Sbir phase II: air-breathing electric propulsion

The National Science Foundation awarded a Cooperative Agreement totaling $1,218,494 to Viridian Space Corp on August 1, 2026, under the NSF Technology, Innovation, and Partnerships program (CFDA 47.084) to develop air-breathing electric propulsion (ABEP) technology for ultra-low Earth orbit operations.

Viridian will design, construct, and test a Hall-effect thruster tailored for atmospheric gases, paired with an inlet developed under the project's Phase I. Work includes identification and validation of materials for critical air-fed thruster components and optimization of the thruster system for in-situ atmospheric refueling. The ABEP system enables satellites operating in very low Earth orbit between 200 and 300 kilometers altitude to refuel directly from the atmosphere, extending mission life and enabling earth observation, disaster monitoring, broadband communication, and direct-to-cell connectivity applications not feasible from conventional low-Earth orbit altitudes.

Viridian Space Corp is a small business based in El Segundo, California, specializing in air-breathing electric propulsion systems for satellite operations. Performance occurs in El Segundo, California, with a period of performance from August 1, 2026, through July 31, 2028. The award obligates $1,218,494.

Abstract

The broader/commercial impact of this small business innovation research (sbir) phase II project is creating a spacecraft architecture that utilizes in-situ resources (atmosphere) to enable long-lasting, more capable services. The biggest limitation to existing spacecraft architecture is the fixed amount of propellant that is brought on-board a satellite at launch. By flying in very low earth orbit (vleo), air breathing electric propulsion (abep) allows refueling of the satellite directly from the atmosphere. There is another significant benefit to flying satellites as low as possible, specifically in vleo. This orbital regime allows significant improvements in most earth-facing services, such as earth observation, disaster monitoring, broadband communication, and even enables services that are not possible from low-earth orbit (LEO), such as direct-to-cell connection. The development and commercialization of abep technology will thus revolutionize satellite operations, unlocking the potential of vleo as a new frontier for scientific research, ambient monitoring, and national security applications for commercial and government applications. With an ever-increasing number of satellites in LEO, IT will be critical to create a reliable space infrastructure that is enabled by technologies like abep. By operating primarily in new, untapped orbits, abep-enabled satellites will provide good stewardship of the near-earth surroundings. This small business innovation research phase II project will focus on developing the thruster for the air breathing electric propulsion system to pair with the inlet that was developed under phase i of this sbir. Key objectives include (1) identification and validation of materials for critical air-FED hall-effect thruster (HET) components; and (2) design, construction, testing, and optimization of the thruster specifically tailored for atmospheric gases. To support these objectives, a modular thruster prototype will be developed with adjustable discharge channel length, anode configuration, and magnetic field topology to enable iterative design optimization. Thruster prototypes will be tested in a vacuum chamber to identify the most effective configurations. Under this effort, various materials will undergo coupon testing in an air plasma environment to identify durable materials capable of sustaining thruster performance in vleo. Additionally, phase II will permit an improved understanding of plasma-material interactions, guiding future material development efforts. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the foundation's intellectual merit and broader impacts review criteria.- subawards are not planned for this award.