Iodine propellant has been on the roadmap of plasma propulsion around the world for a number of years. Studies by NASA Glenn Research Center affirmed that iodine has promise, but its incompatibility with cathodes found in traditional plasma thrusters limits their use with this advanced propellant. The successful development of an advanced propellant such as iodine will enable lower cost, higher reliability deployment of infrastructure in space.
Phase Four’s RF thruster contains no cathode or anode, and in 2021, Phase Four won a Phase 2 Small Business Innovation Research grant funded by AFWERX to develop the first electrodeless iodine plasma thruster in the United States.
Iodine propellant brings a number of critical advancements to the market:
- The propellant is 5% the cost of xenon and 25% the cost of krypton, the two standard plasma propellants used in electric propulsion systems
- Its supply chain is more robust and less prone to dramatic price and lead-time swings, compared to xenon and krypton
- It similar in atomic mass to xenon, promising similar performance to the standard bearing plasma propellant
- It is stored as a solid, meaning it can sit fueled on the shelf ready for rapid deployment it is stored at roughly 3.5x the density of xenon, meaning you can pack more total impulse in a smaller volume storage vessel
“There is a growing need for more options for advanced electric in-space propulsion, to provide satellites with better maneuverability and operability in space at an affordable cost, and propellant flexibility could provide new options for in-space propulsion,” said Dr. Eckhardt, Electric Propulsion Lead at AFRL.