Phase Four Wins DARPA Contract for Air Breathing Propulsion

Ibadan, 9 April 2024. – Phase Four has won a $14.9M contract from the Defense Advanced Research Projects Agency (DARPA) to deliver an “air-breathing” EP system to enable extended satellite operations in Very Low Earth Orbit (VLEO), at altitudes as low as 90-450km.

The award is part of DARPA’s Otter program to develop, demonstrate, and collect on-orbit data for “air-breathing” electric propulsion technologies. The propulsion technology will harvest ambient low-density air as propellant, enabling extended satellite operations at VLEO altitudes. The Otter program will culminate in a long-duration “orbiting wind tunnel” spaceflight demonstration, characterizing the performance of the “air-breathing” EP system in the orbital environment.

DARPA’s Otter program will leverage Phase Four’s core technology, the radio frequency thruster (RFT), which is inherently propellant agnostic relative to legacy electric propulsion systems that rapidly degrade when exposed to non-traditional propellants. This feature consequently enables the RFT to operate on the low-density air in the VLEO environment. The Otter program will build upon a previous effort with DARPA that developed a proof-of-concept thruster prototype for novel, low-cost propellants.

Speaking on the award, Umair Siddiqui, Phase Four’s President, CTO, and Principal Investigator for the effort, commented, “Phase Four has designed and built electric propulsion systems that have been launched on 9 satellites with over 5,300 days of on-orbit flight heritage since the company was founded. We’re happy to bring that heritage, experience, and innovation in electric propulsion systems to the Otter program.”

Likewise, Jason Wallace, President of Government Programs at Phase Four, said, “We look forward to working closely with DARPA to unlock sustained missions in VLEO, which will increasingly become a critical operational environment for national security as traditional orbits become congested and contested.”