Phase Four Wins U.S. Air Force Contract for Electric Propulsion of Satellites

April 8, 2021

Phase Four has secured a contract with the U.S. Air Force for the company's propellant-agnostic Maxwell thruster. Under the contract, Maxwell will utilize iodine, a new alternative fuel, to replace the costly, legacy electric propulsion propellants in high-performance commercial and defense applications.

Under a new contract with the U.S. Air Force, Phase Four’s propellant-agnostic Maxwell thruster (pictured here) will utilize iodine, a new alternative fuel, to replace the costly, legacy electric propulsion propellants in high-performance commercial and defense applications.

"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. Dan Eckhardt, Electric Propulsion Lead at the U.S. Air Force Research Laboratory.

The hallmark of Phase Four's versatile RF Thruster technology is its flexible architecture, which can utilize traditional noble gases and new alternative sources ranging from iodine to water to air. Together with the Air Force, Phase Four will demonstrate major new advantages that the Maxwell iodine-fueled engine can provide to large satellite constellations, including: 

Vastly lower propellant costs

Increased satellite range and lifetime on orbit, due to the ability to store more fuel onboard, as iodine is 4x more dense than traditional xenon propellants

Lower risk of debris incidents, due to the elimination of high-pressure storage

Increased sustainability, due to the ability to decommission and responsibly dispose of satellites at their end of life

"Iodine is a promising propellant, due to its densely storable nature, lack of high-pressure components, and performance potential, compared to traditional noble gas propellants like xenon," said Phase Four CTO, Umair Siddiqui. "More efficient smallsat propulsion systems, such as an iodine RF thruster, will enable new missions in remote sensing, space surveillance, communications and other areas."

Phase Four's project received several letters of support from industry and government agencies that anticipate iodine-fueled propulsion engines will lower costs and create new opportunities for commercial and defense satellite operators.

Phase Four is also working with other government customers to further develop the Maxwell RF thruster to increase performance for long-duration missions where significant maneuverability is required. Phase Four's RF thruster is simpler, smaller, lighter and less expensive than legacy electric propulsion systems, due to technical innovations and the use of low-cost RF electronics developed by the smartphone and wireless charging industries. These improvements will enable government and commercial space operators to deploy critical mission capabilities in space at a lower cost and faster cadence than currently possible.

"As the space industry rapidly expands between the Earth, Moon and Mars, we need technologies that lower the cost, shorten lead times and improve the quality of mass-manufactured space hardware," said Phase Four CEO Beau Jarvis. "With our RF Thruster and support from the U.S. Air Force, Phase Four is working to bring the industry lower cost, mass-manufactured, high-performance satellite engines."