When Voyager 1 launched in 1977, scientists hoped it would be able to capture up-close images of Jupiter and Saturn, as its original purpose was. It did the job. And it did much more.
Voyager 1 discovered active volcanoes, the moon, and planetary rings, proving that Earth and all of humanity can be compressed into a single pixel in a photograph, what astronomer Carl Sagan called a “pale blue dot.” The four-year mission extends to the present, marking the deepest journey into space.
Now it may have said its final farewell to the dot in the distance.
Voyager 1, the most distant man-made object in space, has not sent consistent data to Earth since November. NASA has been trying to diagnose what Suzanne Dodd, the Voyager mission's project manager, calls the “most serious problem” facing the robotic probe since she took over the mission in 2010.
The spacecraft suffered a glitch in one of its computers, eliminating its ability to send engineering and scientific data back to Earth.
The loss of Voyager 1 would stifle decades of scientific breakthroughs and signal the beginning of the end for a mission that embodied humanity's grandest ambitions and inspired generations to look to the skies.
“For science, this is a huge loss,” Mr. Dodd said. “I think – emotionally – it’s probably a bigger loss.”
Voyager 1 is half of the Voyager mission. There is a twin spacecraft, Voyager 2.
Launched in 1977, the spacecraft was primarily built for a four-year journey to Jupiter and Saturn, extending the flights of earlier probes Pioneer 10 and 11.
The Voyager mission took advantage of a rare alignment of exoplanets that occurs once every 175 years, allowing the probe to visit all four.
According to NASA, the Voyager spacecraft can use each planet's gravity to move to the next planet.
Missions to Jupiter and Saturn were successful.
Flybys in the 1980s brought several new discoveries, including new insights into the so-called Great Red Spot of Jupiter, the rings around Saturn and each planet's many moons.
Voyager 2 also explored Uranus and Neptune, and in 1989 became the only spacecraft to explore all four exoplanets.
Meanwhile, Voyager 1 set a course for deep space, using its cameras to take pictures of the planets it left behind along its path. Voyager 2 would later begin its journey into deep space.
“Anyone interested in space will be interested in what Voyager discovered about exoplanets and moons,” said Dr. Sagan, a public education specialist at the Planetary Society, an organization he co-founded to promote space exploration. said Kate Howells.
“But I think the pale blue dot was one of the more poetic and moving ones,” she added.
On Valentine's Day 1990, Voyager 1, hurtling 3.7 billion miles from the sun outward from the solar system, turned around and took what Dr. Sagan and others understood as a humbling self-portrait of humanity.
“This is known around the world and connects humanity to the stars,” Mr. Dodd said of the mission.
She added: “So many people come up to me and say, ‘Wow, I love Voyager. This is why I got interested in space. That’s what got me thinking about our place here on Earth and what it means.’”
Howells, 35, counts herself among those people.
About 10 years ago, to celebrate the start of his space career, Mr. Howells spent his first paycheck from the Planetary Society to get a Voyager tattoo.
The spaceship “looks the same” but she said more people than she expected recognized the tattoo.
“I think it speaks to how famous Voyager is.” she said
Voyager made its mark in pop culture, inspiring the highly intelligent Voyager 6 in Star Trek: The Motion Picture and making references to The X-Files and The West Wing.
Even as more advanced probes were launched from Earth, Voyager 1 continued to enrich our understanding of the universe.
In 2012, it became the first man-made object to leave the heliosphere, the space around the solar system directly influenced by the sun. There is technical debate among scientists as to whether Voyager 1 actually left the solar system, but it nonetheless ended up traversing interstellar space, or the space between stars.
This opened up a new avenue for solar physics, examining how the sun affects 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 materials came only from within the heliosphere, says Dr. Jamie Rankin, associate scientist for the Voyager project.
“Now, for the first time, we can see from the outside in,” Dr. Rankin said. “That’s a big part,” she added. “But the other half is simply that most of this material cannot be measured any other way than by sending spacecraft.”
Voyager 1 and 2 are the only spacecraft. Before going offline, Voyager 1 was studying anomalous disturbances in magnetic fields and plasma particles in interstellar space.
“Nothing else has been released to go out,” Mr. Dodd said. “So we’re taking our time and working carefully to recover this spacecraft, because the science is so valuable.”
But recovery means going under the hood of an aging spacecraft more than 15 billion miles away, equipped with technology from the past. It takes 45 hours to exchange information with the spacecraft.
It has been repeated over the years that smartphones have hundreds of thousands of times more memory than Voyager 1, and that wireless transmitters put out as many watts as a refrigerator light bulb.
“One analogy was that it was like trying to figure out where the cursor is on a laptop screen when it’s not working,” Mr. Dodd said.
Her team remains hopeful, she said, especially as the 50th anniversary of its launch approaches in 2027. Voyager 1 has had flaws before, but none as serious as this one.
Voyager 2 is still operational but aging. We also experienced technical difficulties.
NASA has already estimated that the nuclear generators on both spacecraft will die around 2025.
Even though Voyager's interstellar exploration is nearing completion, the voyage still has a long way to go.
Voyager 1 and its twin are each 40,000 years away from the next nearest star and will no doubt continue their mission indefinitely.
“If in the distant future Voyager encounters the beings of another civilization in space, it will carry a message,” Dr. Sagan said in a 1980 interview.
Each spacecraft carries a gold-plated gramophone record containing a series of recordings and images representing the richness of humanity, its diverse cultures, and life on Earth.
“It is a gift that travels across the universe from one island of civilization to another,” said Dr. Sagan.