The two probes have left the solar system and are still collecting data from the interstellar environment—but their atomic hearts are growing weaker and weaker.

The spacecraft—humanity's most distant probe—managed to resumed contact by switching to a secondary radio not used since 1981.

The spacecraft, launched in 1977, is 15 billion miles away from Earth. It stopped sending data but NASA managed to get it restarted.

A Space.com report indicated that the issue arose when engineers instructed Voyager 1 to activate a heater for its instruments. This led the spacecraft's fault protection system to switch off the primary X-band transmitter, as non-essential systems had already been deactivated to conserve energy.