Mjölnir refers to the hammer of the thunder god, Thor, in Norse mythology. The hammer is used as both a devastating weapon and as an instrument to deliver blessings. The Washington-based startup New Frontier Aerospace (NFA) gave its 3D printed rocket engine the same name, giving the tool a powerful impression. Now, the Mjölnir rocket engine is making headlines since its series of successful hot fire tests, advancing the technology for defense, aerospace and commercial applications.
According to NFA, the Mjölnir is the world’s most advanced compact pump-fed rocket engine. With a full-flow staged combustion cycle, Mjölnir is ideal for high-performance reusable rockets, hypersonic vehicles and orbital transfer spacecraft. The engine was also designed with sustainability in mind. It is powered by clean liquid natural gas (LNG) and is net carbon negative when sourced from bio-waste, highlighting NFA’s commitment to environmental responsibility. The engine is reusable as well, with deep throttling (which refers to the ability of a rocket engine to significantly reduce its thrust output) and easy start and stop. Mjölnir is now available as a standalone product, offering customers a propulsion solution for their missions.
The 3D printed Mjölnir rocket engine (left) and NFA’s Intercontinental Rocket Liner (right)
This engine’s development was made possible through seed funding from National Security Innovation Capital, part of the Defense Innovation Unit, with this sustained engine test series funded by NASA. The consistent results from these hot fire tests mark a significant step forward for NFA as it continues to redefine aerospace propulsion. Bill Bruner, CEO of NFA, exclaimed his enthusiasm: “We are proud of the amazing team that built this program and thrilled with the engine’s performance during this series of hot fire tests. Mjölnir’s compact design, unmatched efficiency, and clean fuel make it a game-changer for hypersonic flight and space propulsion. It is poised to power our ambitious roadmap and open new possibilities for our customers.”
Mjölnir In Flight
In early 2026, Mjölnir will propel NFA’s Pathfinder hypersonic Vertical Takeoff and Landing (VTOL) Unmanned Aerial System (UAS) to its first hovering flight. NFA has its sights set on VTOL for one principal reason: market access. According to the startup, there are over 6,000 improved heliports in the US and over 4,000 paved runways longer than 1,000 meters. NFA can take off and land from these 10,000 airports and heliports, but there are fewer than 2,000 paved runways over 1,500 meters. Why is that a problem? Well, runway-dependent supersonic and hypersonic aircraft are limited to these <2,000 runways. VTOL will help break away from supersonic and hypersonic dependence on runways, opening the door to more flight opportunities.
By 2027, Mjölnir will also drive NFA’s Bifröst High-Performance Cryogenic Orbit Transfer Spacecraft (OTS). This OTS is optimized for small satellites and NASA “Venture Class” launch vehicles. From low Earth orbit, a 3,000 lb. gross weight Bifröst enables rapid Hohmann transfers of 400 lb. payloads to geostationary orbit, 200 lbs. to any location in cislunar space or 110 lbs. to Venus transfer, Mars transfer or Earth escape velocity. In addition to its use by NASA, this technology could be used for commercial and military projects. To learn more about NFA and Mjölnir, click here.
NFA’s Bifröst High-Performance Cryogenic Orbit Transfer Spacecraft
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*All Photo Credits: New Frontier Space