predictive hypotheses and betting
It's harder to distort evidence to fit one's mental frame if you make the prediction first before the evidence/experiment is conducted. And I've found that considering a monetary bet over an issue tends to concentrate the mind as to just how certain you really are about an outcome.
Getting back to Europa, the future orbiter will be able to tell us the ice thickness. If that's a conspiracy to cover up evidence of a thin-ice Europa, then the conspirators aren't doing a very good job.
Similar to the satellite temperature readings for earth about ten years ago that didn't show warming. A scientific conspiracy would have tried to shut down analysis of the data. Instead more analysis showed the original data interpretations were flawed.