Mars Curiosity Rover

NASA's car-sized rover landed on Mars in August 2012 using a never-before-tried "sky crane" maneuver that looked like science fiction. Curiosity confirmed that Mars once had liquid water, found organic molecules in 3.5-billion-year-old rocks, and detected seasonal methane fluctuations that could hint at biological processes. Designed for a 2-year mission, it's still exploring Gale Crater over a decade later. It proved Mars was once habitable — the single most important question in planetary science.