Periodic Reporting for period 1 - BREATHE (Building a space Revolution: Electric Air-breathing Technology for High-atmosphere Exploration)
Período documentado: 2023-09-01 hasta 2026-02-28
In the vast region between 50 km and 400 km above Earth’s surface, the presence of Earth's atmosphere has limited spacecraft operations. Funded by the European Research Council, the BREATHE project aims to revolutionise space exploration with air-breathing electric rockets (AERs). These innovative rockets, powered by the spacecraft solar arrays, capture the residual atmosphere and use it to generate thrust, enabling operations in very low Earth orbits. These orbits offer unparalleled benefits such as enhanced accessibility and payload performance, radiation protection and sustainable end-of-life disposal. As such, the project will advance AER feasibility through simulations and on-ground testing. By merging real-world experiments with virtual simulations, BREATHE strives to derive scaling laws and optimise AER design, paving the way for a transformative leap in space technology.
During the first reporting period, the project focused on developing theoretical, numerical, and experimental foundations for the development of air-breathing electric rockets (AERs). The work addressed the modelling of AER operation, the characterization of the relevant environment, and the design and validation of AER stages and diagnostics.
A key scientific result was the development of integrated system and mission models for spacecraft equipped with AER technology. These studies identified a single requirement parameter, the AER efficiency, as a unified criterion for assessing feasibility and design trade-offs. A new simulation framework was also established, coupling AER operation, atmospheric dynamics, spacecraft aerodynamics, power management, and guidance and control. The framework demonstrated that continuous drag compensation in very-low Earth orbit (VLEO) is feasible with properly optimized AER architectures.
On the experimental side, a major achievement was the realization of the BREATHE vacuum test facility and the development of a novel ground-testing methodology for AER thrusters. This dual-chamber configuration enables realistic simulation of air-breathing operation by independently controlling inlet pressure and mass flow. The first experimental campaigns validated this approach using early AER prototypes.
The design and testing of simple RF, ExB, and ECR discharge prototypes provided the initial experimental basis for understanding plasma generation and acceleration under representative conditions. Together, these advances mark a significant step toward the maturation of AER technology and its future in-orbit demonstration.
A key scientific result was the development of integrated system and mission models for spacecraft equipped with AER technology. These studies identified a single requirement parameter, the AER efficiency, as a unified criterion for assessing feasibility and design trade-offs. A new simulation framework was also established, coupling AER operation, atmospheric dynamics, spacecraft aerodynamics, power management, and guidance and control. The framework demonstrated that continuous drag compensation in very-low Earth orbit (VLEO) is feasible with properly optimized AER architectures.
On the experimental side, a major achievement was the realization of the BREATHE vacuum test facility and the development of a novel ground-testing methodology for AER thrusters. This dual-chamber configuration enables realistic simulation of air-breathing operation by independently controlling inlet pressure and mass flow. The first experimental campaigns validated this approach using early AER prototypes.
The design and testing of simple RF, ExB, and ECR discharge prototypes provided the initial experimental basis for understanding plasma generation and acceleration under representative conditions. Together, these advances mark a significant step toward the maturation of AER technology and its future in-orbit demonstration.
From a system modelling perspective, the work carried out in the project led to the identification of a single key parameter defining the feasibility of AER-based missions. This result, though conceptually simple, is highly impactful as it enables an effective comparison of different design solutions in a relatively young field — that of air-breathing electric propulsion — where there remains considerable uncertainty about the most appropriate metrics to assess concept validity. Combined with the guidance, navigation, and control (GNC) modelling activities, this represents the first study of its kind applied to very-low Earth orbit (VLEO) missions. It constitutes a clear step forward in the understanding and simulation of such systems, providing essential tools for the design of AER-based spacecraft operating in VLEO. Through interactions with space agencies and industry, it has become evident that significant uncertainties persist regarding navigation and control aspects of these missions; therefore, these achievements are key enablers for the realization of future AER-based operations in VLEO.
In parallel, the development of a novel yet practical testing methodology for AER thrusters represents a major milestone toward the technological maturation of this propulsion concept. Although conceptually straightforward, the proposed approach had never been implemented before and now offers a robust, flexible, and replicable framework for ground testing, effectively bridging the gap between laboratory experiments and flight-representative conditions.
Finally, while AER prototype development is still in its early stages, the results achieved so far confirm the feasibility of at least one CubeSat-scale configuration compatible with VLEO missions. In the next phase, continued design refinement and experimental characterization will further mature the technology. Looking ahead, an in-orbit demonstration mission will be essential to validate the AER concept in realistic conditions, assess spacecraft operation and GNC performance in VLEO, and verify the representativeness of the developed ground-test strategy. Such a mission would also provide an opportunity to evaluate the performance improvement of optical and telecommunications payloads enabled by sustained low-altitude operation, paving the way toward the commercial exploitation and broader adoption of AER technology.
In parallel, the development of a novel yet practical testing methodology for AER thrusters represents a major milestone toward the technological maturation of this propulsion concept. Although conceptually straightforward, the proposed approach had never been implemented before and now offers a robust, flexible, and replicable framework for ground testing, effectively bridging the gap between laboratory experiments and flight-representative conditions.
Finally, while AER prototype development is still in its early stages, the results achieved so far confirm the feasibility of at least one CubeSat-scale configuration compatible with VLEO missions. In the next phase, continued design refinement and experimental characterization will further mature the technology. Looking ahead, an in-orbit demonstration mission will be essential to validate the AER concept in realistic conditions, assess spacecraft operation and GNC performance in VLEO, and verify the representativeness of the developed ground-test strategy. Such a mission would also provide an opportunity to evaluate the performance improvement of optical and telecommunications payloads enabled by sustained low-altitude operation, paving the way toward the commercial exploitation and broader adoption of AER technology.