Speaker
Description
Safe and sustainable end-of-life disposal is becoming a key requirement in satellite design, particularly for reducing ground risk from surviving debris during uncontrolled atmospheric re-entry. In this study, a substrate-level Design-for-Demise (D4D) approach is being investigated that uses physical vapour deposition (PVD) coatings to increase the demisability of otherwise robust structural and functional alloys.
The objective of this work is to assess whether surface engineering can provide a scalable, component-compatible method to promote earlier heating and accelerated degradation during re-entry, without requiring substitution of structural and functional materials. The coating concept is designed to modify the thermo-chemical interaction between the surface and the re-entry environment by (i) reducing radiative heat losses, (ii) enhancing surface-driven chemical processes that increase net heat transfer to the substrate, and (iii) enabling diffusion-driven compositional changes that can lower the local melting range of the substrate material. In this way, the approach aims to shift the thermal balance toward faster temperature rise and earlier structural failure of high-survivability components.
A combined laboratory and ground-test campaign was conducted to evaluate coating performance, robustness, and degradation mechanisms. In this study, stainless steel was used as the substrate material. Laboratory exposures in air at temperatures up to 1200 °C were used to investigate oxidation behaviour, coating adhesion, interdiffusion, and thermally induced microstructural evolution on representative metallic substrates. Complementary tests in an arc-heated wind tunnel reproduced key features of atmospheric re-entry, including hypersonic high-enthalpy flow and chemically aggressive non-equilibrium conditions. Surface and internal temperature measurements were used to reconstruct absorbed heat flux and compare the thermal response of coated and reference samples under consistent loading conditions.
Post-test characterization using diffraction, microscopy, and compositional analysis was performed to correlate thermo-chemical response with coating morphology and degradation pathways. The results demonstrate the potential of PVD-based surface engineering as a generic D4D tool for improving the demise behaviour of structural satellite components.