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Bifröst - high-Performance Cryogenic Orbit Transfer Stage (OTS) 
Bifröst is an orbital transfer spacecraft powered by NFA’s 3D printed, full-flow staged combustion, LOX/LNG Mjölnir engine - and 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. 

Key Benefits

The high-performance engine enables the design of a small and lightweight OTS due to its performance and the high bulk density of LOX/LNG fuel, which is over twice that of LOX/LH2 fuels. This level of performance and dense propellants allow for the delivery of a reliable, long-life, light-weight, and low-cost OTS with key performance parameters:

  • Powered by a high performance full-flow staged combustion engine

  • Higher thrust and Delta v than the competition

  • Throttleable thrust from 30% to 100%

  • Autogenous pressurization with unlimited zero-g restarts 

  • Access to all Earth, Lunar and cislunar orbits

  • Faster transfers to the libration points

  • Proprietary zero-boiloff technology


Bifröst has the potential to evolve from a transfer stage into a lunar lander - and ultimately a refuelable and fully re-usable OTS. From LEO a 3,000 lb gross OTS can deploy a 400 lb payload to GEO and over 200 lbs to any location in cislunar space, including Earth escape velocity.

For more information go to the NASA Tech Portal. 


A 3,000 lb OTS enables responsive military access throughout cislunar space for space domain awareness and other missions.

  • Bifröst has a small form factor optimized for launch inside the fairing of venture class vehicles. 

  • The Mjölnir engine will be available for Bifröst, lunar lander, or related capabilities in 2024.



Download the factsheet.

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