(CN) – Early results from NASA’s Juno mission to Jupiter reveal Earth-sized polar cyclones, a “fuzzy” core and a massive, irregularly shaped magnetic field – all of which challenge previously held theories on the solar system’s largest planet.

The findings are detailed in more than 40 papers discussing the surprising data from NASA’s mission to Jupiter, which reveal greater complexity and variability than scientists had expected.

“It was a long trip to get to Jupiter, but these first results already demonstrate it was well worth the journey,” said Diane Brown, Juno program executive at NASA.

Launched Aug. 5, 2011, from Florida’s Cape Canaveral, Juno made a gravity-assist flyby of Earth in October 2013 to generate enough speed to complete its roundabout 1.7-billion-mile voyage to Jupiter. The spacecraft successfully braked into a highly elliptical orbit around the gas giant in April 2016.

The information retrieved during Juno’s first data-collection pass on Aug. 27 – when the spacecraft flew within 2,600 miles of Jupiter’s swirling cloud tops – will likely fuel considerable speculation and analysis of the planet as scientists await data from subsequent passes.

“We knew going in that Jupiter would throw us some curves,” said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. “But now that we are here we are finding that Jupiter can throw the heat, as well as knuckleballs and sliders. There is so much going on here that we didn’t expect that we have had to take a step back and begin to rethink of this as a whole new Jupiter.”

Among the surprising discoveries provided by Juno are Earth-sized swirling storms that cover both of Jupiter’s poles.

“We’re puzzled as to how they could be formed, how stable the configuration is, and why Jupiter’s north pole doesn’t look like the south pole,” Bolton said. “We’re questioning whether this is a dynamic system, and are we seeing just one stage and over the next year we’re going to watch it disappear, or is this a stable configuration and these storms are circulating around one another?”

Data from the Aug. 27, 2016, pass also show that Jupiter’s iconic belts and zones are unique and mysterious, with the belt near the equator spanning through the planet’s atmosphere, while the belts and zones at other latitudes seem to lead to other structures. The information suggests the ammonia in the gas giant’s atmosphere varies and continues to increase as far down as could be seen by Juno’s microwave radiometer, which is a few hundred miles.

While scientists knew Jupiter features the most intense magnetic field in the solar system, measurements of the planet’s magnetosphere indicate that it is even stronger than models predicted – and more irregular in shape. The data show that the magnetic field is about 10 times stronger than the strongest magnetic field found on Earth.

“Juno is giving us a view of the magnetic field close to Jupiter that we’ve never had before,” said Jack Connerney, Juno deputy principal investigator. “Already we see that the magnetic field looks lumpy; it is stronger in some places and weaker in others. This uneven distribution suggests that the field might be generated by dynamo action closer to the surface, above the layer of metallic hydrogen. Every flyby we execute gets us closer to determining where and how Jupiter’s dynamo works.”

Another question Juno is supposed to help answer is whether it has a core. Scientists have presented competing theories, which range from Jupiter having a small, compact core roughly the size of Earth, to the gas giant having formed without a core entirely. The data suggest the presence of a non-discrete, “fuzzy” core. Researchers say more information is needed to develop a precise understanding of the planet’s center.

As the scientific community digests the first results from Juno, further missions will likely add to the revelations described Thursday.

“Every 53 days, we go screaming by Jupiter, get doused by a fire hose of Jovian science, and there is always something new,” Bolton said. “On our next flyby on July 11, we will fly directly over one of the most iconic features in the entire solar system – one that every school kid knows – Jupiter’s Great Red Spot.

“If anybody is going to get to the bottom of what is going on below those mammoth swirling crimson cloud tops, it’s Juno and her cloud-piercing science instruments.” </s> Data collected by NASA’s Juno spacecraft using its Jovian InfraRed Auroral Mapper (JIRAM) instrument point to a new heat source close to the south pole of Io that could indicate a previously undiscovered volcano on the small moon of Jupiter. The infrared data were collected on Dec. 16, 2017, when Juno was about 290,000 miles (470,000 kilometers) away from the moon.

“The new Io hotspot JIRAM picked up is about 200 miles (300 kilometers) from the nearest previously mapped hotspot,” said Alessandro Mura, a Juno co-investigator from the National Institute for Astrophysics in Rome. “We are not ruling out movement or modification of a previously discovered hot spot, but it is difficult to imagine one could travel such a distance and still be considered the same feature.”

The Juno team will continue to evaluate data collected on the Dec. 16 flyby, as well as JIRAM data that will be collected during future (and even closer) flybys of Io. Past NASA missions of exploration that have visited the Jovian system (Voyagers 1 and 2, Galileo, Cassini and New Horizons), along with ground-based observations, have located over 150 active volcanoes on Io so far. Scientists estimate that about another 250 or so are waiting to be discovered.

Juno has logged nearly 146 million miles (235 million kilometers) since entering Jupiter’s orbit on July 4, 2016. Juno’s 13th science pass will be on July 16.

Juno launched on Aug. 5, 2011, from Cape Canaveral, Florida. During its mission of exploration, Juno soars low over the planet’s cloud tops — as close as about 2,100 miles (3,400 kilometers). During these flybys, Juno is probing beneath the obscuring cloud cover of Jupiter and studying its auroras to learn more about the planet’s origins, structure, atmosphere and magnetosphere.

JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the Science Mission Directorate. The Italian Space Agency (ASI), contributed two instruments, a Ka-band frequency translator (KaT) and the Jovian Infrared Auroral Mapper (JIRAM). Lockheed Martin Space, Denver, built the spacecraft. JPL is a division of Caltech in Pasadena, California. </s> Nasa announces Juno craft circling gas giant had to shut down camera and instruments, while ESA says Schiaparelli lander may have crashed on red planet

Bad day for space probes: one lost on Mars, another in 'safe mode' at Jupiter

Nasa’s Juno space probe orbiting Jupiter went into “safe mode” with cameras and instruments offline just as it prepared to pass over the immense planet’s dense cloud tops, the space agency said.

Juno had rebooted its onboard computer and could communicate with Earth but its activities were limited until engineers diagnosed what went wrong, Nasa said.



“The spacecraft is healthy and we are working our standard recovery procedure,” said Rick Nybakken, Juno project manager from Nasa’s Jet Propulsion Laboratory.

“It’s too early to take a guess” but the issue with Juno was not caused by the intense radiation belts surrounding Jupiter because the spacecraft was far away when it entered safe mode, said mission chief scientist Scott Bolton of the Southwest Research Institute in San Antonio.



On Mars, scientists with the European Space Agency lost contact with the Schiaparelli experimental lander that was supposed to touch down. The mother ship successfully slipped into orbit around Mars but the fate of the lander was unknown.



Schiaparelli lander's planned descent to Mars Schiaparelli lander’s planned descent to Mars

For Juno it is the second setback in less than a week. The solar-powered craft has been orbiting Jupiter since July on a $1.1bn mission to explore its poles, atmosphere and interior.

Last week mission managers decided to postpone an engine firing planned for Wednesday after a pair of valves in the spacecraft’s propulsion system did not work as expected. Nasa said this and the latest problem were not related.

The delay means Juno will not swing close again to Jupiter until December. The spacecraft made its first close pass in August, beaming back pictures of Jupiter’s stormy north pole, which appeared bluer than the rest of the planet.



Scientists continued to pore over close-up images from the first flyby, determining that Jupiter’s magnetic fields and northern and southern auroras were more powerful than expected.

The Juno mission was designed to fly closer to Jupiter than previous spacecraft, coming within 2,500 miles of the surface. Some three dozen close passes are planned during the 20-month mission.

With the Associated Press </s> (CNN) Beneath its heavy cloud cover, Jupiter has been able to keep its secrets from astronomers. Now, first results from NASA's Juno mission are challenging researchers' beliefs about the gas giant.

The results were revealed during a media teleconference Thursday with NASA researchers and published in corresponding studies through the journal Science and Geophysical Research Letters

Juno launched in August 2011 but didn't arrive at Jupiter until July . The craft has been orbiting the planet and performing calculated flybys over the clouds. These happen every 53 days as Juno "screams by" Jupiter, going from the north to south pole in about two hours.

"The general theme of our discoveries is really how different Jupiter looked from how we expected," said Scott Bolton, Juno principal investigator, from the Southwest Research Institute in San Antonio. "This is a close-up and personal look at Jupiter. We thought it was uniform inside and relatively boring. What we're finding is anything but that. It's very complex. Jupiter from the poles doesn't look anything like it does from our usual view."

During the flybys, observations and data showed Jupiter's previously unseen poles. Bright ovals at the poles were revealed to be gigantic cyclones spanning 870 miles. Juno was also able to probe the cloud cover and discover wells of ammonia that form giant and violent weather systems in the deep atmosphere.

The giant cyclones at the poles are also new to researchers. Further study could reveal whether these are like the Great Red Spot, which has been observable for at least 300 years, or more ephemeral.

"We're puzzled as to how they could be formed, how stable the configuration is and why Jupiter's north pole doesn't look like the south pole," Bolton said. "We're questioning whether this is a dynamic system, and are we seeing just one stage, and over the next year, we're going to watch it disappear, or is this a stable configuration and these storms are circulating around one another?"

"The idea of seeing those little cloud features full of ammonia and water ice, it's like it's snowing on Jupiter and we're seeing how it works," Bolton said. Or it could be hail, he said.

Juno revealed that Jupiter's magnetic field is 10 times stronger than the strongest magnetic field on Earth and and twice as strong as anticipated, exceeding researchers' expectations. The mission had an encounter with the planet's "bow shock," akin to a type of stationary shockwave, when exploring Jupiter's magnetosphere.

The researchers compared this bow shock to a Hadley cell on Earth, without the rain. A Hadley cell is the atmospheric circulation of air rising near the equator that creates hurricanes, jet streams, trade winds and rain belts.

"Juno is giving us a view of the magnetic field close to Jupiter that we've never had before," said Jack Connerney, Juno deputy principal investigator. "Already, we see that the magnetic field looks lumpy: It is stronger in some places and weaker in others. This uneven distribution suggests that the field might be generated by dynamo action closer to the surface, above the layer of metallic hydrogen. Every flyby we execute gets us closer to determining where and how Jupiter's dynamo works."

And Juno was able to measure Jupiter's gravitational field. Those data, combined with information to be gathered as Juno's mission continues, can help researchers determine the structure of Jupiter's atmosphere and answer the big question: Does the planet have a solid core?

Previous models have suggested this, but Juno's unique data could provide actual insight. If the planet has a solid core, it could change the belief that the gas giant is largely composed of hydrogen and helium.

Even though Jupiter is the largest planet in our solar system, astronomers don't know much about its origin. The Juno mission was designed to collect data and observations that will reveal the origin and evolution of the gas giant. Its other objectives include mapping Jupiter's gravitational and magnetic fields, observing auroras, measuring the amount of water and ammonia in its atmosphere and finding evidence of a solid core.

The planet's cloudy atmosphere has contributed greatly to obscuring general knowledge. Juno was designed to dip below those clouds to look at the planet underneath. This will also help astronomers determine finer points about Jupiter's composition and how much of it is water.

Jupiter was most likely the first planet to form in the solar system and contains some of the same ingredients of the collapsing nebula that formed the system. Knowing more about Jupiter can provide greater insight about its beginnings.

"If anybody is going to get to the bottom of what is going on below those mammoth swirling crimson cloud tops, it's Juno and her cloud-piercing science instruments," Bolton said. </s> Beneath its heavy cloud cover, Jupiter has been able to keep its secrets from astronomers. Now, first results from NASA’s Juno mission are challenging researchers’ beliefs about the gas giant.

The results were revealed during a media teleconference Thursday with NASA researchers and published in corresponding studies through the journal Science and Geophysical Research Letters.

Juno launched in August 2011 but didn’t arrive at Jupiter until July. The craft has been orbiting the planet and performing calculated flybys over the clouds.

During those flybys, observations and data showed Jupiter’s previously unseen poles. Bright ovals at the poles were revealed to be gigantic cyclones spanning 870 miles. Juno was also able to probe the cloud cover and discover wells of ammonia that form giant and violent weather systems in the deep atmosphere.

Juno revealed that Jupiter’s magnetic field is 10 times that of Earth’s and and twice as strong as anticipated, exceeding researchers’ expectations. The mission had an encounter with the planet’s “bow shock,” akin to a type of stationary shockwave, when exploring Jupiter’s magnetosphere.

The researchers compared this bow shock to a Hadley cell on Earth, without the rain. A Hadley cell is the atmospheric circulation of air rising near the equator that creates hurricanes, jet streams, trade winds and rain belts.

Juno also encountered Jupiter’s huge auroras, captured in ultraviolet and infrared images, and the electron beam pushing energy into the planet’s upper atmosphere, which could be creating the auroras.

And Juno was able to measure Jupiter’s gravitational field. That data, combined with information to be gathered as Juno’s mission continues, can help researchers determine the structure of Jupiter’s atmosphere and answer the big question: Does the planet have a solid core?

Previous models have suggested this, but Juno’s unique data could provide actual insight. If the planet has a solid core, it could change the belief that the gas giant is largely composed of hydrogen and helium.

Luckily, Juno is just getting started.

Even though Jupiter is the largest planet in our solar system, astronomers don’t know much about its origin. The Juno mission was designed to collect data and observations that will reveal the origin and evolution of the gas giant. Its other objectives include mapping Jupiter’s gravitational and magnetic fields, observing auroras, measuring the amount of water and ammonia in its atmosphere and finding evidence of a solid core.

The planet’s cloudy atmosphere has contributed greatly to obscuring general knowledge. Juno was designed to dip below those clouds to look at the planet underneath. This will also help astronomers determine finer points about Jupiter’s composition and how much of it is water.

Jupiter was most likely the first planet to form in the solar system and contains some of the same ingredients of the collapsing nebula that formed the system. Knowing more about Jupiter can provide greater insight about its beginnings.

Given the fact that gas giants are common around other stars, this could inform future observations of exoplanets and other planetary systems. </s> NASA is learning some of the secrets of the largest planet in the solar system, revealing data Thursday from the space agency’s Juno mission to Jupiter.

Jupiter, the fifth planet from the sun, is a gas giant with an atmosphere mainly composed of helium and hydrogen, and characterized by towering clouds of ammonia and turbulent storms, including one that has raged for hundreds of years and is larger than Earth, known as the Great Red Spot.

With the initial scientific information from Juno, researchers are realizing the planet is even more complex than scientists imagined.

The spacecraft’s camera, called the JunoCam, recorded images of Jupiter’s north and south poles that show colossus, swirling Earth-sized storms, knocking into each other as they rocket around the top and bottom of the planet. The storms covering the north pole are very different from those in the south, though.

>> Related: Space travel is measured in light years, but what’s a light year anyway?

“We’re puzzled as to how they could be formed, how stable the configuration is, and why Jupiter’s north pole doesn’t look like the south pole,” Juno’s principal investigator Scott Bolton said in a briefing about the new data.

Bolton said it’s also unclear whether these are permanent storms at the poles.

“We’re questioning whether this is a dynamic system, and are we seeing just one stage, and over the next year, we’re going to watch it disappear, or is this a stable configuration and these storms are circulating around one another,” Bolton said.

Juno has also revealed new information about the planet’s irregular and lumpy magnetic field and its gaseous atmosphere.

>> Related: Alien life possible on small Saturn moon, maybe on a Jupiter moon, too

Researchers are hoping to learn more about the Giant Red Spot, too, one of the “most iconic features in the entire solar system.

“If anybody is going to get to the bottom of what is going on below those mammoth swirling crimson cloud tops, it’s Juno and her cloud-piercing science instruments,” Bolton predicted.

The Juno spacecraft launched on Aug. 5, 2011, and entered Jupiter’s orbit last summer on July 4.

The results from Thursday’s briefing were collected in a Juno fly-by last August when the craft was within 2,600 miles of Jupiter’s cloud tops, NASA said. </s> Since it arrived in orbit around Jupiter in July of 2016, the Juno mission has been sending back vital information about the gas giant’s atmosphere, magnetic field and weather patterns. With every passing orbit – known as perijoves, which take place every 53 days – the probe has revealed things about Jupiter that scientists will rely on to learn more about its formation and evolution.

Interestingly, some of the most recent information to come from the mission involves how two of its moons affect one of Jupiter’s most interesting atmospheric phenomenon. As they revealed in a recent study, an international team of researchers discovered how Io and Ganymede leave “footprints” in the planet’s aurorae. These findings could help astronomers to better understand both the planet and its moons.

The study, titled “Juno observations of spot structures and a split tail in Io-induced aurorae on Jupiter“, recently appeared in the journal Science. The study was led by A. Mura of the International Institute of Astrophysics (INAF) and included members from NASA’s Goddard Space Flight Center, NASA’s Jet Propulsion Laboratory, the Italian Space Agency (ASI), the Southwest Research Institute (SwRI), the Johns Hopkins University Applied Physics Laboratory (JHUAPL), and multiple universities.

Much like aurorae here on Earth, Jupiter’s aurorae are produced in its upper atmosphere when high-energy electrons interact with the planet’s powerful magnetic field. However, as the Juno probe recently demonstrated using data gathered by Ultraviolet Spectrograph (UVS) and Jovian Energetic Particle Detector Instrument (JEDI), Jupiter’s magnetic field is significantly more powerful than anything we see on Earth.

In addition to reaching power levels 10 to 30 times greater than anything higher than what is experienced here on Earth (up to 400,000 electron volts), Jupiter’s norther and southern auroral storms also have oval-shaped disturbances that appear whenever Io and Ganymede pass close to the planet. As they explain in their study:

A Von Kármán vortex street, a concept in fluid dynamics, is basically a repeating pattern of swirling vortices caused by a disturbance. In this case, the team found evidence of a vortex streaming for hundreds of kilometers when Io passed close to the planet, but which then disappeared as the moon moved farther away from the planet.

The team also found two spots in the auroral belt created by Ganymede, where the extended tail from the main auroral spots eventually split in two. While the team was not sure what causes this split, they venture that it could be caused by interaction between Ganymede and Jupiter’s magnetic field (since Ganymede is the only Jovian moon to have its own magnetic field).

These features, they claim, suggest that magnetic interactions between Jupiter and Ganymede are more complex than previously thought. They also indicate that neither of the footprints were where they expected to find them, which suggests that models of the planet’s magnetic interactions with its moons may be in need of revision.

Studying Jupiter’s magnetic storms is one of the primary goals of the Juno mission, as is learning more about the planet’s interior structure and how it has evolved over time. In so doing, astronomers hope to learn more about how the Solar System came to be. NASA also recently extended the mission to 2021, giving it three more years to gather data on these mysteries.

And be sure to enjoy this video of the Juno mission, courtesy of the Jet Propulsion Laboratory:

By Matt Williams - 

 Matt Williams is the Curator of Universe Today's Guide to Space. He is also a freelance writer, a science fiction author and a Taekwon-Do instructor. He lives with his family on Vancouver Island in beautiful British Columbia. </s> NASA's Juno probe reached Jupiter in July 2016, and scientists' view of the solar system has not been the same since.

The $1 billion mission has taken stunning images of the gas giant several hundred million miles from Earth.

More importantly, though, the tennis-court-size spacecraft has probed some of the planet's deepest, darkest secrets with a suite of high-tech instruments.

Here are some of the most fascinating scientific discoveries made by Juno at Jupiter — and a taste of what's possibly to come, since the probe has several years of exploration left before NASA crashes it into the planet.

Juno flies in an elliptical orbit around Jupiter, getting close to the planet once every 53.5 days.

Juno's closest flyby of Jupiter lasts several hours and is called a perijove. During that time, the probe flies over Jupiter's north pole and exits with views of the south pole.

Juno passes within thousands of miles of the planet's surface during a perijove, enabling the probe to make detailed and unprecedented measurements of gravity, magnetism, and plasma fields using a suite of high-tech instruments. It also beams back stunning images.

Until Juno's arrival at Jupiter in July 2016, no top-down or bottom-up images had ever been taken of Jupiter's poles.

The probe flew over Jupiter's poles for the first time and sent back data that blew scientists away.

Observatories like NASA's Hubble Space Telescope had recorded auroras at Jupiter's poles, but nobody had ever seen the enigmatic regions in the detail Juno revealed.

"[I]t looks like nothing we have seen or imagined before," Scott Bolton, a planetary scientist at the Southwest Research Institute in San Antonio and the Juno mission's leader, said in a NASA press release in September 2016.

"It's bluer in color up there than other parts of the planet, and there are a lot of storms," he added. "There is no sign of the latitudinal bands or zone and belts that we are used to — this image is hardly recognizable as Jupiter."

The planet's weather goes much deeper than anyone thought.

Juno's first ultra-close pass helped researchers peel back Jupiter's atmospheric layers like an onion and see hundreds of miles deep into the planet's hydrogen, helium, and other gases.

"The structure of the zones and belts still exists deep down," Bolton said during a news conference in 2016. "So whatever's making those colors, whatever's making those stripes, is still existing pretty far down into Jupiter. That came as a surprise to many of the scientists."

Later studies revealed that the appearance of belts, bands, and storms may originate more than 1,900 miles below the planet's gassy surface.

In April, NASA released eye-catching images of symmetric clusters of storms.

The images were created from multiple photos taken in infrared light (a wavelength that's normally invisible to us). Next, scientists merged the pictures together made them 3D to emphasize brightness and temperature.

Scientists are still trying to understand what, exactly, creates these stormy super-cells that stretch thousands of miles wide.

Most lightning is concentrated at Jupiter's north pole.

During Juno's first eight perijoves, or flybys, the spacecraft detected 377 lightning discharges via their crackle of radio emissions. When researchers mapped the locations of the lightning, they found it concentrated at the planet's poles, not its equator.

Researchers think this happens because when the sun warms Jupiter's atmosphere, the heat stabilizes the planet's mid-areas against upwelling storms. But at the poles, where it's much cooler, big cells of warm inner gases can punch to the surface and create lightning.

Weirdly, most of the lightning was recorded at Jupiter's north pole — something researchers have yet to explain.

The planet's gravity is kind of lopsided.

Juno has a special instrument that allows it to precisely map Jupiter's gravitational field. The first major results from that data show that field is slightly lopsided, with a bit more "pull" from its northern hemisphere.

Researchers think this is tied to Jupiter's deep-running weather systems, which can push huge masses of its atmospheric gases to certain parts of the planet.

Its magnetic field is also lopsided — and stronger than scientists thought.

Jupiter's magnetic field is the strongest in the solar system and drives all sorts of important behaviors, including polar auroras, plasma fields around the planet, and radiation that can threaten space missions. So it's important to understand in detail. Luckily, magnetic instruments on Juno can continuously map the planet's magnetic field.

Those readings have surprised researchers in multiple ways. They showed Jupiter's magnetic field strength is about two times more powerful than researchers previously thought.

The data also revealed that the entire magnetic field, like the planet's gravity field, is slightly lopsided. The reasons for that that have yet to be explained.

Jupiter's Great Red Spot suggests the planet is rich with water.

Many moons around Jupiter hold water and may even harbor vast oceans that are habitable to aliens. But Jupiter looks pretty dry on the surface, and shoring up evidence for water molecules inside the planet itself has proven difficult.

Juno is confronting this problem with its suite of sensitive instruments and ultra-close flybys. Researchers combined Juno's data with telescope data gathered about the Great Red Spot, which affords a deeper view of Jupiter's atmosphere. They discovered that the world may have two to nine times more oxygen than the sun — and oxygen is a key component of water.

The planet may have a "fuzzy" core.

"There seems to be a fuzzy core, and it may be much larger than anybody had anticipated," Bolton said during a NASA press conference in May 2017.

Hydrogen in the depths of Jupiter exists in a semi-gaseous, semi-dissolved — hence, "fuzzy" —state. Earth, by comparison, has outer liquid that moves around a solid core.

Jupiter's fuzzy core may be what drives its powerful dynamo and magnetic fields, sort of like the metallic dynamo at Earth's core. The previous thinking was that hydrogen — normally a gas as we know it — compressed into a liquid-metal state was the culprit for Jupiter's magnetic fields.

Auroras start with a planet's magnetic field. That field grabs charged solar particles blown into space, then races them toward the planet's poles. When the particles slam into atoms of gas in the atmosphere, they create a light show.

But Juno researchers have discovered that Jupiter's polar auroras have 10-30 times more energy than expected, and they give off that energy mostly in ultraviolet light, which is invisible to human eyes. What's more, the auroras dim when the planet rotates into darkness.

Researchers have yet to figure out how auroras work at Jupiter, though they suspect it has something to do with an energetic field of plasma around the planet, according to Space.com.

Juno found a possible new volcano on Jupiter's moon Io.

Juno was designed to study Jupiter in detail, but the planet's dozens of moons make for interesting targets, too.

The planet's moon Io — a hellish, sulfur-choked moon that's about as wide as North America and littered with volcanoes — is one example. Scientists got just a few glances at the moon decades ago, using spacecraft like Galileo and Voyager.

But in December 2017, Juno's infrared-seeing camera found what looks like a previously undetected volcano on the moon. According to NASA's Jet Propulsion Laboratory, the world has 150 active volcanoes — yet 250 more await discovery, based on how much material is spewing off the planet's surface and into space. </s> The space agency said Wednesday that Juno detected a problem, went into safe mode and shut off its cameras and instruments hours before it was supposed to pass over Jupiter’s dense cloud tops.

Juno rebooted its onboard computer and can communicate with Earth, but its activities are limited until engineers diagnose what went wrong.

“It’s too early to take a guess,” but the issue isn’t caused by the intense radiation belts surrounding Jupiter because the spacecraft was far away when it entered safe mode, said mission chief scientist Scott Bolton of the Southwest Research Institute in San Antonio.

It’s the second setback in less than a week for the solar-powered Juno, which has been orbiting the giant planet since July on a $1.1 billion mission to explore its poles, atmosphere and interior.

Last week, mission managers decided to postpone an engine firing planned for Wednesday after a pair of valves in the spacecraft’s propulsion system didn’t work as expected.

NASA said the two problems weren’t related.

The delay means Juno won’t swing close again to Jupiter until December. The spacecraft made its first close pass in August, beaming back pictures of Jupiter’s stormy north pole, which appeared bluer than the rest of the planet.

Scientists continued to pore over close-up images from the first flyby, determining that Jupiter’s magnetic fields and northern and southern lights were more powerful than expected.

The Juno mission was designed to fly closer to Jupiter than previous spacecraft, coming within 2,500 miles of the surface. Some three dozen close passes are planned during the 20-month mission.

Over at Mars, an experimental lander that was supposed to touch down on the red planet Wednesday lost contact with ground controllers at the European Space Agency. The mother ship successfully slipped into orbit around Mars and will study the atmosphere, but the fate of the lander was still unknown.
Results of the Juno mission are announced by NASA researchers, revealing new and unexpected information concerning Jupiter's poles, meteorology, and magnetic and gravitational fields.