text: who and what did lonnie g.johnson?   for years, lonnie g. johnson has been inventing thermodynamics systems for nasa and other organizations; but he has won his greatest fame for re-inventing the squirt gun.  johnson capped a childhood of tinkering with appliances in his senior year of high school, when he won a national inventing competition for "linex," a remote-control robot he had built out of junkyard scraps. he went on to more formal training at tuskegee university, where he earned first a b.s. in mechanical engineering (1972) and then an m.s. in nuclear engineering (1974).   soon thereafter, johnson joined the u.s. air force, where he became an advanced space systems requirements officer at the headquarters of the strategic air command in omaha, nebraska. after directing many projects and earning several decorations, as well as a nomination for astronaut training, johnson moved on to nasa's jet propulsion laboratory in california. here he helped develop thermodynamic and controls systems for space projects, including award-winning work for the galileo jupiter probe and the mars observer project; his crowning achievement at jpl was the johnson tube, a cfc-free refrigeration system with a hydraulic heat pump, which later earned johnson his seventh patent (#4,724,683; 1988).   while with the usaf and jpl, johnson continued to invent at home. in 1985, he founded his own company, later renamed johnson research and development.. johnson had first conceived his most famous invention in 1982: when a homemade nozzle at his bathroom sink shot a spray of water across the room, johnson resolved to invent the world's first high-performance, pressurized water gun.   johnson with partner bruce d'andrade finally created a workable prototype of the now famous supersoaker® in 1989. they filed for a joint patent (granted 1991) and found a manufacturer, larami corp. (now a subsidiary of hasbro, inc.). the supersoaker® uses an air pump to pressurize its water supply, allowing for tremendous distance and accuracy in water-marksmanship. those unfamiliar with this product cannot appreciate its popularity: since 1990, over 40 million supersoakers® have generated over $200 million in sales; today, dozens of websites are devoted to them.   meanwhile, johnson has earned over 40 patents, and continues to invent in the realms of thermo- and fluid dynamics as well as toys. in addition to ongoing controls work for nasa, johnson and his company are developing an improved home radon detector, a rechargeable battery, and a heat pump that uses water instead of freon, among other projects.   lonnie johnson has won numerous honors for his success in inventing and entrepreneurship, and his constant encouragement of young people to invent. he is a legendary businessman and public figure in his hometown of marietta, georgia---whose mayor declared february 25, 1994 "lonnie g. johnson day" in his honor---and, thanks to the supersoaker®, he is a hero to kids nationwide.