leverages miniaturized RF electronics and our electrodeless thruster in a
compact form factor.
Phase Four, a leading provider of next-generation electric propulsion (EP) solutions for satellites, announced the planned commercialization of their monopropellant multi-mode capability. Using their Maxwell Block III, Phase Four meets electric propulsion performance for a variety of mission profiles, using either ASCENT or hydrazine chemical propellants. Phase Four anticipates taking orders for these systems in the first half of next year.
Monopropellant multi-mode in-space propulsion represents a groundbreaking advancement for satellite performance, offering the high thrust of chemical propulsion combined with the high efficiency of electric propulsion—all powered by a single chemical propellant. Phase Four’s proprietary radio frequency (RF) thruster enables this multi-mode capability by integrating any chemical propellant into the electric propulsion system.
Phase Four is set to supply the electric propulsion component in a series of operational ground demonstrations of both ASCENT and of a hydrazine-based multi-mode systems by the end of Q1, 2025. These efforts are in partnership with the Department of defense and private sector partners.
Both these chemical propellants are important. As hydrazine is currently the most widely used chemical propellant in the commercial market, this advance is poised to have broad implications for satellite endurance, maneuverability, and dynamic space operations. ASCENT, a non-toxic propellant developed by AFRL, offers similar performance characteristics to hydrazine but without the stringent handling and safety protocols required for hydrazine systems.
A key advantage Phase Four provides satellite operators is their system is truly monopropellant. The Maxwell Block III can run exclusively on the chemical propellant, removing the need for auxiliary xenon or krypton tanks, typically used in other developmental multi-mode programs. This significantly simplifies the design of the system, while simultaneously reducing its size, weight and cost.
Traditional electric propellant issues continue to challenge the industry. As xenon and krypton supply chains continue to pose economic and security concerns, a multi-mode system completely avoids the need for such propellants has positive implications for both commercial and national security missions.
Importantly, Phase Four continues to invest in their multi-mode capability, focusing their development efforts to meet important national security missions scheduled for later this decade. The company has built and is currently testing a follow-on electric string thruster specifically designed for multi-mode operations, which is already demonstrating significant expansion of both thrust and specific impulse. Additionally, a single chemical propellant significantly simplifies on-orbit refueling. Phase Four is developing multiple commercial partnerships to advance this very important capability.
Umair Siddiqui, President and CTO of Phase Four, said, “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.”
Steve Kiser, CEO of Phase Four, said, “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.“
About Phase Four
Phase Four is a disruptive provider of next generation electric propulsion (EP) solutions and services for small satellites. The company was founded in 2015 to address the demands of the rapid proliferation of satellite constellations and to accelerate breakthroughs in novel propulsion technology.
