Building the Next Generation of

In-Space Mobility


Maxwell Systems Delivered


Maxwell systems on-orbit today


Systems produced by Q2 2022



Phase Four is a disruptive provider of next generation electric propulsion (EP) solutions for small satellites. Phase Four’s RF Thruster represents a revolutionary new architecture that realizes lower cost, mass-manufacturability, miniaturized power electronics, and propellant agnosticism over incumbent technologies, without compromising performance. In 2021 Phase Four’s Maxwell turn-key propulsion system achieved flight heritage and is now being regularly utilized by satellite operators.




At Phase Four we are constantly pushing the envelope of RF plasma propulsion. We have active R&D in plasma physics of RF thrusters, advanced propellants, and new applications of plasma propulsion in space.


Maxwell is a high performance turn-key plasma propulsion system that leverages miniaturized RF electronics and our electrodeless thruster in a compact form factor.



Read more about us and updates in the news.

Phase Four and Orbit Fab to work on Maxwell engine refueling
Propulsion startup Phase Four has signed a memorandum of understanding with satellite refueling startup Orbit Fab aimed at preparing future Phase Four Maxwell engines for on-orbit refueling.
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2021 by the Numbers & a Sneak Preview of 2022
2021 has been by far the most significant year in the history of Phase Four
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PhaseFour Debuts Improved Thruster
Satellite electric propulsion company Phase Four has completed testing of a new thruster that it says offers significantly improved performance
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