High temperature lightweight structures for space applications

Milestones of the Development

The system-oriented development work in the department of space travel system integration concentrates on the two groups thermal safety systems and hot primary structures of re-entry vehicles, as well as on thrust chamber technology for effusion cooled, cryogenic rocket engines in a new hybrid construction using polymere and ceramic composite materials. Both domains are important key technologies for the development of future space transportation systems.
 
Beside basic research the work is predominantly project oriented and shall lead to proven and applicable structures. This system oriented approach leads to the integration of different disciplines during the development process and covers for example the system design of hot fiber ceramic panel structures on the outer side up to the design of a metallic sub structure and necessary interfaces of a TPS. Within the department all necessary disciplines are covered from the preliminary draft up to qualification testing. In terms of design and analysis special simulation tools for the coupled structure-flow analysis or for the structural thrust chamber simulation are available beside commercial FEM and CAD software.

Due to these applications the following development tasks result for instance:

• Behaviour of fiber ceramic high temperature materials under re-entry conditions (high temperatures, low pressures, oxygen and nitrogen dissociation)
• Protective layers for fiber-ceramics
• Insulation, seal, assembly and load transmission concepts for hot external structures on cold sub structures
• Numeric calculation of the interaction between hot gas flow and structures (calculation and development of numerical tools)
• Development of effusion-cooled structures on the basis of porous materials
• Quality assurance methods

Production of fiber-ceramic primary components from C/C-SiC happens within the Institute in the department Ceramic Composite Structures by means of the liquid siliconization process developed by DLR. For qualification purposes of the systems own hot testing facilities and different non-destructive testing methods are available and also other means such as plasma wind tunnels and rocket engine test facilities of other DLR Institutes can be used. Structures in testing facilities can however only be pre-qualified. Their use under close-to-reality conditions, such as in flight tests, is indispensable. This experimental testing takes place almost exclusively within joint projects on national and European level and in co-operation with other research establishments as well as the industry.