Modern rockets originated when Goddard attached a supersonic (de Laval) nozzle to the combustion chamber of a liquid-fueled rocket engine. These nozzles turn the hot gas from the combustion chamber into a cooler, hypersonic, highly directed jet of gas, more than doubling the thrust and raising the engine efficiency from 2% to 64%.[58][59] On 16 March 1926 Robert Goddard launched the world's first liquid-fueled rocket in Auburn, Massachusetts.