Today NASA will attempt its eighth successful landing of a robot on the red planet by venturing to place its InSight lander--a spacecraft almost 10 years and nearly one billion dollars in the making--as gently as possible on the vast planes of Mars' Elysium Planitia. But a soft touchdown is far from guaranteed. The 1500-pound robot will enter the planet's atmosphere around 12:00 PST in excess of 12,000 miles per hour, its protective aeroshell shielding it from heat-generating friction and treacherous sandstorms on its descent toward the Martian surface. Yet the planet's thin atmosphere can only slow the spacecraft so much; InSight will also deploy a 39-foot-wide supersonic parachute and activate its descent thrusters to decelerate to just five miles per hour before finally plopping down on its shock-absorbing legs. An uneventful arrival is crucial to protecting the spacecraft's cargo.