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| Surface features of Jupiter’s icy moon Europa are revealed in an image obtained by Juno’s Stellar Reference Unit (SRU) during the spacecraft’s Sept. 29, 2022, flyby. Credit: NASA/JPL-Caltech/SwRI |
Observations from the spacecraft's pass of the moon provided the first
close-up in over two decades of this ocean world, resulting in remarkable
imagery and unique science.
The highest-resolution photo NASA's Juno mission has ever taken of a
specific portion of Jupiter's moon Europa reveals a detailed view of a
puzzling region of the moon's heavily fractured icy crust.
The image covers about 93 miles (150 kilometers) by 125 miles (200
kilometers) of Europa's surface, revealing a region crisscrossed with a
network of fine grooves and double ridges (pairs of long parallel lines
indicating elevated features in the ice). Near the upper right of the image,
as well as just to the right and below center, are dark stains possibly
linked to something from below erupting onto the surface. Below center and
to the right is a surface feature that recalls a musical quarter note,
measuring 42 miles (67 kilometers) north-south by 23 miles (37 kilometers)
east-west. The white dots in the image are signatures of penetrating
high-energy particles from the severe radiation environment around the moon.
Juno's Stellar Reference Unit (SRU)—a star camera used to orient the
spacecraft—obtained the black-and-white image during the spacecraft's flyby
of Europa on Sept. 29, 2022, at a distance of about 256 miles (412
kilometers). With a resolution that ranges from 840 to 1,115 feet (256 to
340 meters) per pixel, the image was captured as Juno raced past at about 15
miles per second (24 kilometers per second) over a part of the surface that
was in nighttime, dimly lit by "Jupiter shine"—sunlight reflecting off
Jupiter's cloud tops.
Designed for low-light conditions, the SRU has also proven itself a valuable
science tool, discovering shallow lightning in Jupiter's atmosphere, imaging
Jupiter's enigmatic ring system, and now providing a glimpse of some of
Europa's most fascinating geologic formations.
"This image is unlocking an incredible level of detail in a region not
previously imaged at such resolution and under such revealing illumination
conditions," said Heidi Becker, the lead co-investigator for the SRU. "The
team's use of a star-tracker camera for science is a great example of Juno's
groundbreaking capabilities. These features are so intriguing. Understanding
how they formed—and how they connect to Europa's history—informs us about
internal and external processes shaping the icy crust."
It won't just be Juno's SRU scientists who will be busy analyzing data in
the coming weeks. During Juno's 45th orbit around Jupiter, all of the
spacecraft's science instruments were collecting data both during the Europa
flyby and then again as Juno flew over Jupiter's poles a short 7 ½ hours
later.
"Juno started out completely focused on Jupiter. The team is really excited
that during our extended mission, we expanded our investigation to include
three of the four Galilean satellites and Jupiter's rings," said Juno
Principal Investigator Scott Bolton of the Southwest Research Institute in
San Antonio. "With this flyby of Europa, Juno has now seen close-ups of two
of the most interesting moons of Jupiter, and their ice shell crusts look
very different from each other. In 2023, Io, the most volcanic body in the
solar system, will join the club." Juno sailed by Jupiter's moon
Ganymede—the solar system's largest moon—in June 2021.
Europa is the solar system's sixth-largest moon with about 90% the
equatorial diameter of Earth's moon. Scientists are confident a salty ocean
lies below a miles-thick ice shell, sparking questions about the potential
habitability of the ocean. In the early 2030s, the NASA's Europa Clipper
spacecraft will arrive and strive to answer these questions about Europa's
habitability. The data from the Juno flyby provides a preview of what that
mission will reveal.
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Space & Astrophysics