NASA Juno Estimates Europa’s Ice Shell at 29 Kilometers, Backing Thick-Ice Models
Updated
Updated · spacedaily.com · Jul 26
NASA Juno Estimates Europa’s Ice Shell at 29 Kilometers, Backing Thick-Ice Models
2 articles · Updated · spacedaily.com · Jul 26
Summary
Juno’s 2022 flyby data put Europa’s conductive ice shell at an average 29 kilometers thick in the region observed, with a reported uncertainty of plus or minus 10 kilometers.
129 measurements in each of six microwave channels let researchers model temperature gradients and reflected radio emission, producing what NASA called the first estimate able to distinguish sub-1-kilometer shells from ones tens of kilometers thick.
The result is regional and model-dependent: it assumes pure water ice and a laterally uniform shell, while modest salt could trim the estimate by about 5 kilometers and any deeper convecting ice would make the total solid barrier thicker.
A thicker shell complicates habitability studies because oxidants and nutrients from the radiation-processed surface would have a harder time reaching the deep ocean, and shallow scatterers detected only hundreds of meters down are unlikely to provide that route.
The finding gives Europa Clipper—due at Jupiter in 2030—a stronger baseline to test as it makes about 50 flybys to map how Europa’s ice shell varies and how it connects to the ocean below.
Juno’s 2022 flyby of Europa provided the first direct measurements of the moon’s ice shell, revealing it is about 29 kilometers thick—much thicker than some scientists hoped. This thick, rigid ice acts as a strong barrier, making it very hard for oxygen and nutrients created on the surface to reach the ocean below. The cracks and pores detected by Juno are small and shallow, so they are unlikely to help surface chemicals reach the ocean. As a result, scientists are now focusing on Europa’s internal energy sources for possible life, and missions like Europa Clipper and JUICE are being designed to search for hidden pathways and better understand the moon’s habitability.