Curiosity Rover

Curiosity is a car-sized mobile laboratory that has been exploring Mars since 2012, and it fundamentally advanced the case that the planet was once habitable. Launched by NASA in November 2011, it made a spectacular arrival in August 2012, lowered onto the surface of Gale Crater by a rocket-powered "sky crane" in a landing sequence so complex that engineers called it the seven minutes of terror.

Curiosity's central mission was to determine whether Mars ever had the conditions to support microbial life. It answered that question decisively and early: analyzing rocks in Gale Crater, it found an ancient lakebed environment with the right chemistry, energy sources, and building blocks — a place where life could plausibly have survived, had it existed. The rover has since detected complex organic molecules preserved in the rock and observed seasonal fluctuations of methane in the atmosphere, a gas whose origin remains one of the great open mysteries of Mars.

Powered by a nuclear battery rather than solar panels, Curiosity has been free from the dust-driven power loss that ended earlier missions, and it has spent years climbing the layered slopes of a mountain at the crater's center, reading the planet's history in the rock like pages in a book. It also carried a radiation detector that measured the dose an astronaut would receive on the journey to and stay on Mars, providing essential data for planning future human missions. Curiosity's success directly shaped the design of its successor, Perseverance.