\n<\/p>\n
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 \u2014 and much more.<\/p>\n
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 \u201cpale blue dot,\u201d 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.<\/p>\n
Now, it may have bid its final farewell to that faraway dot.<\/p>\n
Voyager 1, the farthest man-made object in space, hasn\u2019t sent coherent data to Earth since November. NASA has been trying to diagnose what the Voyager mission\u2019s project manager, Suzanne Dodd, called the \u201cmost serious issue\u201d the robotic probe has faced since she took the job in 2010.<\/p>\n
The spacecraft encountered a glitch in one of its computers that has eliminated its ability to send engineering and science data back to Earth.<\/p>\n<\/div>\n<\/div>\n
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\u2019s most distant ambition and inspired generations to look to the skies.<\/p>\n
\u201cScientifically, it\u2019s a big loss,\u201d Ms. Dodd said. \u201cI think \u2014 emotionally \u2014 it\u2019s maybe even a bigger loss.\u201d<\/p>\n
Voyager 1 is one half of the Voyager mission. It has a twin spacecraft, Voyager 2.<\/p>\n
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.<\/p>\n
The Voyager mission capitalized on a rare alignment of the outer planets \u2014 once every 175 years \u2014 allowing the probes to visit all four.<\/p>\n
Using the gravity of each planet, the Voyager spacecraft could swing onto the next, according to NASA.<\/p>\n<\/div>\n<\/div>\n
The mission to Jupiter and Saturn was a success.<\/p>\n
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.<\/p>\n
Voyager 2 also explored Uranus and Neptune, becoming in 1989 the only spacecraft to explore all four outer planets.<\/p>\n<\/div>\n<\/div>\n
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.<\/p>\n
\u201cAnybody who is interested in space is interested in the things Voyager discovered about the outer planets and their moons,\u201d said Kate Howells, the public education specialist at the Planetary Society, an organization co-founded by Dr. Sagan to promote space exploration.<\/p>\n<\/div>\n<\/div>\n
\u201cBut I think the pale blue dot was one of those things that was sort of more poetic and touching,\u201d she added.<\/p>\n
On Valentine\u2019s 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.<\/p>\n
\u201cIt\u2019s known the world over, and it does connect humanity to the stars,\u201d Ms. Dodd said of the mission.<\/p>\n
She added: \u201cI\u2019ve had many, many many people come up to me and say: \u2018Wow, I love Voyager. It\u2019s what got me excited about space. It\u2019s what got me thinking about our place here on Earth and what that means.\u2019\u201d<\/p>\n
Ms. Howells, 35, counts herself among those people.<\/p>\n
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.<\/p>\n<\/div>\n<\/div>\n
Though spacecraft \u201call kind of look the same,\u201d she said, more people recognize the tattoo than she anticipated.<\/p>\n
\u201cI think that speaks to how famous Voyager is,\u201d she said.<\/p>\n
The Voyagers made their mark on popular culture, inspiring a highly intelligent \u201cVoyager 6\u201d in \u201cStar Trek: The Motion Picture\u201d and references on \u201cThe X Files\u201d and \u201cThe West Wing.\u201d<\/p>\n
Even as more advanced probes were launched from Earth, Voyager 1 continued to reliably enrich our understanding of space.<\/p>\n
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 \u2014 traversing the space between stars.<\/p>\n
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.<\/p>\n<\/div>\n<\/div>\n
Before Voyager 1, scientific data on the sun\u2019s gases and material came only from within the heliosphere\u2019s confines, according to Dr. Jamie Rankin, Voyager\u2019s deputy project scientist.<\/p>\n
\u201cAnd so now we can for the first time kind of connect the inside-out view from the outside-in,\u201d Dr. Rankin said, \u201cThat\u2019s a big part of it,\u201d she added. \u201cBut the other half is simply that a lot of this material can\u2019t be measured any other way than sending a spacecraft out there.\u201d<\/p>\n
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.<\/p>\n
\u201cNothing else is getting launched to go out there,\u201d Ms. Dodd said. \u201cSo that\u2019s why we\u2019re spending the time and being careful about trying to recover this spacecraft \u2014 because the science is so valuable.\u201d<\/p>\n
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.<\/p>\n<\/div>\n<\/div>\n
It has been repeated over the years that a smartphone has hundreds of thousands of times Voyager 1\u2019s memory \u2014 and that the radio transmitter emits as many watts as a refrigerator lightbulb.<\/p>\n
\u201cThere was one analogy given that is it\u2019s like trying to figure out where your cursor is on your laptop screen when your laptop screen doesn\u2019t work,\u201d Ms. Dodd said.<\/p>\n
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.<\/p>\n
Voyager 2 is still operational, but aging. It has faced its own technical difficulties too.<\/p>\n
NASA had already estimated that the nuclear-powered generators of both spacecrafts would likely die around 2025.<\/p>\n
Even if the Voyager interstellar mission is near its end, the voyage still has far to go.<\/p>\n
Voyager 1 and its twin, each 40,000 years away from the next closest star, will arguably remain on an indefinite mission.<\/p>\n<\/div>\n<\/div>\n
\u201cIf Voyager should sometime in its distant future encounter beings from some other civilization in space, it bears a message,\u201d Dr. Sagan said in a 1980 interview.<\/p>\n
Each spacecraft carries a gold-plated phonograph record loaded with an array of sound recordings and images representing humanity\u2019s richness, its diverse cultures and life on Earth.<\/p>\n
\u201cA gift across the cosmic ocean from one island of civilization to another,\u201d Dr. Sagan said.<\/p>\n<\/div>\n<\/div>\n