Press Release

Phase Four Secures DARPA Funding for High Delta-V Cubesat Electric Propulsion System

By SpaceRef Editor
November 21, 2015
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Phase Four LLC, a satellite propulsion company, has received a $1 million contract from the Defense Advanced Research Projects Agency (DARPA), in support of the effort to deliver a fully-integrated flight unit of the CubeSat Ambipolar Thruster (“CAT”). The contract also includes options for long-duration orbital flight testing and design enhancements for microsatellite-class missions.

Configurable for a variety of Earth-orbiting applications as well as potentially for interplanetary exploration, the CAT engine is a novel, electrodeless plasma thruster originally developed at the University of Michigan and exclusively licensed to Phase Four. Designed for high delta-V applications, CAT has a high thrust-to-power ratio and is operable with an assortment of propellants for mission customization. Phase Four has partnered with The University of Michigan’s Plasmadynamics and Electric Propulsion Laboratory (PEPL) to provide detailed characterization of CAT’s performance.

“CubeSats and small satellites suffer from a lack of high delta-V propulsion options, limiting the orbits they can achieve and shortening their lifespans. We designed CAT using the CubeSat standard to quickly build, test and iterate on our design,” said Phase Four Co-Founder and CEO Simon Halpern. “Our thruster seeks to test the bounds of what is possible in such a small form factor. CAT has been proven in the lab and initial measurements are very promising. We are eager to commence in-space testing.”

Halpern continues, “One inspiration for CAT was in response to a 2013 NASA ‘Game-Changing Opportunities’ solicitation. Small spacecraft are the key to opening up a deeper understanding of not only our planet, but also our place amongst the stars.” The announcement (13-043) states: “As NASA develops and improves the use of small satellites for science and exploration, we recognize propulsion as a critical need to open the door for small spacecraft applications. We need better miniaturized systems to propel and maneuver our small space adventurers.”

The purpose of the DARPA contract is to deliver a flight-ready CAT engine, raising it to Technology Readiness Level (TRL) 7, with an option for an in-space demonstration of the entire system. If successful, CubeSats with large delta-V capability could lead to maneuvering spacecraft that support formation flying, increase ground coverage from satellite constellations deployed from single launch vehicles and enable long-lived, variable altitude flight.

About Phase Four

Using new applications of plasma-related technology, Phase Four plans to advance space missions through unprecedented innovation and cost effectiveness. At Phase Four, we are building the next generation in plasma propulsion technologies for satellites. For more information, visit

SpaceRef staff editor.