NASA's Voyager probes are starting to power down after 45 years of operation

The two probes are losing steam as the greatest adventure ever reaches the final stretch.
Brad Bergan
Voyager 2 in the testing stages (left), and the planet Jupiter (right).1, 2

We're tremendously close to the end of an era.

Way back in 1977, NASA's Voyager 1 and 2 launched and began the greatest adventure ever taken by an uncrewed space probe. Traveling past all of the outer planets (minus Pluto), they fundamentally transformed our grasp of the solar system, and how it came into being. But the interstellar journey of the iconic probes — which has already lasted nearly 45 years — is coming to a close, as NASA is continuing its slow shutdown of the spacecrafts' systems, according to an initial report from Scientific American.

Update: The teams at NASA have "been managing the power supply" by drawing down power on some systems for decades, "and more aggressively in the past 3 years," according to an email sent by Calla Cofield, a NASA representative, to IE.

Nothing made by humans has traveled as far as these probes. And it proves that deep space beckons humanity to take its next steps in a wider universe.

NASA's Voyager 1 and 2 are running out of power

Launched in 1977, the two probes pushed the envelope for space exploration, and have continued to do so ever since. It's impossible to overemphasize how deep in space these probes have gone, traveling farther from the planet Earth than any object ever built by humans. As such, these voyagers will likely hold the record of the most distant human-made objects for decades, if not a century.

The decision to cut power to a minimum was made to extend the probes' lifespans for a few more years, with a soft cutoff deadline set for 2030, according to the Scientific American report. "We've done 10 times the warranty on the darn things," said Physicist Ralph McNutt at the Johns Hopkins University Applied Physics Laboratory in the report, concerning the unprecedented longevity of the probes expected to last four short years.

Four years!

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"The shutoffs have to happen because the onboard power supplies are decaying, reducing their output by 4 watts per year — so both spacecraft have less power to 'spend'," said the NASA representative to IE. This "has been the case since launch, but after 45 years of flight, the power budget is getting to the point where the team has to turn off whatever they can to keep the spacecraft running and doing science."

"Over the last 3 years the team has turned off the heaters on 5 of the science instruments (between the two spacecraft) and amazingly all 5 have continued to operate well below the temperatures they were tested at!" added Cofield. This is a testament to the superior engineering marvels that both Voyager spacecraft remain, after nearly half a century in space.

While incredible, this isn't a total surprise. Both probes are powered with radioactive plutonium reactors, which have maintained a warm supply of power to the tiny onboard computers that have run for decades without a break.

But, alas, the break is coming.

Pale Blue Dot
The 'pale blue dot' image snapped by Voyager 1 in 1990. Source: NASA / JPL-Caltech

NASA's Voyager 1 and 2 are humanity's first tentative step into a wider universe

With less power available, progressively more components and devices need to be shut down as the power supply dwindles. "If everything goes really well, maybe we can get the missions extended into the 2030s," said Linda Spilker, a JPL planetary scientist who worked on the dawn of the Voyager missions, in 1977.

"It just depends on the power. That's the limiting point," added Spilker. "This August, the Voyager Science Steering Group will make a decision about the next steps for managing the power budget," added Cofield, in her email to IE. "The engineering team has been extremely creative and has some ideas for how to keep both Voyagers doing as much science as possible for as long as possible."

The science team's plan might, "in theory, stretch the power into the 2030s," added Cofield. "But NASA has not made a decision to end the mission, and the probes both continue to return unique science." And we really can't overemphasize how profoundly unique and significant the spacecrafts' science has been, and remains to this day.

The primary mission of the probes was to do a flyby of the gas giants Jupiter and Saturn — and they did it with flying colors (literally); sending the first up-close and detailed images of Europa, Ganymede, Titan, and more. But perhaps the most significant image took more than a decade to make happen.

In 1990, Voyager 1 snapped an image of Earth, 3.7 billion miles away from the sun. Famously popularized by the late astronomer Carl Sagan, the "pale blue dot" served to expose how small and fragile our entire existence really is — from the wars of ancient civilization, our petty political grandstanding, the exploitation of the planet's ecosystem, and our entire evolutionary journey to the present day. It was all there, in a tiny blue speck in a seemingly infinite, black, and indifferent universe.

If there's one thing we should think of the iconic probes, it's this: the human race has existed for a very small blink of the eye in the history of the universe, on a tiny and fragile planet that won't be here for long. And there's an entire universe beckoning us to step out of our comfort zones of human hubris, and into the greatest adventure yet. Voyager 1 and 2 are and will continue to be our first tentative step into cosmic adulthood, as a young population of sentient beings.


Editor's note: This article was updated to reflect the ongoing mission of the Voyager probes, which NASA has not made a decision to end. The title was changed to reflect this, and new quotes from a NASA representative were also included to clarify the status of the two probes.

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