Three weeks after the Spirit rover touched down on Mars, its twin rover, Opportunity, landed on the opposite side of the Red Planet. Its descent was known at NASA as the “six minutes of terror,” during which it had to employ a parachute and retrorockets to decelerate almost completely from 11,800 mph (18,900 km/h) before impacting the surface. The touchdown was successful, though: Encased protectively in airbags, Opportunity hit the surface, bounced 26 times, and came to rest. Completely by luck, that resting place was inside Eagle Crater in the midst of several scientific targets, which allowed Opportunity to begin its survey immediately when deployed. It would go on to explore Mars for the next 15 years, covering over 28 miles of terrain, before a severe dust storm in June 2018 ended its mission.
