has voyager 1 found anything in interstellar space

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Some hope —

Finally, engineers have a clue that could help them save voyager 1, a new signal from humanity's most distant spacecraft could be the key to restoring it..

Stephen Clark - Mar 15, 2024 11:23 pm UTC

It's been four months since NASA's Voyager 1 spacecraft sent an intelligible signal back to Earth, and the problem has puzzled engineers tasked with supervising the probe exploring interstellar space.

But there's a renewed optimism among the Voyager ground team based at NASA's Jet Propulsion Laboratory in California. On March 1, engineers sent a command up to Voyager 1—more than 15 billion miles (24 billion kilometers) away from Earth—to "gently prompt" one of the spacecraft's computers to try different sequences in its software package. This was the latest step in NASA's long-distance troubleshooting to try to isolate the cause of the problem preventing Voyager 1 from transmitting coherent telemetry data.

Cracking the case

Officials suspect a piece of corrupted memory inside the Flight Data Subsystem (FDS), one of three main computers on the spacecraft, is the most likely culprit for the interruption in normal communication. Because Voyager 1 is so far away, it takes about 45 hours for engineers on the ground to know how the spacecraft reacted to their commands—the one-way light travel time is about 22.5 hours.

The FDS collects science and engineering data from the spacecraft's sensors, then combines the information into a single data package, which goes through a separate component called the Telemetry Modulation Unit to beam it back to Earth through Voyager's high-gain antenna.

Engineers are almost entirely certain the problem is in the FDS computer. The communications systems onboard Voyager 1 appear to be functioning normally, and the spacecraft is sending a steady radio tone back to Earth, but there's no usable data contained in the signal. This means engineers know Voyager 1 is alive, but they have no insight into what part of the FDS memory is causing the problem.

But Voyager 1 responded to the March 1 troubleshooting command with something different from what engineers have seen since this issue first appeared on November 14.

"The new signal was still not in the format used by Voyager 1 when the FDS is working properly, so the team wasn’t initially sure what to make of it," NASA said in an update Wednesday. "But an engineer with the agency’s Deep Space Network, which operates the radio antennas that communicate with both Voyagers and other spacecraft traveling to the Moon and beyond, was able to decode the new signal and found that it contains a readout of the entire FDS memory."

Now, engineers are meticulously comparing each bit of code from the FDS memory readout to the memory readout Voyager 1 sent back to Earth before the issue arose in November. This, they hope, will allow them to find the root of the problem. But it will probably take weeks or months for the Voyager team to take the next step. They don't want to cause more harm.

"Using that information to devise a potential solution and attempt to put it into action will take time," NASA said.

This is perhaps the most serious ailment the spacecraft has encountered since its launch in 1977. Voyager 1 flew by Jupiter and Saturn before getting a kick from Saturn's gravity to speed into the outer solar system. In 2012, Voyager 1 entered interstellar space when it crossed the heliopause, where the solar wind, the stream of particles emanating from the Sun, push against a so-called galactic wind, the particles that populate the void between the stars.

Engineers have kept Voyager 1 and its twin, Voyager 2, alive for more than 46 years , overcoming technical problems that have doomed other space missions. Both probes face waning power from their nuclear batteries, and there are concerns about their thrusters aging and fuel lines becoming clogged, among other things. But each time there is a problem, ground teams have come up with a trick to keep the Voyagers going, often referencing binders of fraying blueprints and engineering documents from the spacecraft's design and construction nearly 50 years ago.

Suzanne Dodd, NASA's project manager for Voyager 1 and its twin, Voyager 2, recently told Ars that engineers would need to pull off their "biggest miracle" to restore Voyager 1 to normal operations. Now, Voyager 1's voice from the sky has provided engineers with a clue that could help them realize this miracle.

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Nasa discovers source of voyager 1 glitch in interstellar space.

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A NASA image of one of the Voyager space probes. Voyager 1 and its identical sister craft Voyager 2 ... [+] were launched in 1977 to study the outer Solar System and eventually interstellar space. (Photo by NASA/Hulton Archive/Getty Images)

NASA’s pioneering Voyager 1 spacecraft has a memory problem. The space agency has been troubleshooting the elderly machine since it began sending back gibberish communications in November. NASA hasn’t fixed Voyager 1 yet, but engineers now know what’s vexing the spacecraft.

The glitch paused Voyager 1’s science work and kicked off a long-distance diagnosis process. The team traced the issue to the flight data subsystem, a computer that talks to the spacecraft’s telemetry modulation unit to send science and engineering data to Earth. The data came back unintelligible. The culprit appears to be a single chip that’s part of the FDS.

The breakthrough came thanks to a “poke” NASA sent in March that prompted Voyager 1 to send back a readout of its FDS memory. “Using the readout, the team has confirmed that about 3% of the FDS memory has been corrupted, preventing the computer from carrying out normal operations,” NASA said in a statement on April 4.

Voyager 1’s position so far away from home creates a lot of challenges when it comes to fixing problems. NASA talks to the spacecraft over a distance of over 15 billion miles. It takes 22.5 hours for a radio signal to reach Voyager 1 and it takes an equally long time to receive a response. It’s troubleshooting in slow motion. It also means figuring out the exact cause of the glitch is mostly educated guesswork. It could be damage or it could be a matter of age. “Engineers can’t determine with certainty what caused the issue,” said NASA. “Two possibilities are that the chip could have been hit by an energetic particle from space or that it simply may have worn out after 46 years.”

There’s reason for optimism, though Voyager 1 won’t make a quick recovery. “Although it may take weeks or months, engineers are optimistic they can find a way for the FDS to operate normally without the unusable memory hardware, which would enable Voyager 1 to begin returning science and engineering data again,” NASA said.

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Voyager 1 has made an unprecedented journey across space. It launched in 1977 on an initial mission to study our solar system and visit Jupiter and Saturn. That was just the beginning. The resilient spacecraft kept on going and eventually entered interstellar space in 2012. It was the first human-made object to venture into the unexplored territory outside our solar system. Voyager 1’s twin Voyager 2 crossed over into interstellar space in 2018.

NASA turned off some of Voyager 1’s science instruments as the spacecraft aged, but the probe has still been returning valuable data on interstellar space. If a fix works, Voyager 1 will get back into the swing of science and write yet another chapter in an epic story of exploration.

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The most distant human-made object

No spacecraft has gone farther than NASA's Voyager 1. Launched in 1977 to fly by Jupiter and Saturn, Voyager 1 crossed into interstellar space in August 2012 and continues to collect data.

Mission Type

What is Voyager 1?

Voyager 1 has been exploring our solar system for more than 45 years. The probe is now in interstellar space, the region outside the heliopause, or the bubble of energetic particles and magnetic fields from the Sun.

• Voyager 1 was the first spacecraft to cross the heliosphere, the boundary where the influences outside our solar system are stronger than those from our Sun.
• Voyager 1 is the first human-made object to venture into interstellar space.
• Voyager 1 discovered a thin ring around Jupiter and two new Jovian moons: Thebe and Metis.
• At Saturn, Voyager 1 found five new moons and a new ring called the G-ring.

In Depth: Voyager 1

Voyager 1 was launched after Voyager 2, but because of a faster route, it exited the asteroid belt earlier than its twin, having overtaken Voyager 2 on Dec. 15, 1977.

Voyager 1 at Jupiter

Voyager 1 began its Jovian imaging mission in April 1978 at a range of 165 million miles (265 million km) from the planet. Images sent back by January the following year indicated that Jupiter’s atmosphere was more turbulent than during the Pioneer flybys in 1973–1974.

Beginning on January 30, Voyager 1 took a picture every 96 seconds for a span of 100 hours to generate a color timelapse movie to depict 10 rotations of Jupiter. On Feb. 10, 1979, the spacecraft crossed into the Jovian moon system and by early March, it had already discovered a thin (less than 30 kilometers thick) ring circling Jupiter.

Voyager 1’s closest encounter with Jupiter was at 12:05 UT on March 5, 1979 at a range of about 174,000 miles (280,000 km). It encountered several of Jupiter’s Moons, including Amalthea, Io, Europa, Ganymede, and Callisto, returning spectacular photos of their terrain, opening up completely new worlds for planetary scientists.

The most interesting find was on Io, where images showed a bizarre yellow, orange, and brown world with at least eight active volcanoes spewing material into space, making it one of the most (if not the most) geologically active planetary body in the solar system. The presence of active volcanoes suggested that the sulfur and oxygen in Jovian space may be a result of the volcanic plumes from Io which are rich in sulfur dioxide. The spacecraft also discovered two new moons, Thebe and Metis.

Voyager 1 at Saturn

Following the Jupiter encounter, Voyager 1 completed an initial course correction on April 9, 1979 in preparation for its meeting with Saturn. A second correction on Oct. 10, 1979 ensured that the spacecraft would not hit Saturn’s moon Titan.

Its flyby of the Saturn system in November 1979 was as spectacular as its previous encounter. Voyager 1 found five new moons, a ring system consisting of thousands of bands, wedge-shaped transient clouds of tiny particles in the B ring that scientists called “spokes,” a new ring (the “G-ring”), and “shepherding” satellites on either side of the F-ring—satellites that keep the rings well-defined.

During its flyby, the spacecraft photographed Saturn’s moons Titan, Mimas, Enceladus, Tethys, Dione, and Rhea. Based on incoming data, all the moons appeared to be composed largely of water ice. Perhaps the most interesting target was Titan, which Voyager 1 passed at 05:41 UT on November 12 at a range of 2,500 miles (4,000 km). Images showed a thick atmosphere that completely hid the surface. The spacecraft found that the moon’s atmosphere was composed of 90% nitrogen. Pressure ad temperature at the surface was 1.6 atmospheres and 356 °F (–180°C), respectively.

Atmospheric data suggested that Titan might be the first body in the solar system (apart from Earth) where liquid might exist on the surface. In addition, the presence of nitrogen, methane, and more complex hydrocarbons indicated that prebiotic chemical reactions might be possible on Titan.

Voyager 1’s closest approach to Saturn was at 23:46 UT on 12 Nov. 12, 1980 at a range of 78,000 miles(126,000 km).

Voyager 1’s ‘Family Portrait’ Image

Following the encounter with Saturn, Voyager 1 headed on a trajectory escaping the solar system at a speed of about 3.5 AU per year, 35° out of the ecliptic plane to the north, in the general direction of the Sun’s motion relative to nearby stars. Because of the specific requirements for the Titan flyby, the spacecraft was not directed to Uranus and Neptune.

The final images taken by the Voyagers comprised a mosaic of 64 images taken by Voyager 1 on Feb. 14, 1990 at a distance of 40 AU of the Sun and all the planets of the solar system (although Mercury and Mars did not appear, the former because it was too close to the Sun and the latter because Mars was on the same side of the Sun as Voyager 1 so only its dark side faced the cameras).

This was the so-called “pale blue dot” image made famous by Cornell University professor and Voyager science team member Carl Sagan (1934-1996). These were the last of a total of 67,000 images taken by the two spacecraft.

Voyager 1’s Interstellar Mission

All the planetary encounters finally over in 1989, the missions of Voyager 1 and 2 were declared part of the Voyager Interstellar Mission (VIM), which officially began on Jan. 1, 1990.

The goal was to extend NASA’s exploration of the solar system beyond the neighborhood of the outer planets to the outer limits of the Sun’s sphere of influence, and “possibly beyond.” Specific goals include collecting data on the transition between the heliosphere, the region of space dominated by the Sun’s magnetic field and solar field, and the interstellar medium.

On Feb. 17, 1998, Voyager 1 became the most distant human-made object in existence when, at a distance of 69.4 AU from the Sun when it “overtook” Pioneer 10.

On Dec. 16, 2004, Voyager scientists announced that Voyager 1 had reported high values for the intensity for the magnetic field at a distance of 94 AU, indicating that it had reached the termination shock and had now entered the heliosheath.

The spacecraft finally exited the heliosphere and began measuring the interstellar environment on Aug. 25, 2012, the first spacecraft to do so.

On Sept. 5, 2017, NASA marked the 40th anniversary of its launch, as it continues to communicate with NASA’s Deep Space Network and send data back from four still-functioning instruments—the cosmic ray telescope, the low-energy charged particles experiment, the magnetometer, and the plasma waves experiment.

The Golden Record

Each of the Voyagers contain a “message,” prepared by a team headed by Carl Sagan, in the form of a 12-inch (30 cm) diameter gold-plated copper disc for potential extraterrestrials who might find the spacecraft. Like the plaques on Pioneers 10 and 11, the record has inscribed symbols to show the location of Earth relative to several pulsars.

The records also contain instructions to play them using a cartridge and a needle, much like a vinyl record player. The audio on the disc includes greetings in 55 languages, 35 sounds from life on Earth (such as whale songs, laughter, etc.), 90 minutes of generally Western music including everything from Mozart and Bach to Chuck Berry and Blind Willie Johnson. It also includes 115 images of life on Earth and recorded greetings from then U.S. President Jimmy Carter (1924– ) and then-UN Secretary-General Kurt Waldheim (1918–2007).

By January 2024, Voyager 1 was about 136 AU (15 billion miles, or 20 billion kilometers) from Earth, the farthest object created by humans, and moving at a velocity of about 38,000 mph (17.0 kilometers/second) relative to the Sun.

National Space Science Data Center: Voyager 1

A library of technical details and historic perspective.

Beyond Earth: A Chronicle of Deep Space Exploration

A comprehensive history of missions sent to explore beyond Earth.

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Voyager 1, First Craft in Interstellar Space, May Have Gone Dark

The 46-year-old probe, which flew by Jupiter and Saturn in its youth and inspired earthlings with images of the planet as a “Pale Blue Dot,” hasn’t sent usable data from interstellar space in months.

By Orlando Mayorquin

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.

Orlando Mayorquin is a general assignment and breaking news reporter based in New York. More about Orlando Mayorquin

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Voyager 1 has entered interstellar space at last, NASA says

A spacecraft from Earth has left its cosmic backyard and taken its first steps in interstellar space, NASA says.

After streaking through space for nearly 35 years, NASA's robotic Voyager 1 probe entered interstellar space in August 2012, a study published Thursday in the journal Science reports.

"Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science, and as it enters interstellar space, it adds a new chapter in human scientific dreams and endeavors," NASA science chief John Grunsfeld said in a statement. "Perhaps some future deep-space explorers will catch up with Voyager, our first interstellar envoy, and reflect on how this intrepid spacecraft helped enable their future." [ NASA's Voyager Probes: 5 Surprising Facts ]

A long and historic journey Voyager 1 launched on Sept. 5, 1977, about two weeks after its twin, Voyager 2. Together, the two probes conducted a historic "grand tour" of the outer planets, giving scientists some of their first up-close looks at Jupiter , Saturn, Uranus, Neptune and the moons of these faraway worlds.

The duo completed its primary mission in 1989, and then kept on flying toward the edge of the heliosphere, the huge bubble of charged particles and magnetic fields that the sun puffs out around itself. Voyager 1 has now popped free of this bubble into the exotic and unexplored realm of interstellar space , the scientists behind the latest study said.

They reached this historic conclusion with a little help from the sun. A powerful solar eruption caused electrons in Voyager 1's location to vibrate significantly between April 9 and May 22 of this year. The probe's plasma wave instrument detected these oscillations, and researchers used the measurements to figure out that Voyager 1's surroundings contained about 0.005 electrons per cubic inch (0.08 electrons per cubic centimeter).

That's far higher than the density observed in the outer regions of the heliosphere (roughly 0.0001 electrons per cubic inch, or 0.002 electrons per cubic cm) and very much in line with the 0.006 electrons per cubic inch (0.10 electrons per cubic cm) or so expected in interstellar space. [ Photos from NASA's Voyager 1 and 2 Probes ]

"We literally jumped out of our seats when we saw these oscillations in our data — they showed us that the spacecraft was in an entirely new region, comparable to what was expected in interstellar space, and totally different than in the solar bubble," study lead author Don Gurnett of the University of Iowa, the principal investigator of Voyager 1's plasma wave instrument, said in a statement.

It may seem surprising that electron density is higher beyond the solar system than in its extreme outer reaches. Interstellar space is, indeed, emptier than the regions in Earth's neighborhood, but the density inside the solar bubble drops off dramatically at great distances from the sun, researchers said.

Calculating a departure date The study team wanted to know if Voyager 1 left the heliosphere sometime before April 2013, so they combed through some of the probe's older data. They found a monthlong period of electron oscillations in October and November 2012 that translated to a density of 0.004 electrons per cubic inch (0.006 electrons per cubic centimeter).

Using these numbers and the amount of ground that Voyager 1 covers — about 325 million miles (520 million kilometers) per year — the researchers calculated that the spacecraft probably entered interstellar space in August 2012.

That time frame matches up well with several other important changes Voyager 1 observed. On Aug. 25, 2012, the probe recorded a 1,000-fold drop in the number of charged solar particles while also measuring a 9 percent increase in fast-moving galactic cosmic rays , which originate beyond the solar system.

"These results, and comparison with previous heliospheric radio measurements, strongly support the view that Voyager 1 crossed the heliopause into the interstellar plasma on or about Aug. 25, 2012," Gurnett and his colleagues write in the new study.

At that point, Voyager 1 was about 11.25 billion miles (18.11 billion kilometers) from the sun, or roughly 121 times the distance between Earth and the sun. The probe is now 11.66 billion miles (18.76 billion kilometers) from the sun. (Voyager 2, which took a different route through the solar system, is currently 9.54 billion miles, or 15.35 billion kilometers, from the sun.)

Magnetic-field mystery Mission scientists have long pegged Voyager 1's departure from the heliosphere on the observation of three phenomena: a big drop in solar particles, a dramatic jump in galactic cosmic rays and a shift in the orientation of the surrounding magnetic field.

Voyager 1 has measured the first two changes, but not the third; the magnetic field is stronger than it used to be in the probe's location, but it hasn't changed direction.

This key point led NASA and the mission team to proceed with caution. For example, they held off on making any big announcements, despite several recent studies by outside researchers — including one published last month  — suggesting that Voyager 1 entered interstellar space in July or August 2012.

But the new electron-density measurements have convinced Voyager mission scientists that the probe is, indeed, beyond the solar bubble.

After all, magnetic-field measurements were always regarded as a proxy for observations of electron density, said Voyager chief scientist Ed Stone, a physicist at the California Institute of Technology in Pasadena.

"The solar wind carries the solar magnetic field with it, and the interstellar wind carries the galactic magnetic field with it," Stone, who is not an author of the new Science paper, told Space.com. "Once we got the plasma data itself in interstellar space, we knew we must have left the bubble."

(Voyager 1 launched with an instrument designed to measure plasma density directly, but it failed in 1980, forcing the team to get more creative.)

Scientists need a better understanding of the complex interface between the solar and galactic magnetic fields to figure out why Voyager 1 hasn't measured the predicted change in field direction, Stone said.

"What we need to do now is go back and look more carefully at the models of that interaction," he said.

Voyage of exploration The Voyager mission has racked up a series of discoveries over the last 36 years, revealing key insights about the giant planets and their moons, as well as conditions at the edge of the solar system.

The spacecraft's arrival in interstellar space could bring many more exciting finds, the researchers said.

"Every day we look at data, we know we're looking at data that no one has seen before and is in a region where nothing has ever been before," Stone said. "I think we're all looking forward to learning a lot in the years ahead."

Voyager 1 could keep beaming data home for a while, provided nothing too important breaks down. The spacecraft's declining power supply won't force engineers to shut off the first instrument until 2020, mission scientists have said. All of Voyager 1's science gear will probably stop working by 2025.

This story has been revised to emphasize Voyager's entry into interstellar space rather than claims that the probe has left the solar system.

Follow Mike Wall on Twitter  @michaeldwall and  Google+ . Follow us @Spacedotcom , Facebook or Google+ . Originally published on  Space.com.

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Voyager 1 Helps Solve Interstellar Medium Mystery

A study provides new insights about the magnetic field of the interstellar medium, using data from Voyager 1 and other spacecraft.

NASA's Voyager 1 spacecraft made history in 2012 by entering interstellar space, leaving the planets and the solar wind behind. But observations from the pioneering probe were puzzling with regard to the magnetic field around it, as they differed from what scientists derived from observations by other spacecraft.

A new study offers fresh insights into this mystery. Writing in the Astrophysical Journal Letters, Nathan Schwadron of the University of New Hampshire, Durham, and colleagues reanalyzed magnetic field data from Voyager 1 and found that the direction of the magnetic field has been slowly turning ever since the spacecraft crossed into interstellar space. They believe this is an effect of the nearby boundary of the solar wind, a stream of charged particles that comes from the sun.

"This study provides very strong evidence that Voyager 1 is in a region where the magnetic field is being deflected by the solar wind," said Schwadron, lead author of the study.

Researchers predict that in 10 years Voyager 1 will reach a more "pristine" region of the interstellar medium where the solar wind does not significantly influence the magnetic field.

Voyager 1's crossing into interstellar space meant it had left the heliosphere -- the bubble of solar wind surrounding our sun and the planets. Observations from Voyager's instruments found that the particle density was 40 times greater outside this boundary than inside, confirming that it had indeed left the heliosphere.

But so far, Voyager 1's observation of the direction of the local interstellar magnetic field is more than 40 degrees off from what other spacecraft have determined. The new study suggests this discrepancy exists because Voyager 1 is in a more distorted magnetic field just outside the heliopause, which is the boundary between the solar wind and the interstellar medium.

"If you think of the magnetic field as a rubber band stretched around a beach ball, that band is being deflected around the heliopause," Schwadron said.

In 2009, NASA's Interstellar Boundary Explorer (IBEX) discovered a "ribbon" of energetic neutral atoms that is thought to hold clues to the direction of the pristine interstellar magnetic field. The so-called "IBEX ribbon," which forms a circular arc in the sky, remains mysterious, but scientists believe it is produced by a flow of neutral hydrogen atoms from the solar wind that were re-ionized in nearby interstellar space and then picked up electrons to become neutral again.

The new study uses multiple data sets to confirm that the magnetic field direction at the center of the IBEX ribbon is the same direction as the magnetic field in the pristine interstellar medium. Observations from the NASA/ESA Ulysses and SOHO spacecraft also support the new findings.

"All of these different data sets that have been collected over the last 25 years have been pointing toward the same meeting point in the field," Schwadron said.

Over time, the study suggests, at increasing distances from the heliosphere, the magnetic field will be oriented more and more toward "true north," as defined by the IBEX ribbon. By 2025, if the field around Voyager 1 continues to steadily turn, Voyager 1 will observe the same magnetic field direction as IBEX. That would signal Voyager 1's arrival in a less distorted region of the interstellar medium.

"It's an interesting way to look at the data. It gives a prediction of how long we'll have to go before Voyager 1 is in the medium that's no longer strongly perturbed," said Ed Stone, Voyager project scientist, based at the California Institute of Technology in Pasadena, who was not involved in this study.

While Voyager 1 will continue delivering insights about interstellar space, its twin probe Voyager 2 is also expected to cross into the interstellar medium within the next few years. Voyager 2 will make additional observations of the magnetic field in interstellar space and help scientists refine their estimates.

Voyager 1 and Voyager 2 were launched 16 days apart in 1977. Both spacecraft flew by Jupiter and Saturn. Voyager 2 also flew by Uranus and Neptune. Voyager 2, launched before Voyager 1, is the longest continuously operated spacecraft. Voyager 1 is the most distant object touched by human hands.

JPL, a division of Caltech, built the twin Voyager spacecraft and operates them for the Heliophysics Division within NASA's Science Mission Directorate in Washington.

For more information about Voyager, visit:

http://voyager.jpl.nasa.gov

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September 12, 2013

Voyager 1 Finally Leaves Solar System—for Real This Time

After much debate over the murky boundary of interstellar space, a solar eruption gives scientists the evidence to say Voyager 1 has finally crossed it

By Clara Moskowitz

Voyager 1 was starting to get a reputation as the spacecraft that cried wolf, after scientists repeatedly claimed it was leaving the solar system, only to change their minds and say it wasn’t quite there yet . Now researchers say new evidence shows Voyager really has departed the sun’s sphere of influence and become the first man-made object to reach interstellar space.

Voyager 1, launched in 1977, is speeding away from us, traveling about 3.5 times the Earth–sun distance every year. The probe is now about 18.2 billion kilometers from Earth, farther away than anything human beings have sent into space. (Its sister spacecraft, Voyager 2, launched more than a month earlier, took a more circuitous path from Earth and is now about 14.8 billion kilometers away.)

Scientists have long been expecting Voyager 1 to exit the bubble of space containing particles from the sun, called the heliosphere, and enter a region where particles are much more plentiful and come from ancient explosions of other stars. But because Voyager 1 has lost its ability to measure this particle plasma, there was no easy way to tell when the transition had occurred .

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A boon came from an eruption on the sun in March 2012, which sent waves of solar material out into space. When this ejection reached Voyager 1 13 months later in April 2013, it set the local plasma vibrating. Voyager 1's plasma wave instrument (separate from the defunct plasma particle detector) was able to measure the pitch of these vibrations, which in turn reflected the density of plasma around the spacecraft. The results show that Voyager 1 is surrounded by plasma more than 40 times denser than it encountered earlier, when it was in the heliosphere. “Because there’s no other possible conclusion, I think we’re forced to and obliged to conclude that we’re truly in the interstellar medium,” physicist Gary Zank of the University of Alabama in Huntsville said during a press conference today.

Based on abrupt changes in the apparent plasma density around the spacecraft, the researchers were even able to pinpoint August 25, 2012 as the most likely date that Voyager 1 left the solar system , crossing the heliopause, the boundary between the heliosphere and the interstellar medium.

The “little spacecraft that could,” in the words of project manager Suzanne Dodd of the NASA Jet Propulsion Laboratory in Pasadena, Calif., is getting old in years and is technologically weak: the average smartphone has thousands of times more memory than the spacecraft. Yet most of Voyager 1’s instruments still work, and they continue to send signals back to Earth. The team estimates the probe still has enough power from its plutonium power plant to operate all its instruments through 2020, when it will begin shutting them off one by one, until it goes dark in 2025. That still gives Voyager 1 more than a decade to study the realm of the universe it has entered. “It marks the beginning of a new era of exploration for Voyager: the exploration of the space between the stars,” said Ed Stone, Voyager’s longtime project scientist.

The new findings represent a turnaround for the Voyager team, which as recently as June predicted the spacecraft may have years to go before it reached interstellar space. But the latest data remove most of the team members’ doubts, Stone said.

The new report, published online today in Science, also agrees with the conclusions of a separate paper claiming Voyager 1 had left the solar system, based on magnetic field data, which was published August 14 in The Astrophysical Journal Letters. The lead author of that paper, University of Maryland, College Park, physicist Marc Swisdak, says the two projects are complementary. “I thought the authors make an excellent case for their measurements and their interpretation,” Swisdak says.

Over the course of 36 years, between the two of them, the Voyager probes have visited all the outer planets of the solar system and discovered 23 moons around these worlds. They also each carry time capsules in the form of phonograph records loaded with recordings of music, natural sounds, voice greetings in 56 languages, and photographs and diagrams of life on Earth. Voyager 1 is on a course that should eventually take it within 1.6 light-years of a star called AC+79 3888, which lies in the constellation of Camelopardalis. It’s due to arrive in about 40,000 years, long after the spacecraft loses its ability to tell whomever is on Earth what comes of that encounter.

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• Published: 12 September 2013

Voyager 1 has reached interstellar space

• Ron Cowen  

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High electron densities show the craft left the Sun's bubble of influence in 2012.

The debate is over. The venerable Voyager 1 spacecraft has entered the uncharted territory of interstellar space.

A team led by Don Gurnett, a space physicist at the University of Iowa in Iowa City, reports compelling evidence that Voyager has exited the heliosphere, the Solar System’s protective bubble of charged particles. The findings, published online today in Science 1 , settle an argument that has raged among members of the Voyager team for more than a year.

“This is a milestone,” says Ed Stone, a physicist at the California Institute of Technology in Pasadena, who has been the project scientist for the Voyager 1 and 2 spacecraft since 1972, five years before their launch. Voyager 1’s entry into interstellar space “ranks with circumnavigating the globe and the first steps on the Moon,” says Stone, who was not involved in the latest study.

The research is based on measurements of the ionized gas, or plasma, through which the spacecraft travels. The frequency at which the plasma vibrates is a sensitive indicator of its electron density, which is predicted to be about 100 times higher in the cold interstellar medium than it is within the warmer bubble of the heliosphere.

Gurnett and his collaborators calculate that recent increases in electron density found by Voyager 1 match the predicted density of the interstellar medium. The findings, combined with other spacecraft data, indicate that Voyager 1 left the heliosphere on or about 25 August 2012, when the craft was 121 astronomical units (18 billion kilometres) from the Sun.

Gary Zank, a theoretical physicist at the University of Alabama in Huntsville, calls the results definitive. “There is no doubt that we’re in interstellar space,” he says.

Uncharted territory

Previous data had suggested that the craft had already left the solar bubble. Evidence included a drop in the number of relatively low-energy cosmic rays that are thought to reside within the Solar System, along with a simultaneous upswing in higher-energy cosmic rays coming from outside the Solar System. However, that shift was not accompanied by a predicted change in the direction of the magnetic field in Voyager’s vicinity.

Gurnett says that the calculated electron densities should settle the controversy. Those oscillations were serendipitous, the team notes, because some energy source has to disturb the material to generate the vibrations. It takes a solar tsunami — shocks carried into space from eruptions on the Sun — to set the plasma in motion, ringing it like a bell, Stone says.

Questions remain about Voyager’s journey. The unchanging direction of the magnetic field is still a puzzle, says Stone. It may be a product of a chance alignment between the Solar System’s magnetic field and that of the interstellar space, he suggests. It is also possible that the boundary between the heliosphere and what lies beyond is fuzzy, or that the magnetic field carried by the solar wind is linked in some unknown way to that of interstellar space.

Stone is careful to say that, although Voyager 1 has exited the heliosphere, it has not left the Solar System. The Oort cloud, a distant reservoir of comets, lies far beyond the solar bubble in interstellar space, but it is part of the Solar System and gravitationally bound to the Sun.

But with Voyager 1 firmly outside the heliosphere, “it’s a whole new mission”, Stone says. Until about 2025, when the craft is expected to run out of its plutonium power source, Voyager 1 can explore the magnetic field, cosmic rays and density of interstellar space. Voyager 2, now 102 astronomical units (15 billion kilometres) from the Sun, is only a few years behind in joining its sister craft in the vastness of space beyond the solar bubble.

Gurnett, D. A., Kurth, W. S., Burlaga, L. F. & Ness, N. F. Science http://dx.doi.org/science.1241681 (2013).

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Scientific exploration: What a long, strange trip it's been 2008-Jul-02

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NASA engineers discover why Voyager 1 is sending a stream of gibberish from outside our solar system

Voyager 1 has been sending a stream of garbled nonsense since November. Now NASA engineers have identified the fault and found a potential workaround.

For the past five months, the Voyager 1 spacecraft has been sending a steady stream of unreadable gibberish back to Earth. Now, NASA engineers finally know why.

The 46-year-old spacecraft sends regular radio signals as it drifts further from our solar system . But in November 2023, the signals suddenly became garbled, meaning  scientists were unable to read any of its data, and they were left mystified about the fault's origins. 

In March, NASA engineers sent a command prompt, or "poke," to the craft to get a readout from its flight data subsystem (FDS) — which packages Voyager 1's science and engineering data before beaming it back to Earth. 

After decoding the spacecraft's response, the engineers have found the source of the problem: The FDS's memory has been corrupted.

Related: NASA's Voyager 1 sends readable message to Earth after 4 nail-biting months of gibberish

"The team suspects that a single chip responsible for storing part of the affected portion of the FDS memory isn't working," NASA said in a blog post Wednesday (March 13) . "Engineers can't determine with certainty what caused the issue. Two possibilities are that the chip could have been hit by an energetic particle from space or that it simply may have worn out after 46 years."

— NASA hears 'heartbeat' signal from Voyager 2 probe a week after losing contact

— Historic space photo of the week: Voyager 2 spies a storm on Saturn 42 years ago

— NASA reestablishes full contact with Voyager 2 probe after nail-biting 2-week blackout

Although it may take several months, the engineers say they can find a workaround to run the FDS without the fried chip — restoring the spacecraft's messaging output and enabling it to continue to send readable information from outside our solar system.

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Launched in 1977, Voyager 1 zipped past Saturn and Jupiter in 1979 and 1980 before flying out into interstellar space in 2012. It is now recording the conditions outside of the sun's protective magnetic field , or heliosphere, which blankets our solar system.

Voyager 1 is currently more than 15 billion miles (24 billion kilometers) from Earth, and it takes 22.5 hours for any radio signal to travel from the craft to our planet.

Ben Turner is a U.K. based staff writer at Live Science. He covers physics and astronomy, among other topics like tech and climate change. He graduated from University College London with a degree in particle physics before training as a journalist. When he's not writing, Ben enjoys reading literature, playing the guitar and embarrassing himself with chess.

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• TorbjornLarsson Bon voyage, Voyager! Reply
• Jay McHue What if aliens are doing it to try to communicate with us? 🤪 Reply

Jay McHue said: What if aliens are doing it to try to communicate with us? 🤪

admin said: Voyager 1 has been sending a stream of garbled nonsense since November. Now NASA engineers have identified the fault and found a potential workaround. NASA engineers discover why Voyager 1 is sending a stream of gibberish from outside our solar system : Read more

sourloaf said: What does FSB mean?

Rusty Lugnuts said: Where are you seeing "FSB"? The closest thing I can see in the article is "FDS". In modern computers, FSB would most likely refer to the Fr0nt S1ide Bu5, though I have no idea if a system as old as Voyagers, let alone engineered so specifically, would have an FSB. (apparently I can't spell out "Fr0nt S1ide Bu5" or my post gets flagged as spam or inappropriate??)

• SkidWard Just cut the % of ram needed... skip the bad sectors Reply
• kloudykat FDS = fl1ght da1a sub5ystem5 Reply
• 5ft24dave This is pretty old news, like 6 months old. Are you guys just now discovering this? Reply

Commodore Browncoat said: That's about as sane a theory as many of the others that have become ridiculously popular in the past several years, so sure - why not? What reply do you think we should send?

• View All 10 Comments

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NASA's Voyager 1 probe has been glitching for months and we finally know why

An artist’s concept of the Voyager 1 spacecraft in interstellar space.

After months of sending unusable data to mission control, there’s finally hope for the Voyager 1 spacecraft. NASA engineers pinpointed the cause behind the mission’s odd anomaly, and think they can help the interstellar probe make sense again.

Engineers at NASA’s Jet Propulsion Laboratory believe the Voyager 1 spacecraft has been sending nonsensical data due to corrupted memory hardware in the spacecraft’s flight data system (FDS). “The team suspects that a single chip responsible for storing part of the affected portion of the FDS memory isn’t working,” NASA wrote in an update.

FDS collects data from Voyager’s science instruments, as well as engineering data about the health of the spacecraft, and combines them into a single package that’s transmitted to Earth through one of the probe’s subsystems, the telemetry modulation unit (TMU), in binary code.

FDS and TMU have been having trouble communicating with one another. As a result, TMU has been sending data to mission control in a repeating pattern of ones and zeroes. NASA’s engineers aren’t quite sure what corrupted the FDS memory hardware; they think that either the chip was hit by an energetic particle from space or that it’s just worn out after operating for 46 years.

Voyager 1 launched in 1977, less than a month after its twin probe, Voyager 2, began its own journey to space. The probe ventured into interstellar space in August 2012, becoming the first spacecraft to leave the heliosphere.

The problem first began in May 2022, when the probe suddenly started sending nonsensical attitude articulation and control (AACS) data . Engineers resolved the issue by sending the telemetry data through one of the spacecraft’s other computers. In December 2023, Voyager 1 started speaking gibberish again .

On March 1, the team sent a “poke” to the spacecraft’s data system, a command that gently prompts FDS to try different sequences in its software package in an effort to pinpoint the corrupted section. Two days later, Voyager 1 sent a signal that contained a readout of the entire FDS memory , which helped the team pinpoint the source of the glitch by comparing this memory readout with a previous one to look for discrepancies in the code.

“Using the readout, the team has confirmed that about 3% of the FDS memory has been corrupted, preventing the computer from carrying out normal operations,” NASA wrote in its update.

The engineers are hoping to resolve the issue by finding a way for FDS to operate normally without the corrupted memory hardware, enabling Voyager 1 to begin transmitting data about the cosmos and continue its journey through deep space.

A version of this article originally appeared on Gizmodo .

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• The Contents
• The Making of
• Where Are They Now
• Frequently Asked Questions
• Q & A with Ed Stone

golden record

Where are they now.

• frequently asked questions
• Q&A with Ed Stone

The Voyager Planetary Mission

The twin spacecraft Voyager 1 and Voyager 2 were launched by NASA in separate months in the summer of 1977 from Cape Canaveral, Florida. As originally designed, the Voyagers were to conduct closeup studies of Jupiter and Saturn, Saturn's rings, and the larger moons of the two planets.

To accomplish their two-planet mission, the spacecraft were built to last five years. But as the mission went on, and with the successful achievement of all its objectives, the additional flybys of the two outermost giant planets, Uranus and Neptune, proved possible -- and irresistible to mission scientists and engineers at the Voyagers' home at the Jet Propulsion Laboratory in Pasadena, California.

As the spacecraft flew across the solar system, remote-control reprogramming was used to endow the Voyagers with greater capabilities than they possessed when they left the Earth. Their two-planet mission became four. Their five-year lifetimes stretched to 12 and more.

Eventually, between them, Voyager 1 and 2 would explore all the giant outer planets of our solar system, 48 of their moons, and the unique systems of rings and magnetic fields those planets possess.

Had the Voyager mission ended after the Jupiter and Saturn flybys alone, it still would have provided the material to rewrite astronomy textbooks. But having doubled their already ambitious itineraries, the Voyagers returned to Earth information over the years that has revolutionized the science of planetary astronomy, helping to resolve key questions while raising intriguing new ones about the origin and evolution of the planets in our solar system.

History of the Voyager Mission

The Voyager mission was designed to take advantage of a rare geometric arrangement of the outer planets in the late 1970s and the 1980s which allowed for a four-planet tour for a minimum of propellant and trip time. This layout of Jupiter, Saturn, Uranus and Neptune, which occurs about every 175 years, allows a spacecraft on a particular flight path to swing from one planet to the next without the need for large onboard propulsion systems. The flyby of each planet bends the spacecraft's flight path and increases its velocity enough to deliver it to the next destination. Using this "gravity assist" technique, first demonstrated with NASA's Mariner 10 Venus/Mercury mission in 1973-74, the flight time to Neptune was reduced from 30 years to 12.

While the four-planet mission was known to be possible, it was deemed to be too expensive to build a spacecraft that could go the distance, carry the instruments needed and last long enough to accomplish such a long mission. Thus, the Voyagers were funded to conduct intensive flyby studies of Jupiter and Saturn only. More than 10,000 trajectories were studied before choosing the two that would allow close flybys of Jupiter and its large moon Io, and Saturn and its large moon Titan; the chosen flight path for Voyager 2 also preserved the option to continue on to Uranus and Neptune.

From the NASA Kennedy Space Center at Cape Canaveral, Florida, Voyager 2 was launched first, on August 20, 1977; Voyager 1 was launched on a faster, shorter trajectory on September 5, 1977. Both spacecraft were delivered to space aboard Titan-Centaur expendable rockets.

The prime Voyager mission to Jupiter and Saturn brought Voyager 1 to Jupiter on March 5, 1979, and Saturn on November 12, 1980, followed by Voyager 2 to Jupiter on July 9, 1979, and Saturn on August 25, 1981.

Voyager 1's trajectory, designed to send the spacecraft closely past the large moon Titan and behind Saturn's rings, bent the spacecraft's path inexorably northward out of the ecliptic plane -- the plane in which most of the planets orbit the Sun. Voyager 2 was aimed to fly by Saturn at a point that would automatically send the spacecraft in the direction of Uranus.

After Voyager 2's successful Saturn encounter, it was shown that Voyager 2 would likely be able to fly on to Uranus with all instruments operating. NASA provided additional funding to continue operating the two spacecraft and authorized JPL to conduct a Uranus flyby. Subsequently, NASA also authorized the Neptune leg of the mission, which was renamed the Voyager Neptune Interstellar Mission.

Voyager 2 encountered Uranus on January 24, 1986, returning detailed photos and other data on the planet, its moons, magnetic field and dark rings. Voyager 1, meanwhile, continues to press outward, conducting studies of interplanetary space. Eventually, its instruments may be the first of any spacecraft to sense the heliopause -- the boundary between the end of the Sun's magnetic influence and the beginning of interstellar space. (Voyager 1 entered Interstellar Space on August 25, 2012.)

Following Voyager 2's closest approach to Neptune on August 25, 1989, the spacecraft flew southward, below the ecliptic plane and onto a course that will take it, too, to interstellar space. Reflecting the Voyagers' new transplanetary destinations, the project is now known as the Voyager Interstellar Mission.

Voyager 1 is now leaving the solar system, rising above the ecliptic plane at an angle of about 35 degrees at a rate of about 520 million kilometers (about 320 million miles) a year. Voyager 2 is also headed out of the solar system, diving below the ecliptic plane at an angle of about 48 degrees and a rate of about 470 million kilometers (about 290 million miles) a year.

Both spacecraft will continue to study ultraviolet sources among the stars, and the fields and particles instruments aboard the Voyagers will continue to search for the boundary between the Sun's influence and interstellar space. The Voyagers are expected to return valuable data for two or three more decades. Communications will be maintained until the Voyagers' nuclear power sources can no longer supply enough electrical energy to power critical subsystems.

The cost of the Voyager 1 and 2 missions -- including launch, mission operations from launch through the Neptune encounter and the spacecraft's nuclear batteries (provided by the Department of Energy) -- is $865 million. NASA budgeted an additional $30 million to fund the Voyager Interstellar Mission for two years following the Neptune encounter.

Voyagers 1 and 2 are identical spacecraft. Each is equipped with instruments to conduct 10 different experiments. The instruments include television cameras, infrared and ultraviolet sensors, magnetometers, plasma detectors, and cosmic-ray and charged-particle sensors. In addition, the spacecraft radio is used to conduct experiments.

The Voyagers travel too far from the Sun to use solar panels; instead, they were equipped with power sources called radioisotope thermoelectric generators (RTGs). These devices, used on other deep space missions, convert the heat produced from the natural radioactive decay of plutonium into electricity to power the spacecraft instruments, computers, radio and other systems.

The spacecraft are controlled and their data returned through the Deep Space Network (DSN), a global spacecraft tracking system operated by JPL for NASA. DSN antenna complexes are located in California's Mojave Desert; near Madrid, Spain; and in Tidbinbilla, near Canberra, Australia.

The Voyager project manager for the Interstellar Mission is George P. Textor of JPL. The Voyager project scientist is Dr. Edward C. Stone of the California Institute of Technology. The assistant project scientist for the Jupiter flyby was Dr. Arthur L. Lane, followed by Dr. Ellis D. Miner for the Saturn, Uranus and Neptune encounters. Both are with JPL.

JUPITER Voyager 1 made its closest approach to Jupiter on March 5, 1979, and Voyager 2 followed with its closest approach occurring on July 9, 1979. The first spacecraft flew within 277,400 kilometers (172,368 miles) of the planet's cloud tops, and Voyager 2 came within 650,180 kilometers (404,003 miles).

Jupiter is the largest planet in the solar system, composed mainly of hydrogen and helium, with small amounts of methane, ammonia, water vapor, traces of other compounds and a core of melted rock and ice. Colorful latitudinal bands and atmospheric clouds and storms illustrate Jupiter's dynamic weather system. The giant planet is now known to possess 16 moons. The planet completes one orbit of the Sun each 11.8 years and its day is 9 hours, 55 minutes.

Although astronomers had studied Jupiter through telescopes on Earth for centuries, scientists were surprised by many of the Voyager findings.

The Great Red Spot was revealed as a complex storm moving in a counterclockwise direction. An array of other smaller storms and eddies were found throughout the banded clouds.

Discovery of active volcanism on the satellite Io was easily the greatest unexpected discovery at Jupiter. It was the first time active volcanoes had been seen on another body in the solar system. Together, the Voyagers observed the eruption of nine volcanoes on Io, and there is evidence that other eruptions occurred between the Voyager encounters.

Plumes from the volcanoes extend to more than 300 kilometers (190 miles) above the surface. The Voyagers observed material ejected at velocities up to a kilometer per second.

Io's volcanoes are apparently due to heating of the satellite by tidal pumping. Io is perturbed in its orbit by Europa and Ganymede, two other large satellites nearby, then pulled back again into its regular orbit by Jupiter. This tug-of-war results in tidal bulging as great as 100 meters (330 feet) on Io's surface, compared with typical tidal bulges on Earth of one meter (three feet).

It appears that volcanism on Io affects the entire jovian system, in that it is the primary source of matter that pervades Jupiter's magnetosphere -- the region of space surrounding the planet influenced by the jovian magnetic field. Sulfur, oxygen and sodium, apparently erupted by Io's many volcanoes and sputtered off the surface by impact of high-energy particles, were detected as far away as the outer edge of the magnetosphere millions of miles from the planet itself.

Europa displayed a large number of intersecting linear features in the low-resolution photos from Voyager 1. At first, scientists believed the features might be deep cracks, caused by crustal rifting or tectonic processes. The closer high-resolution photos from Voyager 2, however, left scientists puzzled: The features were so lacking in topographic relief that as one scientist described them, they "might have been painted on with a felt marker." There is a possibility that Europa may be internally active due to tidal heating at a level one-tenth or less than that of Io. Europa is thought to have a thin crust (less than 30 kilometers or 18 miles thick) of water ice, possibly floating on a 50-kilometer-deep (30-mile) ocean.

Ganymede turned out to be the largest moon in the solar system, with a diameter measuring 5,276 kilometers (3,280 miles). It showed two distinct types of terrain -- cratered and grooved -- suggesting to scientists that Ganymede's entire icy crust has been under tension from global tectonic processes.

Callisto has a very old, heavily cratered crust showing remnant rings of enormous impact craters. The largest craters have apparently been erased by the flow of the icy crust over geologic time. Almost no topographic relief is apparent in the ghost remnants of the immense impact basins, identifiable only by their light color and the surrounding subdued rings of concentric ridges.

A faint, dusty ring of material was found around Jupiter. Its outer edge is 129,000 kilometers (80,000 miles) from the center of the planet, and it extends inward about 30,000 kilometers (18,000 miles).

Two new, small satellites, Adrastea and Metis, were found orbiting just outside the ring. A third new satellite, Thebe, was discovered between the orbits of Amalthea and Io.

Jupiter's rings and moons exist within an intense radiation belt of electrons and ions trapped in the planet's magnetic field. These particles and fields comprise the jovian magnetosphere, or magnetic environment, which extends three to seven million kilometers toward the Sun, and stretches in a windsock shape at least as far as Saturn's orbit -- a distance of 750 million kilometers (460 million miles).

As the magnetosphere rotates with Jupiter, it sweeps past Io and strips away about 1,000 kilograms (one ton) of material per second. The material forms a torus, a doughnut-shaped cloud of ions that glow in the ultraviolet. Some of the torus's heavy ions migrate outward, and their pressure inflates the Jovian magnetosphere, while the more energetic sulfur and oxygen ions fall along the magnetic field into the planet's atmosphere, resulting in auroras.

Io acts as an electrical generator as it moves through Jupiter's magnetic field, developing 400,000 volts across its diameter and generating an electric current of 3 million amperes that flows along the magnetic field to the planet's ionosphere.

SATURN The Voyager 1 and 2 Saturn flybys occurred nine months apart, with the closest approaches falling on November 12 and August 25, 1981. Voyager 1 flew within 64,200 kilometers (40,000 miles) of the cloud tops, while Voyager 2 came within 41,000 kilometers (26,000 miles).

Saturn is the second largest planet in the solar system. It takes 29.5 Earth years to complete one orbit of the Sun, and its day was clocked at 10 hours, 39 minutes. Saturn is known to have at least 17 moons and a complex ring system. Like Jupiter, Saturn is mostly hydrogen and helium. Its hazy yellow hue was found to be marked by broad atmospheric banding similar to but much fainter than that found on Jupiter. Close scrutiny by Voyager's imaging systems revealed long-lived ovals and other atmospheric features generally smaller than those on Jupiter.

Perhaps the greatest surprises and the most puzzles were found by the Voyagers in Saturn's rings. It is thought that the rings formed from larger moons that were shattered by impacts of comets and meteoroids. The resulting dust and boulder- to house-size particles have accumulated in a broad plane around the planet varying in density.

The irregular shapes of Saturn's eight smallest moons indicates that they too are fragments of larger bodies. Unexpected structure such as kinks and spokes were found in addition to thin rings and broad, diffuse rings not observed from Earth. Much of the elaborate structure of some of the rings is due to the gravitational effects of nearby satellites. This phenomenon is most obviously demonstrated by the relationship between the F-ring and two small moons that "shepherd" the ring material. The variation in the separation of the moons from the ring may the ring's kinked appearance. Shepherding moons were also found by Voyager 2 at Uranus.

Radial, spoke-like features in the broad B-ring were found by the Voyagers. The features are believed to be composed of fine, dust-size particles. The spokes were observed to form and dissipate in time-lapse images taken by the Voyagers. While electrostatic charging may create spokes by levitating dust particles above the ring, the exact cause of the formation of the spokes is not well understood.

Winds blow at extremely high speeds on Saturn -- up to 1,800 kilometers per hour (1,100 miles per hour). Their primarily easterly direction indicates that the winds are not confined to the top cloud layer but must extend at least 2,000 kilometers (1,200 miles) downward into the atmosphere. The characteristic temperature of the atmosphere is 95 kelvins.

Saturn holds a wide assortment of satellites in its orbit, ranging from Phoebe, a small moon that travels in a retrograde orbit and is probably a captured asteroid, to Titan, the planet-sized moon with a thick nitrogen-methane atmosphere. Titan's surface temperature and pressure are 94 kelvins (-292 Fahrenheit) and 1.5 atmospheres. Photochemistry converts some atmospheric methane to other organic molecules, such as ethane, that is thought to accumulate in lakes or oceans. Other more complex hydrocarbons form the haze particles that eventually fall to the surface, coating it with a thick layer of organic matter. The chemistry in Titan's atmosphere may strongly resemble that which occurred on Earth before life evolved.

The most active surface of any moon seen in the Saturn system was that of Enceladus. The bright surface of this moon, marked by faults and valleys, showed evidence of tectonically induced change. Voyager 1 found the moon Mimas scarred with a crater so huge that the impact that caused it nearly broke the satellite apart.

Saturn's magnetic field is smaller than Jupiter's, extending only one or two million kilometers. The axis of the field is almost perfectly aligned with the rotation axis of the planet.

URANUS In its first solo planetary flyby, Voyager 2 made its closest approach to Uranus on January 24, 1986, coming within 81,500 kilometers (50,600 miles) of the planet's cloud tops.

Uranus is the third largest planet in the solar system. It orbits the Sun at a distance of about 2.8 billion kilometers (1.7 billion miles) and completes one orbit every 84 years. The length of a day on Uranus as measured by Voyager 2 is 17 hours, 14 minutes.

Uranus is distinguished by the fact that it is tipped on its side. Its unusual position is thought to be the result of a collision with a planet-sized body early in the solar system's history. Given its odd orientation, with its polar regions exposed to sunlight or darkness for long periods, scientists were not sure what to expect at Uranus.

Voyager 2 found that one of the most striking influences of this sideways position is its effect on the tail of the magnetic field, which is itself tilted 60 degrees from the planet's axis of rotation. The magnetotail was shown to be twisted by the planet's rotation into a long corkscrew shape behind the planet.

The presence of a magnetic field at Uranus was not known until Voyager's arrival. The intensity of the field is roughly comparable to that of Earth's, though it varies much more from point to point because of its large offset from the center of Uranus. The peculiar orientation of the magnetic field suggests that the field is generated at an intermediate depth in the interior where the pressure is high enough for water to become electrically conducting.

Radiation belts at Uranus were found to be of an intensity similar to those at Saturn. The intensity of radiation within the belts is such that irradiation would quickly darken (within 100,000 years) any methane trapped in the icy surfaces of the inner moons and ring particles. This may have contributed to the darkened surfaces of the moons and ring particles, which are almost uniformly gray in color.

A high layer of haze was detected around the sunlit pole, which also was found to radiate large amounts of ultraviolet light, a phenomenon dubbed "dayglow." The average temperature is about 60 kelvins (-350 degrees Fahrenheit). Surprisingly, the illuminated and dark poles, and most of the planet, show nearly the same temperature at the cloud tops.

Voyager found 10 new moons, bringing the total number to 15. Most of the new moons are small, with the largest measuring about 150 kilometers (about 90 miles) in diameter.

The moon Miranda, innermost of the five large moons, was revealed to be one of the strangest bodies yet seen in the solar system. Detailed images from Voyager's flyby of the moon showed huge fault canyons as deep as 20 kilometers (12 miles), terraced layers, and a mixture of old and young surfaces. One theory holds that Miranda may be a reaggregration of material from an earlier time when the moon was fractured by an violent impact.

The five large moons appear to be ice-rock conglomerates like the satellites of Saturn. Titania is marked by huge fault systems and canyons indicating some degree of geologic, probably tectonic, activity in its history. Ariel has the brightest and possibly youngest surface of all the Uranian moons and also appears to have undergone geologic activity that led to many fault valleys and what seem to be extensive flows of icy material. Little geologic activity has occurred on Umbriel or Oberon, judging by their old and dark surfaces.

All nine previously known rings were studied by the spacecraft and showed the Uranian rings to be distinctly different from those at Jupiter and Saturn. The ring system may be relatively young and did not form at the same time as Uranus. Particles that make up the rings may be remnants of a moon that was broken by a high-velocity impact or torn up by gravitational effects.

NEPTUNE When Voyager flew within 5,000 kilometers (3,000 miles) of Neptune on August 25, 1989, the planet was the most distant member of the solar system from the Sun. (Pluto once again will become most distant in 1999.)

Neptune orbits the Sun every 165 years. It is the smallest of our solar system's gas giants. Neptune is now known to have eight moons, six of which were found by Voyager. The length of a Neptunian day has been determined to be 16 hours, 6.7 minutes.

Even though Neptune receives only three percent as much sunlight as Jupiter does, it is a dynamic planet and surprisingly showed several large, dark spots reminiscent of Jupiter's hurricane-like storms. The largest spot, dubbed the Great Dark Spot, is about the size of Earth and is similar to the Great Red Spot on Jupiter. A small, irregularly shaped, eastward-moving cloud was observed "scooting" around Neptune every 16 hours or so; this "scooter," as Voyager scientists called it, could be a cloud plume rising above a deeper cloud deck.

Long, bright clouds, similar to cirrus clouds on Earth, were seen high in Neptune's atmosphere. At low northern latitudes, Voyager captured images of cloud streaks casting their shadows on cloud decks below.

The strongest winds on any planet were measured on Neptune. Most of the winds there blow westward, or opposite to the rotation of the planet. Near the Great Dark Spot, winds blow up to 2,000 kilometers (1,200 miles) an hour.

The magnetic field of Neptune, like that of Uranus, turned out to be highly tilted -- 47 degrees from the rotation axis and offset at least 0.55 radii (about 13,500 kilometers or 8,500 miles) from the physical center. Comparing the magnetic fields of the two planets, scientists think the extreme orientation may be characteristic of flows in the interiors of both Uranus and Neptune -- and not the result in Uranus's case of that planet's sideways orientation, or of any possible field reversals at either planet. Voyager's studies of radio waves caused by the magnetic field revealed the length of a Neptunian day. The spacecraft also detected auroras, but much weaker than those on Earth and other planets.

Triton, the largest of the moons of Neptune, was shown to be not only the most intriguing satellite of the Neptunian system, but one of the most interesting in all the solar system. It shows evidence of a remarkable geologic history, and Voyager 2 images showed active geyser-like eruptions spewing invisible nitrogen gas and dark dust particles several kilometers into the tenuous atmosphere. Triton's relatively high density and retrograde orbit offer strong evidence that Triton is not an original member of Neptune's family but is a captured object. If that is the case, tidal heating could have melted Triton in its originally eccentric orbit, and the moon might even have been liquid for as long as one billion years after its capture by Neptune.

An extremely thin atmosphere extends about 800 kilometer (500 miles) above Triton's surface. Nitrogen ice particles may form thin clouds a few kilometers above the surface. The atmospheric pressure at the surface is about 14 microbars, 1/70,000th the surface pressure on Earth. The surface temperature is about 38 kelvins (-391 degrees Fahrenheit) the coldest temperature of any body known in the solar system.

The new moons found at Neptune by Voyager are all small and remain close to Neptune's equatorial plane. Names for the new moons were selected from mythology's water deities by the International Astronomical Union, they are: Naiad, Thalassa, Despina, Galatea, Larissa, Proteus.

Voyager 2 solved many of the questions scientists had about Neptune's rings. Searches for "ring arcs," or partial rings, showed that Neptune's rings actually are complete, but are so diffuse and the material in them so fine that they could not be fully resolved from Earth. From the outermost in, the rings have been designated Adams, Plateau, Le Verrier and Galle.

Interstellar Mission

The spacecraft are continuing to return data about interplanetary space and some of our stellar neighbors near the edges of the Milky Way.

As the Voyagers cruise gracefully in the solar wind, their fields, particles and waves instruments are studying the space around them. In May 1993, scientists concluded that the plasma wave experiment was picking up radio emissions that originate at the heliopause -- the outer edge of our solar system.

The heliopause is the outermost boundary of the solar wind, where the interstellar medium restricts the outward flow of the solar wind and confines it within a magnetic bubble called the heliosphere. The solar wind is made up of electrically charged atomic particles, composed primarily of ionized hydrogen, that stream outward from the Sun.

Exactly where the heliopause is has been one of the great unanswered questions in space physics. By studying the radio emissions, scientists now theorize the heliopause exists some 90 to 120 astronomical units (AU) from the Sun. (One AU is equal to 150 million kilometers (93 million miles), or the distance from the Earth to the Sun.

The Voyagers have also become space-based ultraviolet observatories and their unique location in the universe gives astronomers the best vantage point they have ever had for looking at celestial objects that emit ultraviolet radiation.

The Ultraviolet Spectrometer (UVS) is the only experiment on the scan platform that is still functioning. The scan platform is parked at a fixed position and is not being articulated. The Infrared Spectrometer and Radiometer (IRIS) heater was turned off to save power on Voyager 1 on December 7, 2011. On January 21, 2014 the Scan Platform Supplemental Heater was also turned off to conserve power. The IRIS heater and the Scan Platform Heater were used to keep UVS warm. The UVS temperature has dropped to below the measurement limits of the sensor; however, UVS is still operating. The scientist expect to continue to receive data from the UVS until 2016, at which time the instrument will be turned off to save power.

Yet there are several other fields and particle instruments that can continue to send back data as long as the spacecraft stay alive. They include: the cosmic ray subsystem, the low-energy charge particle instrument, the magnetometer, the plasma subsystem, the plasma wave subsystem and the planetary radio astronomy instrument. Barring any catastrophic events, JPL should be able to retrieve this information for at least the next 20 and perhaps even the next 30 years.

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Voyager 1 Enters Interstellar Space

By University of Maryland August 16, 2013

An artist’s concept shows the Voyager spacecraft traveling through space against a field of stars. Credit: NASA/JPL-Caltech

In a newly published study, UMD scientists state that Voyager 1 has left our solar system and has entered interstellar space, contradicting recent papers by NASA and other scientists suggesting the spacecraft was still in a transition zone between the Sun’s sphere of influence and the rest of the galaxy.

Voyager 1 appears to have at long last left our solar system and entered interstellar space, says a University of Maryland-led team of researchers.

Carrying Earthly greetings on a gold plated phonograph record and still-operational scientific instruments – including the Low Energy Charged Particle detector designed, built and overseen, in part, by UMD’s Space Physics Group – NASA’s Voyager 1 has traveled farther from Earth than any other human-made object. And now, these researchers say, it has begun the first exploration of our galaxy beyond the Sun’s influence.

“It’s a somewhat controversial view, but we think Voyager has finally left the Solar System, and is truly beginning its travels through the Milky Way ,” says UMD research scientist Marc Swisdak, lead author of a new paper published online this week in The Astrophysical Journal Letters . Swisdak and fellow plasma physicists James F. Drake, also of the University of Maryland, and Merav Opher of Boston University have constructed a model of the outer edge of the Solar System that fits recent observations, both expected and unexpected.

Their model indicates Voyager 1 actually entered interstellar space a little more than a year ago, a finding directly counter to recent papers by NASA and other scientists suggesting the spacecraft was still in a fuzzily-defined transition zone between the Sun’s sphere of influence and the rest of the galaxy.

But why the controversy?

At issue is what the boundary-crossing should look like to Earth-bound observers 11 billion miles (18 billion kilometers) away. The Sun’s envelope, known as the heliosphere, is relatively well-understood as the region of space dominated by the magnetic field and charged particles emanating from our star. The heliopause transition zone is both of unknown structure and location. According to conventional wisdom, we’ll know we’ve passed through this mysterious boundary when we stop seeing solar particles and start seeing galactic particles, and we also detect a change in the prevailing direction of the local magnetic field.

NASA scientists recently reported that last summer, after eight years of travel through the outermost layer of the heliosphere, Voyager 1 recorded “multiple crossings of a boundary unlike anything previously observed.” Successive dips in, and subsequent recovery of, solar particle counts caught researchers’ attention. The dips in solar particle counts corresponded with abrupt increases in galactic electrons and protons. Within a month, solar particle counts disappeared, and only galactic particle counts remained. Yet Voyager 1 observed no change in the direction of the magnetic field.

To explain this unexpected observation, many scientists theorize that Voyager 1 has entered a “heliosheath depletion region,” but that the probe is still within the confines of the heliosphere. Swisdak and colleagues, who are not part of the Voyager 1 mission science teams, say there is another explanation.

In previous work, Swisdak and Drake have focused on magnetic reconnection, or the breaking and reconfiguring of close and oppositely-directed magnetic field lines. It’s the phenomenon suspected to lurk at the heart of solar flares, coronal mass ejections and many of the sun’s other dramatic, high-energy events. The UMD researchers argue that magnetic reconnection is also key to understanding NASA’s surprising data.

Though often depicted as a bubble encasing the heliosphere and its contents, the heliopause is not a surface neatly separating “outside” and “inside.” In fact, Swisdak, Drake, and Opher assert that the heliopause is both porous to certain particles and layered with complex magnetic structure. Here, magnetic reconnection produces a complex set of nested magnetic “islands,” self-contained loops which spontaneously arise in a magnetic field due to a fundamental instability. Interstellar plasma can penetrate into the heliosphere along reconnected field lines, and galactic cosmic rays and solar particles mix vigorously.

Most interestingly, drops in solar particle counts and surges in galactic particle counts can occur across “slopes” in the magnetic field, which emanate from reconnection sites, while the magnetic field direction itself remains unchanged. This model explains observed phenomena from last summer, and Swisdak and his colleagues suggest that Voyager 1 actually crossed the heliopause on July 27, 2012.

In a NASA statement, Ed Stone, Voyager project scientist and a professor of physics of the California Institute of Technology, says, in part, “Other models envision the interstellar magnetic field draped around our solar bubble and predict that the direction of the interstellar magnetic field is different from the solar magnetic field inside. By that interpretation, Voyager 1 would still be inside our solar bubble. The fine-scale magnetic connection model [of Swisdak and colleagues] will become part of the discussion among scientists as they try to reconcile what may be happening on a fine scale with what happens on a larger scale.” 

Voyager Interstellar Mission

In the 36th year after their 1977 launches, the twin Voyager 1 and 2 spacecraft continue exploring where nothing from Earth has flown before. Their primary mission was the exploration of Jupiter and Saturn . After making a string of discoveries there — such as active volcanoes on Jupiter’s moon Io and intricacies of Saturn ’s rings — the mission was extended. Voyager 2 went on to explore Uranus and Neptune , and is still the only spacecraft to have visited those outer planets. The current mission for both spacecraft, the Voyager Interstellar Mission, is to explore the outermost edge of the Sun’s domain and beyond. Both Voyagers are capable of returning scientific data from a full range of instruments, with adequate electrical power and attitude control propellant to keep operating until 2020. Voyager 2 is expected to enter interstellar space a few years after its twin. The Voyager spacecraft were built and continue to be operated by NASA’s Jet Propulsion Laboratory, in Pasadena, California.

University of Maryland scientists lead the Deep Impact spacecraft science team and are part of the science teams of many of the other spacecraft exploring our Solar System, including both Voyagers and Cassini .

Reference: “A Porous, Layered Heliopause” by M. Swisdak, J. F. Drake and M. Opher, 14 August 2013, The Astrophysical Journal Letters . DOI: 10.1088/2041-8205/774/1/L8 arXiv:1307.0850  

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1 comment on "voyager 1 enters interstellar space".

Sailing 18 billion kilometers and 36 years after 1977 voyager is still not certain to have crossed solar influence. The magnetic field and direction has not changed though solar particle depletion and galactic particles detection increasing has happened. When some of the comets from Oort cloud takes thousands of years to go round the Sun , this 36 years is just a trickle only in cosmos. There is no defined zone to segregate. Inter galactic magnetic field is also a riddle to be found. Thank You.

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Engineers Pinpoint Cause of Voyager 1 Issue, Are Working on Solution

Engineers have confirmed that a small portion of corrupted memory in one of the computers aboard NASA’s Voyager 1 has been causing the spacecraft to send unreadable science and engineering data to Earth since last November. Called the flight data subsystem (FDS), the computer is responsible for packaging the probe’s science and engineering data before the telemetry modulation unit (TMU) and radio transmitter send the data to Earth.

In early March , the team issued a “poke” command to prompt the spacecraft to send back a readout of the FDS memory, which includes the computer’s software code as well as variables (values used in the code that can change based on commands or the spacecraft’s status). Using the readout, the team has confirmed that about 3% of the FDS memory has been corrupted, preventing the computer from carrying out normal operations.

The team suspects that a single chip responsible for storing part of the affected portion of the FDS memory isn’t working. Engineers can’t determine with certainty what caused the issue. Two possibilities are that the chip could have been hit by an energetic particle from space or that it simply may have worn out after 46 years.

Although it may take weeks or months, engineers are optimistic they can find a way for the FDS to operate normally without the unusable memory hardware, which would enable Voyager 1 to begin returning science and engineering data again.

Launched in 1977 , the twin Voyager spacecraft flew by Saturn and Jupiter, and Voyager 2 flew by Uranus and Neptune. They are both exploring interstellar space, outside the bubble of particles and magnetic fields created by the Sun, called the heliosphere. Voyager 2 continues to operate normally.

News Media Contact Calla Cofield Jet Propulsion Laboratory, Pasadena, Calif. 626-808-2469 [email protected]

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Watch this Space: Voyager 1 goes ‘senile’ and the interstellar object lie

Voyager 1, the farthest human-made object in space, has been sending back nonsensical data since november, raising concerns about its functionality. this potential loss is more sentimental than scientific, as voyager 1 has already made groundbreaking discoveries..

NASA’s Voyager 1 has been travelling in space for nearly 50 years and in that time, it became the first spacecraft to go into interstellar space and continues to be the man-made object farthest from the Earth. But since last November, it has been sending back nothing but “incoherent” data back to mission controllers, raising serious concerns about whether its time has ended.

Voyager 1’s demise would not be as much of a scientific loss as it would be an emotional one. For the scientific community, what is happening right now is the equivalent of watching a really old relative go senile. The spacecraft seems to have already lost its bearings and what it says does not make much sense.

“It basically stopped talking to us in a coherent manner,” said Suzanne Dodd of NASA’s Jet Propulsion Laboratory to NPR. Dodd has been the project manager for the Voyager interstellar mission since 2010.

A Voyager update: Engineers are still working to resolve a data issue on Voyager 1. We can talk to the spacecraft, and it can hear us, but it's a slow process given the spacecraft's incredible distance from Earth. We’ll keep you informed on its status. 🤞 pic.twitter.com/qSxG0au1Nn — NASA JPL (@NASAJPL) February 6, 2024

Apart from being the first spacecraft to venture beyond the protective heliosphere of our Sun, it also helped make many important discoveries, including a thin ring around Jupiter, two new Jovian moons, five new Saturnian moons and a new ring for the planet called the G-ring.

Voyager 1 and Voyager 2 were launched in the year 1977 to take advantage of a rare geometric alignment of the outer planets which allowed NASA to take a four-planet tour in a relatively short period of time with minimal fuel use. The layout of Jupiter, Saturn, Uranus and Neptune last seen in the 1970s and the 1980s lets a spacecraft on a special flight path swing from one planet to another without large onboard propulsion systems. The layout only happens about once in 175 years.

Rather counterintuitively, Voyager 2 launched on August 20, 1977, before Voyager 1 launched on September 5, 1977. But the latter was put on a faster and shorter trajectory. This meant that Voyager 1 reached Jupiter on March 5, 1979 and Saturn on November 12, 1980, while Voyager 2 accomplished the same feat on July 9, 1979 and August 25, 1981, respectively.

For the initially planned two-planet mission, the spacecrafts were built to last five years but with its successful achievement of its objectives and as the mission went on, NASA engineers realised that it would also be possible to do flybys of the two outermost giant planets Uranus and Neptune.

NASA claims that even if the Voyager mission had ended after Jupiter and Saturn, it would still have been enough material to “rewrite” astronomy textbooks. But the information they have returned over the past 45 years has revolutionised planetary astronomy and our understanding of the solar system.

Now, enough about things that we have sent into interstellar space, what about things that have come to Earth from there?

In 2014, a meteor also known as Interstellar meteor 1, crashed into the Earth in the Pacific Ocean. A 2019 preprint paper by Harvard astrophysicist Avi Loeb and astronomer Amir Siraj claimed that it was an interstellar object. Other astronomers already doubted this claim but in 2023, Loeb was part of an expedition in the part of the ocean where the meteor was believed to have fallen and claimed he discovered “materials of interstellar origin.”

I'm currently more than 20.4 billion kilometers (12.6 billion miles) away from Earth. But on this day in 1986, I was doing my closest flyby of Uranus. I came within 81,500 kilometers (50,600 miles) of its cloud tops! -V2 pic.twitter.com/v6bMws70BY — NASA Voyager (@NASAVoyager) January 24, 2024

The location was derived from ground vibrations detected at the time at a seismic station in Papua New Guinea’s Manus Island. Now, a new research study led by Johns Hopkins University found that those vibrations were actually caused by a truck driving through the highway.

The research paper also concludes that the material found by Loeb and his colleagues were actually probably either bits of tiny run-of-the-mill meteorites or formed by the impact of meteorites on Earth’s surface. So we do not really have anything from interstellar space, even though it has something of ours. Two things actually — Voyager 1 and Voyager 2.

Haryana Police Saturday registered an FIR under the charges of attempt to murder after the car of IAS officer Yash Jaluka, who had gone for inspection of illegal mining in Ambala district at midnight, was chased and an attempt was made to hit the vehicle.

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It's Official! Voyager 1 Spacecraft Has Left Solar System

A spacecraft from Earth has left its cosmic backyard and taken its first steps in interstellar space.

After streaking through space for nearly 35 years, NASA's robotic Voyager 1 probe finally left the solar system in August 2012, a study published today (Sept. 12) in the journal Science reports.

"Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science, and as it enters interstellar space, it adds a new chapter in human scientific dreams and endeavors," NASA science chief John Grunsfeld said in a statement. "Perhaps some future deep-space explorers will catch up with Voyager, our first interstellar envoy, and reflect on how this intrepid spacecraft helped enable their future." [ Voyager 1 in Interstellar Space: Complete Coverage ]

A long and historic journey

Voyager 1 launched on Sept. 5, 1977, about two weeks after its twin, Voyager 2. Together, the two probes conducted a historic "grand tour" of the outer planets, giving scientists some of their first up-close looks at Jupiter , Saturn, Uranus, Neptune and the moons of these faraway worlds.

The duo completed its primary mission in 1989, and then kept on flying toward the edge of the heliosphere, the huge bubble of charged particles and magnetic fields that the sun puffs out around itself. Voyager 1 has now popped free of this bubble into the exotic and unexplored realm of interstellar space , scientists say.

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They reached this historic conclusion with a little help from the sun. A powerful solar eruption caused electrons in Voyager 1's location to vibrate signficantly between April 9 and May 22 of this year. The probe's plasma wave instrument detected these oscillations, and researchers used the measurements to figure out that Voyager 1's surroundings contained about 1.3 electrons per cubic inch (0.08 electrons per cubic centimeter).

That's far higher than the density observed in the outer regions of the heliosphere (roughly 0.03 electrons per cubic inch, or 0.002 electrons per cubic cm) and very much in line with the 1.6 electrons per cubic inch (0.10 electrons per cubic cm) or so expected in interstellar space. [ Photos from NASA's Voyager 1 and 2 Probes ]

"We literally jumped out of our seats when we saw these oscillations in our data — they showed us that the spacecraft was in an entirely new region, comparable to what was expected in interstellar space, and totally different than in the solar bubble," study lead author Don Gurnett of the University of Iowa, the principal investigator of Voyager 1's plasma wave instrument, said in a statement.

It may seem surprising that electron density is higher beyond the solar system than in its extreme outer reaches. Interstellar space is, indeed, emptier than the regions in Earth's neighborhood, but the density inside the solar bubble drops off dramatically at great distances from the sun, researchers said.

Calculating a departure date

The study team wanted to know if Voyager 1 left the solar system  sometime before April 2013, so they combed through some of the probe's older data. They found a monthlong period of electron oscillations in October-November 2012 that translated to a density of 0.004 electrons per cubic inch (0.006 electrons per cubic cm).

Using these numbers and the amount of ground that Voyager 1 covers — about 325 million miles (520 million kilometers) per year — the researchers calculated that the spacecraft likely left the solar system in August 2012.

That time frame matches up well with several other important changes Voyager 1 observed. On Aug. 25, 2012, the probe recorded a 1,000-fold drop in the number of charged solar particles while also measuring a 9 percent increase in fast-moving galactic cosmic rays , which originate beyond the solar system.

"These results, and comparison with previous heliospheric radio measurements, strongly support the view that Voyager 1 crossed the heliopause into the interstellar plasma on or about Aug. 25, 2012," Gurnett and his colleagues write in the new study.

At that point, Voyager 1 was about 11.25 billion miles (18.11 billion km) from the sun, or roughly 121 times the distance between Earth and the sun. The probe is now 11.66 billion miles (18.76 billion km) from the sun. (Voyager 2, which took a different route through the solar system, is currently 9.54 billion miles, or 15.35 billion km, from the sun.)

Magnetic-field mystery

Mission scientists have long pegged Voyager 1's departure from the solar system on the observation of three phenomena: a big drop in solar particles, a dramatic jump in galactic cosmic rays and a shift in the orientation of the surrounding magnetic field.

Voyager 1 has measured the first two changes, as noted above, but not the third; the magnetic field is stronger than it used to be in the probe's location, but it hasn't changed direction.

This key point has led NASA and the mission team to proceed with caution. For example, they have held off on making any big announcements, despite several recent studies by outside researchers — including one published last month — suggesting that Voyager 1 entered interstellar space in July or August 2012.

But the new electron-density measurements have convinced Voyager mission  scientists that the probe is, indeed, beyond the solar bubble.

After all, magnetic-field measurements were always regarded as a proxy for observations of electron density, said Voyager chief scientist Ed Stone, a physicist at the California Institute of Technology in Pasadena.

"The solar wind  carries the solar magnetic field with it, and the interstellar wind carries the galactic magnetic field with it," Stone, who is not an author of the new Science paper, told SPACE.com. "Once we got the plasma data itself in interstellar space, we knew we must have left the bubble."

(Voyager 1 launched with an instrument designed to measure plasma density directly, but it failed in 1980, forcing the team to get more creative.)

Scientists need a better understanding of the complex interface between the solar and galactic magnetic fields to figure out why Voyager 1 hasn't measured the predicted change in field direction, Stone said.

"What we need to do now is go back and look more carefully at the models of that interaction," he said.

Voyage of exploration

The Voyager mission has racked up a series of discoveries over the last 36 years, revealing key insights about the giant planets and their moons, as well as conditions at the edge of the solar system.

The spacecraft's arrival in interstellar space could bring many more exciting finds, the researchers said.

"Every day we look at data, we know we're looking at data that no one has seen before and is in a region where nothing has ever been before," Stone said. "I think we're all looking forward to learning a lot in the years ahead."

Voyager 1 could keep beaming data home for a while, provided nothing too important breaks down. The spacecraft's declining power supply won't force engineers to shut off the first instrument until 2020, mission scientists have said. All of Voyager 1's science gear will probably stop working by 2025.

Follow Mike Wall on Twitter  @michaeldwall  and  Google+ . Follow us @Spacedotcom , Facebook  or Google+ . Originally published on  SPACE.com.

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Michael Wall is a Senior Space Writer with  Space.com  and joined the team in 2010. He primarily covers exoplanets, spaceflight and military space, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.

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NASA engineers have renewed hope to fix hobbled Voyager 1 after interstellar space data outage

The process of troubleshooting an issue with voyager 1 traveling through interstellar space is complicated. it takes about 45 hours for commands to be sent and a response to come back, but nasa engineers recently got a new clue to solving the spacecraft computer issue..

Discovering Uranus

FILE VIDEO: Uranus was discovered 241 years ago.

NASA engineers are acting as detectives to resolve a communication issue with the Voyager 1 spacecraft, one of the space agency's 46-year-old twin spacecraft zooming through interstellar space.

Voyager 1 and 2 launched in 1977 a few weeks apart, taking advantage of a 176-year planetary alignment to take a grand tour of all four giant outer planets – Neptune , Uranus , Saturn and Jupiter . The spacecraft missions have continued decades after those final planet flybys, eventually entering interstellar space.

Voyager 1 is more than 15.1 billion miles from Earth, and in mid-November, the spacecraft began sending back nonsense computer code instead of science data.

VOYAGER 1 AND 2 CONTINUE OFFERING NEW MYSTERIES FROM INTERSTELLAR SPACE

"It looked like it was just sending back what was the equivalent of just a single tone, you could think about, like a dial tone," Voyager Program scientist Linda Spilker said. "It had gone from sending back useful information, all those ones and zeros turning into data, to now just sort of being stuck sort of in a repetitive loop of ones and zeros and no longer basically communicating with us."

NASA engineers have honed in on one of three computers on the spacecraft, known as the Flight Data System (FDS), as the cause behind the communication problem. The FDS is returning unusable data from the telemetry modulation unit (TMU). 

" Its role is to basically collect all of the data from the science instruments and the spacecraft, package them all neatly up and send them back to the Earth," Spilker said of the FDS.

Artist rendering of the Voyager 1 spacecraft

These two systems work in tandem to get science and engineering data back to Earth from 15 billion miles away.  

Troubleshooting an issue with a spacecraft traveling through interstellar space is complicated. It takes about 22.5 hours for a message from Earth to reach the spacecraft and another 22.5 hours for a response back to Earth. The Voyagers were also constructed before the digital age.

Spilker said this combination makes the problem-solving effort multifaceted. Circuit diagrams for the FDS computer are posted in a room at JPL covered with sticky notes as engineers search through paper notes and contact retired Voyager engineers.

NASA REESTABLISHES CONTACT WITH VOYAGER 2 LOCATED MORE THAN 12 BILLION MILES FROM EARTH  

About once a week, Spilker said a team of engineers "sit down and think about what we can try next." After carefully creating and checking the plan, a command or a "poke" is sent to Voyager in hopes of fixing the corrupted section of the computer. Then, they wait two days to find out if it worked.

"The waiting in between is hard. That's for sure," Spilker said.

Archival image showing an engineer on the Voyager team working on the construction of the dish-shaped Voyager antenna. July 9, 1976.

(NASA/JPL-Caltech, NASA/JPL-Caltech Photojournal / NASA)

On Wednesday, NASA shared hopeful news that the Voyager team saw different activity on one section of the FDS but still not in the correct format. However, an engineer with NASA's Deep Space Network – a network of radio antennas to communicate with Voyagers and other spacecraft – was able to decode the signal and discovered a readout of the entire FDS memory.

This could be the breadcrumb Voyager's engineering team needs to get the spacecraft to speak the correct language again.

"The FDS memory includes its code, or instructions for what to do, as well as variables, or values used in the code that can change based on commands or the spacecraft’s status. It also contains science or engineering data for downlink," NASA's Jet Propulsion Laboratory wrote in a blog post . "The team will compare this readout to the one that came down before the issue arose and look for discrepancies in the code and the variables to potentially find the source of the ongoing issue."

This isn’t the first scare for either spacecraft. Another issue with garbled data for Voyager 1 in 2022 was fixed over several months. In 1981, the team experienced a similar communication issue to the current problem.

This illustration shows the positions of NASA’s Voyager 1 and Voyager 2 probes outside the heliosphere, the region surrounding our star, beyond which interstellar space begins. (Credit: NASA/JPL-Caltech)

Last year, an incorrect command sent Voyager 2 pointing away from Earth , unable to send back data. Teams were able to send a patch and reorient the spacecraft. 

Spilker and the rest of the Voyager team are used to bumps on this long road. However, it's worth it because the twin interstellar explorers are still collecting valuable data. 

Voyager 1 crossed the heliopause 11 years ago, and what it continues to send back is reshaping what scientists know about the interstellar medium. Eventually, future spacecraft missions traveling even farther from the Sun's influence will benefit from lessons learned from the Voyager missions. 

"It's just really an amazing story to think that two spacecraft are still operating after 46 years and having basically flown through the outer solar system … the entire heliosphere, across the heliopause, now on out into interstellar space," Spilker said. 

With the latest clue in this case, Voyager engineers are devising their next plan of action to help the spacecraft start sending back data from 15 billion miles from Earth.