Classical solutions for debris shielding of spacecraft are bulky volume and mass inefficient assemblies like Whipple Shields, Stuffed Whipple Shields or Multi-Shock Shields, only used in large spacecraft. New space applications such as cubesats, with limited space and scientific missions such as COMET INTERCEPTOR, with very tough impact requirements, need more efficient approaches. Additive manufacturing could pave the way for a new shielding generation.
In the frame of the GSTP AM4ALL, CITD Engineering & Technologies, Centro Avanzado de Tecnologías Aeroespaciales (CATEC) and Elecnor Deimos, have researched on the possibilities of a new generation of AM sandwich core able to protect space structures against small particle impacts. Lattices, gyroids, and other geometries have been anayzed from different perspectives: manufacturing and assembly feasibility as well as shielding performance. The objective of this research is to reduce the overall volume and mass of the classical shield by increasing the energy absorption capabilities of the sandwich structures.
The initial studies have focused on ice particles below 30mm in diameter and metallic Scalmalloy core manufactured using PBLF (Powder Bed Laser Fusion) technology. Coupons with the selected configurations have been manufactured and tested. The effectiveness of the shield is based not only in the material properties but also in the fragmentation and dispersion capabilities of the geometries; that is why the impactor in the tests is made of poliamide 12, a polymer that will also show a fragmentation pattern similar to ice particles. Even when the maximum test velocity is 650m/s, the size and density of the impactor is higher in order to increase the energy in the impact. The size of the core cells is also increased aiming to reproduce the ratio cell/particle diameter in the use case.
The results shown by the test are very promising although further research is needed in order to solve different uncertainties such as the effect of hypervelocity, AM core assembly and integration, surface and material treatments aiming to increase ductility…etc. Thanks to the growing community around hypervelocity impacts led by European Space Agency - ESA and Tiziana Cardone for their new insights and contribution. We are willing to implement them and will share our findings with all of you at the next ECSSMET congress.
Thanks also to: Lidia H., Marta García-Cosío, Andrés Caparrós Quero, Fernando Lasagni, Antonio Periñán, Pablo Morillo Gonzalez, Andrew Norman, José Luis García Sacristán, Jorge Lopez-Puente