As 2023 draws to a close, NASA’s Juno spacecraft is gearing up for an exciting event – a remarkably close flyby of Jupiter’s moon Io, known for being the most volcanically active body in our solar system.
Since its arrival at Jupiter in 2016, Juno has been observing Io from a distance but will soon venture within 930 miles of the moon’s surface. According to NASA, Io’s volcanic eruptions are so intense that they can be observed from Earth using powerful telescopes, and the moon even boasts lakes composed of molten silicate lava.
Scott Bolton, the lead scientist for Juno at the Southwest Research Institute in San Antonio, emphasized the significance of this mission. The team aims to analyze variations in Io’s volcanic behavior by merging data from this upcoming flyby with earlier observations. This includes examining the frequency, intensity, and thermal properties of the eruptions, as well as the dynamics of lava flows and their connection to Jupiter’s magnetospheric particle flows.
Juno, which entered Jupiter’s orbit on July 4, 2016, has the distinction of being the first spacecraft to explore beneath the planet’s thick cloud cover. It aims to shed light on various aspects of the gas giant, which is the largest planet in our solar system. To date, the orbiter has completed 56 flybys of Jupiter, with the upcoming one marking its 57th. It has also closely observed Jupiter’s largest moon, Ganymede, and its fourth-largest, Europa. Io, being the third-largest, is the latest target, while Callisto, the second-largest moon with a more distant orbit, remains unapproached.
NASA has planned another close encounter with Io for February 3, 2024. Juno has been tracking Io’s volcanic activity from distances ranging between 6,830 miles to 62,100 miles, offering unprecedented views of the moon’s polar regions.
Bolton highlighted the importance of the upcoming flybys in December and February. Juno will delve into the origins of Io’s intense volcanic activity, investigate the possibility of a subsurface magma ocean, and study the impact of Jupiter’s tidal forces, which exert continuous stress on this dynamic moon.
Juno’s instruments, including the Jovian Infrared Auroral Mapper, will capture thermal signatures from Io’s volcanoes and craters. The spacecraft’s Stellar Reference Unit aims to secure the highest-resolution images of the moon’s surface to date, complemented by color imagery from the JunoCam.
During its Jupiter missions, Juno has endured one of the most challenging radiation environments in our solar system. Jupiter’s magnetic field, significantly stronger than Earth’s, traps and accelerates charged particles, creating intense radiation that affects the inner moons and can harm spacecraft.
Ed Hirst, the Juno project manager at NASA’s Jet Propulsion Laboratory in Southern California, noted the impact of this radiation on JunoCam, with recent images showing diminished dynamic range and the presence of ‘striping’ noise. The engineering team is actively working on mitigating this radiation damage to ensure the continued operation of the imager.
Juno’s mission is set to conclude in September 2025, with plans to deliberately plunge the spacecraft into Jupiter’s atmosphere.
