NASA’s Voyager 1 spacecraft recently switched to a backup radio transmitter, unused since 1981, following communication issues.

On Oct. 16, a command to turn on a heater triggered the spacecraft’s fault protection system, causing it to conserve power and switch off its primary X-band transmitter.

Communication was lost but resumed on Oct. 24 when NASA connected through the lower-power S-band transmitter.

The team is now investigating what prompted the fault protection, as Voyager 1 should have had sufficient power, Space.com has reported.

Launched in 1977, the interstellar explorer faces increasing technical challenges due to its age and distance.

Written by B.C. Begley