SPIRIT and Opportunity, NASA’s twin rovers on Mars, have made it look almost too easy. They were designed to work for about 90 days, but this month they will have soldiered on for a year without appreciable deterioration. Their mission was to look for evidence of past water, which they did with time to spare.
Luck was undoubtedly on their side. Landing zones for the rovers were accurate only to within tens of kilometres, yet Opportunity managed to score a cosmic hole-in-one by landing in a fascinating crater. Here it struck gold as soon as it opened its eyes: the…
