecraft continues its historic journey, now so distant from Earth that a radio signal traveling at the speed of light requires more than 22 hours to reach it. By November 2026, this communication delay will extend to 24 hours.

Remarkably, Voyager 1 is still transmitting valuable data from interstellar space, powered by a nuclear source comparable in size to a car battery. This enduring functionality underscores the longevity of NASA's Voyager program, the longest-running mission in the agency's history. Alongside its twin, Voyager 2, it remains the only spacecraft to have ventured beyond the boundaries of our solar system into interstellar space.

Each Voyager probe is equipped with an eight-track tape player for data recording, possessing approximately three million times less memory than modern mobile phones. Their data transmission rate is about 38,000 times slower than a 5G internet connection. The probes also carry golden records containing images, scientific diagrams, and audio recordings from Earth, serving as a cosmic "message in a bottle" intended to last over 1,000 years.

Over four decades, the Voyagers have provided crucial scientific insights. They explored Jupiter and Saturn, revealing secrets of these gas giants and their moons. Voyager 2 uniquely flew by Uranus in 1986 and Neptune in 1989, capturing extraordinary images and data from these distant worlds. Voyager 1 crossed the heliosphere boundary in 2012, discovering that this protective bubble blocks about 70% of cosmic rays. Voyager 2 followed in 2018.

Currently over 25 billion kilometers from Earth, more than 170 times the distance between Earth and the Sun, Voyager 1 operates using a radioisotope thermoelectric generator. This device uses plutonium to produce heat, which is converted into electricity. As the plutonium decays, power output decreases; the generator initially produced 470 watts, dropping to 230 watts by 2026, with an estimated loss of four watts annually. To conserve power, the mission team has deactivated non-essential systems and heaters protecting instruments from extreme cold.