Speaker
Description
Design-for-demise is becoming a key requirement for future satellite systems in the context of Zero Debris and sustainable space operations. Structural concepts enabling controlled disintegration while preserving in-orbit performance are therefore of increasing interest. Demisable joints for sandwich panel primary structures represent a promising solution by introducing temperature-triggered structural discontinuities at predefined locations.
Building on a previously developed joint design concept based on tailored material combinations and geometry-driven thermal weakening, this work presents recent progress in experimental validation and system-level re-entry modelling. Plasma wind tunnel tests were performed on representative joint configurations to investigate their thermo-mechanical response under re-entry-like heat fluxes. The experiments showed very promising results, with successful separation of the connected sandwich panels achieved in the majority of test cases, especially under comparatively low and more realistic heat flux conditions. These findings provide strong evidence for the robustness and effectiveness of the trigger mechanism, while also offering detailed insight into failure initiation and the interaction between joint constituents and sandwich panel facesheets and cores.
A modelling strategy was developed to represent the behaviour of demisable joints within SCARAB re-entry simulations. The approach captures joint failure through temperature-dependent degradation laws, derived from both design assumptions and experimental observations. Particular emphasis is placed on the definition and variation of trigger temperatures, enabling a systematic assessment of their influence on break-up timing and fragmentation behaviour. Re-entry simulations were conducted using a spacecraft model based on a large Earth observation mission, representative of current large satellite architectures with optical payloads. A parametric analysis investigates the influence of initial attitude, joint trigger temperature, and joint integration strategies within the primary structure. The results show that demisable joints can significantly alter fragmentation sequences and improve the demise of otherwise critical components by promoting earlier structural disintegration and increased exposure to aerothermal loads.
The combined experimental and numerical findings highlight the significant potential of the current demisable joint design to actively control structural break-up and improve demise performance at system level. Future work will therefore focus on advancing the concept towards higher Technology Readiness Levels, alongside the exploration of new demisable joint architectures addressing the latest ESA and industry-driven design-for-demise requirements.