A research team led by Professor Lee Anna in the Department of Mechanical Engineering at Pohang University of Science and Technology POSTECH said on the 28th that it developed a "zero carbon emission" ammonia propellant in collaboration with Senior Researcher Kang Hong-jae at the Korea Institute of Machinery & Materials (KIMM).
Most rockets, including Nuri, use hydrocarbon fuels and emit soot and carbon dioxide, drawing criticism for environmental limits.
The team focused on ammonia, which does not emit carbon dioxide or soot and is easy to store and handle. Ammonia has high hydrogen storage efficiency and can be stored long term, but its low ignitability, which makes it hard to light, has been an obstacle to practical use.
In this study, the team used nitrous oxide as an oxidizer and combined it with "rotating gliding arc (RGA) plasma ignition technology." RGA plasma activates plasma in three-dimensional space to reliably ignite ammonia and sustain combustion stably.
As a result of the experiments, the ammonia–nitrous oxide propulsion system achieved higher specific impulse (propulsion efficiency) and lower combustion temperature than the conventional nitrous oxide–hydrocarbon combination, securing both performance and thermal stability. In particular, using either ammonia or nitrous oxide as a plasma starting gas greatly improved restart capability and operational flexibility.
The achievement is evaluated as a key turning point that will accelerate the transition to carbon-free space propulsion. By combining an easy-to-store fuel, a simple oxidizer pairing, and stable plasma ignition, it presents a new roadmap that can simultaneously deliver carbon neutrality, low thermal load, and restart capability.
The team said, "We overcame ammonia's low ignitability and combustion stability issues with innovative plasma technology," adding, "We effectively suggested a direction for developing an eco-friendly propellant that also offers storability."
The findings were published in the international journal on propellants and combustion, "Fuel," on Sep.
References
Fuel (2025), DOI: https://doi.org/10.1016/j.fuel.2025.136893