Mars Exploration Rover A, known as Spirit, launched from Cape Canaveral, Florida, on June 10, 2003, and arrived at Gusev Crater on January 3, 2004. Mars Exploration Rover B, known as Opportunity, launched on July 7, 2003, and arrived at the Meridiani Planum on January 25, 2004, on the opposite side of Mars from Spirit. Like the Mars Pathfinder mission before it, Spirit and Opportunity landed on Mars by slowing down from twelve thousand miles per hour to twelve miles per hour by parachute and rocket, then tumbling and bouncing across the Martian surface on huge, eighteen-foot-high cushioned air bags until they came to rest. Both landings were completely successful.