Juno Archives

Lava World Recon: Juno Measures Subsurface Temperature Of Io

by Keith CowingAugust 2, 2026August 2, 2026

[SwRI] NASA’s Juno mission has made the first direct measurements of the temperature below the surface of Jupiter’s moon Io, which reveal significant heating in the upper few feet of […]

The north polar region of Jupiter’s volcanic moon Io was captured by NASA’s Juno during the spacecraft’s 57th close pass of the gas giant on Dec. 30, 2023. Data from that flyby and one on Feb. 3, 2024, is helping scientists understand Io’s interior. Image data: NASA/JPL-Caltech/SwRI/MSSS Image processing by Gerald Eichstädt

Lava World Recon: Juno Studies Io’s Volcanoes

by Keith CowingJuly 23, 2026July 23, 2026

[NASA] NASA’s Juno mission has provided the first measurements of the temperature below the surface of Jupiter’s moon Io, revealing significant heating within the shallow subsurface of the most volcanically […]

Jupiter's moon Europa was captured by the JunoCam instrument aboard NASA's Juno spacecraft during the mission's close flyby on Sept. 29, 2022. The images show the fractures, ridges, and bands that crisscross the moon's surface. Credit: Image data: NASA/JPL-Caltech/SwRI/MSSS Image processing: Björn Jónsson (CC BY 3.0)

Astrogeology, Europa, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Jupiter, Missions & Hardware, Press Release, Water/Hycean Worlds & Oceanography

Juno Measures The Thickness Of Europa’s Ice Shell

by Keith CowingJanuary 28, 2026

Results from the solar-powered spacecraft provide a new measurement of the thickness of the ice shell encasing the Jovian moon’s ocean.

The 0.6-GHz data are much brighter due to reflected synchrotron emission and are, therefore, shown with a different colour scale. The terminator was at approximately 10° W longitude, with the right-hand side in sunlight for these maps. The approximate sounding depth (50% contribution for pure, solid ice) is shown in the lower right of each map, and a typical beam size is shown in the lower left of each map. -- Nature

Analog Studies, Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Europa, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report

Europa’s Ice Thickness And Subsurface Structure Characterized By The Juno Microwave Radiometer

by Keith CowingJanuary 5, 2026January 2, 2026

Jupiter’s moon Europa is thought to harbour a saltwater ocean beneath a variously disrupted ice shell, and it is, thus, one of the highest priority astrobiology targets in the Solar […]

Major icy bodies in the Solar System, with the Earth’s moon to scale. The images are shown at the proper relative size. From NASA’s Planetary Photojournal (https://photojournal.jpl.nasa.gov/), Earth’s Moon (PIA00302), Europa (PIA00502), Ganymede (PIA00716), Callisto (PIA03456), Mimas (PIA06258), Enceladus (PIA06254), Tethys (PIA07738), Dione (PIA08256), Rhea (PIA08256), Titan (PIA08256), Hyperion (PIA07740), Iapetus (PIA08384), Phoebe (PIA06064), Miranda (PIA18185), Ariel (PIA01534), Umbriel (PIA00040), Titania (PIA01979), Oberon (PIA00034), Triton (PIA00317), Pluto (PIA19952). -- astro-ph.EP

Ariel, Astrogeology, Callisto, Ceres, Charon, Dione, Enceladus, Europa, Ganymede, Iapetus, Ice Giant, Icy Worlds, Mapping, Geodesy, Cartography, Bathymetry, Mars, Mimas, Miranda, Missions & Hardware, Moon, Oberon, Phoebe, Pluto, Polar / Alpine Expeditions, Rhea, Status Report, Tethys, Titan, Titania, Triton, Umbriel, Water/Hycean Worlds & Oceanography

Icy Worlds: Moons And Dwarf Planets

by Keith CowingDecember 1, 2025December 1, 2025

In the outer solar system beyond Jupiter, water ice is a dominant component of planetary bodies, and most solid objects in this region are classified as icy bodies.

The north polar region of Jupiter’s volcanic moon Io was captured by the JunoCam imager aboard NASA’s Juno during the spacecraft’s 57th close pass of the gas giant on Dec. 30, 2023. A technique called annealing was used to help repair radiation damage to the camera in time to capture this image. Credit: Image data: NASA/JPL-Caltech/SwRI/MSSS. Image processing by Gerald Eichstädt Full Image Details

Exploration Gear & Tech, Imaging & Spectroscopy, Jupiter, Missions & Hardware, Press Release

How To Save A Spacecraft Camera 370 Million Miles Away In Jupiter Orbit

by Keith CowingJuly 22, 2025July 22, 2025

An experimental technique rescued a camera aboard the agency’s Juno spacecraft, offering lessons that will benefit other space systems that experience high radiation.

A massive hotspot — larger the Earth’s Lake Superior — can be seen just to the right of Io’s south pole in this annotated image taken by the JIRAM infrared imager aboard NASA’s Juno on Dec. 27, 2024, during the spacecraft’s flyby of the Jovian moon. Credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

Astrogeology, Biogeochemical Cycles & Geobiology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Io, Jupiter, Lava / magma ocean / Volcanic Worlds, Press Release

Juno Spots The Most Powerful Volcanic Activity On Io To Date

by Keith CowingJanuary 29, 2025January 29, 2025

Even by the standards of Io, the most volcanic celestial body in the solar system, recent events observed on the Jovian moon are extreme.

Astrogeology, Biogeochemical Cycles & Geobiology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Io, Jupiter, Lava / magma ocean / Volcanic Worlds, Mapping, Geodesy, Cartography, Bathymetry, Press Release

How Io Became The Most Volcanic Body In Our Solar System

by Keith CowingDecember 26, 2024

Scientists with NASA’s Juno mission to Jupiter have discovered that the volcanoes on Jupiter’s moon Io are each likely powered by their own chamber of roiling hot magma rather than […]

Panel A: crust age and thickness for 15 different zones of Loki Patera. Panel B: location of the zones chosen for the analysis. The color of the zones is coded according to the age of the crust, as indicated by the color bar to the right. The reference time for the crust age is set to the final observation epoch: April 9, 2024. -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Imaging & Spectroscopy, Io, Jupiter, Lava / magma ocean / Volcanic Worlds, Mapping, Geodesy, Cartography, Bathymetry, Missions & Hardware, Status Report

Volcano World Survey: Observations Of Loki Patera By Juno During Close Flybys

by Keith CowingOctober 15, 2024October 15, 2024

We used data from the Juno spacecraft to investigate both the spatial and temporal properties of Loki Patera on Io, acquired in two infrared bands between December 2022 and April […]

Calibrated images of Ganymede’s 630.0 nm auroral emission displayed in 20 R contours. To better reveal the spatial variability we smoothed the data using a Gaussian kernel with a FWHM of 0. ′′5 approximating typical seeing conditions for the morning of 2021-06-08 UTC. The time in the upper left of each image is the UTC time at the start of the observation, the annotation in the lower right is the distance to the plasma sheet centrifugal equator; positive when Ganymede is above the mid-plane and negative when it is below. As Ganymede moved vertically through the plasma sheet, the hemisphere closest to the mid-plane exhibited the brightest aurora. From approximately 14:00 to 14:45 UTC, Ganymede is within ±0.5 RJ and the brightness is more evenly-distributed across the disk. Ganymede passed through the highestdensity plasma mid-plane at 14:20 UTC, so the top two rows display data when Ganymede was above the mid-plane (with enhanced brightness at southern latitudes) and the bottom row displays data when Ganymede was below the mid-plane (with enhanced brightness at northern latitudes). Because of the blurring effect of atmospheric seeing, the calibrated brightness distribution of the individual pixels is lower than the disk-averaged value reported in de Kleer et al. (2023) and table 1, which assume all emission originates from a disk with Ganymede’s solid-angular size. The white grid shows the physical size and orientation of Ganymede, with north pointing upward (for more details on this observing geometry, see figure 2). -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Ganymede, Icy Worlds, Jupiter, Space Weather & Heliophysics, Status Report, Water/Hycean Worlds & Oceanography

Short-Timescale Spatial Variability of Ganymede’s Optical Aurora

by Keith CowingSeptember 11, 2024September 11, 2024

Ganymede’s aurora are the product of complex interactions between its intrinsic magnetosphere and the surrounding Jovian plasma environment and can be used to derive both atmospheric composition and density.