Ursa Major Successfully Completes Ground Tests of New Draper Liquid Engine

Rocket propulsion startup Ursa Major has announced the successful completion of ground tests for its new Draper liquid engine, which is being developed with funding from the U.S. Air Force.

The hot-fire tests, conducted at the company's facilities in Berthoud, Colorado, have validated the basic design of the engine, according to Joe Laurienti, founder and CEO of Ursa Major.

The Draper engine, a 4,000-pound-thrust closed catalyst cycle engine, was ignited more than 50 times in March, with each firing lasting several seconds.

"We expect qualification next year," - Joe Laurienti, Ursa Major Founder and CEO

While a hot fire is a significant milestone in the development process, many more tests will be needed with multiple engines before Draper is ready for flight.

The tests were conducted on a Draper-specific test stand built with funding from the Air Force Research Laboratory under a contract awarded last year.

Innovative Fuel Choice for Storage and Performance

The Draper engine uses a non-cryogenic kerosene peroxide fuel combination, which offers a simpler storage solution compared to engines using liquid oxygen.

Non-cryogenic fuels remain liquid at room temperature, which could be advantageous for some in-space propulsion applications like lunar landers, where propellants need to be stored for extended periods.

“Draper combines the storable attributes of a solid rocket motor with the active throttle control and throttle range of a liquid engine, providing the maneuverability and flexibility needed for hypersonic defense...For things like responsive hypersonics interceptors, you need the ability to fly on a moment’s notice. So our propellant choice was intended to do that while preserving performance.” - Joe Laurienti, Ursa Major Founder and CEO

The benefits of the engine's closed cycle architecture, which allows the kerosene to be shut off completely. The engine can then run either with just hydrogen peroxide decomposed or with peroxide and kerosene.

“Draper can throttle down below 10% max power, which is really nice for applications like terminal phase on hypersonics or landing on a non-terrestrial surface,” - Joe Laurienti, Ursa Major Founder and CEO

Broader Applications and Future Plans

Ursa Major's other engine, the 5,000-pound-thrust liquid oxygen and kerosene Hadley engine, flew for the first time in March, powering a Stratolaunch hypersonic test vehicle.

Draper is aimed at customers looking to develop test targets that simulate hypersonic threats and will also be offered for space applications, such as orbital transfer vehicles requiring high impulse maneuvers or orbital insertions into cislunar space.

Ursa Major is currently in discussions with potential partners for test flights of the Draper engine, with plans for these flights to take place in 2026.

The successful ground tests mark a significant step forward for Ursa Major and its Draper engine.