Juno: Unlocking Jupiter's Mysteries (NASA New Frontiers)

[bystander]

Juno Completes Flyby over Jupiter's Great Red Spot
NASA | JPL-Caltech | SwRI | Juno | 2017 Jul 11

Illustration depicts Juno in orbit above Jupiter's Great Red Spot. Image Credit: NASA/JPL-Caltech

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NASA's Juno mission completed a close flyby of Jupiter and its Great Red Spot on July 10, during its sixth science orbit.

All of Juno's science instruments and the spacecraft's JunoCam were operating during the flyby, collecting data that are now being returned to Earth. Juno's next close flyby of Jupiter will occur on Sept. 1.

Raw images from the spacecraft's latest flyby will be posted in coming days. ...

Juno reached perijove (the point at which an orbit comes closest to Jupiter's center) on July 10 at 6:55 p.m. PDT (9:55 p.m. EDT). At the time of perijove, Juno was about 2,200 miles (3,500 kilometers) above the planet's cloud tops. Eleven minutes and 33 seconds later, Juno had covered another 24,713 miles (39,771 kilometers), and was passing directly above the coiling crimson cloud tops of the Great Red Spot. The spacecraft passed about 5,600 miles (9,000 kilometers) above the clouds of this iconic feature. ...

[Case]

I’m curious to see if such a close flyby will reveal different heights in cloud tops, especially in/around the Great Red Spot. Will there be visual photography that may show that kind of depth?

[bystander]

Juno Spots Jupiter's Great Red Spot
NASA | JPL-Caltech | SwRI | Juno | 2017 Jun 12

This enhanced-color image of Jupiter's Great Red Spot was created by citizen scientist Gerald Eichstädt using data from the JunoCam imager on NASA's Juno spacecraft. Credits: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstadt

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This enhanced-color image of Jupiter's Great Red Spot was created by citizen scientist Kevin Gill using data from the JunoCam imager on NASA's Juno spacecraft. Credits: NASA/JPL-Caltech/SwRI/MSSS/Kevin Gill

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This enhanced-color image of Jupiter's Great Red Spot was created by citizen scientist Jason Major using data from the JunoCam imager on NASA's Juno spacecraft. Credits: NASA/JPL-Caltech/SwRI/MSSS/Jason Major

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Images of Jupiter's Great Red Spot reveal a tangle of dark, veinous clouds weaving their way through a massive crimson oval. The JunoCam imager aboard NASA's Juno mission snapped pics of the most iconic feature of the solar system's largest planetary inhabitant during its Monday (July 10) flyby. The images of the Great Red Spot were downlinked from the spacecraft's memory on Tuesday and placed on the mission's JunoCam website Wednesday morning.

"For hundreds of years scientists have been observing, wondering and theorizing about Jupiter's Great Red Spot," said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. "Now we have the best pictures ever of this iconic storm. It will take us some time to analyze all the data from not only JunoCam, but Juno's eight science instruments, to shed some new light on the past, present and future of the Great Red Spot."

As planned by the Juno team, citizen scientists took the raw images of the flyby from the JunoCam site and processed them, providing a higher level of detail than available in their raw form. The citizen-scientist images, as well as the raw images they used for image processing, can be found at:

https://www.missionjuno.swri.edu/junocam/processing
https://www.nasa.gov/jupiter

...

[bystander]

Jupiter's Auroras Present a Powerful Mystery
NASA | JPL-Caltech | SwRI | Juno | 2017 Sep 06

This image, created with data from Juno's Ultraviolet Imaging Spectrograph, marks the path of Juno's readings of Jupiter's auroras, highlighting the electron measurements that show the discovery of the so-called discrete auroral acceleration processes indicated by the 'inverted Vs' in the lower panel. Image Credit: NASA/JPL-Caltech/SwRI/Randy Gladstone

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Scientists on NASA's Juno mission have observed massive amounts of energy swirling over Jupiter's polar regions that contribute to the giant planet's powerful auroras - only not in ways the researchers expected.

Examining data collected by the ultraviolet spectrograph and energetic-particle detector instruments aboard the Jupiter-orbiting Juno spacecraft, a team led by Barry Mauk of the Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, observed signatures of powerful electric potentials, aligned with Jupiter's magnetic field, that accelerate electrons toward the Jovian atmosphere at energies up to 400,000 electron volts. This is 10 to 30 times higher than the largest auroral potentials observed at Earth, where only several thousands of volts are typically needed to generate the most intense auroras -- known as discrete auroras -- the dazzling, twisting, snake-like northern and southern lights seen in places like Alaska and Canada, northern Europe, and many other northern and southern polar regions.

Jupiter has the most powerful auroras in the solar system, so the team was not surprised that electric potentials play a role in their generation. What's puzzling the researchers, Mauk said, is that despite the magnitudes of these potentials at Jupiter, they are observed only sometimes and are not the source of the most intense auroras, as they are at Earth. ...

Scientists consider Jupiter to be a physics lab of sorts for worlds beyond our solar system, saying the ability of Jupiter to accelerate charged particles to immense energies has implications for how more distant astrophysical systems accelerate particles. But what they learn about the forces driving Jupiter's auroras and shaping its space weather environment also has practical implications in our own planetary backyard. ...

Discrete and broadband electron acceleration in Jupiter’s powerful aurora - B. H. Mauk et al

• Nature 549(7670):66 (07 Sep 2017) DOI: 10.1038/nature23648

[bystander]

Juno Aces Eighth Science Pass of Jupiter
NASA | JPL-Caltech | SwRI | Juno | 2017 Nov 03

Data returned Tuesday, Oct. 31, indicate that NASA's Juno spacecraft successfully completed its eighth science flyby over Jupiter's mysterious cloud tops on Tuesday, Oct. 24. The confirmation was delayed by several days due to solar conjunction at Jupiter, which affected communications during the days prior to and after the flyby. ...

[sallyseaver]

Jupiter's Stunning Southern Hemisphere
SwRI | Juno | 2017 Nov 09

See Jupiter’s southern hemisphere in beautiful detail in this new image taken by NASA’s Juno spacecraft. The color-enhanced view captures one of the white ovals in the “String of Pearls,” one of eight massive rotating storms at 40 degrees south latitude on the gas giant planet.

The image was taken on Oct. 24, 2017 at 11:11 a.m. PDT (2:11 p.m. EDT), as Juno performed its ninth close flyby of Jupiter [the eighth science flyby]. At the time the image was taken, the spacecraft was 20,577 miles (33,115 kilometers) from the tops of the clouds of the planet at a latitude of minus 52.96 degrees. The spatial scale in this image is 13.86 miles/pixel (22.3 kilometers/pixel).

Citizen scientists Gerald Eichstädt and Seán Doran processed this image using data from the JunoCam imager.

[bystander]

Juno Probes the Depths of Jupiter's Great Red Spot
NASA | JPL-Caltech | SwRI | Juno | 2017 Dec 11

Jupiter's Great Red Spot[/url]: A rotation animation was made by applying a wind movement model to a mosaic of JunoCam images. Credit: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstadt/Justin Cowart

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Data collected by NASA's Juno spacecraft during its first pass over Jupiter's Great Red Spot in July 2017 indicate that this iconic feature penetrates well below the clouds. Other revelations from the mission include that Jupiter has two previously uncharted radiation zones. ... The science instrument responsible for this in-depth revelation was Juno's Microwave Radiometer (MWR). ...

Juno also has detected a new radiation zone, just above the gas giant's atmosphere, near the equator. The zone includes energetic hydrogen, oxygen and sulfur ions moving at almost light speed. ...

The new zone was identified by the Jupiter Energetic Particle Detector Instrument (JEDI) investigation. The particles are believed to be derived from energetic neutral atoms (fast-moving ions with no electric charge) created in the gas around the Jupiter moons Io and Europa. The neutral atoms then become ions as their electrons are stripped away by interaction with the upper atmosphere of Jupiter.

Juno also found signatures of a high-energy heavy ion population within the inner edges of Jupiter's relativistic electron radiation belt -- a region dominated by electrons moving close to the speed of light. The signatures are observed during Juno's high-latitude encounters with the electron belt, in regions never explored by prior spacecraft. The origin and exact species of these particles is not yet understood. Juno's Stellar Reference Unit (SRU-1) star camera detects the signatures of this population as extremely high noise signatures in images collected by the mission's radiation monitoring investigation. ...

[bystander]

NASA Juno Findings - Jupiter’s Jet-Streams Are Unearthly
NASA | JPL-Caltech | SwRI | Juno | 2018 Mar 07

Click to play embedded YouTube video.

Juno Reveals the Depth of Jupiter's Colored Bands
Credit: NASA/JPL-Caltech/SwRI/ASI

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Data collected by NASA’s Juno mission to Jupiter indicate that the atmospheric winds of the gas-giant planet run deep into its atmosphere and last longer than similar atmospheric processes found here on Earth. The findings will improve understanding of Jupiter’s interior structure, core mass and, eventually, its origin.

Other Juno science results released today include that the massive cyclones that surround Jupiter’s north and south poles are enduring atmospheric features and unlike anything else encountered in our solar system. The findings are part of a four-article collection on Juno science results being published in the March 8 edition of the journal Nature.

“These astonishing science results are yet another example of Jupiter’s curve balls, and a testimony to the value of exploring the unknown from a new perspective with next-generation instruments. Juno’s unique orbit and evolutionary high-precision radio science and infrared technologies enabled these paradigm-shifting discoveries,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute, San Antonio. “Juno is only about one third the way through its primary mission, and already we are seeing the beginnings of a new Jupiter.” ...

A deeper look at Jupiter
Nature | News & Views | 2018 Mar 08

NASA’s Juno spacecraft has made precise measurements of the gravitational field of Jupiter. The data reveal details of the structure and dynamics of the planet’s interior.

Clusters of cyclones encircling Jupiter’s poles - A. Adriani et al

• Nature 555(7695):216 (08 Mar 2018) DOI: 10.1038/nature25491

Measurement of Jupiter’s asymmetric gravity field - L. Iess et al

• Nature 555(7695):220 (08 Mar 2018) DOI: 10.1038/nature25776

Jupiter’s atmospheric jet streams extend thousands of kilometres deep - Y. Kaspi et al

• Nature 555(7695):223 (08 Mar 2018) DOI: 10.1038/nature25793

A suppression of differential rotation in Jupiter’s deep interior - T. Guillot et al

• Nature 555(7695):227 (08 Mar 2018) DOI: 10.1038/nature25775

[bystander]

Juno Provides Infrared Tour of Jupiter's North Pole
NASA | JPL-Caltech | SwRI | Juno | 2018 Apr 11

Click to play embedded YouTube video.

Scientists working on NASA's Juno mission to Jupiter shared a 3-D infrared movie depicting densely packed cyclones and anticyclones that permeate the planet's polar regions, and the first detailed view of a dynamo, or engine, powering the magnetic field for any planet beyond Earth. Those are among the items unveiled during the European Geosciences Union General Assembly in Vienna, Austria, on Wednesday, April 11.

Juno mission scientists have taken data collected by the spacecraft's Jovian InfraRed Auroral Mapper (JIRAM) instrument and generated the 3-D fly-around of the Jovian world's north pole. Imaging in the infrared part of the spectrum, JIRAM captures light emerging from deep inside Jupiter equally well, night or day. The instrument probes the weather layer down to 30 to 45 miles (50 to 70 kilometers) below Jupiter's cloud tops. The imagery will help the team understand the forces at work in the animation -- a north pole dominated by a central cyclone surrounded by eight circumpolar cyclones with diameters ranging from 2,500 to 2,900 miles (4,000 to 4,600 kilometers). ...

[bystander]

Juno Solves 39-Year Old Mystery of Jupiter Lightning
NASA | JPL-Caltech | SwRI | Juno | 2018 Jun 06

This artist’s concept of lightning distribution in Jupiter’s northern hemisphere incorporates a JunoCam image with artistic embellishments. Data from NASA’s Juno mission indicates that most of the lightning activity on Jupiter is near its poles. Credits: NASA/JPL-Caltech/SwRI/JunoCam

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Ever since NASA’s Voyager 1 spacecraft flew past Jupiter in March, 1979, scientists have wondered about the origin of Jupiter’s lightning. That encounter confirmed the existence of Jovian lightning, which had been theorized for centuries. But when the venerable explorer hurtled by, the data showed that the lightning-associated radio signals didn’t match the details of the radio signals produced by lightning here at Earth.

In a new paper published in Nature today, scientists from NASA’s Juno mission describe the ways in which lightning on Jupiter is actually analogous to Earth’s lightning. Although, in some ways, the two types of lightning are polar opposites.

“No matter what planet you’re on, lightning bolts act like radio transmitters -- sending out radio waves when they flash across a sky,” said Shannon Brown of NASA’s Jet Propulsion Laboratory in Pasadena, California, a Juno scientist and lead author of the paper. “But until Juno, all the lightning signals recorded by spacecraft [Voyagers 1 and 2, Galileo, Cassini] were limited to either visual detections or from the kilohertz range of the radio spectrum, despite a search for signals in the megahertz range. Many theories were offered up to explain it, but no one theory could ever get traction as the answer.”

Enter Juno, which has been orbiting Jupiter since July 4, 2016. Among its suite of highly sensitive instruments is the Microwave Radiometer Instrument (MWR), which records emissions from the gas giant across a wide spectrum of frequencies.

“In the data from our first eight flybys, Juno’s MWR detected 377 lightning discharges,” said Brown. “They were recorded in the megahertz as well as gigahertz range, which is what you can find with terrestrial lightning emissions. We think the reason we are the only ones who can see it is because Juno is flying closer to the lighting than ever before, and we are searching at a radio frequency that passes easily through Jupiter’s ionosphere.”

While the revelation showed how Jupiter lightning is similar to Earth’s, the new paper also notes that where these lightning bolts flash on each planet is actually quite different. ...

Prevalent Lightning Sferics at 600 Megahertz Near Jupiter’s Poles - Shannon Brown et al

• Nature 558(7708):87 (2018 Jun 07) DOI: 10.1038/s41586-018-0156-5

[bystander]

NASA Re-plans Juno's Jupiter Mission
NASA | JPL-Caltech | SwRI | Juno | 2018 Jun 06

During its continued mission, NASA's Juno spacecraft will maintain its 53-day polar
orbit around Jupiter. At its closest, Juno passes within 3,000 miles (5,000 kilometers)
of Jupiter's cloud tops once during each 53-day orbit. At the high end of each orbit,
Juno is about 5 million miles (8-million kilometers) from the planet - which is just
beyond the orbit of the Jovian moon Themisto. Image credit: NASA/JPL-Caltech

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NASA has approved an update to Juno's science operations until July 2021. This provides for an additional 41 months in orbit around Jupiter and will enable Juno to achieve its primary science objectives.Juno is in 53-day orbits rather than 14-day orbits as initially planned because of a concern about valves on the spacecraft's fuel system. This longer orbit means that it will take more time to collect the needed science data.

An independent panel of experts confirmed in April that Juno is on track to achieve its science objectives and is already returning spectacular results.The Juno spacecraft and all instruments are healthy and operating nominally.

NASA has now funded Juno through FY 2022. The end of prime operations is now expected in July 2021, with data analysis and mission close-out activities continuing into 2022. ...

[bystander]

10 Things: Two Years of Juno at Jupiter
NASA Science | Solar System Exploration | Jupiter | 2018 Jul 09

[bystander]

Juno data indicate another possible volcano on Jupiter moon Io
NASA | JPL-Caltech | SwRI | Juno | 2018 Jul 13

Click to view full size image 1 or image 2

Image Credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

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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.

[bystander]

Study Helps Solve Mystery under Jupiter's Coloured Bands
Australian National University | 2018 Aug 09

Colorful swirling cloud belts dominate Jupiter’s southern hemisphere in this image captured by NASA’s Juno spacecraft. (Credit: NASA/JPL-Caltech/SwRI/MSSS/KM Gill)

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Scientists from Australia and the United States have helped to solve the mystery underlying Jupiter's coloured bands in a new study on the interaction between atmospheres and magnetic fields.

Jupiter is the largest planet in our solar system. Unlike Earth, Jupiter has no solid surface - it is a gaseous planet, consisting mostly of hydrogen and helium.

Several strong jet streams flow west to east in Jupiter's atmosphere that are, in a way, similar to Earth's jet streams. Clouds of ammonia at Jupiter's outer atmosphere are carried along by these jet streams to form Jupiter's coloured bands, which are shades white, red, orange, brown and yellow. ...

Recent evidence from NASA's spacecraft Juno indicates these jet streams reach as deep as 3,000 kilometres below Jupiter's clouds. ...

Magnetic Fields Impact Atmospheric Circulation of Gas Giant Planets
Lawrence Livermore National Laboratory | 2018 Aug 09

This image captures a high-altitude cloud formation surrounded by swirling patterns in the atmosphere of Jupiter's North North Temperate Belt region. The North North Temperate Belt is one of Jupiter's many colorful, swirling cloud bands. Scientists have wondered for decades how deep these bands extend. Gravity measurements collected by Juno during its close flybys discovered that these bands of flowing atmosphere actually penetrate deep into the planet, to a depth of about 1,900 miles (3,000 km). (Credit: NASA/JPL-Caltech/SwRI/MSSS/J Major)

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Magnetic fields around a planet or a star can overpower the zonal jets that affect atmospheric circulation. ...

Zonal flows are observed in the banded zones in the atmosphere of Jupiter. Previous work performed simulations that showed a magnetic field suppressed zonal flows. The new research provides a mechanism explaining that suppression. The study shows that with magnetic fields present, even a weak shear flow causes subtle but coherent correlations in the magnetic fluctuations that oppose zonal flows. ...

Zonal flows are ubiquitous in rotating systems. Prominent examples include the Earth's polar and subtropical jet streams in the atmosphere, the Antarctic Circumpolar Current in the ocean, the winds in Jupiter's atmosphere and flows in the atmospheres of Saturn, Uranus and Neptune.

The flows act as a barrier and don't allow for fluid from the two sides to exchange properties (such as heat or carbon). Thus, zonal flows have a large impact on the Earth’s weather because they separate cold and warm air. ...

Magnetic Suppression of Zonal Flows on a Beta Plane - Navid C. Constantinou, Jeffrey B. Parker

• Astrophysical Journal 863(1):46 (10 Aug 2018) DOI: 10.3847/1538-4357/aace53
  arXiv.org > astro-ph > arXiv:1805.09847 > 24 May 2018 (v1), 07 Aug 2018 (v2)

[bystander]

Juno Detects Jupiter Wave Trains
NASA | JPL-Caltech | SwRI | Juno | 2018 Oct 23

Three waves can be seen in this excerpt of a JunoCam image taken on 2017 Feb 02 during Juno's fourth flyby of Jupiter. The region imaged in this picture is part of the visibly dark band just north of Jupiter's equator known as the North Equatorial Belt. Credits: NASA/JPL-Caltech/SwRI/MSSS/JunoCam

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Massive structures of moving air that appear like waves in Jupiter's atmosphere were first detected by NASA's Voyager missions during their flybys of the gas-giant world in 1979. The JunoCam camera aboard NASA's Juno mission to Jupiter has also imaged the atmosphere. JunoCam data has detected atmospheric wave trains, towering atmospheric structures that trail one after the other as they roam the planet, with most concentrated near Jupiter's equator.

The JunoCam imager has resolved smaller distances between individual wave crests in these trains than ever seen before. This research provides valuable information on both the dynamics of Jupiter’s atmosphere and its structure in the regions underneath the waves. ...

Most of the waves are seen in elongated wave trains, spread out in an east-west direction, with wave crests that are perpendicular to the orientation of the train. Other fronts in similar wave trains tilt significantly with respect to the orientation of the wave train, and still other wave trains follow slanted or meandering paths. ...

Although analysis is ongoing, most waves are expected to be atmospheric gravity waves – up-and-down ripples that form in the atmosphere above something that disturbs air flow, such as a thunderstorm updraft, disruptions of flow around other features, or from some other disturbance that JunoCam does not detect. ...

[bystander]

Juno Halfway to Jupiter Science
NASA | JPL-Caltech | SwRI | Juno | 2018 Dec 12

A south tropical disturbance has just passed Jupiter's iconic Great Red Spot, and is captured stealing threads of orange haze from the Great Red Spot in this series of color-enhanced images from NASA's Juno spacecraft. From left to right, this sequence of images was taken between 2:57 a.m. and 3:36 a.m. PDT (5:57 a.m. and 6:36 a.m. EDT) on April 1, 2018, as the spacecraft performed its 12th close flyby of Jupiter. Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/Seán Doran

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On Dec. 21, at 8:49:48 a.m. PST (11:49:48 a.m. EST) NASA's Juno spacecraft will be 3,140 miles (5,053 kilometers) above Jupiter's cloud tops and hurtling by at a healthy clip of 128,802 mph (207,287 kilometers per hour). This will be the 16th science pass of the gas giant and will mark the solar-powered spacecraft's halfway point in data collection during its prime mission.

Juno is in a highly-elliptical 53-day orbit around Jupiter. Each orbit includes a close passage over the planet's cloud deck, where it flies a ground track that extends from Jupiter's north pole to its south pole.

"With our 16th science flyby, we will have complete global coverage of Jupiter, albeit at coarse resolution, with polar passes separated by 22.5 degrees of longitude," said Jack Connerney, Juno deputy principal investigator from the Space Research Corporation in Annapolis, Maryland. "Over the second half of our prime mission — science flybys 17 through 32 — we will split the difference, flying exactly halfway between each previous orbit. This will provide coverage of the planet every 11.25 degrees of longitude, providing a more detailed picture of what makes the whole of Jupiter tick." ...

[bystander]

Juno Navigators Enable Jupiter Cyclone Discovery
NASA | JPL_Caltech | SwRI | Juno | 2019 Dec 12

A new, smaller cyclone can be seen at the lower right of this infrared image of Jupiter's South pole taken on Nov. 4, 2019, during Juno's 23rd science pass. Credits: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

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Jupiter's south pole has a new cyclone. The discovery of the massive Jovian tempest occurred on Nov. 3, 2019, during the most recent data-gathering flyby of Jupiter by NASA's Juno spacecraft. It was the 22nd flyby during which the solar-powered spacecraft collected science data on the gas giant, soaring only 2,175 miles (3,500 kilometers) above its cloud tops. The flyby also marked a victory for the mission team, whose innovative measures kept the solar-powered spacecraft clear of what could have been a mission-ending eclipse.

"The combination of creativity and analytical thinking has once again paid off big time for NASA," said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. "We realized that the orbit was going to carry Juno into Jupiter's shadow, which could have grave consequences because we're solar powered. No sunlight means no power, so there was real risk we might freeze to death. While the team was trying to figure out how to conserve energy and keep our core heated, the engineers came up with a completely new way out of the problem: Jump Jupiter's shadow. It was nothing less than a navigation stroke of genius. Lo and behold, first thing out of the gate on the other side, we make another fundamental discovery."

When Juno first arrived at Jupiter in July 2016, its infrared and visible-light cameras discovered giant cyclones encircling the planet's poles - nine in the north and six in the south. Were they, like their Earthly siblings, a transient phenomenon, taking only weeks to develop and then ebb? Or could these cyclones, each nearly as wide as the continental U.S., be more permanent fixtures?

With each flyby, the data reinforced the idea that five windstorms were swirling in a pentagonal pattern around a central storm at the south pole and that the system seemed stable. None of the six storms showed signs of yielding to allow other cyclones to join in.

"It almost appeared like the polar cyclones were part of a private club that seemed to resist new members," said Bolton.

Then, during Juno's 22nd science pass, a new, smaller cyclone churned to life and joined the fray. ...

[bystander]

Findings from Juno Update Jupiter Water Mystery
NASA | JPL-Caltech | Juno | 2020 Feb 18

The mission publishes its first stream of data on the amount of water in Jupiter's atmosphere - the first findings on the gas giant's water since the agency's 1995 Galileo mission.

The JunoCam imager aboard NASA's Juno spacecraft captured this image of Jupiter's southern equatorial region on Sept. 1, 2017. The image is oriented so Jupiter's poles (not visible) run left-to-right of frame. Image credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill

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NASA's Juno mission has provided its first science results on the amount of water in Jupiter's atmosphere. Published recently in the journal Nature Astronomy, the Juno results estimate that at the equator, water makes up about 0.25% of the molecules in Jupiter's atmosphere - almost three times that of the Sun. These are also the first findings on the gas giant's abundance of water since the agency's 1995 Galileo mission suggested Jupiter might be extremely dry compared to the Sun (the comparison is based not on liquid water but on the presence of its components, oxygen and hydrogen, present in the Sun).

An accurate estimate of the total amount of water in Jupiter's atmosphere has been on the wish lists of planetary scientists for decades: The figure in the gas giant represents a critical missing piece to the puzzle of our solar system's formation. Jupiter was likely the first planet to form, and it contains most of the gas and dust that wasn't incorporated into the Sun.

The leading theories about its formation rest on the amount of water the planet soaked up.Water abundance also has important implications for the gas giant's meteorology (how wind currents flow on Jupiter) and internal structure. While lightning - a phenomenon typically fueled by moisture - detected on Jupiter by Voyager and other spacecraft implied the presence of water, an accurate estimate of the amount of water deep within Jupiter's atmosphere remained elusive. ...

The Water Abundance in Jupiter’s Equatorial Zone ~ Cheng Li et al

• Nature Astronomy (online 10 Feb 2020) DOI: 10.1038/s41550-020-1009-3

[bystander]

Juno Takes First Images of Jovian Moon Ganymede's North Pole
NASA | JPL-Caltech | SwRI | Juno | 2020 Jul 22

Infrared images from Juno provide the first glimpse of Ganymede's icy north pole.

The north pole of Ganymede can be seen in center of this annotated image taken by the JIRAM infrared imager aboard NASA's Juno spacecraft on Dec. 26, 2019. The thick line is 0-degrees longitude. Image Credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

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On its way inbound for a Dec. 26, 2019, flyby of Jupiter, NASA's Juno spacecraft flew in the proximity of the north pole of the ninth-largest object in the solar system, the moon Ganymede. The infrared imagery collected by the spacecraft's Jovian Infrared Auroral Mapper (JIRAM) instrument provides the first infrared mapping of the massive moon's northern frontier.

The only moon in the solar system that is larger than the planet Mercury, Ganymede consists primarily of water ice. Its composition contains fundamental clues for understanding the evolution of the 79 Jovian moons from the time of their formation to today.

Ganymede is also the only moon in the solar system with its own magnetic field. On Earth, the magnetic field provides a pathway for plasma (charged particles from the Sun) to enter our atmosphere and create aurora. As Ganymede has no atmosphere to impede their progress, the surface at its poles is constantly being bombarded by plasma from Jupiter's gigantic magnetosphere. The bombardment has a dramatic effect on Ganymede's ice. ...

The ice near both poles of the moon is amorphous. This is because charged particles follow the moon's magnetic field lines to the poles, where they impact, wreaking havoc on the ice there, preventing it from having an ordered (or crystalline) structure. In fact, frozen water molecules detected at both poles have no appreciable order to their arrangement, and the amorphous ice has a different infrared signature than the crystalline ice found at Ganymede's equator. ...

[bystander]

Juno Mission Expands Into the Future
NASA | JPL-Caltech | SwRI | Juno | 2021 Jan 13

The spacecraft, which has been gathering data on the gas giant since July 2016, will become an explorer of the full Jovian system – Jupiter and its rings and moons.

NASA has extended the mission of its Juno spacecraft exploring Jupiter. The extended mission involves 42 additional orbits, expands on discoveries Juno has already made and adds exploration of the rings encircling the planet as well as flybys of Ganymede, Europa, and Io. Credits: NASA/JPL-Caltech/SwRI

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NASA has authorized a mission extension for its Juno spacecraft exploring Jupiter. The agency’s most distant planetary orbiter will now continue its investigation of the solar system’s largest planet through September 2025, or until the spacecraft’s end of life. This expansion tasks Juno with becoming an explorer of the full Jovian system – Jupiter and its rings and moons – with multiple rendezvous planned for three of Jupiter’s most intriguing Galilean moons: Ganymede, Europa, and Io. ...

Proposed in 2003 and launched in 2011, Juno arrived at Jupiter on July 4, 2016. The prime mission will be completed in July 2021. The extended mission involves 42 additional orbits, including close passes of Jupiter’s north polar cyclones; flybys of Ganymede, Europa, and Io; as well as the first extensive exploration of the faint rings encircling the planet. ...

The data Juno collects will contribute to the goals of the next generation of missions to the Jovian system – NASA’s Europa Clipper and the ESA (European Space Agency) JUpiter ICy moons Explorer (JUICE) mission. Juno’s investigation of Jupiter’s volcanic moon Io addresses many science goals identified by the National Academy of Sciences for a future Io explorer mission.

The extended mission’s science campaigns will expand on discoveries Juno has already made about Jupiter’s interior structure, internal magnetic field, atmosphere (including polar cyclones, deep atmosphere, and aurora), and magnetosphere. ...

[neufer]

Juno Radiation Vault (the box being lowered onto the partially constructed spacecraft) in the process of being installed on Juno, 2010

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<<Juno Radiation Vault is a compartment inside the Juno spacecraft that houses much of the probe's electronics and computers, and is intended to offer increased protection of radiation to the contents as the spacecraft endures the radiation environment at planet Jupiter. The Juno Radiation Vault is roughly a cube, with walls made of 1 cm thick titanium metal, and each side having an area of about a square meter. The vault weights about 200 kg. Inside the vault are the main command and data handling and power control boxes, along with 20 other electronic boxes. The vault should reduce the radiation exposure by about 800 times, as the spacecraft is exposed to an anticipated 20 million rads of radiation It does not stop all radiation, but significantly reduces it in order to limit damage to the spacecraft's electronics. Despite the intense radiation, JunoCam and the Jovian Infrared Auroral Mapper (JIRAM) are expected to endure at least eight orbits, while the Microwave Radiometer (MWR) should endure at least eleven orbits. Juno will receive much lower levels of radiation in its polar orbit than the Galileo orbiter received in its equatorial orbit; Galileo's subsystems were damaged by radiation during its mission, including an LED in its data recording system.

"Without its protective shield, or radiation vault, Juno’s brain would get fried on the very first pass near Jupiter"

The vault is one of many features of the mission to help counter the high radiation levels near Jupiter, including an orbit that reduces time spent in the highest radiation regions, radiation-hardened electronics, and additional shielding on components. The wires that lead out from the vault also have increased protection, they have a sheath of braided copper and stainless steel. Some other components used tantalum metal for shielding in Juno, and while lead is known for its shielding effect it was found to be too soft in this application. One reason that titanium was chosen over lead in this application was because titanium was better at handling launch stresses. Another shield part of the spacecraft is the Stellar Reference Unit (SRU), which has six times the shielding to prevent static forming on images due to radiation.>>