Electron beam curing for manufacturing of high dimensionally stable cfrp structures like space telecommunication satellite antenna reflectors

The final main objective of this project has been to develop a high dimensionally stable composite antenna sub reflector for specific space telecommunication satellite applications working in the range of 40/50GHz. This specification requires very high dimensional accuracy which has been quantified with a target of a maximum error in the range of 10-40 microns RMS over the functional surface of the reflector. In this context, this paper describes the materials selection, manufacturing and testing activities carried out at specimen level in order to complete the evaluation and comparison of Electron Beam cured samples versus the Autoclave cured ones in order to analyse the feasibility and advantages of using this alternative curing process. The expected benefits correspond to the fact of using low temperature curing techniques with lower dimensional distortion due to the CTE effect of the structure material and the tooling. This paper includes the description of the test set-up, procedure, results and the evaluation of the results. According to the results obtained, regarding the space environment conditions behaviour, no significant differences are found between the EB material option and the thermal curing solution. Mechanical properties, CTE and outgassing properties are similar. The adhesion performed tests on the metallic coated specimens show also similar performance. Therefore, the electron beam cured material is a promising solution for this application. This activity has been developed within the research project 'Hybrid mechanical-electronic pointing system', under ESA contract 18186/04/NL/CH.