NASA image Earth's radiation belts during Juice mission flyby

NASA image Earth's radiation belts during Juice mission flyby
by Clarence Oxford
Los Angeles CA (SPX) Oct 08, 2024

From Aug. 19-20, ESA's (European Space Agency's) Juice (Jupiter Icy Moons Explorer) mission achieved a milestone during a lunar-Earth flyby, executing a double gravity assist maneuver. As the spacecraft passed both the Moon and Earth, its onboard instruments, including two from NASA, recorded the sharpest image ever taken of Earth's radiation belts - regions of charged particles held within Earth's magnetosphere.

The image was captured by the Jovian Energetic Neutrals and Ions (JENI) instrument, managed by the Johns Hopkins Applied Physics Laboratory (APL) for NASA. Unlike traditional cameras, JENI detects energetic neutral atoms emitted when charged particles interact with Earth's atmospheric hydrogen, making visible what would otherwise be unseen to the human eye. The instrument builds on technology previously used in NASA's Cassini mission, which explored the magnetospheres of Saturn and Jupiter.

"As soon as we saw the crisp, new images, high fives went around the room," said Matina Gkioulidou, deputy lead of JENI at APL. "It was clear we had captured the vast ring of hot plasma encircling Earth in unprecedented detail, an achievement that has sparked excitement for what is to come at Jupiter."

On Aug. 19, JENI and its counterpart, the Jovian Energetic Electrons (JoEE) instrument, also took advantage of Juice's brief flyby of the Moon, gathering data from 465 miles (750 kilometers) above its surface. Scientists anticipate these observations will be valuable for studying interactions between Jupiter's moons and its powerful magnetosphere.

The next day, on Aug. 20, Juice entered Earth's magnetosphere at an altitude of 37,000 miles (60,000 kilometers) above the Pacific Ocean. JoEE and JENI collected data from the lower-energy plasma before venturing into the heart of the radiation belts, where they measured plasma at temperatures reaching millions of degrees. This data will help scientists better understand the mechanisms driving plasma heating, which leads to dramatic magnetic phenomena in space environments.

"I couldn't have hoped for a better flyby," commented Pontus Brandt, principal investigator for JoEE and JENI at APL. "The richness of the data from our deep-dive through the magnetosphere is astounding. JENI's image of the entire system we just flew through was the cherry on top. It's a powerful combination we will exploit in the Jovian system."

With this successful flyby complete, Juice's trajectory is set for a future encounter with Venus in August 2025. The spacecraft will use Venus's gravity to accelerate toward Earth, setting up for two additional flybys in September 2026 and January 2029 before it arrives at Jupiter in July 2031.