Reaction Engines

Reaction Engines Ltd., founded in 1989 and headquartered in Culham, Oxfordshire, developed the Synergetic Air-Breathing Rocket Engine (SABRE), a combined-cycle propulsion concept designed to enable single-stage-to-orbit spaceplanes and hypersonic flight using a novel precooler heat exchanger. The company also pursued thermal management and zero-carbon technology applications derived from its core microtube technology. Investors included BAE Systems and Boeing HorizonX Ventures, and the company maintained a test facility in Colorado through its US subsidiary. Reaction Engines filed for bankruptcy in November 2024.