Voyager 1, the most distant human-made object in existence, became the first probe to leave the Solar System in 2012. It is powered by a radioisotope thermoelectric generator that harvests electricity from decaying plutonium, but it loses 4 watts of power every year. An unexpected low power issue was first detected during a planned roll maneuver on 27 February, and mission engineers warned that any additional drop would trigger a protection system shutting down components.
NASA is working on a 'far-out plan' to extend the spacecraft's lifespan, though the specifics of this plan and when it will be implemented remain unknown. The nuclear-powered spacecraft is running low on power, and turning off the Low-energy Charged Particles experiment (LECP) is considered the best way to keep humanity's first interstellar explorer going. According to Voyager mission manager Kareem Badaruddin, shutting down a science instrument is not ideal but is the best option available.
The LECP, which has been operating almost continuously for 49 years, measures low-energy charged particles like cosmic rays from the Milky Way and has provided critical data about the structure of the interstellar medium. Voyager 1 is currently more than 25 billion kilometers (15 billion miles) from Earth, and it still has two remaining operating science instruments: one that listens to plasma waves and one that measures magnetic fields. Badaruddin noted that these instruments are still working great, sending back data from a region of space no other human-made craft has ever explored.
The twin Voyagers are the only spacecraft far enough from Earth to provide information about the interstellar medium, but it is unclear how long Voyager 1 can continue operating with the current power loss rate and instrument shutdown, or what specific scientific objectives might be lost due to the LECP shutdown. The exact cause of the unexpected low power issue detected on 27 February also remains undetermined.