DLR Concepts of Advanced Thermal Protection Systems for Reusable Cryogenic Propellant Tanks

Abstract

Reusable launch vehicles (RLV) require robust and lightweight thermal protection systems (TPS) for cryogenic propellant tanks. These tanks experience extreme temperature gradients during flight, ranging from cryogenic temperatures within the tank to temperatures exceeding several hundred degrees Celsius on the exterior during reentry, demanding innovative solutions. To address this, the German Aerospace Center (DLR e.V.) investigates advanced insulation concepts, including purge gaps to decouple cryogenic and high-temperature insulation layers, enabling independent optimization of each layer and reducing overall thickness and weight. The AKIRA project demonstrated the feasibility of this approach for metallic tanks, while the TRANSIENT project extended it to carbon fiber reinforced polymer tanks. One subject of the ongoing TWEAK project focuses on developing a new TPS attachment system considering lightweight, maintenance and sustainability aspects. This paper summarizes DLR’s research in this topic and outlines future directions in developing advanced insulation and TPS concepts for future RLVs.