Shawyer's EmDrive: twenty years of selling an engine that broke physics

Roger Shawyer founded Satellite Propulsion Research Ltd in 2001 on a single claim: a sealed metal cone that bounces microwaves around inside can produce thrust with no propellant — a reactionless drive that would break conservation of momentum. In December 2002 he demonstrated 0.02 newtons of thrust from an 850-watt rig for a few dozen seconds before it overheated. The result was never published and never independently replicated; he sold the idea anyway.

For fifteen years the EmDrive was Shawyer's pitch: no fuel, no reaction mass, Mars in weeks. Boeing looked in 2009 and walked away by 2012. The claim found its best marketing by accident in 2014, when slides from NASA's tiny Eagleworks lab leaked early and made headlines around the world; in November 2016 Eagleworks published a peer-reviewed paper reporting 1.2 millinewtons per kilowatt in vacuum — 'peer-reviewed' being the word that did the work.

Independent labs never saw real thrust. In 2018 Martin Tajmar's group at Dresden found the drive 'pushed' just as hard in configurations where physics says it cannot — an artefact of Earth's magnetic field pulling on unshielded power cables. In 2021 they rebuilt the NASA experiment exactly and found the scale itself: the engine warms, the fastening elements warp, and the balance settles on a new zero point. 'Our measurements refute all EmDrive claims by at least 3 orders of magnitude.'

Twenty years after the first demo, nothing had flown, no buyer had signed, and the company's name had become a byword for the impossible. The debunk earned a fraction of the headlines the leak earned, and the peer-reviewed paper became the meme's best evidence. The real bill landed on the founder: a lifetime claim that a warm scale had made briefly, gloriously credible.