NASA shuts down another instrument on the first Voyager probe to save power

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The power supply of the Voyager 1 space probe is becoming increasingly precarious, almost 49 years after the start of the mission. After a routine flight maneuver, the probe's power level dropped unexpectedly, creating the risk that some components might shut themselves down for safety reasons. Therefore, NASA has temporarily switched off the low-energy charged particle instrument to save power. However, there is hope that it can be reactivated in the coming months, according to NASA's power-saving plans.

About a year ago, NASA already switched off further instruments on the Voyager probes so that they can continue to operate until the 2030s. But this requires saving power. The two probes are powered by radioisotope thermoelectric generators, which generate electrical current from the heat produced by the decay of plutonium-238. However, such a battery loses about 4 watts of power per year. Therefore, more and more systems have been deactivated over the years.

Voyager as NASA's longest and most distant mission

Voyager 1, along with its sister probe Voyager 2, was launched in the summer of 1977, about two weeks apart. The primary mission was designed for four years. The probes are now farther from Earth than any other human-made object: Voyager 1 has traveled 25 billion kilometers, Voyager 2 has traveled 21 billion kilometers. They have left the solar system and are traveling in interstellar space: Voyager 1 since 2012, Voyager 2 since 2018. With their remaining instruments, they are still providing valuable data.

However, due to their age, there are recurring problems with the two probes. Communication breaks down, systems fail. Repairs are difficult simply because of the long signal travel times: it takes more than 23 hours for a signal to reach Voyager 1, and 19.5 hours for Voyager 2. The Voyager probes had the same set of ten instruments on board, but some of them were switched off relatively soon after passing the large gas giants Jupiter, Saturn, and Neptune.

Shutdown for longer operating duration

On February 27, 2026, Voyager 1 performed a planned and routine roll maneuver according to NASA, but the space probe's power level dropped unexpectedly afterward. A further drop in power would activate the undervoltage protection system, which automatically deactivates various components to maintain the probe's operation. However, manual reactivation is a lengthy process with its risks. Therefore, NASA engineers had to act quickly and switched off the Low-energy Charged Particles (LECP) instrument. This had already been deactivated on Voyager 2 last year.

“While shutting down a scientific instrument is never ideal, it's the best available option,” explains Kareem Badaruddin, Voyager mission lead. “Voyager 1 still has two functioning scientific instruments – one for measuring plasma waves and one for measuring magnetic fields. They continue to work perfectly and send data from a region of space never before explored by any human-made spacecraft.”

Power reduction plans and hope for reactivation

However, the LECP instrument is not completely shut down. A small motor that rotates the sensor in a circle to cover all directions remains active. This requires only 0.5 watts of power and gives NASA the best chance to reactivate the instrument if additional energy can be found. Because that is the next goal of the Voyager team.

Currently, NASA engineers are working on a plan they call “the Big Bang” to further extend the operation of the Voyager probes. This involves replacing some parts of several powered devices with more energy-efficient alternatives, while keeping the probes warm enough to continue collecting scientific data. This will first be tested on Voyager 2 in May and June of this year, as this probe is closer to Earth. If successful, it will be performed on Voyager 1 at the earliest in July. Then, the LECP instrument could also be reactivated.

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