https://en.wikipedia.org/wiki/RF_resonant_cavity_thruster

Jerry Eugene Pournelle (born August 7, 1933) is an American science fiction writer, essayist and journalist who contributed for many years to the computer magazine Byte. Pournelle was an intellectual protégé of Russell Kirk and Stefan T. Possony. Pournelle wrote numerous publications with Possony, including The Strategy of Technology (1970). The Strategy has been used as a textbook at the United States Military Academy (West Point), the United States Air Force Academy (Colorado Springs), the Air War College, and the National War College.

Pournelle worked in the aerospace industry includes time he worked at Boeing in the late-1950s. While there, he worked on Project Thor, conceiving of "hypervelocity rod bundles", also known as "rods from God". He edited Project 75, a 1964 study of 1975 defense requirements. He worked in operations research at The Aerospace Corporation, and North American Rockwell Space Division, and was founding President of the Pepperdine Research Institute. In 1989, Pournelle, Max Hunter, and retired Army Lieutenant General Daniel O. Graham made a presentation to then Vice President Dan Quayle promoting development of the DC-X rocket.