Ammonia-bearing compounds found on Europa in Galileo data

Advanced analysis of NASA’s Galileo spacecraft data identifies ammonia-bearing compounds on the surface of Jupiter’s moon Europa, shown in a composite image credited 01/29/2026. The detections come from Galileo’s Near-Infrared Mapping Spectrometer (NIMS) data captured during the spacecraft’s 11th orbit of Jupiter in 1997 and focus on an area about 250 miles (400 kilometers) wide.

The composite pairs a black-and-white mosaic composed of multiple images from Galileo’s Solid-State Imaging camera with overlaid representations of NIMS results. In the overlay, red pixels mark locations where ammonia-bearing compounds were detected and purple pixels indicate no detections of the compounds.

Dark, crisscrossing bands visible in the underlying mosaic represent fracturing of Europa’s icy surface. The reported ammonia-bearing detections appear near those fractured features in the mapped region. The NASA release notes that detection of ammonia-bearing compounds near such features could indicate they were actively placed there by cryo-volcanic processes bringing liquid water up from Europa’s subsurface ocean.

The finding comes from reanalysis of decades-old Galileo data; the Galileo mission launched in 1989 and concluded its extended mission to the Jupiter system in September 2003. What is known: specific NIMS pixels from 1997 show ammonia-bearing compounds within the mapped 250-mile area on Europa.

ammonia-bearing compounds europa, galileo nims detections, near-infrared mapping spectrometer, cryovolcanic processes europa, 1997 galileo orbit 11, europa subsurface ocean, solid-state imaging mosaic, fractured icy surface europa, nasa jpl caltech, composite image europa