Draper Ursa major Test Fire
Image Credit: Ursa Major.

Air Force-Funded Ursa Major Successfully Test Fires “Draper” Engine Built to Power Spacecraft of the Future

Colorado-based space and defense contractor Ursa Major has announced the first successful “hot fire” test of its Draper liquid propellant engine. Funded by the Air Force Research Labs (AFRL), Ursa Major first introduced the 4,000lb thrust closed-cycle engine in May 2023, with the ultimate goal of having a fully operational engine that can operate in the atmosphere or outer space by the end of 2024.

According to a company statement, this successful May test firing puts the development of Draper ahead of schedule, “outpacing industry standards.”

“We’re excited with how quickly the development program has progressed and look forward to fielding the engine for hypersonics and in-space applications in the coming years,” explained Brad Appel, Chief Technology Officer at Ursa Major.

Non-Cryogenic Fuel Makes Draper Ideal for Hypersonics and In-Space Applications

In the company’s statement, the developers of the Draper engine say its ability to create a powerful thrust profile without the use of cryogenic fuels offers spacecraft engineers unprecedented versatility. Fuels that don’t need to be stored at below-freezing temperatures save significant space over liquid oxygen engines, resulting in the ability to carry significantly more fuel into space.

Draper test fire
Image Credit: Ursa Major

“Based on its thrust profile, the engine is not only capable of maneuvering objects in orbit but doing so without fully depleting its store of propellant, potentially allowing for additional mission functions,” the company explains.

According to Ursa Major, this level of versatility is increasingly important as adversary nations develop numerous weapons platforms designed to disable or destroy America’s space assets. As this space race progresses, the company says, “the need for defensive technology will continue to grow.” This means engines like Draper that can offer spacecraft numerous firings in space before running out of fuel will become increasingly critical to protecting those space assets.

Draper test fire
Ursa Major Test Fires the in-development Ripley rocket. Image Credit: Ursa Major.

In the promotion material for the in-development engine, the company notes that Draper is an evolution of their in-production Hadley rocket engine. However, unlike Hadley, which is fueled by a combination of liquid oxygen and kerosene, Draper runs on a combination of hydrogen peroxide and kerosene. According to the company, this change means that Draper “combines the storable attributes of a solid rocket motor with active throttle control and throttle range of a liquid engine.” This combination, they explain, also provides Draper “the maneuverability and flexibility that is needed for hypersonic defense.”

Air Force Research Labs Touts Engine’s Power and Versatility

While Ursa Major has a number of engines in development, including the 50,000lb of thrust Ripley and the 200,000lb of thrust heavy-lift Arroway rocket, the Draper non-cryogenic liquid propellant engine was specifically funded by the Air Force Research Labs. This funding included the design and construction of a specialized test stand at Ursa Major’s Berthoud, Colorado, test facility, where this test firing took place. According to the company, this specialized test stand “has and will continue to allow for greater testing capabilities and, in turn, quicker iteration and development of the Draper engine.”

While there is no definitive timeline for Draper’s real-world deployment, the AFRL says it is impressed by the recent test firing and the rapid pace of the engine’s development over the last twelve months.

“Perhaps the most impressive aspect of this program is the delivery of a versatile, storable rocket engine in such an incredibly short timeframe,” said Dr. Shawn Phillips, Chief of AFRL’s Rocket Propulsion Division. “AFRL and industry is taking on the challenge our USAF and USSF leadership has asked of us…to deliver faster capabilities, craft tighter bonds with industry, and leverage what is already in existence to provide asymmetric advances.”

“Thankfully, this is just the tip of the iceberg when it comes to what we are doing as One Team,” Dr. Phillips added.

Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.