NASA is sending a tiny unmanned helicopter to Mars in a mission aiming for to make the first aircraft launch from the surface of another planet.
Scientists spent years shrinking down a fully working spacecraft to a size smaller than a football to meet the challenges of operating in the red planet's thin atmosphere.
It is set to be the first time that a heavier-than-air craft - ie not a bubble or blimp - has been flown through an alien planet's skies.
They hope that it will prove the technology for future flight explorations of Mars and provide more data on the atmosphere.
The helicopter will be shuttled to Mars on board a rocket arriving in 2020, but once there it is designed to be able to take off autonomously on a series of short flights.
The launch team on Earth will be able to send commands to the helicopter via the rocket - but it is too far away from them to control it directly.
The helicopter's rotating blades will have to spin at 3,000 rpm – about 10 times the rate of a helicopter on Earth – in order to cut through the air.
It will also have solar cells to charge its lithium-ion batteries, and a heating mechanism to keep it warm through the cold Martian nights.
The team say it's an ambitious project that carries a high risk of failure - but if it comes off it could offer new frontiers for space exploration.
Thomas Zurbuchen, Associate Administrator for NASA's Science Mission Directorate, said the mission provided "a unique opportunity to advance Mars exploration for the future".
“The ability to see clearly what lies beyond the next hill is crucial for future explorers,” he said.
“We already have great views of Mars from the surface as well as from orbit.With the added dimension of a bird’s-eye view from a ‘marscopter,’ we can only imagine what future missions will achieve.”