The Air Force Research Laboratory (AFRL) and Ursa Major have successfully completed the second flight of the liquid-fueled Affordable Rapid Missile Demonstrator (ARMD), powered by the Draper liquid rocket engine.

The program behind the missile demonstrator, designed for hypersonic speeds, is building towards future tests where it will show off its full capabilities.

The Affordable Rapid Missile Demonstrator (ARMD) first flew just 45 days prior to the second launch. Both tests so far have seen the demonstrator reach supersonic speeds.

Ursa Major’s versatile Draper engine

The ARMD, funded by the Air Force Research Laboratory (AFRL), is powered by Ursa Major’s Draper liquid rocket engine. While most tactical missiles today rely on solid rocket motors, Draper is a throttleable and restartable liquid engine.

According to Denver-based Ursa Major, this allows for complex maneuvers as well as speed adjustments that are simply not possible using solid rocket motors. It also enables easier storage, leading to rapid deployability.

Solid rocket motors are typically favored for missile operations as their fuel is more easily stored, allowing for faster deployment. However, this comes with a key tradeoff. Namely, that solid motors don’t provide the same performance as liquid engines used for large rockets.

The Draper engine uses a non-cryogenic kerosene peroxide fuel combination, which remains liquid at room temperature. This allows for simpler storage than a typical liquid oxygen engine, eliminating the need for complex cooling systems. Essentially, the 4,000-lbf thrust Draper engine combines the storable characteristics of a solid motor with the higher performance and maneuverability associated with liquid engines.

An ‘unprecedented development-to-flight timeline’

The agile deployability of Draper seems to be enabling a rapid testing campaign for ARMD. In a press statement from Ursa Major announcing the second flight, the company noted that “ARMD continues at an aggressive pace, achieving an unprecedented development-to-flight timeline of just eight months.”

The company claims its two flights so far have proven the performance, control, and adaptability of the Draper liquid rocket engine during critical phases of flight.

As AFRL Rocket Propulsion Chief Dr. Javier Urzay pointed out: “The swift technology advancements we are making in ARMD on affordable and mass-producible liquid rocket propulsion are a testament to the resolve, boldness, and strategic vision with which we are researching the unknown with discipline and rapidity, always with the all-absorbing purpose of developing revolutionary capabilities for war.”

“ARMD revolutionizes capability development for the nation’s Arsenal of Freedom through agile Public-Private Partnerships and proves that we have ingredients to rapidly design, build, integrate, and fly rocket-powered high-speed weapons fast and affordably,” added Ursa Major CEO Chris Spagnoletti.

According to Ursa Major, its Draper liquid engine can be used for military applications, as well as a host of applications within the commercial space sector. These include space logistics use cases, such as space tugs and satellites.