Ursa Major demos Draper liquid engine

The Air Force Research Laboratory and Ursa Major have now disclosed two 2026 flight tests of the Draper liquid rocket engine, giving the public a clearer picture of what the program is trying to prove. AFRL said on March 12 that the two organizations had flown the Affordable Rapid Missile Demonstrator, or ARMD, with Draper power, achieving supersonic speeds and demonstrating concepts of operations. Ursa Major said on May 5 that a follow-on flight took place 45 days later, expanding the flight envelope and showing rapid turnaround of flight hardware. The story matters because Draper is not being pitched as a lab-only engine. Ursa Major describes it as a storable liquid rocket engine derived from work on its Hadley engine and aimed at tactical hypersonics, missile defense, in-space propulsion and space-based interception. AFRL and the company have framed the flights as part of a push to raise the engine’s readiness in an operationally relevant setting rather than only through ground tests. (afrl.af.mil) ### What exactly flew? The vehicle that flew was AFRL’s Affordable Rapid Missile Demonstrator. AFRL said the demonstrator was powered by the Draper liquid rocket engine and reached supersonic speed in the March-announced flight. A photo caption published by AFRL identified one ARMD flight article as staged for launch on Jan. 27, 2026, using a Transportable Target Launcher. (afrl.af.mil) Ursa Major said the May-announced mission was another ARMD flight using the same engine family. The company said that second mission expanded the flight envelope, which indicates additional operating conditions were tested, though neither AFRL nor Ursa Major publicly released detailed speed, altitude or duration figures. That is an inference from the wording of the release, not a published performance breakdown. (afrl.af.mil) ### Why is a liquid engine notable here? Ursa Major says Draper is a storable liquid system, a combination the company markets as offering the storability associated with solid motors and the maneuverability of liquid propulsion. The company also says the engine is throttleable and designed from the flight-proven Hadley architecture. AFRL’s March release tied the demonstration to several years of joint work with Ursa Major on new rocket propulsion technologies. (prnewswire.com) In that release, an AFRL official said the team went “from contract to flight-ready” for an all-up round and propulsion system in eight months, underscoring the program’s emphasis on schedule as well as hardware performance. (ursamajor.com) ### What did the two flights show? The first publicized flight established that Draper could power ARMD in flight at supersonic speed and support the program’s operating concept, according to AFRL. The second publicized flight, announced May 5, showed the team could return to flight in 45 days and continue gathering data on the engine in the air. (afrl.af.mil) MSN, citing the May 5 announcement, said the Air Force-funded 4,000-pound-thrust engine had gone supersonic twice in 45 days. That figure aligns with Ursa Major’s own description of Draper elsewhere as a 4,000-lbf-class engine, though the thrust figure was not highlighted in AFRL’s March release. ### How does this fit Ursa Major’s broader defense push? (afrl.af.mil) Ursa Major has been building a defense propulsion portfolio around both liquid and solid motors. Its hypersonics page places Draper alongside missile defense and interception missions, while a December 2025 company post said ARMD had already completed a full-duration static fire before the 2026 flight campaign. The next disclosed step is more flight work. (msn.com) Ursa Major said on May 5 that it remains under contract with AFRL to advance characterization of the Draper engine in flight, pointing to additional ARMD missions as the program moves beyond the two publicly announced demonstrations. (ursamajor.com 1) (ursamajor.com 2)