Building the Next Generation of

In-Space Mobility


Maxwell Systems Delivered


Maxwell systems launched into low Earth orbit


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.

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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.



Phase Four is moving into a new facility located at: 12605 S Van Ness Ave, Hawthorne CA

We've Moved


Read more about us and updates in the news.

The plasma glow created by Phase Four’s novel RF spacecraft engine firing on AFRL’s “green” propellant.
Phase Four’s spacecraft engine first to demo AFRL’s game-changing ‘green’ fuel
Former NASA administrator Jim Bridenstine told Breaking Defense that Phase Four has the potential to "disrupt the in-space propulsion market," and its technology "is important for the country."
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Phase Four Unveils Game Changing Engine for LEO Constellations
Leveraging its new Block 2 architecture, Phase Four announces Max-V, a revolutionary plasma propulsion system available in 2023
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Phase Four adopts iodine for next-gen Max-V engine
Propulsion startup Phase Four is expanding its Maxwell plasma propulsion line by offering Max-V, an iodine-fueled engine.
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We'd love to learn more from you. Please use the contact form to the right to get in touch with us, or a specific team, and we will get back to you as soon as we can!