voyager 2 found

First to visit all four giant planets

Voyager 2 is the only spacecraft to visit Uranus and Neptune. The probe is now in interstellar space, the region outside the heliopause, or the bubble of energetic particles and magnetic fields from the Sun.

Mission Type

What is Voyager 2?

NASA's Voyager 2 is the second spacecraft to enter interstellar space. On Dec. 10, 2018, the spacecraft joined its twin – Voyager 1 – as the only human-made objects to enter the space between the stars.

• Voyager 2 is the only spacecraft to study all four of the solar system's giant planets at close range.
• Voyager 2 discovered a 14th moon at Jupiter.
• Voyager 2 was the first human-made object to fly past Uranus.
• At Uranus, Voyager 2 discovered 10 new moons and two new rings.
• Voyager 2 was the first human-made object to fly by Neptune.
• At Neptune, Voyager 2 discovered five moons, four rings, and a "Great Dark Spot."

In Depth: Voyager 2

The two-spacecraft Voyager missions were designed to replace original plans for a “Grand Tour” of the planets that would have used four highly complex spacecraft to explore the five outer planets during the late 1970s.

NASA canceled the plan in January 1972 largely due to anticipated costs (projected at $1 billion) and instead proposed to launch only two spacecraft in 1977 to Jupiter and Saturn. The two spacecraft were designed to explore the two gas giants in more detail than the two Pioneers (Pioneers 10 and 11) that preceded them.

In 1974, mission planners proposed a mission in which, if the first Voyager was successful, the second one could be redirected to Uranus and then Neptune using gravity assist maneuvers.

Each of the two spacecraft was equipped with a slow-scan color TV camera to take images of the planets and their moons and each also carried an extensive suite of instruments to record magnetic, atmospheric, lunar, and other data about the planetary systems.

The design of the two spacecraft was based on the older Mariners, and they were known as Mariner 11 and Mariner 12 until March 7, 1977, when NASA Administrator James C. Fletcher (1919-1991) announced that they would be renamed Voyager.

Power was provided by three plutonium oxide radioisotope thermoelectric generators (RTGs) mounted at the end of a boom.

Voyager 2 at Jupiter

Voyager 2 began transmitting images of Jupiter April 24, 1979, for time-lapse movies of atmospheric circulation. Unlike Voyager 1, Voyager 2 made close passes to the Jovian moons on its way into the system, with scientists especially interested in more information from Europa and Io (which necessitated a 10 hour-long “volcano watch”).

During its encounter, it relayed back spectacular photos of the entire Jovian system, including its moons Callisto, Ganymede, Europa (at a range of about 127,830 miles or 205,720 kilometers, much closer than Voyager 1), Io, and Amalthea, all of which had already been surveyed by Voyager 1.

Voyager 2’s closest encounter to Jupiter was at 22:29 UT July 9, 1979, at a range of about 400,785 miles (645,000 kilometers). It transmitted new data on the planet’s clouds, its newly discovered four moons, and ring system as well as 17,000 new pictures.

When the earlier Pioneers flew by Jupiter, they detected few atmospheric changes from one encounter to the second, but Voyager 2 detected many significant changes, including a drift in the Great Red Spot as well as changes in its shape and color.

With the combined cameras of the two Voyagers, at least 80% of the surfaces of Ganymede and Callisto were mapped out to a resolution of about 3 miles (5 kilometers).

Voyager 2 at Saturn

Following a course correction two hours after its closest approach to Jupiter, Voyager 2 sped to Saturn, its trajectory determined to a large degree by a decision made in January 1981, to try to send the spacecraft to Uranus and Neptune later in the decade.

Its encounter with the sixth planet began Aug. 22, 1981, two years after leaving the Jovian system, with imaging of the moon Iapetus. Once again, Voyager 2 repeated the photographic mission of its predecessor, although it actually flew about 14,290 miles (23,000 kilometers) closer to Saturn. The closest encounter to Saturn was at 01:21 UT Aug. 26, 1981, at a range of about 63,000 miles (101,000 kilometers).

The spacecraft provided more detailed images of the ring “spokes” and kinks, and also the F-ring and its shepherding moons, all found by Voyager 1. Voyager 2’s data suggested that Saturn’s A-ring was perhaps only about 980 feet (300 meters) thick.

As it flew behind and up past Saturn, the probe passed through the plane of Saturn’s rings at a speed of 8 miles per second (13 kilometers per second). For several minutes during this phase, the spacecraft was hit by thousands of micron-sized dust grains that created “puff” plasma as they were vaporized. Because the vehicle’s attitude was repeatedly shifted by the particles, attitude control jets automatically fired many times to stabilize the vehicle.

During the encounter, Voyager 2 also photographed the Saturn moons Hyperion (the “hamburger moon”), Enceladus, Tethys, and Phoebe as well as the more recently discovered Helene, Telesto and Calypso.

Voyager 2 at Uranus

Although Voyager 2 had fulfilled its primary mission goals with the two planetary encounters, mission planners directed the veteran spacecraft to Uranus—a journey that would take about 4.5 years.

In fact, its encounter with Jupiter was optimized in part to ensure that future planetary flybys would be possible.

The Uranus encounter’s geometry was also defined by the possibility of a future encounter with Neptune: Voyager 2 had only 5.5 hours of close study during its flyby.

Voyager 2 was the first human-made object to fly past the planet Uranus.

Long-range observations of the planet began Nov. 4, 1985, when signals took approximately 2.5 hours to reach Earth. Light conditions were 400 times less than terrestrial conditions. Closest approach to Uranus took place at 17:59 UT Jan. 24, 1986, at a range of about 50,640 miles (81,500 kilometers).

During its flyby, Voyager 2 discovered 10 new moons (given such names as Puck, Portia, Juliet, Cressida, Rosalind, Belinda, Desdemona, Cordelia, Ophelia, and Bianca -- obvious allusions to Shakespeare), two new rings in addition to the “older” nine rings, and a magnetic field tilted at 55 degrees off-axis and off-center.

The spacecraft found wind speeds in Uranus’ atmosphere as high as 450 miles per hour (724 kilometers per hour) and found evidence of a boiling ocean of water some 497 miles (800 kilometers) below the top cloud surface. Its rings were found to be extremely variable in thickness and opacity.

Voyager 2 also returned spectacular photos of Miranda, Oberon, Ariel, Umbriel, and Titania, five of Uranus’ larger moons. In flying by Miranda at a range of only 17,560 miles (28,260 kilometers), the spacecraft came closest to any object so far in its nearly decade-long travels. Images of the moon showed a strange object whose surface was a mishmash of peculiar features that seemed to have no rhyme or reason. Uranus itself appeared generally featureless.

The spectacular news of the Uranus encounter was interrupted the same week by the tragic Challenger accident that killed seven astronauts during their space shuttle launch Jan. 28, 1986.

Voyager 2 at Neptune

Following the Uranus encounter, the spacecraft performed a single midcourse correction Feb. 14, 1986—the largest ever made by Voyager 2—to set it on a precise course to Neptune.

Voyager 2’s encounter with Neptune capped a 4.3 billion-mile (7 billion-kilometer) journey when, on Aug. 25, 1989, at 03:56 UT, it flew about 2,980 miles (4,800 kilometers) over the cloud tops of the giant planet, the closest of its four flybys. It was the first human-made object to fly by the planet. Its 10 instruments were still in working order at the time.

During the encounter, the spacecraft discovered six new moons (Proteus, Larissa, Despina, Galatea, Thalassa, and Naiad) and four new rings.

The planet itself was found to be more active than previously believed, with 680-mile (1,100-kilometer) per hour winds. Hydrogen was found to be the most common atmospheric element, although the abundant methane gave the planet its blue appearance.

Images revealed details of the three major features in the planetary clouds—the Lesser Dark Spot, the Great Dark Spot, and Scooter.

Voyager photographed two-thirds of Neptune’s largest moon Triton, revealing the coldest known planetary body in the solar system and a nitrogen ice “volcano” on its surface. Spectacular images of its southern hemisphere showed a strange, pitted cantaloupe-type terrain.

The flyby of Neptune concluded Voyager 2’s planetary encounters, which spanned an amazing 12 years in deep space, virtually accomplishing the originally planned “Grand Tour” of the solar system, at least in terms of targets reached if not in science accomplished.

Voyager 2's Interstellar Mission

Once past the Neptune system, Voyager 2 followed a course below the ecliptic plane and out of the solar system. Approximately 35 million miles (56 million kilometers) past the encounter, Voyager 2’s instruments were put in low power mode to conserve energy.

After the Neptune encounter, NASA formally renamed the entire project the Voyager Interstellar Mission (VIM).

Of the four spacecraft sent out to beyond the environs of the solar system in the 1970s, three of them -- Voyagers 1 and 2 and Pioneer 11 -- were all heading in the direction of the solar apex, i.e., the apparent direction of the Sun’s travel in the Milky Way galaxy, and thus would be expected to reach the heliopause earlier than Pioneer 10 which was headed in the direction of the heliospheric tail.

In November 1998, 21 years after launch, nonessential instruments were permanently turned off, leaving seven instruments still operating.

At 9.6 miles per second (15.4 kilometers per second) relative to the Sun, it will take about 19,390 years for Voyager 2 to traverse a single light year.

Asif Siddiqi

Beyond Earth: A Chronicle of Deep Space Exploration

Through the turn of the century, NASA's Jet Propulsion Laboratory (JPL) continued to receive ultraviolet and particle fields data. For example, on Jan. 12, 2001, an immense shock wave that had blasted out of the outer heliosphere on July 14, 2000, finally reached Voyager 2. During its six-month journey, the shock wave had plowed through the solar wind, sweeping up and accelerating charged particles. The spacecraft provided important information on high-energy shock-energized ions.

On Aug. 30, 2007, Voyager 2 passed the termination shock and then entered the heliosheath. By Nov. 5, 2017, the spacecraft was 116.167 AU (about 10.8 billion miles or about 17.378 billion kilometers) from Earth, moving at a velocity of 9.6 miles per second (15.4 kilometers per second) relative to the Sun, heading in the direction of the constellation Telescopium. At this velocity, it would take about 19,390 years to traverse a single light-year.

On July 8, 2019, Voyager 2 successfully fired up its trajectory correction maneuver thrusters and will be using them to control the pointing of the spacecraft for the foreseeable future. Voyager 2 last used those thrusters during its encounter with Neptune in 1989.

The spacecraft's aging attitude control thrusters have been experiencing degradation that required them to fire an increasing and untenable number of pulses to keep the spacecraft's antenna pointed at Earth. Voyager 1 had switched to its trajectory correction maneuver thrusters for the same reason in January 2018.

To ensure that both vintage robots continue to return the best scientific data possible from the frontiers of space, mission engineers are implementing a new plan to manage them. The plan involves making difficult choices, particularly about instruments and thrusters.

National Space Science Data Center: Voyager 2

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NASA detects 'heartbeat' in search for Voyager 2 spacecraft 20 billion kilometres away

After days of silence, NASA has heard from spacecraft Voyager 2, which is almost 20 billion kilometres from Earth.

Key points:

• NASA has found the spacecraft after a wrong command severed communication
• The antenna, tilted away from earth, is only 2 per cent off-kilter
• Controllers may have to wait until October for an automatic reset

Flight controllers accidentally sent a wrong command nearly two weeks ago that tilted the spacecraft's antenna away from Earth and severed contact.

But NASA's Deep Space Network, giant radio antennas across the globe, picked up a "heartbeat signal", on Tuesday.

It means the 46-year-old craft is alive and operating, project manager Suzanne Dodd said in an email.

The news "buoyed our spirits," she said.

The distance to the spacecraft is about four times the average distance between the Sun and Pluto, meaning it takes more than 18 hours for a signal to travel one way. 

Flight controllers will now try to turn Voyager 2's antenna back toward Earth.

If the command doesn't work — and controllers doubt it will — they'll have to wait until October for an automatic spacecraft reset.

The antenna is only 2 per cent off-kilter.

"That is a long time to wait, so we'll try sending up commands several times [before then]," Ms Dodd said.

Voyager 2 rocketed into space in 1977, along with its identical twin Voyager 1, on a quest to explore the outer planets.

Still communicating and working fine, Voyager 1 is now 24 billion kilometres from Earth, making it the most distant spacecraft.

Voyager 2 trails its twin in interstellar space at more than 19 billion kilometres from Earth.

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Voyager 2: An iconic spacecraft that's still exploring 45 years on

The interstellar vagabond continues to explore the cosmos along with its twin, Voyager 1.

Voyager 2 as the backup

Jupiter and saturn flyby, uranus and neptune flyby, voyager 2's interstellar adventure, voyager 2's legacy, additional information.

Voyager 2, was the first of two twin probes NASA sent to investigate the outer planets of our solar system. 

The probe was launched aboard a Titan IIIE-Centaur from Cape Canaveral Space Launch Complex 41 (previously Launch Complex 41) on Aug. 20, 1977, its twin spacecraft Voyager 1 was launched about two weeks later on Sept. 5. NASA planned for the Voyager spacecraft to take advantage of an alignment of the outer planets that takes place only every 176 years. The alignment would allow both probes to swing from one planet to the next, with a gravity boost to help them along the way.

While Voyager 1 focused on Jupiter and Saturn , Voyager 2 visited both those planets and also ventured to Uranus and Neptune. Voyager 2's mission to those last two planets would be humanity's only visit in the 20th century.

Related: Celebrate 45 years of Voyager with these amazing images of our solar system (gallery)

Voyager 2 is now traveling through interstellar space. As of early November 2018, NASA announced that Voyager 2 had crossed the outer edge of our solar system ( Voyager 1 crossed the boundary into interstellar space in 2012. ) Voyager 2 is now approximately 12 billion miles (19 billion kilometers) away from Earth and counting!  

Although there was not enough money in Voyager 2's budget to guarantee it would still work when flying past Uranus and Neptune, its trajectory was designed to go past those planets anyway. If the spacecraft were still working after Saturn, NASA could try to take pictures of the other planets.

Voyager 2 was ready as a backup for Voyager 1. If Voyager 1 failed when taking pictures of Jupiter and Saturn, NASA was prepared to alter Voyager 2's path to follow Voyager 1's trajectory. It would cut off the Uranus and Neptune option, but still, preserve the possibility of capturing images.

The backup plan was never executed, though, because Voyager 1 went on to make many discoveries at Jupiter and Saturn, working well enough for NASA to carry out its original plans for Voyager 2.

Voyager 2 reached Jupiter in 1979, two years after launching from Cape Canaveral. Since Voyager 1 had just gone through the system four months earlier, Voyager 2's arrival allowed NASA to take valuable comparison shots of Jupiter and its moons. It captured changes in the Great Red Spot and also resolved some of the moon's surfaces in greater detail.

Voyager 2 took pictures of many of Jupiter's satellites. Among its most spectacular findings were pictures from the icy moon Europa . Voyager 2 snapped detailed photos of the icy moon's cracks from 128,000 miles (205,996 km) away and revealed no change in elevation anywhere on the moon's surface.

Proving that moons are abundant around the outer planets, Voyager 2 happened to image Adrastea, a small moon of Jupiter, only months after Voyager 1 found two other Jupiter moons, Thebe and Metis. Adrastea is exceptionally small, only about 19 miles (30.5 kilometers) in diameter at the smallest estimate.

Next in line was Saturn. Voyager 2  became the third spacecraft to visit Saturn when it arrived at its closest point to the ringed planet on Aug. 26, 1981, and took hundreds of pictures of the planet, its moons and its rings . Suspecting that Saturn might be circled by many ringlets, scientists conducted an experiment. They watched the star Delta Scorpii for nearly two and a half hours as it passed through the plane of the rings. As expected, the star's flickering light revealed ringlets as small as 330 feet (100 meters) in diameter. 

Voyager 2's made its closest approach to Uranus on Jan. 24, 1986, becoming the first spacecraft to visit the ice giant. The probe made several observations of the planet, noting that the south pole was facing the sun and that its atmosphere is about 85% hydrogen and 15% helium. 

Additionally, Voyager 2 discovered rings around Uranus, 10 new moons and a magnetic field that, oddly, was 55 degrees off the planet's axis. Astronomers are still puzzling over Uranus' orientation today.

Voyager 2's pictures of the moon Miranda revealed it to be perhaps the strangest moon in the solar system. Its jumbled-up surface appears as though it was pushed together and broken apart several times.

The spacecraft then made it to Neptune , reaching the closest point on Aug. 25, 1989. It skimmed about 3,000 miles from the top of the planet's atmosphere and spotted five new moons as well as four rings around the planet. Remarkably, Voyager 2 is currently the only human-made object to have flown by the intriguing ice giant, according to NASA .

On November 5, 2018, Voyager 2 crossed the heliopause — the boundary between the heliosphere and interstellar space. At this stage, the probe was 119 astronomical units from the sun. (One AU is the average Earth-sun distance, which is about 93 million miles, or 150 million kilometers.) Voyager 1 made the crossing at nearly the same distance, 121.6 AU.

According to NASA Jet Propulsion Laboratory (JPL) , Voyager 2 has enough fuel to keep its instruments running until at least 2025. By then, the spacecraft will be approximately 11.4 billion miles (18.4 billion kilometers) away from the sun. 

But Voyager 2 is destined to roam the Milky Way long after its instruments have stopped working.

In about 40,000 years Voyager 2 will pass 1.7 light-years (9.7 trillion miles) from the star Ross 248, according to NASA JPL. The cosmic vagabond will continue its journey through interstellar space and pass 4.3 light-years, (25 trillion miles) from Sirius in about 296,000 years. 

Voyager 2's observations paved the way for later missions. The Cassini spacecraft, which was at Saturn between 2004 and 2017, tracked down evidence of liquid water at the planet's icy moons several decades after the Voyagers initially revealed the possible presence of water. Cassini also mapped the moon, Titan , after the Voyagers took pictures of its thick atmosphere.

Voyager 2's images of Uranus and Neptune also serve as a baseline for current observations of those giant planets. In 2014, astronomers were surprised to see giant storms on Uranus — a big change from when Voyager 2 flew by the planet in 1986. 

To see where Voyager 2 is now you can check out the mission status with resources from NASA . Learn more about the iconic spacecraft with the National Air and Space Museum .  

Bibliography

NASA. In depth: Voyager 2. NASA. Retrieved August 17, 2022, from www.solarsystem.nasa.gov/missions/voyager-2/in-depth/

NASA. Voyager - mission status. NASA. Retrieved August 17, 2022, from www.voyager.jpl.nasa.gov/mission/status/

NASA. Voyager - the interstellar mission. NASA. Retrieved August 17, 2022, from www. voyager.jpl.nasa.gov/mission/interstellar-mission

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Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for Space.com for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, " Why Am I Taller ?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: https://qoto.org/@howellspace

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After a 12.3-billion-mile 'shout,' NASA regains full contact with Voyager 2

Emily Olson

Ayana Archie

A NASA image of one of the twin Voyager space probes. The Jet Propulsion Laboratory lost contact with Voyager 2 on July 21 after mistakenly pointing its antenna 2 degrees away from Earth. On Friday, contact was fully restored. NASA/Getty Images hide caption

A NASA image of one of the twin Voyager space probes. The Jet Propulsion Laboratory lost contact with Voyager 2 on July 21 after mistakenly pointing its antenna 2 degrees away from Earth. On Friday, contact was fully restored.

Talk about a long-distance call.

NASA said it resumed full communications with the Voyager 2 on Friday after almost two weeks of silence from the interstellar spacecraft.

The agency's Jet Propulsion Laboratory said a series of ground antennas, part of the Deep Space Network, registered a carrier signal from Voyager 2 on Tuesday. However, the signal was too faint.

A Deep Space Network facility in Australia then sent "the equivalent of an interstellar 'shout' " to the Voyager 2 telling it to turn its antenna back toward Earth. The signal was sent more than 12.3 billion miles away and it took 37 hours to get a response from the spacecraft, NASA said.

Scientists received a response at about 12:30 a.m. ET Friday. Voyager 2 is now operating normally, returning science and telemetry data, and "remains on its expected trajectory," NASA said.

NASA said Friday that it lost contact with Voyager 2 on July 21 after "a series of planned commands" inadvertently caused the craft to turn its antenna 2 degrees away from the direction of its home planet.

NASA is keeping Voyager 2 going until at least 2026 by tapping into backup power

What might seem like a slight error had big consequences: NASA previously said it wouldn't be able to communicate with the craft until October, when the satellite would go through one of its routine repositioning steps.

"That is a long time to wait, so we'll try sending up commands several times" before October, program manager Suzanne Dodd told The Associated Press.

These are the 4 astronauts who'll take a trip around the moon next year

Even if Voyager 2 had failed to reestablish communications until fall, the engineers expected it to stay moving on its planned trajectory on the edge of the solar system.

Voyager 2 entered interstellar space in November 2018 — more than 40 years since it launched from Cape Canaveral, Fla. To this day, Voyager 2 remains one of only two human-made objects to ever operate outside the heliosphere, which NASA defines as "the protective bubble of particles and magnetic fields generated by the Sun."

Its primary mission was to study the outer solar system, and already, Voyager 2 has proved its status as a planetary pioneer . Equipped with several imaging instruments, the spacecraft is credited with documenting the discovery of 16 new moons, six new rings and Neptune's "Great Dark Spot."

Voyager 2 Bids Adieu To The Heliosphere, Entering Interstellar Space

Voyager 2 is also carrying some precious cargo, like a message in a bottle, should it find itself as the subject of another world's discovery: a golden record containing a variety of natural sounds, greetings in 55 languages and a 90-minute selection of music.

Last month's command mix-up foreshadows the craft's inevitable end an estimated three years from now.

"Eventually, there will not be enough electricity to power even one instrument," reads a NASA page documenting the spacecraft's travels . "Then, Voyager 2 will silently continue its eternal journey among the stars."

Meanwhile, Voyager 2's sister spacecraft, Voyager 1, is still broadcasting and transmitting data just fine from a slightly farther vantage point of 15 billion miles away.

Correction Aug. 3, 2023

A previous version of this article implied that Voyager 2 flew past Uranus in 2018 when, in fact, the spacecraft concluded its encounter with the planet and started heading toward Neptune in 1986. Voyager 2 entered interstellar space in November 2018.

• Jet Propulsion Laboratory

An illustration shows the position of NASA's Voyager 1 and Voyager 2 probes outside of the heliosphere, a protective bubble created by the sun that extends well past the orbit of Pluto.

Interstellar space even weirder than expected, NASA probe reveals

The spacecraft is just the second ever to venture beyond the boundary that separates us from the rest of the galaxy.

In the blackness of space billions of miles from home, NASA’s Voyager 2 marked a milestone of exploration, becoming just the second spacecraft ever to enter interstellar space in November 2018. Now, a day before the anniversary of that celestial exit, scientists have revealed what Voyager 2 saw as it crossed the threshold—and it’s giving humans new insight into some of the big mysteries of our solar system.

The findings, spread across five studies published today in Nature Astronomy , mark the first time that a spacecraft has directly sampled the electrically charged hazes, or plasmas, that fill both interstellar space and the solar system’s farthest outskirts. It’s another first for the spacecraft, which was launched in 1977 and performed the first—and only—flybys of the ice giant planets Uranus and Neptune. ( Find out more about the Voyager probes’ “grand tour”—and why it almost didn’t happen .)

See pictures from Voyager 2's solar system tour

Voyager 2’s charge into interstellar space follows that of sibling Voyager 1, which accomplished the same feat in 2012. The two spacecrafts’ data have many features in common, such as the overall density of the particles they’ve encountered in interstellar space. But intriguingly, the twin craft also saw some key differences on their way out—raising new questions about our sun’s movement through the galaxy.

“This has really been a wonderful journey,” Voyager project scientist Ed Stone , a physicist at Caltech, said in a press briefing last week.

“It’s just really exciting that humankind is interstellar,” adds physicist Jamie Rankin , a postdoctoral researcher at Princeton University who wasn’t involved with the studies. “We have been interstellar travelers since Voyager 1 crossed, but now, Voyager 2’s cross is even more exciting, because we can now compare two very different locations ... in the interstellar medium.”

Inside the bubble

To make sense of Voyager 2’s latest findings, it helps to know that the sun isn’t a quietly burning ball of light. Our star is a raging nuclear furnace hurtling through the galaxy at about 450,000 miles an hour as it orbits the galactic center.

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The sun is also rent through with twisted, braided magnetic fields and, as a result, its surface constantly throws off a breeze of electrically charged particles called the solar wind. This gust rushes out in all directions, carrying the sun’s magnetic field with it. Eventually, the solar wind smashes into the interstellar medium, the debris from ancient stellar explosions that lurks in the spaces between stars.

Like oil and water, the solar wind and the interstellar medium don’t perfectly mix, so the solar wind forms a bubble within the interstellar medium called the heliosphere. Based on Voyager data, this bubble extends about 11 billion miles from the sun at its leading edge, surrounding the sun, all eight planets, and much of the outer objects orbiting our star. Good thing, too: The protective heliosphere shields everything inside it, including our fragile DNA, from most of the galaxy’s highest-energy radiation.

The heliosphere’s outermost edge, called the heliopause, marks the start of interstellar space. Understanding this threshold has implications for our picture of the sun’s journey through the galaxy, which in turn can tell us more about the situations of other stars scattered across the cosmos.

“We are trying to understand the nature of that boundary, where these two winds collide and mix,” Stone said during the briefing. “How do they mix, and how much spillage is there from inside to outside the bubble, and from outside the bubble to inside?”

Scientists got their first good look at the heliopause on August 25, 2012, when Voyager 1 first entered interstellar space. What they began to see left them scratching their heads. For instance, researchers now know that the interstellar magnetic field is about two to three times stronger than expected, which means, in turn, that interstellar particles exert up to ten times as much pressure on our heliosphere than previously thought.

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“It is our first platform to actually experience the interstellar medium, so it is quite literally a pathfinder for us,” says heliophysicist Patrick Koehn , a program scientist at NASA headquarters.

Leaky boundary

But for all that Voyager 1 upended expectations, its revelations were incomplete. Back in 1980, its instrument that measured the temperature of plasmas stopped working. Voyager 2’s plasma instrument is still working just fine, though, so when it crossed the heliopause on November 5, 2018, scientists could get a much better look at this border.

For the first time, researchers could see that as an object gets within 140 million miles of the heliopause, the plasma surrounding it slows, heats up, and gets more dense. And on the other side of the boundary, the interstellar medium is at least 54,000 degrees Fahrenheit, which is hotter than expected. However, this plasma is so thin and diffuse, the average temperature around the Voyager probes remains extremely cold.

In addition, Voyager 2 confirmed that the heliopause is one leaky border—and the leaks go both ways. Before Voyager 1 passed through the heliopause, it zoomed through tendrils of interstellar particles that had punched into the heliopause like tree roots through rock. Voyager 2, however, saw a trickle of low-energy particles that extended more than a hundred million miles beyond the heliopause.

Another mystery appeared as Voyager 1 came within 800 million miles of the heliopause, where it entered a limbo-like area in which the outbound solar wind slowed to a crawl. Before it crossed the heliopause, Voyager 2 saw the solar wind form an altogether different kind of layer that, oddly, was nearly the same width as the stagnant one seen by Voyager 1.

“That is very, very weird,” Koehn says. “It really shows us that we need more data.”

Interstellar sequel?

Solving these puzzles will require a better view of the heliosphere as a whole. Voyager 1 exited near the heliosphere’s leading edge, where it collides with the interstellar medium, and Voyager 2 exited along its left flank. We have no data on the heliosphere’s wake, so its overall shape remains a mystery. The interstellar medium’s pressure might keep the heliosphere roughly spherical, but it’s also possible that it has a tail like a comet—or that it is shaped like a croissant .

But while other spacecraft are currently outward bound, they won’t be able to return data from the heliopause. NASA’s New Horizons spacecraft is zooming out of the solar system at more than 31,000 miles an hour , and when it runs out of power in the 2030s, it’ll fall silent more than a billion miles short of the heliosphere’s outer edge. That’s why Voyager scientists and others are calling for a follow-up interstellar probe . The goal: a 50-year, multi-generation mission that explores the outer solar system on its way into unexplored regions beyond the solar wind.

“Here's an entire bubble, [and] we only crossed it with two points,” study coauthor Stamatios Krimigis , the emeritus head of the Johns Hopkins University Applied Physics Laboratory's space department, said at the briefing. “Two examples are not enough.”

A new generation of scientists is eager to run with the baton—including Rankin, who did her Ph.D. at Caltech with Voyager 1’s interstellar data with Stone as her adviser.

“It was amazing to work on this cutting-edge data from spacecraft that were launched before I was born and still doing amazing science,” she says. “I’m just really thankful for all the people who have spent so much time on Voyager.”

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NASA’s Voyager Will Do More Science With New Power Strategy

Editor’s note: Language was added in the second paragraph on May 1 to underscore that the mission will continue even after a science instrument is retired.

The plan will keep Voyager 2’s science instruments turned on a few years longer than previously anticipated, enabling yet more revelations from interstellar space.

The Voyager proof test model, shown in a space simulator chamber at JPL in 1976, was a replica of the twin Voyager space probes that launched in 1977. The model’s scan platform stretches to the right, holding several of the spacecraft’s science instruments in their deployed positions.

Launched in 1977, the Voyager 2 spacecraft is more than 12 billion miles (20 billion kilometers) from Earth, using five science instruments to study interstellar space. To help keep those instruments operating despite a diminishing power supply, the aging spacecraft has begun using a small reservoir of backup power set aside as part of an onboard safety mechanism. The move will enable the mission to postpone shutting down a science instrument until 2026, rather than this year.

Switching off a science instrument will not end the mission. After shutting off the one instrument in 2026, the probe will continue to operate four science instruments until the declining power supply requires another to be turned off. If Voyager 2 remains healthy, the engineering team anticipates the mission could potentially continue for years to come.

Voyager 2 and its twin Voyager 1 are the only spacecraft ever to operate outside the heliosphere, the protective bubble of particles and magnetic fields generated by the Sun. The probes are helping scientists answer questions about the shape of the heliosphere and its role in protecting Earth from the energetic particles and other radiation found in the interstellar environment.

“The science data that the Voyagers are returning gets more valuable the farther away from the Sun they go, so we are definitely interested in keeping as many science instruments operating as long as possible,” said Linda Spilker, Voyager’s project scientist at NASA’s Jet Propulsion Laboratory in Southern California, which manages the mission for NASA.

Power to the Probes

Both Voyager probes power themselves with radioisotope thermoelectric generators (RTGs), which convert heat from decaying plutonium into electricity. The continual decay process means the generator produces slightly less power each year. So far, the declining power supply hasn’t impacted the mission’s science output, but to compensate for the loss, engineers have turned off heaters and other systems that are not essential to keeping the spacecraft flying.

Each of NASA’s Voyager probes are equipped with three radioisotope thermoelectric generators (RTGs), including the one shown here. The RTGs provide power for the spacecraft by converting the heat generated by the decay of plutonium-238 into electricity.

With those options now exhausted on Voyager 2, one of the spacecraft’s five science instruments was next on their list. (Voyager 1 is operating one less science instrument than its twin because an instrument failed early in the mission. As a result, the decision about whether to turn off an instrument on Voyager 1 won’t come until sometime next year.)

In search of a way to avoid shutting down a Voyager 2 science instrument, the team took a closer look at a safety mechanism designed to protect the instruments in case the spacecraft’s voltage – the flow of electricity – changes significantly. Because a fluctuation in voltage could damage the instruments, Voyager is equipped with a voltage regulator that triggers a backup circuit in such an event. The circuit can access a small amount of power from the RTG that’s set aside for this purpose. Instead of reserving that power, the mission will now be using it to keep the science instruments operating.

Although the spacecraft’s voltage will not be tightly regulated as a result, even after more than 45 years in flight, the electrical systems on both probes remain relatively stable, minimizing the need for a safety net. The engineering team is also able to monitor the voltage and respond if it fluctuates too much. If the new approach works well for Voyager 2, the team may implement it on Voyager 1 as well.

Get the Latest JPL News

“Variable voltages pose a risk to the instruments, but we’ve determined that it’s a small risk, and the alternative offers a big reward of being able to keep the science instruments turned on longer,” said Suzanne Dodd, Voyager’s project manager at JPL. “We’ve been monitoring the spacecraft for a few weeks, and it seems like this new approach is working.”

The Voyager mission was originally scheduled to last only four years, sending both probes past Saturn and Jupiter. NASA extended the mission so that Voyager 2 could visit Neptune and Uranus; it is still the only spacecraft ever to have encountered the ice giants. In 1990, NASA extended the mission again, this time with the goal of sending the probes outside the heliosphere. Voyager 1 reached the boundary in 2012, while Voyager 2 (traveling slower and in a different direction than its twin) reached it in 2018.

More About the Mission

A division of Caltech in Pasadena, JPL built and operates the Voyager spacecraft. The Voyager missions are a part of the NASA Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate in Washington.

For more information about the Voyager spacecraft, visit:

https://www.nasa.gov/voyager

News Media Contact

Calla Cofield

Jet Propulsion Laboratory, Pasadena, Calif.

626-808-2469

[email protected]

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Voyager 2 found! Deep Space Network hears it chattering in space

Not all heroes wear capes – some are 50-year-old antennas.

A signal from Voyager 2 has been detected by NASA's Deep Space Network (DSN) over a week after communications with the distant probe were lost, the US agency's Jet Propulsion Laboratory (JPL) on Tuesday.

The disco-era spacecraft was detected by Canberra Deep Space Communication Complex's 70-metre dish, Deep Space Station 43 (DSS43), after a long-shot search.

The five-storey tall dish is the sole facility capable of reaching Voyager 2. It takes over 18 hours for a signal to travel from the probe to the dish, covering a distance of over 19 billion kilometres.

"The Deep Space Network has picked up a carrier signal from [Voyager 2] during its regular scan of the sky. A bit like hearing the spacecraft's 'heartbeat,' it confirms the spacecraft is still broadcasting, which engineers expected," explained JPL.

Communications to VGER2 were severed when a series of planned commands to the probe inadvertently pointed its antenna's aim two degrees away from Earth on July 21. NASA set expectations that the situation would likely resolve on October 15, when the probe is scheduled to perform a regular and preplanned position recalibration.

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NASA had no reason to suggest Voyager 2 would not operate normally unto that date, as there's nothing to stop it hurtling through space at 15 kilometers per second.

So far that expectation holds true.

Engineers will now try to send a corrective command to the probe to get it to turn its antenna to the correct position. If that doesn't work, there's always that reset on October 15.

DSS43 and the 46-year old Voyager have had interruptions in the past, such as in 2020 when the dish was down for 11 months of maintenance that left it unable to send communication for eight months. During that time, data from Voyager 2 could still be received.

Earlier this year a rainstorm saw the DSS43 subreflector flooded , producing a short outage. ®

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We Finally Know What Happened When Voyager 2 Reached Interstellar Space

A few big takeaways from the craft's incredible journey.

• The spacecraft reached the interstellar boundary between our solar system and interstellar space in 2018. Voyager 1 reached the boundary in 2012.
• Both spacecraft were launched in 1977, and have far surpassed scientists' expectations.

Scientists have finally analyzed data from Voyager 2’s journey to interstellar space and discovered a number of surprising differences—plus a few strange similarities.

Voyager 1 and 2 launched in August and October of 1977, respectively, and set out to explore the far reaches of the solar system and beyond. The spacecraft have revealed a vast amount of insight into distant planets and snapped pictures of previously undiscovered moons. Still, more than 40 years after their launch, they continue to provide scientists with an unparalleled look at the universe.

In 2012, Voyager 1 became the first spacecraft to reach interstellar space. Last year, Voyager 2 joined its companion in the interstellar medium, reaching the boundary set 119 times the Earth–sun distance away from Earth. The transition from our solar system to interstellar space, the researchers say, may take less than a day to cross. The data from Voyager 2’s crossing was published November 4 in a series of five papers in Nature Astronomy .

The heliopause is the theoretical boundary at which the sun’s solar wind meets interstellar winds, which are shot out from supernovae that have exploded millions of years ago. Additionally, galactic cosmic rays try to flow into our solar system, but only 30 percent of these rays actually reach Earth. Voyager 1 and 2 were also able to study changes in the magnetic fields within and outside of our solar system.

The two spacecraft reached interstellar space during different periods of solar activity, meaning conditions along the boundary were markedly different. Voyager 1 reached the interstellar boundary during the sun’s solar minimum, whereas Voyager 2 reached the boundary during the solar maximum, a period of heightened activity. Additionally, unlike its quicker counterpart, Voyager 2’s mission has largely taken place in Earth’s southern hemisphere.

The researchers also discovered that solar material was “leaking” out into the interstellar medium. “That was very different than what happened with Voyager 1, where hardly any material was leaking out,” said Tom Krimigis of John’s Hopkins’s Applied Physics Laboratory in an October 31 press conference.

In the case of Voyager 1, the team saw the opposite, where interstellar particles leaked into our solar system. The team hopes to reconvene to take a closer look at their data in the near future to understand how and why these particles slip out of the grasp of our solar system.

Another perplexing discovery? The direction of the magnetic fields both inside and outside of the heliopause is aligned, as was the case with Voyager 1. Leonard Burlaga of NASA Goddard Space Flight Center said scientists can dismiss the alignment of the magnetic fields once, but twice would be a remarkable coincidence. The strength of the magnetic field was stronger in interstellar space, the Voyager 2 found.

The scientists also discovered that the heliopause itself is much thinner and smoother than expected, and that the interstellar medium tucked close to the boundary layer, where solar and interstellar winds meet, is much hotter and unpredictable than expected. This newest research also revealed that the boundary layer itself may be more complex than initially thought, with multiple layers of different temperature, density, and speed.

Voyager 1 and 2 have roughly five years before they'll lose the use of their scientific instruments, said Ed Stone of the California Institute of Technology during the press conference. "When the two voyagers were launched, the space age was only 20 years old, Stone said. "So it was hard to know at that time that anything could last over 40 years."

There's still a lot left to explore, and the data dump has sparked a desire to explore faster, farther, and deeper into interstellar space.

Jennifer Leman is a science journalist and senior features editor at Popular Mechanics, Runner's World, and Bicycling. A graduate of the Science Communication Program at UC Santa Cruz, her work has appeared in The Atlantic, Scientific American, Science News and Nature. Her favorite stories illuminate Earth's many wonders and hazards.

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NASA's Voyager 2 finds new mysteries at the edge of the solar system

Voyager 2, four decades into its mission, continues to make scientific discoveries as it crosses into interstellar space.

Voyager 2 is only the second spacecraft to reach interstellar space.

If you've ever felt like you're having an incredibly long day at work, spare a thought for NASA's Voyager probes. Launched in 1977, Voyager 1 and Voyager 2 have been traveling through space, revealing the secrets of the solar system, for the last 42 years . In all that time, they've beamed back tons of data about our place in the universe. Their journey has taken both probes beyond the reach of the farthest (dwarf) planet and into interstellar space:  Voyager 1 departed in 2012 , and in November last year, Voyager 2 followed .

"This has really been a wonderful journey," said Ed Stone, a chief scientist on the Voyager mission and author of a new paper, in a press briefing. "It began with the launch of two spacecraft in 1977 to explore Jupiter and Saturn, and everything after that has been step-wise as our journey has extended deeper and deeper into space."

In a suite of five new research papers, published in Nature Astronomy on Monday, Stone and colleagues report the first data from Voyager 2's solar system exit, revealing new characteristics at the border of interstellar space. The findings confirm that Voyager 2 officially entered interstellar space on Nov. 5, 2018, at a distance of 119 au (119 times the distance between the Earth and the Sun, or 11 billion miles). 

The handful of papers are a trove of space data, analyzing the measurements taken by the spacecraft as it made its way over the edge of the solar system. Its on-board instruments were able to assess changes in cosmic rays , plasma density , charged particles and magnetic fields . 

Because Voyager 2 passed through the boundary at a completely different position from that of Voyager 1, researchers were able to get a better understanding of the similarities and differences in the heliosphere, the protective bubble of supersonic solar wind that encapsulates the solar system. The bubble keeps much of the gas, dust and cosmic rays in interstellar space  out  of the solar system. 

When Voyager 1 transitioned through the outer layer of the heliosphere, the so-called heliosheath, seven years ago, it was able to grab finite measurements of the cosmic phenomena taking place within.  

A diagram of the heliosphere, showing where the huge solar wind crashes into the interstellar medium of space. 

The outermost layer, where the interstellar plasma meets the plasma from the solar wind, is known as the heliopause. Given that there had been only one measurement of the heliopause prior to Voyager 2's crossing, astronomers were understandably excited to see how the new measurements stacked up. The two spacecraft passed through the boundary at different regions (Voyager 1 was north of the ecliptic plane, whereas Voyager 2 was south) and six years apart, but the data suggests the distance to cross the heliopause   is remarkably uniform. The density of the two mediums also appears to be incredibly similar.

However, there are some notable differences in the structure of the heliopause.

Notably, Voyager 1's plasma instrument was damaged before it made the crossing, so it couldn't  directly  identify when plasma from the solar wind made way for the cooler material in interstellar space. But the same instrument on board Voyager 2 is still functioning (I told you, working for 42  years ), and allowed researchers a chance to measure plasma in interstellar space for the very first time.

Moreover, during Voyager 1's passage, the boundary appeared to be relatively messy, having been penetrated by the magnetic field of interstellar space and cosmic rays. But Voyager 2 found a more distinctly layered heliopause where there appeared to be less infiltration. Once Voyager 2 had crossed over the boundary, it found signs that some charged particles were leaking into the interstellar medium .

"The crossing by Voyager 2 was very 'leaky'," said Stamatios Krimigis, principal investigator of Voyager's Low Energy Charged Particle Experiment. "In other words, material from the solar bubble was leaking upstream into the galaxy at distances up to 1 billion miles. That was very different to what happened with Voyager 1."    

What could have caused these changes? That remains unclear. There's a suggestion that solar activity could influence some of the differences or even the inherent geometry of the solar system itself. 

Unfortunately, there are no other spacecraft on the way back to the heliopause to answer the outstanding questions. The closest spacecraft, NASA's New Horizons, did explore the furthest "world" from Earth at the beginning of 2019 but it's not expected to have enough fuel to get right to the edge of the solar system.

And sadly, though the two Voyager probes have been working their backsides off for 42 years, the plutonium-238 that provides them with energy is gradually cooling off. Astronomers expect that in around five years' time the probes will be sent into retirement for good. Until that point, they should be able to make more measurements in interstellar space.

And after that? They've earned themselves a long rest.

"The two Voyagers will outlast Earth," said Bill Kurth, co-author on the plasma density study. "They're in their own orbits around the galaxy for 5 billion years or longer. And the probability of them running into anything is almost zero." 

Saturn's icy moons: From Voyager to Cassini (pictures)

August 1, 2023

NASA Detects ‘Heartbeat’ from Voyager 2 Spacecraft after Losing Contact

A glitch may have silenced NASA’s Voyager 2 spacecraft until mid-October—but a “heartbeat” signal offers hope for reestablishing contact earlier

By Meghan Bartels

 Voyagers 1 and 2 and Jupiter.

Corbis via Getty Images

Editor’s Note (8/4/23): On August 4 NASA announced that it had successfully  reestablished communications with Voyager 2 .

Earth may not hear from one of its most beloved spacecraft until mid-October because of a glitch that altered Voyager 2’s orientation to our planet. But NASA engineers have caught a “heartbeat” signal that the agency says might help it reestablish communications sooner.

“A series of planned commands sent to NASA’s Voyager 2 spacecraft July 21 inadvertently caused the antenna to point 2 degrees away from Earth,” wrote NASA officials in a July 28 statement . “As a result, Voyager 2 is currently unable to receive commands or transmit data back to Earth.”

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Since the initial glitch, NASA has detected what mission personnel call a carrier signal from the spacecraft, which confirms that it’s still operating properly.

“A bit like hearing the spacecraft’s ‘heartbeat,’ it confirms the spacecraft is still broadcasting, which engineers expected,” wrote officials at NASA’s Jet Propulsion Laboratory, which operates the spacecraft, in a tweet on August 1 . “Engineers will now try to send Voyager 2 a command to point itself back at Earth.”

If that doesn’t work, NASA expects Voyager 2 will resume communications in October thanks to regularly scheduled commands that direct the spacecraft to reset its orientation. The next of these reorientation maneuvers will occur on October 15.

Voyager 2 launched in August of 1977, about two weeks before its twin Voyager 1, which swung past Jupiter and Saturn, followed by Titan, Saturn’s largest moon. Voyager 2 took a different path, zipping by Jupiter and Saturn and then Uranus and Neptune. To date, it remains the only spacecraft to ever visit the latter two planets.

The Voyager missions have also played a unique role in American culture. Each spacecraft carries a golden record : a phonograph that includes greetings from languages around the world and a host of musical excerpts. Each record is encased in a sleeve that maps Earth’s location with respect to 14 pulsars, which are rotating neutron stars that pulse radiation at very precise intervals. And the Voyager 1 mission captured the iconic photograph known as the “Pale Blue Dot,” which depicts Earth as a tiny speck against the vastness of space.

Both probes have continued trekking across that vastness. Voyager 2 is now nearly 12.4 billion miles from Earth, some 133 times our planet’s distance from the sun. Until the glitch, it took nearly 18.5 hours for a signal from Earth to reach the spacecraft and another 18.5 hours for humans to catch a response.

Five instruments remain operational on Voyager 2. In 2018 it moved into interstellar space, where the influence of the sun wanes. Now the spacecraft is working to help scientists understand what happens, for instance, where cosmic rays overpower the solar wind , the stream of charged particles that constantly flows off the sun.

Voyager 2’s power is waning, however, as it treks ever farther from the sun and its nuclear power source ages. NASA has already shut down certain components to save power, but soon officials expect to turn off additional instruments in hopes of extending the spacecraft’s operations through 2030—a particularly impressive feat, given that the mission was only designed to last four years.

• 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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Nasa detects signal from Voyager 2 after losing contact due to wrong command

‘Heartbeat’ signal from probe, now 12bn miles away, picked up after flight control mistakenly pointed its antenna away from Earth

Efforts to re-establish contact with Nasa’s Voyager 2 probe have received a boost after the space agency detected a “heartbeat” signal from the far-flung probe.

Mission controllers stopped hearing from Voyager 2 more than a week ago after sending a faulty command that tilted its antenna to point two degrees away from Earth. The small change in orientation was enough to cut all contact with the probe.

The signal from Voyager 2, which is now more than 12bn miles from Earth, was detected during a routine scan of the sky, Nasa said, and confirms that the spacecraft is still broadcasting and in “good health”.

Voyager 2 is one of a pair of spacecraft that launched in 1977 to capture images of Jupiter and Saturn, but continued on a journey into interstellar space to become the farthest human-made objects from Earth.

“We enlisted the help of the [Deep Space Network] and Radio Science groups to help to see if we could hear a signal from Voyager 2,” said Suzanne Dodd, Voyager’s project manager on Tuesday. “This was successful in that we see the ‘heartbeat’ signal from the spacecraft. So, we know the spacecraft is alive and operating. This buoyed our spirits.”

The twin probes were launched within a couple of weeks of one another to explore the planets and moons of the outer solar system. Voyager 1 is still in contact with Earth and nearly 15bn miles away. In 2012, it became the first probe to enter interstellar space and is now the most distant spacecraft ever built.

Voyager 2 hurtled into interstellar space in 2018 after discovering a new moon around Jupiter, 10 moons around Uranus and five around Neptune. It remains the only spacecraft to study all four of the solar system’s giant planets at close range.

While the heartbeat signal has reassured Nasa that the probe is still working, it is not yet responding to new commands. The next hope of making contact with the spacecraft will come this week when the Canberra dish, part of Nasa’s deep space network, beams the correct command in the direction of Voyager 2 in the hope of reaching the probe’s antenna, according to the space agency’s Jet Propulsion Laboratory in Pasadena, California.

The spacecraft is so far away that even at the speed of light, software commands sent from Earth take 18 hours to reach the probe.

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Nasa concedes that the attempt to make contact through the huge dish antenna in Canberra is a long shot. If that effort comes to nothing, as engineers expect, mission controllers will have to wait until October, when the spacecraft should reset automatically and restore communications.

The Voyager probes have faced numerous glitches in more than 40 years in space. Voyager 1 was still on the way to Jupiter when it wrongly switched to a backup radio receiver, only to have the primary receiver burn out when engineers switched it back. After its fly-by of Saturn, Voyager 2’s camera platform got stuck because of a lack of lubricant. Much later, in 2010, the probe suffered a glitch that temporarily affected its science data.

Keeping the probes flying became an art as much as a science after many engineers moved on to other Nasa missions, leaving a dwindling number of ageing staff familiar with the probe and its software. Though state-of-the art in the 1970s, the Voyager spacecraft have only four kilobytes of storage onboard and computing power thousands of times slower than a modern smartphone.

The spacecraft entered interstellar space after leaving what astronomers call the heliosphere – a protective bubble of particles and magnetic fields that are created by the sun. But neither Voyager probe has yet left the solar system. The edge of the solar system is beyond the Oort cloud where smaller cosmic bodies are still under the influence of the sun’s gravitational pull. Nasa estimates that it could take 300 years for Voyager 2 to reach the Oort cloud and perhaps 30,000 years to cross it.

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Hope returns —

Nasa knows what knocked voyager 1 offline, but it will take a while to fix, "engineers are optimistic they can find a way for the fds to operate normally.".

Stephen Clark - Apr 6, 2024 12:28 am UTC

Engineers have determined why NASA's Voyager 1 probe has been transmitting gibberish for nearly five months, raising hopes of recovering humanity's most distant spacecraft.

Voyager 1, traveling outbound some 15 billion miles (24 billion km) from Earth, started beaming unreadable data down to ground controllers on November 14. For nearly four months, NASA knew Voyager 1 was still alive—it continued to broadcast a steady signal—but could not decipher anything it was saying.

Confirming their hypothesis, engineers at NASA's Jet Propulsion Laboratory (JPL) in California confirmed a small portion of corrupted memory caused the problem. The faulty memory bank is located in Voyager 1's Flight Data System (FDS), one of three computers on the spacecraft. The FDS operates alongside a command-and-control central computer and another device overseeing attitude control and pointing.

The FDS duties include packaging Voyager 1's science and engineering data for relay to Earth through the craft's Telemetry Modulation Unit and radio transmitter. According to NASA, about 3 percent of the FDS memory has been corrupted, preventing the computer from carrying out normal operations.

Optimism growing

Suzanne Dodd, NASA's project manager for the twin Voyager probes, told Ars in February that this was one of the most serious problems the mission has ever faced. That is saying something because Voyager 1 and 2 are NASA's longest-lived spacecraft. They launched 16 days apart in 1977, and after flying by Jupiter and Saturn, Voyager 1 is flying farther from Earth than any spacecraft in history. Voyager 2 is trailing Voyager 1 by about 2.5 billion miles, although the probes are heading out of the Solar System in different directions.

Normally, engineers would try to diagnose a spacecraft malfunction by analyzing data it sent back to Earth. They couldn't do that in this case because Voyager 1 has been transmitting data packages manifesting a repeating pattern of ones and zeros. Still, Voyager 1's ground team identified the FDS as the likely source of the problem.

The Flight Data Subsystem was an innovation in computing when it was developed five decades ago. It was the first computer on a spacecraft to use volatile memory. Most of NASA's missions operate with redundancy, so each Voyager spacecraft launched with two FDS computers. But the backup FDS on Voyager 1 failed in 1982.

Due to the Voyagers' age, engineers had to reference paper documents, memos, and blueprints to help understand the spacecraft's design details. After months of brainstorming and planning, teams at JPL uplinked a command in early March to prompt the spacecraft to send back a readout of the FDS memory.

The command worked, and Voyager.1 responded with a signal different from the code the spacecraft had been transmitting since November. After several weeks of meticulous examination of the new code, engineers pinpointed the locations of the bad memory.

"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 an update posted Thursday. "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."

Voyager 1's distance from Earth complicates the troubleshooting effort. The one-way travel time for a radio signal to reach Voyager 1 from Earth is about 22.5 hours, meaning it takes roughly 45 hours for engineers on the ground to learn how the spacecraft responded to their commands.

NASA also must use its largest communications antennas to contact Voyager 1. These 230-foot-diameter (70-meter) antennas are in high demand by many other NASA spacecraft , so the Voyager team has to compete with other missions to secure time for troubleshooting. This means it will take time to get Voyager 1 back to normal operations.

"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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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
• View All 9 Comments

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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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40 years ago: voyager 2 explores saturn, johnson space center.

Forty years ago, the Voyager 2 spacecraft made its closest approach to Saturn. Managed by NASA’s Jet Propulsion Laboratory in Pasadena, California, the Voyagers are a pair of spacecraft launched in 1977 to explore the outer planets. Initially targeted only to visit Jupiter and Saturn, Voyager 2 went on to investigate Uranus and Neptune as well, taking advantage of a rare planetary alignment that occurs once every 175 years to use the gravity of one planet to redirect it to the next. Although not the first to explore the ringed planet – Pioneer 11 completed the first flyby in 1979 – the Voyagers carried more sophisticated instruments to conduct in-depth investigations. Voyager 2’s twin, Voyager 1 , made its closest approach to Saturn in November 1980. Forty-four years after their departure from Earth, both spacecraft continue to operate and report on the conditions of interstellar space.

Each Voyager carried a suite of 11 instruments, including: 

• an imaging science system consisting of narrow-angle and wide-angle cameras to photograph the planet and its satellites;
• a radio science system to determine the planet’s physical properties;
• an infrared interferometer spectrometer to investigate local and global energy balance and atmospheric composition;
• an ultraviolet spectrometer to measure atmospheric properties;
• a magnetometer to analyze the planet’s magnetic field and interaction with the solar wind;
• a plasma spectrometer to investigate microscopic properties of plasma ions;
• a low energy charged particle device to measure fluxes and distributions of ions;
• a cosmic ray detection system to determine the origin and behavior of cosmic radiation;
• a planetary radio astronomy investigation to study radio emissions from Jupiter;
• a photopolarimeter to measure the planet’s surface composition; and
• a plasma wave system to study the planet’s magnetosphere.

Voyager 2 launched first on Aug. 20, 1977. The spacecraft successfully crossed the asteroid belt between Dec. 10, 1977, and Oct. 21, 1978. In April 1978, its primary radio receiver failed, and it has been operating on its backup receiver ever since. The spacecraft flew within 350,000 miles of Jupiter’s cloud tops on July 9, 1979, and during the four-month encounter returned 17,000 photographs and useful scientific information about the giant planet and many of its moons.  Using the giant planet for a gravity assist, Voyager 2 began its 29-month journey to its next destination, Saturn. Following Voyager 1’s successful encounter with Saturn , and especially its important study of Titan, in November 1980, mission planners targeted Voyager 2 so it could image some of the moons not studied by its twin and use Saturn’s gravity to speed it onward to encounter Uranus in 1986 and Neptune in 1989.

Voyager 2 began its long-range observations of Saturn on June 5, 1981, when the spacecraft was still 41 million miles from the planet, and sent back progressively sharper images of the planet, its atmosphere, and its rings as Voyager 2 closed in on its target. It returned spectacular photographs of the rings and small shepherd moons such as Prometheus and Pandora that act to herd the rings’ particles. Three days before its closest approach to Saturn, Voyager 2 imaged the two-toned moon Iapetus from 565,000 miles away, and two days later it photographed the moon Hyperion from 310,000 miles. Eighteen hours before closest approach, it passed within 413,000 miles of Saturn’s largest satellite Titan and returned images of its orange cloud cover. After passing within 26,000 miles of Saturn’s cloud tops, Voyager 2 photographed the icy moon Enceladus from 54,000 miles, the small moon Janus from 140,000 miles, and Tethys from 58,000 miles. Three days after its closest approach, Voyager 2 turned its camera on a partially backlit Saturn, returning stunning photographs from 2.1 million miles away. On Sept. 4, it imaged the tiny moon Phoebe from 1.3 million miles, revealing little of its surface features. By the time observations of the Saturn system concluded on Sept. 28, the spacecraft had returned 16,000 images of the planet, its rings, and its satellites.

On Sept. 29, the day after completing its observations of Saturn, Voyager 2 fired its thrusters for a course correction to send it onward to its next target, Uranus. In January 1986 , Voyager 2 carried out the first reconnaissance of that planet, its satellites, and its rings. In turn, Voyager 2 picked up a gravity assist at Uranus to send it to its final planetary encounter, exploring Neptune in August 1989 .  Voyager 2 then began its Interstellar Mission extension that continues to this day. Over the years, several of the spacecraft’s instruments have been turned off to conserve power, beginning with the imaging system in 1998, but it continues to return data about cosmic rays and the solar wind. On Nov. 5, 2018, six years after its twin, Voyager 2 crossed the heliopause, the boundary between the heliosphere, the bubble-like region of space created by the Sun, and the interstellar medium. It is expected that Voyager 2 will continue to return data from interstellar space until about 2025. And just in case it may one day be found by an alien intelligence, Voyager 2, like its twin, carries a gold plated record that contains information about its home planet, including recordings of terrestrial sounds, music, and greetings in 55 languages. Scientists thoughtfully included instructions on how to play the record.

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]

NASA Figured Out Why Its Voyager 1 Probe Has Been Glitching for Months

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.

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

Corrupted memory hardware is causing the mission to transmit gibberish, but there may be a way to fix it.

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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