Phase Four unveils monopropellant multi-mode propulsion systems

Phase Four, a leader in next-generation electric propulsion solutions for satellites, has announced the commercialization of its monopropellant multi-mode propulsion systems. Using their Maxwell Block III, Phase Four's technology supports electric propulsion capabilities for various mission needs, utilizing either ASCENT or hydrazine chemical propellants. The company plans to begin taking orders for these systems in the first half of next year.

The monopropellant multi-mode propulsion system offers a significant improvement in satellite performance by combining the high thrust of chemical propulsion with the high efficiency of electric propulsion-all powered by a single chemical propellant. Phase Four's proprietary radiofrequency (RF) thruster enables this by integrating chemical propellants into its electric propulsion system.

Phase Four will supply the electric propulsion component for a series of ground demonstrations involving both ASCENT and hydrazine-based multi-mode systems by the end of Q1, 2025. These demonstrations are in collaboration with the Department of Defense and private sector partners.

Hydrazine, the most commonly used propellant in the commercial market, plays a critical role in satellite performance, offering enhanced endurance and maneuverability. ASCENT, a non-toxic propellant developed by the Air Force Research Laboratory (AFRL), provides similar performance without the stringent handling requirements associated with hydrazine systems.

One of the main advantages of Phase Four's system is that it runs exclusively on chemical propellant, eliminating the need for additional xenon or krypton tanks typically required in other multi-mode propulsion systems. This simplifies the overall design while reducing size, weight, and cost.

Challenges with traditional electric propulsion propellants persist, as supply chain issues with xenon and krypton pose ongoing economic and security concerns. Phase Four's multi-mode system avoids reliance on these propellants, a move that has positive implications for both commercial and national security missions.

Umair Siddiqui, President and CTO of Phase Four, stated: "At Phase Four, we've been refining the state-of-the-art electrodeless RF thruster for nearly a decade. The absence of a hollow cathode allows our thruster to handle propellants like hydrazine and ASCENT more effectively than traditional electric propulsion systems. We are excited to demonstrate this capability through direct integration with live propellants, in collaboration with the Department of Defense and leading chemical thruster suppliers."

Phase Four continues to invest in developing their multi-mode propulsion system, focusing on key national security missions scheduled for later this decade. The company is currently testing a new electric string thruster designed for multi-mode operations, which is showing significant improvements in thrust and specific impulse. Additionally, the use of a single chemical propellant simplifies on-orbit refueling, and Phase Four is actively developing commercial partnerships to advance this capability.

Steve Kiser, CEO of Phase Four, added: "A true monopropellant multi-mode propulsion is a game-changer for space operations, and Phase Four is excited to bring this product to market. By enabling a propulsion system to quickly and easily toggle between chemical and electric propulsion performance, Phase Four is bringing dynamic space operations (DSO) capabilities to both commercial and government programs now."