CALIPSO addresses great challenges for European defense autonomy, sustainability and operability, focusing on naval and land defense sectors. The project seeks to revolutionize military vehicle propulsion by integrating sustainable fuel technologies (spin-in from civil sector). CALIPSO strategically aligns with the EU Renewable and Low Carbon Fuels industrial alliance, ensuring fuel flexibility, cutting-edge technologies and market opportunities. The project aims to achieve significant impacts, including the spin-in of 22 civil R&D projects, involving 14 Member States and Norway, and alignment with EU Green Deal targets. CALIPSO emerges as a key player in enhancing the autonomy of the EU’s defense industrial sector, fostering cross-border cooperation and contributing to innovation and sustainability across the entire value chain.