Image copyright
NASA / JPL
Nasa is sending a helicopter to Mars, in the first test of a heavier-than-air aircraft on another planet.
The Mars Helicopter will be bundled with the US space agency's Mars rover when it launches July 2020.
Its design team spent more than four years shrinking a working helicopter to "the size of a softball" and cutting its weight to 1.8kg (4lbs).
It is specifically designed to fly in the atmosphere of Mars, which is 100 times thinner than Earth's.
Nasa describes the helicopter as a "heavier-than-air" aircraft because the other type - sometimes called an aerostat - refers to aircraft like balloons and blimps.
The helicopter's two blades will spin at close to 3,000 revolutions a minute, which Nasa says is about 10 times faster than a standard helicopter on Earth.
"The idea of a helicopter flying the skies of another planet is thrilling," said Nasa Administrator Jim Bridenstine.
"The Mars Helicopter holds much promise for our future science, discovery, and exploration missions to Mars."