The main purpose of the present plan is to provide a clear path to demonstrate the TRL5 by the Mission Adoption for the three OBFs on the X-IFU Filter Wheel (FW). An effort has been performed in trying to identify what shall be considered technology, for which the maturity has to be demonstrated, and what is design that can still contribute to improve the performances of the FW filters along phases B and C of development.
The X-IFU FW filters conceptual design is similar to that defined (during phase A) and described in the "X-IFU Filter Wheel Mechanism and Electronics Design Description", and the "X-IFU Thermal Filters (THFs) Description" documents presented at the I-PRR. The preliminary design of the X-IFU FW Filters rely on heritage from previous missions and characterization tests performed in phase-A on breadboards manufactured by LUXEL Corporation (Friday Harbor, WA, USA). The adoption of a design similar to that of the X-IFU THFs for frame shape and materials, and to that of the WFI FW filters for film and coating thicknesses, as well as for overall dimensions, allow migrating part of the achievements reached by the X-IFU THFs and WFI FW filters to the X-IFU FW filters. For this reason, the TDP for the X-IFU FW filters will be mainly focused on the vibro-acoustic performances. With this respect, minor effort will be dedicated to the thick and very robust meshless filter (25 μm PI + 100 nm Al) designed to observe very bright x-ray sources. The goal of this activity is to demonstrate TRL5 before MAR for the baseline technology of filters manufactured by LUXEL (PI/Al on BeCu mesh). However, in parallel to verify also the maturity of other filter technologies and to mitigate the risks of having only one manufacturer, we will procure and test filter samples and bare meshes of other European manufacturers (OXFORD instruments, XRNanotech).
The identified TECHNOLOGY development elements that we consider critical in the X-IFU FW OBFs are described in this document. In section 7 we list the breadboards (BBs) we have identified to perform the necessary characterization tests aimed at demonstrating their maturity
