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A NASA spacecraft is gearing up for the first of a series of close encounters with the most volcanic place in the solar system. The Juno spacecraft will fly by Jupiter’s moon Io on Thursday, December 15.
The maneuver will be one of nine flybys of Io made by Juno over the next year and a half. Two of the encounters will be from a distance of just 930 miles (1,500 kilometers) away from the moon’s surface.
Juno captured a glowing infrared view of Io on July 5 from 50,000 miles (80,000 kilometers) away. The brightest spots in that image correspond with the hottest temperatures on Io, which is home to hundreds of volcanoes — some of which can send lava fountains dozens of miles high.
Scientists will use Juno’s observations of Io to learn more about that network of volcanoes and how its eruptions interact with Jupiter. The moon is constantly tugged by Jupiter’s massive gravitational pull.
“The team is really excited to have Juno’s extended mission include the study of Jupiter’s moons. With each close flyby, we have been able to obtain a wealth of new information,” said Scott Bolton, Juno principal investigator at the Southwest Research Institute in San Antonio, in a statement.
“Juno sensors are designed to study Jupiter, but we’ve been thrilled at how well they can perform double duty by observing Jupiter’s moons.”
The spacecraft recently captured a new image of Jupiter’s northernmost cyclone on September 29. Jupiter’s atmosphere is dominated by hundreds of cyclones, and many cluster at the planet’s poles.
The Juno spacecraft has been orbiting Jupiter since 2016 to uncover details more about the giant planet and is focused on performing flybys of Jupiter’s moons during the extended part of its mission, which began last year and is expected to last through the end of 2025.
Juno flew by Jupiter’s moon Ganymede in 2021, followed by Europa earlier this year. The spacecraft used its instruments to look beneath the icy crust of both moons and gathered data about Europa’s interior, where a salty ocean is thought to exist.
The ice shell that makes up Europa’s surface is between 10 and 15 miles (16 and 24 kilometers) thick, and the ocean it likely sits atop is estimated to be 40 to 100 miles (64 to 161 kilometers) deep.
The data and images captured by Juno could help inform two separate missions heading to Jupiter’s moons in the next two years: the European Space Agency’s JUpiter ICy moons Explorer and NASA’s Europa Clipper mission.
The first, expected to launch in April 2023, will spend three years exploring Jupiter and three of its icy moons — Ganymede, Callisto and Europa — in depth. All three moons are thought to have oceans beneath their ice-covered crusts, and scientists want to explore whether Ganymede’s ocean is potentially habitable.
Europa Clipper will launch in 2024 to perform a dedicated series of 50 flybys around the moon after arriving in 2030. Eventually transitioning from an altitude of 1,700 miles (2,736 kilometers) to just 16 miles (26 kilometers) above the moon’s surface, Europa Clipper may be able to help scientists determine whether an interior ocean truly exists there and if the moon could support life.