Microwave Pain Ray Keeps Frost From Killing Crops

An anonymous reader writes "Philip K. Dick's novella Project Plowshare was set in a world where deadly new weapons are 'plowshared' into consumer products. A few years after that book was set, defense giant Raytheon is spinning its raygun-like Active Denial System from a weapon into an agricultural tool to prevent frost from damaging citrus and grape crops."