Space & Astronomy

NASA's Juno probe has measured the thickness of Europa's icy crust

By T.K. Randall
January 30, 2026

Image Credit: NASA/JPL-Caltech When it comes to finding places within our own solar system capable of supporting primitive alien life, there is perhaps no better candidate than Jupiter's moon Europa.

Believed to be home to an icy shell covering a subsurface ocean of liquid water, this freezing moon could potentially harbor primitive organisms that thrive in its dark, frigid depths.

One of the questions scientists have long pondered is exactly how thick the ice covering Europa's ocean actually is. Could it be much thinner than expected - perhaps only 1 km - or could it in fact be far thicker, possibly even tens of kilometers?

Now, thanks to data recorded by NASA's Juno spacecraft during a flyby back in 2022, we have a much better idea of the actual thickness of Europa's icy crust. According to NASA, the results from the flyby indicate that it is around 18 miles (29 km) thick.

"The 18-mile estimate relates to the cold, rigid, conductive outer layer of a pure water ice shell," said Juno project scientist Steve Levin.

"If an inner, slightly warmer convective layer also exists - which is possible - the total ice shell thickness would be even greater."

"If the ice shell contains a modest amount of dissolved salt, as suggested by some models, then our estimate of the shell thickness would be reduced by about 3 miles."

Source: NASA.gov

Tags: Europa, Jupiter