NASA shuts down Voyager 2's plasma science instrument to conserve energy

NASA has powered down a key scientific instrument on Voyager 2 in an effort to conserve energy as the probe explores interstellar space.

Launched on August 20, 1977, the spacecraft is now 12.8 billion miles from Earth and has been studying the space beyond our solar system since it crossed the heliosphere on November 5, 2018.

Until recently, Voyager 2 was operating four scientific instruments, but a steady decline in power supply has forced NASA to deactivate one more.

The spacecraft’s power is fueled by decaying plutonium, which loses about 4 watts of energy each year. To extend Voyager 2's mission as long as possible, NASA has already deactivated non-essential systems and some instruments, leaving only four out of the original ten instruments still running.

On September 26, 2024, NASA decided to power down the plasma science instrument, which had been instrumental in confirming the spacecraft’s exit from the heliosphere by detecting drops in solar particle levels.

This plasma science instrument originally included four detectors, or "cups," designed to monitor solar winds within the heliosphere. Three of these cups stopped functioning once Voyager 2 left the solar bubble, while the last cup continued to provide valuable data during the probe’s periodic rotations.

NASA’s Jet Propulsion Laboratory has confirmed the shutdown went smoothly, and Voyager 2 remains fully operational. Engineers will continue to closely monitor its power levels to determine the next steps, allowing the mission to gather interstellar data for as long as possible.