Before the Mars Science Laboratory, aka Curiosity, can begin exploring Gale Crater (as shown in this artist's conception), the rover will have to survive a landing NASA calls seven minutes of terror (see video).
In that brief time around 1:30 a.m. ET Monday, friction, a parachute, and an unprecedented "sky crane" hovercraft will help take Curiosity from 13,200 miles (21,200 kilometers) an hour to zero—if everything goes to plan.
"When we proposed this plan, we were almost laughed off the project," Adam Steltzner, NASA's chief engineer for the operation, says in the new National Geographic e-book Mars Landing 2012. "People said it couldn't possibly work."
The Curiosity rover is the largest and most complex of its kind, and so, by necessity, is its landing. What's more, the process couldn't be rehearsed, because Mars's atmosphere is so different from Earth's.
Making matters worse, the rover will truly be on its own as it falls. Because of communications delays, by the time we know anything is wrong, it'll be too late to fix it.
(On TV: Watch Martian Mega Rover August 9 at 10 p.m. ET/PT on the U.S. National Geographic Channel.)