Ingenuity, a technology experiment, is preparing to attempt the first powered, controlled flight on the Red Planet.

When NASA’s Perseverance rover lands on Mars on Feb. 18, 2021, it will be carrying a small but mighty passenger: Ingenuity, the Mars Helicopter.

The helicopter, which weighs about 4 pounds (1.8 kilograms) on Earth and has a fuselage about the size of a tissue box, started out six years ago as an implausible prospect. Engineers at NASA’s Jet Propulsion Laboratory in Southern California knew it was theoretically possible to fly in Mars’ thin atmosphere, but no one was sure whether they could build a vehicle powerful enough to fly, communicate, and survive autonomously with the extreme restrictions on its mass.