Curiosity (Mars rover)

Curiosity is a car-sized rover that NASA landed on Mars on 6 August 2012. It explores Gale Crater, a huge basin with a tall mountain in its centre.

What it carries

A robotic arm, a drill, cameras, a laser that vaporises rock to read its chemistry, and laboratories inside the rover that analyse soil and rock samples.

What it discovered

Curiosity found that Gale Crater once held lakes and streams with water that was not too acidic or salty, and that the rock contains the chemical ingredients that life needs. In other words, ancient Mars could have supported simple microbial life.

How it is controlled

Radio signals take several minutes to travel between Earth and Mars, so nobody can steer it live. Engineers send a plan for the day, and the rover executes it using its own sensors to avoid hazards. This is a good example of semi-autonomy: humans choose the goal, the robot handles the details.

Power

Curiosity runs on a radioisotope power system rather than solar panels, which lets it work through dust and the dark Martian winter.

Why it matters

Curiosity shows that a robot can do science far from any human help, and it set the design for its successor, Perseverance.