Europa Seen Up Close by Juno's SRU
Figure A
This black-and-white image of Europa's surface was taken by the Stellar Reference Unit (SRU) aboard NASA's Juno spacecraft during a Sept. 29, 2022, flyby of the Jovian moon.
The image shows a region crisscrossed with a network of fine grooves and sets of complicated double ridges (pairs of long parallel lines indicating elevated features in the ice). In the upper right corner are dark stains possibly linked to cryovolcanic plume activity (the bubbling up of liquid from beneath the ice).
Just below center and to the right is a surface feature that members of the Juno science team refer to as "the Platypus." This location of surface disruption (called "chaos" in the field of planetary science) measures 42 miles (67 kilometers) north-south and 23 miles (37 kilometers) east-west. (The feature's shape has previously been compared to a musical symbol for a quarter note.) The small white dots that pepper the image are signatures of penetrating high-energy particles from the severe radiation environment around the moon.
The image was taken at a distance of about 256 miles (412 kilometers) over the night side of Europa in a region dimly illuminated by Jupiter-shine. It is Juno's highest resolution image of the moon, at 840 to 1,115 feet per pixel (256 to 340 meters per pixel) and covers about 93 by 125 miles (150 by 200 kilometers) of Europa's surface.
Figure A is an annotated version of the SRU image. The blue box indicates the location of a double ridge system that runs east-west with dark deposits that are possibly associated with plumes. The orange box highlights the location of the Platypus chaos feature: Its "body" is near the top of the box and below that a fractured portion of the ice shell forms its neck, connecting to two dark "eyes," with the platypus's "bill" at bottom.
The SRU collects images of star fields to provide star positions used for attitude determination. Designed for low-light conditions, the camera has proved itself a valuable science tool, discovering shallow lightning in Jupiter's atmosphere, imaging the planet's enigmatic ring system, and now providing a glimpse of Europa's most fascinating geologic formations.
More information about Juno is at https://www.nasa.gov/juno and https://missionjuno.swri.edu.