In the context of New Space Innovation, and under the headers 'Black Engine' or 'Ceramic Rocket Engine', the Institute of Structures and Design at DLR Stuttgart develops highly future competitive structural concepts for hybrid composites-metal designs in high-performance liquid rocket engines. Both the transpiration cooled operation and a unique load de-coupled structural design, promise high operational efficiency as well as significantly higher life-time and reliability at lower weight and cost. Compared to the already existing TRL 5 in LOX/LH2 sub-scale operation scenarios, the next ongoing step is the TRL 5 full-scale demonstration, using LOX and LNG as cryogenic high-performance propellants.