Lonnie Johnson has a degree in mechanical engineering and a master’s in nuclear engineering. He did thermal analysis of plutonium fuel spheres at the Savannah River National Laboratory and developed auxiliary cooling systems at the Oak Ridge National Laboratory. He worked as a systems engineer for the Galileo mission to Jupiter and then joined the USAF and was posted to Strategic Air Command, where he studied nonnuclear-strategic-weapons technology and worked on the Stealth bomber programme.

Later he worked at the Jet Propulsion Lab working on the Cassini mission to Saturn and was the project engineer for the Kraft mission to study an asteroid flyby. He developed a lot of things but it was pottering around in his own home workshop that made him his millions. Johnson is the inventor of the Super Soaker water gun and the spin-off Nerf Gun. Which just goes to show you are never too old to play, so bring back the inventive child you were – the child whose tinkering led to a career in engineering – and revisit those mad inventions you once dreamed up, and refine and complete at least one of them. It will do you good….