The UVS instrument recorded spatial information produced by hydrogen atoms radiating from the Earth. In the background a number of individual stars are identified along with the Pleiades star cluster. Juice-UVS plans to similarly observe hydrogen atoms radiating from Ganymede and Jupiter’s other icy moons. Credit Southwest Research Institute

Callisto, Europa, Ganymede, Icy Worlds, Jupiter, Missions & Hardware, Press Release

Astrobiology Fleet Update: ESA Juice Tests SwRI Ultraviolet Spectrograph

by Keith CowingOctober 9, 2024October 9, 2024

As European Space Agency (ESA)’s Jupiter Icy Moons Explorer (Juice) spacecraft hurtled past the Moon and Earth in mid-August to provide its first gravity assist maneuver to the Jovian system, […]

This image, taken from a data visualization, shows Arctic sea ice minimum extent on September 11, 2024. The yellow boundary shows the minimum extent averaged over the 30-year period from 1981 to 2010. Download high-resolution video and images from NASA’s Scientific Visualization Studio: hhttps://svsdev.gsfc.nasa.gov/5382 NASA’s Scientific Visualization Studio/Trent L. Schindler

Analog Studies, Arctic / Antarctic / Alpine, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Cryobiology, Europa, Ganymede, Habitable Zones, Icy Worlds, Mapping, Geodesy, Cartography, Bathymetry, ROVs/Submersibles/Diving, Status Report, Water/Hycean Worlds & Oceanography

Ice Planet Update: Arctic Sea Ice Near Historic Low – Antarctic Ice Continues Decline

by Keith CowingSeptember 25, 2024September 25, 2024

Editor’s note: we live on a world that is mostly an ocean world, part Icy world, part desert world etc. Other worlds in our solar system exhibit both similar and […]

Comparing CO2 exosphere to surface properties on Ganymede’s leading hemisphere. A) Vertical CO2 gas column density (unit of 1018 m−2 , this work, see also Fig. O.2); B) Depth of CO2-solid absorption band (Paper I); C) Central wavelength of CO2-solid absorption band (Paper I); D) Reflectance at 3.65 µm (Paper I); E) Central wavelength of H2O Fresnel peak (Paper I); F) Relative amplitude of the maximum reflectance between 3.5 and 4 µm (H2O interband amplitude, Paper I). The north pole of the leading hemisphere possesses the most red-shifted absorption band center of solid CO2, consistent with CO2 trapped in amorphous H2O ice (Paper I). It also has the higher reflectance at 3.65 µm and H2O interband amplitude, indicative of a higher density of facets in H2O ice for the photons (i.e., smaller grains and/or more internal defects and/or higher micro-roughness/porosity), and the most blue-shifted central wavelength of the H2O Fresnel peak due to a higher proportion of amorphous water ice (Mastrapa et al. 2009). -- astro-ph.EP

Astrochemistry, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Cryobiology, Ganymede, Icy Worlds, Jupiter, Status Report

A Patchy CO2 Exosphere On Ganymede Revealed By The James Webb Space Telescope

by Keith CowingSeptember 23, 2024September 23, 2024

Jupiter’s icy moon Ganymede has a tenuous exosphere produced by sputtering and possibly sublimation of water ice. To date, only atomic hydrogen and oxygen have been directly detected in this […]

Analog Studies, Arctic / Antarctic / Alpine, Away Teams & Field Reports, Ceres, Cryobiology, Enceladus, Europa, Exoplanets, -moons, -comets, Exploration Gear & Tech, Ganymede, Icy Worlds, Mimas, Missions & Hardware, Robotics/Rovers/UAVs, ROVs/Submersibles/Diving, Sample Return, Status Report, Water/Hycean Worlds & Oceanography

Through-Ice Acoustic Communication For Ocean Worlds Exploration

by Keith CowingSeptember 22, 2024September 22, 2024

Subsurface exploration of ice-covered planets and moons presents communications challenges because of the need to communicate through kilometers of ice. The objective of this task is to develop the capability […]

Above: Examples of typical surfaces of the icy Galilean satellites (panel a: Europa, near Conamara Chaos region at 8.1°N/90.9°E; panel b: Ganymede, Nicholson Regio at ∼14°S/12.7°E; panel c: Callisto, detail of Asgard impact basin at 14.7°N/218°E). All images are scaled to 150 m px−1. The crater density (a proxy of surface age) increases from Europa to Callisto, reflecting the geological history of surface processes. The surface of Europa displays the most complex inventory of landforms that were formed by endogenic processes, whereas Callisto’s surface is almost devoid of any evidence for tectonic and cryovolcanic activity (Image: NASA/DLR). Below: Models of the interiors of the icy Galilean satellites (Images: ESA/ATG Medialab). Details on their examination by JUICE are provided by Van Hoolst et al. (2024, this collection) -- pace Sci Rev via PubMed

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Callisto, Europa, Ganymede, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Jupiter, Mapping, Geodesy, Cartography, Bathymetry, Missions & Hardware, Status Report

Characterization of the Surfaces and Near-Surface Atmospheres of Ganymede, Europa and Callisto by JUICE

by Keith CowingSeptember 17, 2024September 17, 2024

We present the state of the art on the study of surfaces and tenuous atmospheres of the icy Galilean satellites Ganymede, Europa and Callisto, from past and ongoing space exploration […]

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.

MAJIS images of the Pacific Ocean -- ESA

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

Astrobiology Mission Update: Juice Confirms That Earth Is Habitable

by Keith CowingSeptember 10, 2024September 10, 2024

During its flyby of Earth on 20 August, ESA’s Jupiter Icy Moons Explorer (Juice) found ingredients for life in Earth’s atmosphere.

Kobe University HIRATA Naoyuki was the first to realize that the location of an asteroid impact on Jupiter’s moon Ganymede is almost precisely on the meridian farthest away from Jupiter. This implied that Ganymede had undergone a reorientation of its rotational axis and allowed Hirata to calculate what kind of impact could have caused this to happen.CREDIT HIRATA Naoyuki

Astrogeology, Comets and Asteroids, Ganymede, Icy Worlds, Impact events, Jupiter, Pluto, Press Release, Water/Hycean Worlds & Oceanography

A Gigantic Asteroid Impact Shifted The Axis Of Ganymede

by Keith CowingSeptember 4, 2024September 4, 2024

Around 4 billion years ago, an asteroid hit the Jupiter moon Ganymede. Now, a Kobe University researcher realized that the Solar System’s biggest moon’s axis has shifted as a result […]

A schematic configuration of PRIDE (not to scale) supporting two Jovian missions, JUICE (the lower left spacecraft) and Europa Clipper (the upper right spacecraft). The spacecraft are in two-way radio contact (blue arrows) with mission-specific Earth-based tracking stations (blue Earthbased antennas). Earth-based VLBI radio telescopes (three magenta Earth-based antennas) receive radio signals from the spacecraft (yellow arrows) and emission of distant natural celestial radio sources (red arrows). The configuration can operate at X- and/or Ka-bands, (8.4 GHz and/or 32 GHz, respectively). -- astro-ph.EP

Europa, Ganymede, Io, Jupiter, Missions & Hardware, Status Report

Planetary Radio Interferometry and Doppler Experiment as an Operational Component of the Jupiter Icy Moons Explorer Mission

by Keith CowingAugust 29, 2024August 28, 2024

We present an overview of the operations and engineering interface for Planetary Radio Interferometry and Doppler Experiment (PRIDE) radio astronomy observations as a scientific component of the ESA s Jupiter […]

Astrogeology, Biosignatures & Paleobiology, Europa, Ganymede, Habitable Zones, Icy Worlds, Jupiter, Mapping, Geodesy, Cartography, Bathymetry, Missions & Hardware, Status Report, Venus, Water/Hycean Worlds & Oceanography

Astrobiology Fleet Update: Video: Juice’s Lunar-Earth Flyby

by Keith CowingAugust 28, 2024August 27, 2024

On 19–20 August 2024, Juice successfully completed a world-first lunar-Earth flyby, with flight controllers guiding the spacecraft first past the Moon, then past Earth. The gravity of the two changed […]

Ganymede

Astrobiology Fleet Update: ESA Juice Tests SwRI Ultraviolet Spectrograph

Ice Planet Update: Arctic Sea Ice Near Historic Low – Antarctic Ice Continues Decline

A Patchy CO2 Exosphere On Ganymede Revealed By The James Webb Space Telescope

Through-Ice Acoustic Communication For Ocean Worlds Exploration

Characterization of the Surfaces and Near-Surface Atmospheres of Ganymede, Europa and Callisto by JUICE

Short-Timescale Spatial Variability of Ganymede’s Optical Aurora

Astrobiology Mission Update: Juice Confirms That Earth Is Habitable

A Gigantic Asteroid Impact Shifted The Axis Of Ganymede

Planetary Radio Interferometry and Doppler Experiment as an Operational Component of the Jupiter Icy Moons Explorer Mission

Astrobiology Fleet Update: Video: Juice’s Lunar-Earth Flyby

NASA Establishes Mars Forward Operational Risk and Contamination Evaluation (M-FORCE) Tiger Team to Shape Mars Planetary Protection Protocols

Opportunity to Contribute to NASA DARES Community White Paper on Phototrophic Biosignatures

The Search For Life Elsewhere: Avoiding Hype and Fostering Public Understanding

Panchromatic Spectra of Nearby Low-mass and Sun-like Stars with Directly Imageable Habitable Zones

Alfred: A Flexible, User-Friendly Python Package for Exoplanet Confirmation

JAXA Martian Moons eXploration (MMX) Launch

NASA Space Apps Challenge 2026

Rocky Worlds DDT Workshop

Voyager 1 Reaches One Light Day From Earth

Hayabusa Symposium 2026