NASA's Juno spacecraft, which has been exploring the Jupiter system since July 2016, recently completed another close flyby of Io, one of Jupiter's largest moons. This flyby provided scientists with breathtaking images of the volcanic moon and offered new insight into Io's geological composition.

The Juno spacecraft is a pioneering mission that has allowed scientists to study Jupiter up close while orbiting the gas giant. It is the first robotic explorer to delve beneath Jupiter's dense clouds and investigate its magnetic field, composition, and structure. The data obtained from this mission has contributed significantly to our understanding of how Jupiter formed and the origins of the Solar System.

Since 2021, Juno has been in an extended mission phase, conducting flybys of Jupiter's largest moons. On February 3rd, 2024, the spacecraft made another thrilling flyby of Io, capturing mesmerizing images of its pockmarked surface. This was the second part of a twin flyby designed to shed light on Io's volcanic nature and internal structure.

During the flyby, Juno approached within 1,500 km (930 mi) of Io's surface, setting a new record for the closest any spacecraft has ever come to the moon. The previous record was held by Juno itself during its flyby on October 15th, 2023, where it reached a minimum distance of 12,000 km (mi) from Io's surface. These unprecedented close encounters have allowed researchers to gather invaluable data about Io's geological features.

The images captured by Juno during the flyby revealed Io's dark side illuminated by sunlight reflected from Jupiter, an effect known as "Jupitershine." Citizen scientist Emma Wälimäki processed one of these images, showcasing the moon's mysterious and captivating appearance. Furthermore, infrared images unveiled the presence of numerous active volcanoes on Io's surface, with some eruptions even visible on the moon's dark side.

Scientists are particularly interested in investigating whether Io's active volcanoes are fueled by a global magma ocean beneath its surface. Existing geological models suggest that tidal flexing caused by Jupiter's powerful gravity generates this magma ocean within Io's interior. Similarly, other icy satellites like Europa experience hydrothermal activity due to tidal flexing, maintaining liquid water oceans in their interiors.

The Juno mission, which has been operational for twelve years, five months, and twenty-seven days, is set to continue its orbit around Jupiter until September 2025. However, this timeline may be further extended if the spacecraft's solar panel wings continue to provide power. The mission's overarching goal remains the exploration of Jupiter and its satellites, unraveling the fundamental questions surrounding their formation.

For those interested in viewing more images captured by Juno, they can visit the mission's website at the Southwest Research Institute (SwRI).

The Juno probe's latest flyby of Io has yielded awe-inspiring images that are propelling our understanding of the moon's volcanic activity and geological composition. With each passing milestone, Juno brings us closer to unraveling the secrets of Jupiter and the enigmatic moons that surround it.