&gt; Before NASA sent their first drone to Mars they made a lot of predictions, a lot of tests, guessed a lot of things that may get wrong, etc. Do some of their missions still fail? Sure. But the amount of success is much much larger because they didn&#x27;t just sent a drone there and watched what happened.<p>How much effort went into estimating Opportunity&#x27;s lifetime at 90 days? How useful has that estimate proven to be?