Overview
- Archival measurements from Galileo’s Near-Infrared Mapping Spectrometer in 1997 reveal a 2.20 μm absorption attributable to ammonia-bearing compounds.
- Detections cluster along fractures and pits on Europa’s ice, a pattern consistent with recent transport through cryovolcanic or shallow-subsurface pathways.
- Ammonia hydrate and ammonium chloride are identified as the most plausible carriers in a Planetary Science Journal study led by JPL researcher Al Emran.
- Because ammonia degrades quickly under intense radiation, its presence indicates geologically recent emplacement with implications for ocean chemistry and potential habitability.
- NASA says the finding underscores the value of legacy Galileo data and sets concrete targets for Europa Clipper observations when the mission reaches Jupiter in 2030.