Rotorcraft
Mars Helicopter Replica Rotors Into Anaheim
NASA's Mars Helicopter, designed to operate in the red planet's extremely thin air, makes an appearance this week at Heli-Expo 2020 in Anaheim, California.

Helicopters have hovered over and landed on the 29,029-foot summit of Mount Everest, but hovering anywhere on Mars is a whole new ballgame. The Martian atmosphere is less than one percent of the atmospheric volume on Earth—the equivalent of flying at an altitude of about 100,000 feet above Earth.