The first of two new American Mars rovers lands successfully on the red planet. The Mars rover Spirit enters the Martian atmosphere (and cleaves a path right through a dust storm), deploying thick layers of airbags that allow it to bounce safely until landing upright. This is the same landing system employed by the Pathfinder mission in 1997, but the unmanned robot probe in this case is much more sophisticated. Among the primary scientific objectives of Spirit’s mission is to determine if water existed on the surface of Mars for a significant length of time. The Spirit rover will undergo a series of diagnostics and won’t begin its mobile mission for several days. Its identical twin, a rover named Opportunity, will land in three weeks.