Draper liquid rocket engine achieves supersonic speeds in US Air Force test
The Air Force Research Laboratory (AFRL) and Ursa Major have successfully completed the first flight of the Affordable Rapid Missile Demonstrator (ARMD), powered by the Draper liquid rocket engine.
The flight achieved supersonic speeds and represents a shift toward cost-effective, mass-producible defense technology.
It will enhance national deterrence while expanding the toolkit for immediate, long-distance strike missions.
Currently, Ursa Major is focused on the next phase: conducting further flight tests to fully characterize the Draper engine’s performance in real-world conditions.
“This project proves that we can transform and leverage our acquisition models to rapidly deliver critical technology advancements to deter and win in a future conflict,” said AFRL Commander and Air Force Technology Executive Officer Brig. Gen. Jason Bartolomei.
“We are not just building a single missile; we are forging a new path toward a cost-effective, mass-producible deterrent for the nation,” he added.
Draper engine
At the core of the missile is the Draper liquid rocket engine. While most tactical missiles rely on solid rocket motors, Draper is different.
It is a throttleable and restartable liquid engine. This allows for complex maneuvers and speed adjustments that solid rockets simply can’t match.
This milestone is a leap in developing next-generation missile tech, with the AFRL prioritizing affordable, scalable propulsion.
Focusing on these modular systems, the program ensures the U.S. can rapidly adapt its arsenal to meet the shifting demands of future defense landscapes.
The successful Draper engine demonstration is the culmination of a multi-year public-private partnership between the AFRL and Ursa Major.
Beyond the flight itself, the innovation lies in a manufacturing model that leverages the proven architecture of the Hadley engine.
This approach yields a propulsion system that is storable for long-term readiness, optimized for rapid mass production, and more cost-effective than standard designs.
By avoiding expensive, exotic materials, Ursa Major has created a scalable solution specifically built to meet the high-volume demands of modern conflict.
“ARMD represents a key milestone in our efforts to develop revolutionary, affordable and scalable liquid rocket engine technologies to win the wars of tomorrow,” said AFRL Rocket Propulsion Division Chief Dr. Javier Urzay.
Rapid development
Ursa Major CEO Chris Spagnoletti highlighted the mission as a breakthrough for liquid propulsion, proving that high-performance engines can be both safe and throttleable while remaining affordable.
Most impressively, the program shattered traditional timelines by delivering a flight-ready system in just eight months. In a field defined by bureaucratic inertia, moving from contract to flight in under a year is nothing short of a developmental miracle.
Moving forward, Ursa Major remains under contract with the AFRL to conduct further flight tests that will fully validate the Draper engine’s operational potential.
Ultimately, this mission seeks to fortify the U.S. defense industrial base while providing robust security solutions for global allies.
“This flight proves that you can get a vehicle with a safe, storable and throttleable liquid engine in the air quickly and affordably,” said Spagnoletti.
“We went from contract to flight-ready of an all up round and propulsion system in just eight months,” he added in the press release.
Ursa Major also aims to rapidly deploy these critical capabilities across all combat domains — land, air, sea, and space.
