Abstract
Aerospace propulsion research is both a technical frontier and a governance problem. Rotating detonation engines (RDEs) promise compact, high-efficiency propulsion through pressure-gain combustion, but those same performance advantages make them attractive for both civilian aerospace missions and military systems. This dual-use character is the central sociotechnical problem of the paper: the same engine architecture that may support deep-space missions, reusable launch systems, or high-speed transportation can also support hypersonic weapons, missile propulsion, and defense strategy. This paper uses the RDE as a case study in dual-use technology rather than as a passing example of militarized aerospace research. The argument is that RDE development shows how dual-use risk is shaped before a technology reaches deployment. Funding agencies, laboratories, defense contractors, university research groups, and policy frameworks help determine which performance goals matter, which applications seem legitimate, and which futures become easier to imagine. Ethical responsibility therefore cannot be limited to the intentions of individual engineers; it must also address the institutional systems that organize propulsion research. The technical component of this project centers on designing and optimizing an ethylene- nitrous oxide RDE test apparatus to study injector geometry, mixing efficiency, and detonation stability. The STS component examines how RDE research illustrates the governance challenges of dual-use aerospace technology, especially when civilian goals such as efficiency and exploration overlap with defense-funded military applications. Together, these components show that the engineering of advanced propulsion systems is inseparable from the social, political, and ethical structures in which that engineering takes place.