Daniele Piazza PLATO TOU Meeting, Catania, PLATO - TOU Mechanical Design & Future Activities Osservatorio Astronomico – Catania June 11 th, 2014

Daniele Piazza PLATO TOU Meeting, Catania, Overview  TOU Mechanical Design Overview  Architecture  Materials  Future Activities  L6 failure: Investigation & design improvement  Architecture consolidation: FPA interface, integration, baffle, …  Modelling activities (FEM & TMM)  Prototype lens mounts  Resources Availability

Daniele Piazza PLATO TOU Meeting, Catania, The TOU consists of:  Structural tube  Machined AlBeMeT part (outstanding combination of properties)  Outside gold coated to minimize radiative coupling  Inside black coated to optimize straylight behavior  Thermal connection between FPA and baffle (which acts as radiator)  Lens mounts and interface parts  Multi-finger design to minimize bonding surface and provide isostaticity to the lenses  Materials choice to match the glasses CTE  Isostatic interface to tube to compensate for CTE mismatch  Isostatic mounts to the S/C optical bench  3-points interface to allow alignment by shimming TOU Mechanical Design (1)

Daniele Piazza PLATO TOU Meeting, Catania, TOU Mechanical Design (2)

Daniele Piazza PLATO TOU Meeting, Catania, Materials  Material choice drivers  Main Structure: combination of properties (, CTE, Cp, E)  Lens Mounts: Minimization of thermo-elastic stresses in the lenses (CTE, E)

Daniele Piazza PLATO TOU Meeting, Catania, Future Activities

Daniele Piazza PLATO TOU Meeting, Catania,  During the DM campaign cracks were observed at the four bonded interfaces of L6.  The failure is reproducibele, therefore workmanship can be excluded.  The root cause nees to be identified.  A plausible hypotesis is an excessive bonding area, which leads to high thermo-elastic stresses in the glass.  The flexibility of the mount has to be verified  Breadboards will be used to prove the improvements implemented. L6 failure: Investigation & design improvement

Daniele Piazza PLATO TOU Meeting, Catania, The following points will be investigated to update and improve the design:  FPA interface  The last FPA developments were not considered.  Optics integration  Accessibility, fixation points of dedicated tooling,...  Baffle interface  Requiements consolidation for the interface to the S/C OB.  Handling interfaces for integration at S/C level. Architecture Consolidation

Daniele Piazza PLATO TOU Meeting, Catania,  Currently, at UBE there is a strong team capable of performing mechanical and thermal modelling.  NASTRAN, ESARAD, SYSTEMA available.  Performing FEM and TMM at the same location allows a more efficient and fast optimization of the overall design.  Such activities will be included in our PRODEX proposal. Modelling activities (FEM & TMM)

Daniele Piazza PLATO TOU Meeting, Catania,  UBE is ready to support prototyping activities, e.g. lens mounts with improved design and/or alternative materials.  Small scale BB are, as well, foreseen to verify envisaged design improvements. Prototyping

Daniele Piazza PLATO TOU Meeting, Catania,  Due to the very high work loat at UBE it is not possible to allocate full time personnel to PLATO right now.  To support PDCR (mid March 2015) some resources will be made available. In particular FEM/TMM.  In the second quarter of 2015 experienced personnel will be available for PLATO. Short-Term Planning & Resurces