How a missile maker ended up giving kitchens the microwave oven
In 1945 Percy Spencer, an engineer at Raytheon, noticed that the magnetron tubes his company built for wartime radar could heat food very quickly. Two years later Raytheon showed off the Radarange for commercial kitchens. The firm best known for guided missiles had started life making a tube for home radios.
Three men founded the business in Cambridge, Massachusetts, in 1922: MIT electrical engineering professor Vannevar Bush, the engineer Laurence Marshall and the scientist Charles Smith. Called the American Appliance Company, it meant to work on refrigeration but soon pivoted to electronics. Its first hit was a helium-filled tube that regulated voltage, inspired by Smith's research on the star Zeta Puppis. Named Raytheon, from roots meaning light from the gods, the tube let radios run off household mains instead of pricey batteries that died quickly.
The company adopted the tube's name in 1925 and by the 1930s ranked among the biggest vacuum tube makers anywhere. Then war changed everything. British physicists had invented the cavity magnetron, which made radar far better at spotting aircraft, and the American government wanted it mass-produced. Working with MIT's new Radiation Laboratory, Raytheon was turning out magnetrons within months and by 1945 had made about 80 percent of them all, along with shipboard radar and tiny rugged tubes for proximity fuses.
Peacetime brought the microwave oven and, in 1950, the Lark, the first guided missile to knock down an aircraft in flight. Missiles became the core, from the Sparrow and Hawk to the Patriot, and more than 90 percent of revenue eventually came from military work. Yet the side projects were eclectic: a navy computer, the RAYDAC, obsolete by the time it ran in 1953; the hobbyist CK722 transistor; a physics textbook publisher; and the Apollo Guidance Computer, which flew on every Apollo mission.
Buying the appliance maker Amana in 1965 took the microwave home, and in 1967 Raytheon sold the first countertop household model. In 2020 the company merged with United Technologies, and the combined group took the name RTX in July 2023.
Source: Raytheon
