NEW YORK — To save power, NASA has switched off another scientific instrument on its long-running Voyager 2 spacecraft.The space agency said Tuesday that Voyager 2’s plasma science instrument — designed to measure the flow of charged atoms — was powered down in late September so the spacecraft can keep exploring for as long as possible, expected into the 2030s. NASA turned off a suite of instruments on Voyager 2 and its twin Voyager 1 after they explored the gas giant planets in the 1980s. Both are currently in interstellar space, or the space between stars. The plasma instrument on Voyager 1 stopped working long ago and was finally shut down in 2007. Four remaining instruments on Voyager 2 will continue collecting information about magnetic fields and particles. Its goal is to study the swaths of space beyond the sun’s protective bubble.Launched in 1977, Voyager 2 is the only spacecraft to visit Uranus and Neptune. It’s currently more than 12 billion miles (19.31 billion kilometers) from Earth. Voyager 1 is over 15 billion miles (24.14 billion kilometers) from Earth.___The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group. The AP is solely responsible for all content.