NASA engineers have deactivated the plasma science instrument on Voyager 2 due to dwindling power. Despite being over 12.8 billion miles from Earth, Voyager 2 still operates four science instruments to study interstellar space. The spacecraft is expected to function with at least one instrument into the 2030s. Efforts are made to keep instruments active as the data is unique, with no other spacecraft in interstellar space. Powered by decaying plutonium, the Voyagers lose about 4 watts annually. Non-essential systems have been turned off to conserve power, including adjusting voltage monitoring.