Due to concerns about engine, Juno to remain in elongated Jupiter orbit

Flyaway

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The Leros engine has commonalities with other engines that have called issues including MUOS 5 I believe.

“During a thorough review, we looked at multiple scenarios that would place Juno in a shorter-period orbit, but there was concern that another main engine burn could result in a less-than-desirable orbit,” said Rick Nybakken, Juno project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California. “The bottom line is a burn represented a risk to completion of Juno’s science objectives.”

Operating Juno beyond its designed lifetime comes with a price tag, too. The requested budget for Juno operations in fiscal year 2017 was $39.1 million, which was projected to fall to $14.5 million in 2018 as the mission came to a close. Now, if NASA must come up with an additional $100 to $150 million for an extended mission, those costs will almost certainly harm other missions in the agency’s science directorate.

https://arstechnica.com/science/2017/02/due-to-concerns-about-engine-juno-to-remain-in-elongated-jupiter-orbit/
 
How ironic ! Juno (notably its solar panels) was to be fried by Jupiter radiation belts, hence a short lived mission... fate has decided otherwise.
 
Archibald said:
How ironic ! Juno (notably its solar panels) was to be fried by Jupiter radiation belts, hence a short lived mission... fate has decided otherwise.

As I understand it, the maximum dose is encountered at closest approach. It will still have the same number of close approaches, but they will happen further apart because of the bigger orbit. Of course, a longer mission will cost more money.
 
Juno in good health; decision point nears on mission's end or extension

https://www.nasaspaceflight.com/2018/02/juno-good-health-decision-point-missions-end-extension/
 
Jupiter Abyss
NASA’s Juno spacecraft captured this view of an area within a Jovian jet stream showing a vortex that has an intensely dark center. Nearby, other features display bright, high altitude clouds that have puffed up into the sunlight.

The color-enhanced image was taken at 12:55 a.m. PDT (3:55 a.m. EDT) on May 29, 2019, as the spacecraft performed its 20th science flyby of Jupiter. At the time, Juno was about 9,200 miles (14,800 kilometers) from the planet's cloud tops, above approximately 52 degrees north latitude.
Citizen scientists Gerald Eichstädt and Seán Doran created and named this image using data from the spacecraft's JunoCam imager.

JunoCam's raw images are available for the public to peruse and process into image products at https://missionjuno.swri.edu/junocam/processing.

 

'Shallow Lightning' and 'Mushballs' Reveal Ammonia to NASA's Juno Scientists

The spacecraft may have found where the colorless gas has been hiding on the solar system's biggest planetary inhabitant.

New results from NASA's Juno mission at Jupiter suggest our solar system's largest planet is home to what's called "shallow lightning." An unexpected form of electrical discharge, shallow lightning originates from clouds containing an ammonia-water solution, whereas lightning on Earth originates from water clouds.

Other new findings suggest the violent thunderstorms for which the gas giant is known may form slushy ammonia-rich hailstones Juno's science team calls "mushballs"; they theorize that mushballs essentially kidnap ammonia and water in the upper atmosphere and carry them into the depths of Jupiter's atmosphere.
 
Possible Transient Luminous Events Observed in Jupiter's Upper Atmosphere

The Juno spacecraft has been in orbit around Jupiter since 2016. One of the instruments on this spacecraft is an ultraviolet spectrograph (UVS), which is primarily used to make ultraviolet images of Jupiter's auroras. During the first 4 years of the mission, the UVS has observed 11 transient bright flashes. These bright flashes look similar to lightning, but are located much higher in the atmosphere than the cloudy regions of Jupiter where lightning is generated. We suggest that these are observations of transient luminous events (TLEs) in Jupiter's upper atmosphere. In particular, we suggest that these are elves, sprites or sprite halos, three types of TLEs that produce spectacular flashes of light very high in the Earth's atmosphere in response to lightning strikes between clouds or between clouds and the ground. TLEs have previously only been observed on Earth, although theoretical and experimental work has predicted that they should also be present on other planets, including Jupiter. Comparing and contrasting TLE observations between Jupiter and Earth will improve our understanding of electrical activity in planetary atmospheres.

 
October 28, 2021
RELEASE 21-140
NASA’s Juno: Science Results Offer First 3D View of Jupiter Atmosphere

This illustration combines an image of Jupiter from the JunoCam instrument aboard NASA’s Juno spacecraft with a composite image of Earth to depict the size and depth of Jupiter’s Great Red Spot.

Credits: JunoCam Image data: NASA/JPL-Caltech/SwRI/MSSS; JunoCam Image processing by Kevin M. Gill (CC BY); Earth Image: NASA

New findings from NASA’s Juno probe orbiting Jupiter provide a fuller picture of how the planet’s distinctive and colorful atmospheric features offer clues about the unseen processes below its clouds. The results highlight the inner workings of the belts and zones of clouds encircling Jupiter, as well as its polar cyclones and even the Great Red Spot.

Researchers published several papers on Juno’s atmospheric discoveries today in the journal Science and the Journal of Geophysical Research: Planets. Additional papers appeared in two recent issues of Geophysical Research Letters.

“These new observations from Juno open up a treasure chest of new information about Jupiter’s enigmatic observable features,” said Lori Glaze, director of NASA’s Planetary Science Division at the agency’s headquarters in Washington. “Each paper sheds light on different aspects of the planet’s atmospheric processes – a wonderful example of how our internationally-diverse science teams strengthen understanding of our solar system.”

Juno entered Jupiter’s orbit in 2016. During each of the spacecraft’s 37 passes of the planet to date, a specialized suite of instruments has peered below its turbulent cloud deck.

“Previously, Juno surprised us with hints that phenomena in Jupiter’s atmosphere went deeper than expected,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio and lead author of the Journal Science paper on the depth of Jupiter’s vortices. “Now, we’re starting to put all these individual pieces together and getting our first real understanding of how Jupiter’s beautiful and violent atmosphere works – in 3D.”

Juno’s microwave radiometer (MWR) allows mission scientists to peer beneath Jupiter’s cloud tops and probe the structure of its numerous vortex storms. The most famous of these storms is the iconic anticyclone known as the Great Red Spot. Wider than Earth, this crimson vortex has intrigued scientists since its discovery almost two centuries ago.

The new results show that the cyclones are warmer on top, with lower atmospheric densities, while they are colder at the bottom, with higher densities. Anticyclones, which rotate in the opposite direction, are colder at the top but warmer at the bottom.

The findings also indicate these storms are far taller than expected, with some extending 60 miles (100 kilometers) below the cloud tops and others, including the Great Red Spot, extending over 200 miles (350 kilometers). This surprise discovery demonstrates that the vortices cover regions beyond those where water condenses and clouds form, below the depth where sunlight warms the atmosphere.

The height and size of the Great Red Spot means the concentration of atmospheric mass within the storm potentially could be detectable by instruments studying Jupiter’s gravity field. Two close Juno flybys over Jupiter’s most famous spot provided the opportunity to search for the storm’s gravity signature and complement the MWR results on its depth.

With Juno traveling low over Jupiter’s cloud deck at about 130,000 mph (209,000 kph) Juno scientists were able to measure velocity changes as small 0.01 millimeter per second using a NASA’s Deep Space Network tracking antenna, from a distance of more than 400 million miles (650 million kilometers). This enabled the team to constrain the depth of the Great Red Spot to about 300 miles (500 kilometers) below the cloud tops.

“The precision required to get the Great Red Spot’s gravity during the July 2019 flyby is staggering,” said Marzia Parisi, a Juno scientist from NASA’s Jet Propulsion Laboratory in Southern California and lead author of a paper in the Journal Science on gravity overflights of the Great Red Spot. “Being able to complement MWR’s finding on the depth gives us great confidence that future gravity experiments at Jupiter will yield equally intriguing results.”

Belts and Zones

In addition to cyclones and anticyclones, Jupiter is known for its distinctive belts and zones – white and reddish bands of clouds that wrap around the planet. Strong east-west winds moving in opposite directions separate the bands. Juno previously discovered that these winds, or jet streams, reach depths of about 2,000 miles (roughly 3,200 kilometers). Researchers are still trying to solve the mystery of how the jet streams form. Data collected by Juno’s MWR during multiple passes reveal one possible clue: that the atmosphere’s ammonia gas travels up and down in remarkable alignment with the observed jet streams.

“By following the ammonia, we found circulation cells in both the north and south hemispheres that are similar in nature to ‘Ferrel cells,’ which control much of our climate here on Earth”, said Keren Duer, a graduate student from the Weizmann Institute of Science in Israel and lead author of the Journal Science paper on Ferrel-like cells on Jupiter. “While Earth has one Ferrel cell per hemisphere, Jupiter has eight – each at least 30 times larger.”

Juno’s MWR data also shows that the belts and zones undergo a transition around 40 miles (65 kilometers) beneath Jupiter’s water clouds. At shallow depths, Jupiter’s belts are brighter in microwave light than the neighboring zones. But at deeper levels, below the water clouds, the opposite is true – which reveals a similarity to our oceans.

“We are calling this level the ‘Jovicline’ in analogy to a transitional layer seen in Earth’s oceans, known as the thermocline – where seawater transitions sharply from being relative warm to relative cold,” said Leigh Fletcher, a Juno participating scientist from the University of Leicester in the United Kingdom and lead author of the paper in the Journal of Geophysical Research: Planets highlighting Juno’s microwave observations of Jupiter's temperate belts and zones.

Polar Cyclones

Juno previously discovered polygonal arrangements of giant cyclonic storms at both of Jupiter’s poles – eight arranged in an octagonal pattern in the north and five arranged in a pentagonal pattern in the south. Now, five years later, mission scientists using observations by the spacecraft’s Jovian Infrared Auroral Mapper (JIRAM) have determined these atmospheric phenomena are extremely resilient, remaining in the same location.

“Jupiter’s cyclones affect each other’s motion, causing them to oscillate about an equilibrium position,” said Alessandro Mura, a Juno co-investigator at the National Institute for Astrophysics in Rome and lead author of a recent paper in Geophysical Research Letters on oscillations and stability in Jupiter’s polar cyclones. “The behavior of these slow oscillations suggests that they have deep roots.”

JIRAM data also indicates that, like hurricanes on Earth, these cyclones want to move poleward, but cyclones located at the center of each pole push them back. This balance explains where the cyclones reside and the different numbers at each pole.

More About the Mission

JPL, a division of Caltech in Pasadena, California, manages the Juno mission. Juno is part of NASA’s New Frontiers Program, which is managed at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington. Lockheed Martin Space in Denver built and operates the spacecraft.

Follow the mission on Facebook and Twitter, and get more information about Juno online at:

 
Revelations on Jupiter's formation, evolution and interior: Challenges from Juno results

Abstract
The Juno mission has revolutionized and challenged our understanding of Jupiter. As Juno transitioned into its extended mission, we review the major findings of Jupiter's internal structure relevant to understanding Jupiter's formation and evolution. Results from Juno's investigation of Jupiter's interior structure imply that the planet has compositional gradients and is accordingly non-adiabatic, with a complex internal structure. These new results imply that current models of Jupiter's formation and evolution require a revision. In this paper, we discuss potential formation and evolution paths that can lead to an internal structure model consistent with Juno data, and the constraints they provide. We note that standard core accretion formation models, including the heavy-element enrichment during planetary growth is consistent with an interior that is inhomogeneous with composition gradients in its deep interior. However, such formation models typically predict that this region, which could be interpreted as a primordial dilute core, is confined to ∼10% of Jupiter's total mass. In contrast, structure models that fit Juno data imply that this region contains 30% of the mass or more. One way to explain the origin of this extended region is by invoking a relatively long (~2 Myrs) formation phase where the growing planet accretes gas and planetesimals delaying the runaway gas accretion. This is not the same as the delay that appears in standard giant planet formation models because it involves additional accretion of solids in that period. However, both the possible new picture and the old picture are compatible with the formation scenario recently proposed to explain the separation of two meteoritic populations in the solar system. Alternatively, Jupiter's fuzzy core could be a result of a giant impact or convection post-formation. These novel scenarios require somewhat special and specific conditions. Clarity on the plausibility of such conditions could come from future high-resolution observations of planet-forming regions around other stars, from the observed and modeled architectures of extrasolar systems with giant planets, and future Juno data obtained during its extended mission.

 
Wikipedia cites September 29th as Juno's close (~350km) flyby of Europa. It’s entirely possible it could confirm Europan oceans.
 
Nice! I wonder if JPL will do something similar after the end of the mission using all of the orbital mechanics data to do an animation of what Jupiter's core is like?
 
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This highly stylized view of Jupiter's icy moon Europa is based on an image captured by JunoCam, the public engagement camera aboard NASA's Juno spacecraft, during the mission's close flyby on Sept. 29, 2022. Citizen scientist Fernando Garcia Navarro created the image by processing a JunoCam previously worked on by fellow citizen scientist Kevin M. Gill. Navarro calls his rendering "Fall Colors of Europa." In processing raw images taken by JunoCam, members of the public create deep-space portraits of the Jovian moon that aren't only awe-inspiring but also worthy of further scientific scrutiny. Juno citizen scientists have played an invaluable role in processing the numerous JunoCam images obtained during science operations at Jupiter.
Source: https://images.nasa.gov/details-PIA25335
 
12.23.22
Juno Spacecraft Recovering Memory After 47th Flyby of Jupiter
The science data from the solar-powered spacecraft’s most recent flyby of Jupiter and its moon Io appears to be intact.

NASA’s Juno spacecraft completed its 47th close pass of Jupiter on Dec. 14. Afterward, as the solar-powered orbiter was sending its science data to mission controllers from its onboard computer, the downlink was disrupted.

The issue – an inability to directly access the spacecraft memory storing the science data collected during the flyby – was most likely caused by a radiation spike as Juno flew through a radiation-intensive portion of Jupiter’s magnetosphere. Mission controllers at NASA’s Jet Propulsion Laboratory and its mission partners successfully rebooted the computer and, on Dec. 17, put the spacecraft into safe mode, a precautionary status in which only essential systems operate.

As of Dec. 22, steps to recover the flyby data yielded positive results, and the team is now downlinking the science data. There is no indication that the science data through the time of closest approach to Jupiter, or from the spacecraft’s flyby of Jupiter’s moon Io, was adversely affected. The remainder of the science data collected during the flyby is expected to be sent down to Earth over the next week, and the health of the data will be verified at that time. The spacecraft is expected to exit safe mode in about a week’s time. Juno’s next flyby of Jupiter will be on Jan. 22, 2023.

 
The #JunoMission's flyby of Europa provided the first close-up in over two decades of the ocean moon. This image, captured using reflected "Jupiter shine," covers ~93 miles (150 kilometers) by 125 miles (200 kilometers) of Europa's surface.

View: https://twitter.com/NASASolarSystem/status/1577778174997372928
Those two dark spots side by side in that swirl feature look promising to any of you?

Europa’s Loihi welling up?
 
May 15, 2023
NASA’s Juno Mission Getting Closer to Jupiter’s Moon Io
JunoCam image of the Jovian moon Io
This JunoCam image of the Jovian moon Io was collected during Juno’s flyby of the moon on March 1, 2023. At the time of closest approach, Juno was about 32,000 miles (51,500 kilometers) away from Io. Image data: NASA/JPL-Caltech/SwRI/MSSS Image processing: Kevin M. Gill (CC BY)

The gas giant orbiter has flown over 510 million miles and also documented close encounters with three of Jupiter’s four largest moons.

NASA’s Juno spacecraft will fly past Jupiter’s volcanic moon Io on Tuesday, May 16, and then the gas giant itself soon after. The flyby of the Jovian moon will be the closest to date, at an altitude of about 22,060 miles (35,500 kilometers). Now in the third year of its extended mission to investigate the interior of Jupiter, the solar-powered spacecraft will also explore the ring system where some of the gas giant’s inner moons reside.

To date, Juno has performed 50 flybys of Jupiter and also collected data during close encounters with three of the four Galilean moons – the icy worlds Europa and Ganymede, and fiery Io.
Composite image of Io
This composite image of Io was generated using data collected by the JunoCam imager aboard NASA’s Juno spacecraft during four flybys of the Jovian moon. The resolution of the images gets progressively better as the distance between spacecraft and moon decreases with each flyby (perijove, or PJ). Image data: NASA/JPL-Caltech/SwRI/MSSS/ Image processing, left to right: Björn Jónsson (CC NC SA), Jason Perry (CC NC SA), Mike Ravine (CC BY), Kevin M. Gill (CC BY)

“Io is the most volcanic celestial body that we know of in our solar system,” said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. “By observing it over time on multiple passes, we can watch how the volcanoes vary – how often they erupt, how bright and hot they are, whether they are linked to a group or solo, and if the shape of the lava flow changes.”

Slightly larger than Earth’s moon, Io is a world in constant torment. Not only is the biggest planet in the solar system forever pulling at it gravitationally, but so are its Galilean siblings – Europa and the biggest moon in the solar system, Ganymede. The result is that Io is continuously stretched and squeezed, actions linked to the creation of the lava seen erupting from its many volcanoes.

While Juno was designed to study Jupiter, its many sensors have additionally provided a wealth of data on the planet’s moons. Along with its visible light imager JunoCam, the spacecraft’s JIRAM (Jovian InfraRed Auroral Mapper), SRU (Stellar Reference Unit), and MWR (Microwave Radiometer) will be studying Io’s volcanoes and how volcanic eruptions interact with Jupiter’s powerful magnetosphere and auroras.
Composite views depicting volcanic activity on Io
These composite views depicting volcanic activity on Io were generated using both visible light and infrared data collected by NASA’s Juno spacecraft during flybys of the Jovian moon on Dec. 14, 2022 (left) and March 1, 2023.
Credits: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

“We are entering into another amazing part of Juno’s mission as we get closer and closer to Io with successive orbits. This 51st orbit will provide our closest look yet at this tortured moon,” said Bolton. “Our upcoming flybys in July and October will bring us even closer, leading up to our twin flyby encounters with Io in December of this year and February of next year, when we fly within 1,500 kilometers of its surface. All of these flybys are providing spectacular views of the volcanic activity of this amazing moon. The data should be amazing.”

A “Half-Century” at Jupiter

During its flybys of Jupiter, Juno has zoomed low over the planet’s cloud tops – as close as about 2,100 miles (3,400 kilometers). Approaching the planet from over the north pole and exiting over the south during these flybys, the spacecraft uses its instruments to probe beneath the obscuring cloud cover, studying Jupiter’s interior and auroras to learn more about the planet’s origins, structure, atmosphere, and magnetosphere.
Infrared views of volcanic activity of Jupiter’s moon Io
These infrared views of volcanic activity of Jupiter’s moon Io were collected by the JIRAM (Jovian Infrared Auroral Mapper) instrument aboard NASA’s Juno spacecraft during a flyby of the moon on Oct. 16, 2021.
Credits: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

Juno has been orbiting Jupiter for more than 2,505 Earth days and flown over 510 million miles (820 million kilometers). The spacecraft arrived at Jupiter on July 4, 2016. The first science flyby occurred 53 days later, and the spacecraft continued with that orbital period until its flyby of Ganymede on June 7, 2021, which reduced its orbital period to 43 days. The Europa flyby on Sept. 29, 2022, reduced the orbital period to 38 days. After the next two Io flybys, on May 16 and July 31, Juno’s orbital period will remain fixed at 32 days.

“Io is only one of the celestial bodies which continue to come under Juno’s microscope during this extended mission,” said Juno’s acting project manager, Matthew Johnson of NASA’s Jet Propulsion Laboratory in Southern California. “As well as continuously changing our orbit to allow new perspectives of Jupiter and flying low over the nightside of the planet, the spacecraft will also be threading the needle between some of Jupiter’s rings to learn more about their origin and composition.”
Downloadable graphic contains 50 image highlights from NASA’s Juno mission to Jupiter
This downloadable graphic contains 50 image highlights from NASA’s Juno mission to Jupiter. Juno completed its 50th close pass of the gas giant on April 8, 2023.
Download image, get image details and credits.

More About the Mission

NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Juno mission for the principal investigator, Scott J. Bolton, of the Southwest Research Institute in San Antonio. Juno is part of NASA’s New Frontiers Program, which is managed at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington. Lockheed Martin Space in Denver built and operates the spacecraft.

More information about Juno is available at:

 
On the 30th July Juno will be making its closest flyby yet of Io.
I hope the probe survive that ordeal

Io is not nice place, special for space probes
do constant volcanic eruption Io is envelop by of sulfur and sulfur dioxide
who interact with Jupiter's extensive magnetosphere, to form nasty belt of high-energy radiation.
 

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