On Aug. 6, NASA’s Mars Science Laboratory will try to land its new space rover, Curiosity, on Mars. Their record on landing other spacecraft on Mars is spotty. And with this upcoming attempt there is, quite literally, no margin of error. Here, some NASA engineers explain:

More from Extreme Tech on why landing spacecraft on Mars is mind-boggingly difficult (narrated, if you'd like, by William Shatner).

(h/t: Kottke)