The Voyager spacecraft are the farthest human-made objects. NASA is turning off their instruments to keep them going as long as possible

The Voyager spacecraft are the farthest human-made objects. NASA is turning off their instruments to keep them going as long as possible

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Iain Todd

Published: March 15, 2025 at 6:15 am

NASA has announced it will shut down science instruments on the Voyager 2 spacecraft, in order to preserve its power and keep the mission going for as long as it can.

Voyager 1 and Voyager 2 are the farthest human-made objects from Earth.

Voyager 2 launched on 20 August 1977 and Voyager 1 on 5 September 1977, beginning a fly-by of the Solar System that gave scientists amazing close-ups of the Solar System planets and their moons for the first time.

NASA's Voyager 1 spacecraft launched from the Kennedy Space Center Launch Complex in Florida on 5 September 1977. Credit: NASA/JPL-Caltech
NASA's Voyager 1 spacecraft launched from the Kennedy Space Center Launch Complex in Florida on 5 September 1977. Credit: NASA/JPL-Caltech

The Voyager spacecraft use a 'radioisotope power system', NASA says, which generates power through the heat of decaying plutonium. The probes lose 4 watts of power each year.

In order to preserve this diminishing energy and keep the Voyagers' science-gathering abilities going, engineers at NASA’s Jet Propulsion Laboratory turned off the cosmic ray subsystem experiment on Voyager 1 on 25 February 2025.

They will shut off Voyager 2’s low-energy charged particle instrument on 24 March 2025.

This is not a complete shut-down, however; three science instruments will remain operating on each spacecraft.

"The Voyagers have been deep-space rock stars since launch, and we want to keep it that way as long as possible," says Suzanne Dodd, Voyager project manager at JPL.

"But electrical power is running low. If we don’t turn off an instrument on each Voyager now, they would probably have only a few more months of power before we would need to declare end of mission."

Gallery: the best of Voyager

The planet Jupiter, taken by Voyager 1 at a distance of 54 million km from its closest approach. The Great Red Spot dominates the picture and swirling, storm-like features are visible above and to the left of the Spot, showing the turbulent atmosphere. (Credit: NASA/JPL)
The planet Jupiter, taken by Voyager 1 at a distance of 54 million km from its closest approach. The Great Red Spot dominates the picture and swirling, storm-like features are visible above and to the left of the Spot, showing the turbulent atmosphere. (Credit: NASA/JPL)
Jupiter's Great Red Spot captured by Voyager 1 in February 1979, at a distance of 9.2 million km. The wavy cloud pattern to the right of the Red Spot is variable wave motion in the atmosphere; evidence of large-scale storms. (Credit: NASA/JPL)
Jupiter's Great Red Spot captured by Voyager 1 in February 1979, at a distance of 9.2 million km. The wavy cloud pattern to the right of the Red Spot is variable wave motion in the atmosphere; evidence of large-scale storms. (Credit: NASA/JPL)
Image of Jupiter's moon Europa, captured by Voyager 2, 9 July 1979. Credit: NASA/JPL
Image of Jupiter's moon Europa, captured by Voyager 2, 9 July 1979. Credit: NASA/JPL
Jupiter's rings seen as two light orange lines, captured by Voyager 2 from a distance of 1,450,000km (900,000 miles). Credit: NASA/JPL
Jupiter's rings seen as two light orange lines, captured by Voyager 2 from a distance of 1,450,000km (900,000 miles). Credit: NASA/JPL
A view of Jupiter's volcanic moon Io, captured by Voyager 1. Credit: NASA/JPL
A view of Jupiter's volcanic moon Io, captured by Voyager 1. Credit: NASA/JPL
An image of Saturn from Voyager 2. The picture has been colour-enhanced to show in bright details the planet’s surface and the features of the rings. Clearly visible is the gap between the A and B rings, called the Cassini Division. (Credit: NASA/JPL)
An image of Saturn from Voyager 2. The picture has been colour-enhanced to show in bright details the planet’s surface and the features of the rings. Clearly visible is the gap between the A and B rings, called the Cassini Division. (Credit: NASA/JPL)
Saturn and two of its moons photographed in 1980 by Voyager 1. The moons, Tethys (closest to the planet) and Dione, are visible as bright spots in space next to the gas giant. Tethys's shadow can also be seen on Saturn itself. (Credit: NASA/JPL)
Saturn and two of its moons photographed in 1980 by Voyager 1. The moons, Tethys (closest to the planet) and Dione, are visible as bright spots in space next to the gas giant. Tethys's shadow can also be seen on Saturn itself. (Credit: NASA/JPL)
Global map of Saturn's moon Mimas, created using data captured by the Voyager and Cassini missions. Credit: NASA/JPL/Space Science Institute
Global map of Saturn's moon Mimas, created using data captured by the Voyager and Cassini missions. Credit: NASA/JPL/Space Science Institute
Saturn and its moons Tethys, Dion and Rhea, as seen by Voyager 2 in August 1981. Credit: NASA/JPL-Caltech
Saturn and its moons Tethys, Dion and Rhea, as seen by Voyager 2 in August 1981. Credit: NASA/JPL-Caltech
A view of Saturn's rings captured by Voyager 2, 22 August 1981, from a distance of 2.5 million miles. Credit: NASA / JPL-Caltech
A view of Saturn's rings captured by Voyager 2, 22 August 1981, from a distance of 2.5 million miles. Credit: NASA / JPL-Caltech
An image of Uranus taken by Voyager 2. Image Credit: NASA/JPL
An image of Uranus taken by Voyager 2.
Image Credit: NASA/JPL
Uranus as photographed by Voyager 2 in 1986. The view is towards the planet's pole of rotation captured from 18 million km away. The left image is in the original colours that a human would see looking from the spacecraft. To the right, false-colours exaggerate a potential polar haze of smog-like particles. (Credit: NASA/JPL)
Uranus as photographed by Voyager 2 in 1986. The view is towards the planet's pole of rotation captured from 18 million km away. The left image is in the original colours that a human would see looking from the spacecraft. To the right, false-colours exaggerate a potential polar haze of smog-like particles. (Credit: NASA/JPL)
Voyager 2 captures the newly discovered 10th ring of Uranus – it's extremely faint, midway between the bright Epsilon ring at the top and the next obvious one down, the Delta ring. The other nine known rings of Uranus are also visible; and 11th was spotted in Voyager data at a later date. (Credit: NASA/JPL)
Voyager 2 captures the newly discovered 10th ring of Uranus – it's extremely faint, midway between the bright Epsilon ring at the top and the next obvious one down, the Delta ring. The other nine known rings of Uranus are also visible; and 11th was spotted in Voyager data at a later date. (Credit: NASA/JPL)
Farewell shot of the crescent Uranus as Voyager 2 heads towards Neptune in 1986. Despite the limited light on the planet, Uranus maintains its blue-green colour, resulting from methane in its atmosphere.(Credit: NASA/JPL)
Farewell shot of the crescent Uranus as Voyager 2 heads towards Neptune in 1986. Despite the limited light on the planet, Uranus maintains its blue-green colour, resulting from methane in its atmosphere.(Credit: NASA/JPL)
Uranus's moon Ariel as seen by the Voyager 2 spacecraft. Credit: NASA/JPL
Uranus's moon Ariel as seen by the Voyager 2 spacecraft. Credit: NASA/JPL
Moon Miranda's rugged surface, as seen by the Voyager 2 spacecraft on 24 January 1986. Credit: NASA/JPL
Moon Miranda's rugged surface, as seen by the Voyager 2 spacecraft on 24 January 1986. Credit: NASA/JPL
Voyager 2 photograph of Neptune. The Great Dark Spot is dominant close to the left limb, while immediately below it is a white feature nicknamed ‘Scooter’. Near the bottom of the planet's disc is Dark Spot 2, with its light core. These features are rarely seen in close proximity due to their different rotational speeds. (Credit: NASA/JPL)
Voyager 2 photograph of Neptune. The Great Dark Spot is dominant close to the left limb, while immediately below it is a white feature nicknamed ‘Scooter’. Near the bottom of the planet's disc is Dark Spot 2, with its light core. Credit: NASA/JPL
A view of cloud streaks in Neptune's atmosphere, captured by the Voyager 2 spacecraft. Credit: NASA/JPL
A view of cloud streaks in Neptune's atmosphere, captured by the Voyager 2 spacecraft. Credit: NASA/JPL
The dramatic view of Neptune and Triton (its largest moon) as crescents, captured as Voyager 2 flew away from the planet. The spacecraft was 4.8 million km away and heading out of the Solar System. (Credit: NASA/JPL)
The dramatic view of Neptune and Triton (its largest moon) as crescents, captured as Voyager 2 flew away from the planet. The spacecraft was 4.8 million km away and heading out of the Solar System. (Credit: NASA/JPL)
Neptune's Great Dark Spot as seen by the Voyager 2 spacecraft. Credit: NASA/JPL
Neptune's Great Dark Spot as seen by the Voyager 2 spacecraft. Credit: NASA/JPL
Neptune's rings, as seen by Voyager 2
Neptune's rings, as seen by Voyager 2. Credit: NASA/JPL-Caltech
Voyager 2's view of Neptune's moon Triton. Credit: NASA/JPL/USGS
Voyager 2's view of Neptune's moon Triton. Credit: NASA/JPL/USGS

Voyager science instruments

The two Voyagers are equipped with the same sets of 10 science instruments.

Some instruments that were designed for use during the spacecraft's planetary fly-bys were switched off as soon as they'd completed their tours of the Solar System.

Engineers kept activated the Voyagers' instruments used for studying the heliosphere, the boundary of the Sun's influence on the Solar System in the form of solar wind and magnetic fields.

Voyager 1 reached the edge of the heliosphere in 2012; Voyager 2 reached the boundary in 2018.

After this point, the Voyagers' heliosphere instruments were switched off as they reached interstellar space: something no other human-made spacecraft has achieved.

In October 2024, NASA scientists turned off Voyager 2’s plasma science instrument, while Voyager 1’s plasma science instrument had been turned off years before.

One of the Voyager spacecraft undergoing tests at NASA's Jet Propulsion Laboratory, April 1977. Credit: NASA/JPL-Caltech
One of the Voyager spacecraft undergoing tests at NASA's Jet Propulsion Laboratory, April 1977. Credit: NASA/JPL-Caltech

Turning off the low-energy charged particle instrument

Voyager 2's low-energy charged particle instrument that is being switched off in March 2025 measures ions, electrons and cosmic rays originating from our Solar System and Galaxy.

"The Voyager spacecraft have far surpassed their original mission to study the outer planets," says Patrick Koehn, Voyager program scientist at NASA Headquarters in Washington.

"Every bit of additional data we have gathered since then is not only valuable bonus science for heliophysics, but also a testament to the exemplary engineering that has gone into the Voyagers — starting nearly 50 years ago and continuing to this day."

NASA says that, with the two instruments turned off, the Voyagers should be able to keep going for another year before another instrument needs to be deactivated.

Voyager 1 will continue to operate its magnetometer and plasma wave subsystem. Voyager 2 will continue to operate its magnetic field and plasma wave instruments.

NASA says the two Voyagers could potentially keep going with at least one science instrument into the 2030s

An artist's impression of the two Voyager spacecraft at the edge of the heliosphere. Credit: NASA.
An artist's impression of the Voyager spacecraft at the edge of the heliosphere. Credit: NASA.

Voyagers' immense distances

At the time of writing, Voyager 1 is over 15 billion miles (25 billion kilometres) away from Earth. Voyager 2 is over 13 billion miles (21 billion kilometres) away.

It takes over 23 hours to get a radio signal from Earth to Voyager 1, and 19.5 hours to Voyager 2.

"Every minute of every day, the Voyagers explore a region where no spacecraft has gone before," said Linda Spilker, Voyager project scientist at JPL.

"That also means every day could be our last. But that day could also bring another interstellar revelation. So, we’re pulling out all the stops, doing what we can to make sure Voyagers 1 and 2 continue their trailblazing for the maximum time possible."

What are your memories of the Voyager mission? Let us know by emailing contactus@skyatnightmagazine.com

Iain Todd

Science journalist

Iain Todd is BBC Sky at Night Magazine's Content Editor. He fell in love with the night sky when he caught his first glimpse of Orion, aged 10.
Artist's impression of a Voyager probe, the farthest human-ade object. Credit: NASA

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