After years of debate, NASA researchers have zeroed in on the thickness of the Europa's ice shell. Since then, scientists have been in two camps, championing conflicting theories on the thickness of Europa's ice shell. "If an inner, slightly warmer convective layer also exists, which is possible, the total ice shell thickness would be even greater," Levin continued. "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 [5 km]." And a thick ice shell might not be great news for Europa's life-hosting potential.