After 37 months of intensive collaboration, research, and engineering, the DEEP PPU project has successfully reached its conclusion—delivering major advancements in power processing technology for next-generation electric propulsion systems. Bringing together leading European partners with complementary expertise, the project has achieved its core objective: developing and validating an advanced Power Processing Unit (PPU) architecture capable of integrating radio-frequency generation, high-voltage conversion, and fluidics management into a compact, cost-efficient, and flight-ready system.
A Collaborative Achievement Across Europe
The DEEP PPU project united specialists from Airbus CRISA, Airbus, UPM, Axon’ Cable, FRAZA and WIT Berry (communication and dissemination partner), working hand-in-hand to address some of the most challenging aspects of electric propulsion electronics.
Over three years, the team maintained a highly collaborative environment—holding weekly and bi-weekly technical exchanges, iterative design reviews, joint experiments, and coordinated system-level validations.
This close teamwork enabled:
- Full co-design of power electronics, magnetics, and harness technologies
- Seamless integration between the PPU, harness, and RIT-2X thruster
- Benchmarking, simulation, prototyping, and testing aligned with shared objectives
The resulting synergy was a key factor behind the project’s success.
A New Generation of Power Processing for Electric Propulsion
At the heart of the project lies a groundbreaking achievement: the integration of a Radio Frequency Generator (RFG) into the PPU itself.
This innovation replaces the traditional configuration—where the RFG is placed near the thruster and connected through a long harness—with a highly consolidated system located on the spacecraft platform. The benefits are substantial:
- Lower overall mass and volume
- Reduced cost of the propulsion subsystem
- Improved thermal management by relocating electronics away from the hot thruster
- Simplified spacecraft accommodation and harness routing
The newly developed PPU targets the RIT-2X thruster, operating across a wide power envelope (3–7.5 kW) and supporting multiple operating points required for long-duration telecom missions. Its modular architecture is designed to scale to different thrusters and mission profiles.
Technical Breakthroughs Across All Subsystems
1. High-Voltage Conversion
New high-voltage power modules provide up to 2 kW per board, supporting voltage ranges from 800 V to 1500 V.
The architecture allows scaling by adding or removing boards depending on mission needs.
2. Integrated Radio Frequency Generator
UPM developed a compact RFG capable of generating a high-frequency sinusoidal current for xenon ionization.
Key innovations include:
- An advanced resonant inverter
- Control strategies adapted to long AC harness lengths
- Custom filtering solutions to eliminate parasitic harmonics
These solutions ensure stable operation and high efficiency even with 6–11 m harnesses.
3. Advanced Harness Design
Axon’ Cable engineered a completely new harness type, designed as a low-loss, low-impedance transmission line supporting both high voltage and high frequency.
Key achievements:
- Flat-loom construction to minimize skin and proximity effects
- Custom PFA-based dielectric layers
- Partial discharge-free performance up to demanding voltage levels
- Custom high-voltage connectors based on Micro-D technology
4. Breakthrough Magnetics
FRAZA designed and produced seven custom magnetic components, demonstrating:
- 90% reduction in mass and volume
- ~90% reduction in power losses
- Estimated ~50% cost reduction compared to existing space-qualified magnetics
- A new ultra-fast 9 ns current detection sensor
These innovations significantly enhance the overall efficiency and scalability of the system.
TRL Progress and Industrialisation Path
The project achieved TRL 4–5 for most functional blocks, with some subsystems approaching TRL 6 thanks to existing industrial heritage. The engineering models demonstrated correct functional operation, compatibility across partners’ technologies, and readiness for system integration with the RIT-2X thruster in future testing campaigns.
Airbus CRISA will carry the system forward toward:
- Final design consolidation
- Qualification
- Industrialisation
- Market introduction
The PPU is being positioned for commercial GEO and MEO missions as well as emerging applications such as on-orbit servicing and refueling.
A Strategic Step for European Electric Propulsion
The DEEP PPU project strengthens Europe’s competitiveness in high-power electric propulsion—a critical capability for telecommunications satellites, servicing missions, and future deep-space operations. By pushing forward the integration of radio-frequency generation, pioneering new harness technologies, and enabling high-efficiency magnetics, the project sets the foundation for more compact, cost-effective, and scalable propulsion subsystems.
DEEP PPU Project results
Throughout the project, the consortium actively shared the knowledge and experience gained, including through several public webinars—among them the final dissemination event—along with conference presentations, scientific papers, and posters at relevant industry and academic gatherings. All materials are openly accessible for further use and exploitation via the project website, scientific journals, and the Zenodo repository.
Closing a Chapter, Opening New Collaborations
Although the DEEP PPU project formally concludes in November, the consortium recognizes that it has built valuable new connections, partnerships, and collaborations that will endure well beyond the project’s end—and will undoubtedly lead to future joint initiatives.
DEEP PPU project ID 101082685 is co-funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or HADEA. Neither the European Union nor the granting authority can be held responsible for them.
