Phase Four’s Maxwell Block 2 radio-frequency thruster has been successfully demonstrated on a commercial satellite, according to Umair Siddiqui, Phase Four’s Chief Technology Officer. Speaking at the World Satellite Business Week conference in Paris, Siddiqui stated that the thruster is working flawlessly in space with no issues reported so far. However, Phase Four has not disclosed the identity of the satellite customer.
The Maxwell Block 2 thruster builds upon the technology of Phase Four’s previously demonstrated Block 1 thruster in 2021. The key difference between the two versions is the modularity of Block 2. Siddiqui described it as a “Mr. Potato Head of systems,” with the ability to separate its components. Additionally, Block 2 is designed for mass manufacturing and offers higher performance without requiring increased input power. It is directly aimed to compete with Hall-effect thrusters.
Meanwhile, Phase Four is currently conducting tests on Maxwell Block 3 in a vacuum chamber in Hawthorne, California. Each new Block is an iteration of the core product that the company has been developing since 2018, resulting in performance and operational improvements. Block 3 has achieved similar thrust specific impulse to a Hall-effect thruster using krypton, making it the first cathodeless thruster to achieve such results. Phase Four plans to begin delivering Block 3 to customers starting in June 2024.
All of the Maxwell thrusters are compatible with both xenon and krypton propellants. Although xenon is more expensive, Phase Four’s earlier customers preferred it for their small satellites. However, the company’s latest customers, who are opting for larger satellites with larger propellant tanks, are trending towards using krypton. This is advantageous for Phase Four as their thruster performs better with krypton compared to xenon, according to Siddiqui.