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Old Galileo Images of Europa Reveal New Details

Old Galileo Images of Europa Reveal New Details


In March and September of 1998, the Galileo spacecraft that studied Jupiter and its moons, captured images of Europa in a flyby. Now, in 2020, a new look at the photos, in preparation for NASA’s Europa Clipper probe, has yielded some stunning and detailed results.

SETI Institute engineer Mario Valenti applied high tech image processing techniques to three observations captured along the same longitude of Europa. They were pieced together from 36 images covering a vertical strip that goes from the far northern latitudes to the far southern latitude of the moon. The average resolution of these images is 224 meters per pixel.  Since the spacecraft provides its best estimate of each image's location, a lot of work is required to get each image precisely aligned.

Each image was taken using the clear filter, which results in a greyscale image.  The image was colorized by aligning it with a lower resolution reprocessed global image of Europa (  This image uses near-infrared, green, and violet rather than red, green, and blue to exaggerate the color variations to better show differences in chemical composition. Bluer areas show water ice, while redder areas show other minerals and salts.  These images are part of an ongoing project to reprocessed Galileo Europa images leading up to the upcoming Europa Clipper mission.

Each section was taken to show the variations in the terrain across the surface of Europa.

Europa - PIA23873
This image contains Agnor and Katreus Linea, which are unusually bright, light colored bands.  Agnor Linea is the larger of the two, and it extends 1,400 kilometers across the surface.  These features are surrounded by chaos terrain, where ice blocks have been broken up, rotated and shifted around before settling and getting refrozen.


Europa - PIA23872
This image shows crisscrossing ridged bands.  These bands may form when ice fractures and repeatedly closes, creating a feature that's a few kilometers wide that can stretch for thousands of kilometers.


Europa - PIA23871
This image shows a combination of chaos terrain, which then transitions into ridged bands.  The right side shows some lenticulae, which are dome-shaped features.  These are often interpreted as being caused by warmer material upwelling towards the surface.

The Europa Clipper mission will study Europa through a series of flybys and is scheduled to launch in 2024.

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