Artist rendering of Voyager 1 in space. (Image credit: NASA) Following recent communication issues, NASA's Voyager 1 spacecraft resorted to using a backup radio transmitter that has been inactive since 1981.The interstellar explorer experienced a brief pause in communications after putting itself in a protective state to conserve power. This was triggered by a command sent on Oct. 16 from NASA's Deep Space Network (DSN) — a global array of giant radio antennas — instructing the spacecraft to tur...