By Laura Foster, Apr. 19: A small helicopter is set to be the first to fly on another planet.
Ingenuity is a 1.8kg (4lb) helicopter that travelled to Mars inside Nasa's Perseverance rover, which landed in February 2021.
Nasa is testing the rotorcraft on Monday but it will take a few hours before we know whether it has worked.
Flying on the Red Planet isn't straightforward - as BBC science reporter Laura Foster and Nasa systems engineer Farah Alibay explain.