The symbol of the test-pilot school at Edwards Air Force Base in the Mojave desert, where Mr Armstrong spent years testing military jets, flying the X-15 at 4, 000mph to the very edge of the atmosphere, is a slide rule over a stylised aircraft.

ECONOMIST: Neil Armstrong

After returning and graduating from Purdue, Neil applied to become a test pilot at the National Advisory Committee for Aeronautics High-Speed Flight Station at Edwards Air Force Base.

FORBES: Neil Armstrong's Immortal Footprint