Curiosity is scheduled to touch down on the martian surface at around 10:30 pm PDT on Sunday, August 5. After hurtling through the martian atmosphere and decelerating, over the course of seven minutes, from a top speed of 13,000 mph to a virtual halt, the one-ton rover, in a configuration NASA refers to as a “sky crane,” will be slowly lowered onto the surface of Mars on a trio of nylon ropes. Previous missions like Spirit and Opportunity used airbags to bounce down on Mars, but airbags were ruled out because Curiosity is just too big.

“It looks crazy,” admitted JPL’s Rob Manning, Flight System Chief Engineer for NASA’s Curiosity rover, as he outlined the spacecraft’s entry, descent and landing sequence at a recent press briefing. But it was “the result of careful, long, reasoned thought with rooms full of very, very bright engineering people,” Manning said. And in the end, “it was really the least crazy option.”