US space agency NASA says a science instrument aboard the Voyager 2 has been turned off to cope with the gradual reduction of the spacecraft’s electrical power supply.
The Voyager 2 was launched in 1977. It was the first spacecraft to fly past Uranus and Neptune, and has discovered new planetary moons among other achievements. It continues to send signals back to Earth from more than 20 billion kilometers away.
The spacecraft is powered by a generator that converts heat from decaying plutonium into electricity, but it produces slightly less power each year.
NASA announced on Tuesday that the spacecraft’s plasma science instrument — which measures the flow of charged atoms — was turned off in September.
Four other science instruments onboard continue to collect valuable data in interstellar space — the area between the stars.
NASA aims to keep the Voyager 2 operating into the 2030s.