Structural modeling and tests supporting the design of ATHENA X-IFU thermal filters and WFI opt. blocking filter

ATHENA is an astrophysics space mission selected by ESA for a launch earlier than 2030. ATHENA will be equipped with an X-ray telescope 12m focal length and two focal plane detectors: the X-Ray Integral Field Unit (X-IFU) and the Wide Field Imager (WFI). X-IFU operating temperature below 100mK requires five thermal filters (TF) to reflect IR, protect the detector from molecular contamination and attenuate RF from telemetry. WFI requires a large Optical Blocking Filter (OBF), mounted on a filter wheel, to reduce optical load from bright UV/VIS sources. To maximize the X-ray transparency, filters need to be very thin and made of light material: polymer coated with low Z metal such as Al. Filters must survive severe launch loads: sine and random vibration, shock, differential pressure due to vacuum-venting for both detectors. WFI OBF must survive also acoustic loads, since it will be launched in atmospheric pressure, while X-IFU thermal filters must survive to cryogenic operation temperature. Large filter sizes and high mechanical loads suggested to support the film by using metallic reinforcing meshes.