NASA’s Juno mission has achieved a major milestone in understanding Jupiter’s radiation environment. Scientists have created the first complete 3D radiation map of the Jupiter system, including the orbit of icy moon Europa. The map was possible due to data collected by Juno’s star camera Advanced Stellar Compass (ASC) and Stellar Reference Unit (SRU).
The ASC and SRU cameras are designed for deep-space navigation but were repurposed as radiation detectors. The instruments allowed scientists to characterize the radiation environment at different energies. Scott Bolton, Juno principal investigator, noted that this is a major step in understanding Jupiter’s radiation environment.
The ASC camera images of stars to determine the spacecraft’s orientation in space and has also proved valuable in detecting high-energy particle fluxes in Jupiter’s magnetosphere. The SRU camera has also been used as a radiation detector and low-light imager, providing rare images of Jupiter’s rings from Juno’s unique vantage point.
The data suggests that there is more very high energy radiation near Europa’s orbit than previously thought. The map confirms that the amount of high-energy electrons present on the side of Europa facing into its orbital direction of motion is greater than its slipstream. This is due to Jupiter and its magnetic field rotation, which causes most electrons in the magnetosphere to overtake Europa from behind.
The Juno mission has made several unplanned scientific contributions, including measuring interplanetary dust impacting the spacecraft and discovering a previously uncharted comet using the same technique. The results of this research are in the final round of peer review and will be published in the journal Geophysical Research Letters.
Source: https://phys.org/news/2024-08-missions-jupiter-moon-europa.html