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When Voyager 1 launched in 1977, scientists hoped it could do what it was built to do and take up-close images of Jupiter and Saturn. It did that — and much more.
Voyager 1 discovered active volcanoes, moons and planetary rings, proving along the way that Earth and all of humanity could be squished into a single pixel in a photograph, a “pale blue dot,” as the astronomer Carl Sagan called it. It stretched a four-year mission into the present day, embarking on the deepest journey ever into space.
Now, it may have bid its final farewell to that faraway dot.
Voyager 1, the farthest man-made object in space, hasn’t sent coherent data to Earth since November. NASA has been trying to diagnose what the Voyager mission’s project manager, Suzanne Dodd, called the “most serious issue” the robotic probe has faced since she took the job in 2010.
The spacecraft encountered a glitch in one of its computers that has eliminated its ability to send engineering and science data back to Earth.
The loss of Voyager 1 would cap decades of scientific breakthroughs and signal the beginning of the end for a mission that has given shape to humanity’s most distant ambition and inspired generations to look to the skies.
“Scientifically, it’s a big loss,” Ms. Dodd said. “I think — emotionally — it’s maybe even a bigger loss.”
Voyager 1 is one half of the Voyager mission. It has a twin spacecraft, Voyager 2.
Launched in 1977, they were primarily built for a four-year trip to Jupiter and Saturn, expanding on earlier flybys by the Pioneer 10 and 11 probes.
The Voyager mission capitalized on a rare alignment of the outer planets — once every 175 years — allowing the probes to visit all four.
Using the gravity of each planet, the Voyager spacecraft could swing onto the next, according to NASA.
The mission to Jupiter and Saturn was a success.
The 1980s flybys yielded several new discoveries, including new insights about the so-called great red spot on Jupiter, the rings around Saturn and the many moons of each planet.
Voyager 2 also explored Uranus and Neptune, becoming in 1989 the only spacecraft to explore all four outer planets.
Voyager 1, meanwhile, had set a course for deep space, using its camera to photograph the planets it was leaving behind along the way. Voyager 2 would later begin its own trek into deep space.
“Anybody who is interested in space is interested in the things Voyager discovered about the outer planets and their moons,” said Kate Howells, the public education specialist at the Planetary Society, an organization co-founded by Dr. Sagan to promote space exploration.
“But I think the pale blue dot was one of those things that was sort of more poetic and touching,” she added.
On Valentine’s Day 1990, Voyager 1, darting 3.7 billion miles away from the sun toward the outer reaches of the solar system, turned around and snapped a photo of Earth that Dr. Sagan and others understood to be a humbling self-portrait of humanity.
“It’s known the world over, and it does connect humanity to the stars,” Ms. Dodd said of the mission.
She added: “I’ve had many, many many people come up to me and say: ‘Wow, I love Voyager. It’s what got me excited about space. It’s what got me thinking about our place here on Earth and what that means.’”
Ms. Howells, 35, counts herself among those people.
About 10 years ago, to celebrate the beginning of her space career, Ms. Howells spent her first paycheck from the Planetary Society to get a Voyager tattoo.
Though spacecraft “all kind of look the same,” she said, more people recognize the tattoo than she anticipated.
“I think that speaks to how famous Voyager is,” she said.
The Voyagers made their mark on popular culture, inspiring a highly intelligent “Voyager 6” in “Star Trek: The Motion Picture” and references on “The X Files” and “The West Wing.”
Even as more advanced probes were launched from Earth, Voyager 1 continued to reliably enrich our understanding of space.
In 2012, it became the first man-made object to exit the heliosphere, the space around the solar system directly influenced by the sun. There is a technical debate among scientists around whether Voyager 1 has actually left the solar system, but, nonetheless, it became interstellar — traversing the space between stars.
That charted a new path for heliophysics, which looks at how the sun influences the space around it. In 2018, Voyager 2 followed its twin between the stars.
Before Voyager 1, scientific data on the sun’s gases and material came only from within the heliosphere’s confines, according to Dr. Jamie Rankin, Voyager’s deputy project scientist.
“And so now we can for the first time kind of connect the inside-out view from the outside-in,” Dr. Rankin said, “That’s a big part of it,” she added. “But the other half is simply that a lot of this material can’t be measured any other way than sending a spacecraft out there.”
Voyager 1 and 2 are the only such spacecraft. Before it went offline, Voyager 1 had been studying an anomalous disturbance in the magnetic field and plasma particles in interstellar space.
“Nothing else is getting launched to go out there,” Ms. Dodd said. “So that’s why we’re spending the time and being careful about trying to recover this spacecraft — because the science is so valuable.”
But recovery means getting under the hood of an aging spacecraft more than 15 billion miles away, equipped with the technology of yesteryear. It takes 45 hours to exchange information with the craft.
It has been repeated over the years that a smartphone has hundreds of thousands of times Voyager 1’s memory — and that the radio transmitter emits as many watts as a refrigerator lightbulb.
“There was one analogy given that is it’s like trying to figure out where your cursor is on your laptop screen when your laptop screen doesn’t work,” Ms. Dodd said.
Her team is still holding out hope, she said, especially as the tantalizing 50th launch anniversary in 2027 approaches. Voyager 1 has survived glitches before, though none as serious.
Voyager 2 is still operational, but aging. It has faced its own technical difficulties too.
NASA had already estimated that the nuclear-powered generators of both spacecrafts would likely die around 2025.
Even if the Voyager interstellar mission is near its end, the voyage still has far to go.
Voyager 1 and its twin, each 40,000 years away from the next closest star, will arguably remain on an indefinite mission.
“If Voyager should sometime in its distant future encounter beings from some other civilization in space, it bears a message,” Dr. Sagan said in a 1980 interview.
Each spacecraft carries a gold-plated phonograph record loaded with an array of sound recordings and images representing humanity’s richness, its diverse cultures and life on Earth.
“A gift across the cosmic ocean from one island of civilization to another,” Dr. Sagan said.
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Credit: NYTimes.com