. >> matt keennon: don't let it go.as a history of making unusual things that can fly. he's an engineer at a company called aerovironment, which produces drones for military and civilian use. i mean, that's incredible. ten years ago, for a military research project, keennon and his team created this robotic hummingbird, which has a tiny camera onboard. whoa! ( laughs ) >> keennon: there it is. >> cooper: oh, my god. that's amazing. keennon and engineer ben pipenberg led the aerovironment team that created "ingenuity's" rotors, motors, and landing gear. why was this so challenging? >> pipenberg: because it has to be a spacecraft as well as an aircraft, and-- and flying it as a-- as an aircraft on mars is pretty challenging because of the density of the air. it's similar to about earth at 100,000 feet. >> cooper: how do you go about it? >> pipenberg: well, so, building everything extremely lightweight is really, really critical. >> cooper: the helicopter's blades, for example, are made of a styrofoam-like material coated