Histograms for ocean and ice shell thicknesses retrieval accuracy. The accuracy is represented by the relative error, defined as the difference between the true (reference) value and the central value (mean of the distribution) estimated by the MCMC, divided by the former. The black dashed line is Europa Clipper’s interior L1 requirement. Each sample in the histogram is the result of a full MCMC joint inversion of all the geophysical measurements. The arrows indicate the fraction of cases below or above the L1 accuracy requirement for both the ice shell and ocean thicknesses. Cases that do not meet the requirement are end-member models with substantially thin (only a few kilometers) shells or oceans.