DLR project TRANSIENT: Testing reusable cryogenic insulation and thermal protection systems

Reusable launch vehicle stages face intense heat fluxes, particularly during reentry. Thermal protection systems (TPS) are essential for winged stages decelerating through aerodynamic forces, requiring coverage of large vehicle areas. In the case of reusable systems with integral cryogenic tanks, the TPS is exposed to extremely low propellant temperatures. Joint design and integration of TPS and cryogenic insulation are necessary, considering their interdependent nature. The AKIRA project initiated by the German Aerospace Center (DLR) initially explored this area, continued through the TRANSIENT project. Test objects representing RLV propellant tank sections were manufactured with combined TPS and cryogenic insulation, undergoing mechanical and thermal load testing. Initial integration and experimental results are presented