NASA engineers are turning off two instruments on Voyager 1 and Voyager 2 to ensure these twin spacecraft can continue exploring interstellar space.

NASA’s twin Voyager probes, which launched in 1977, are the longest-running missions to send data home. But as their power supplies wane, scientists are saying goodbye to one instrument on each spacec

However, NASA isn’t ready to say goodbye just yet, and is taking measures to get as much life out of the pair as possible. On March 5, Voyager mission engineers at the Jet Propulsion Laboratory in southern California confirmed they have already turned off Voyager 1’s cosmic ray subsystem experiment.