PLATO Mission: TOU Phase B/C1 preliminary KO meeting:Technical Issues December 12 th, 2016

Summary Contractual section (ASI, Leonardo, TAS-I, MLT) Contract and Technical Annex Deliverable Planning Technical Section ( ESA,ASI, Leonardo, UBE, INAF) Optical Design Mechanical Design Thermical Design Project Team WBS Product Tree Risk analysis PLATO – KO meeting, ASI @@ Ottobre 2016

Technical Section

The experimental work performed during phase-A in support to INAF_Padova permitted us to define the technologies, already addressing and solving some major MAIT criticalities. i.e. the L6-Lens (or the… «Plato Ashtray»)

High rate productions for Space programmes have been experienced by LDO (i.e. Iridium, IRES attitude sensors). High rate are generally based on: Design optimized vs defined MAIT procedures; Balancing of the production line steps with equipment/tem operating in parallel

Strong «joined» cooperation already well established with the team ! Concurrent Engineering is foundamental in the present phase!

Design drivers & risk areas The current opto-mechanical design is the result of a number trade-off and iterations for performance optimizations: Some drawbacks or constrains look difficult to be removed or improved, i.e.: Margins for sufficient budgetting from theoretical design to manufacturing & alignment tolerances. Transmission req.t vs radiation resistance glasses. Lenses form and size (i.e. positive lenses edge thickness; L6 interdistance vs FPA ) Stability of entrance-pupil area vs radiometric stability. Some of the current values still TBC/TBD might result as critical issues (i.e. stability vs thermal-dynamics environment)  compromises shall be defined and agreed by the D-SRR event. Full qualification, not included in B2/C1 phase, of the preselected adhesives for materials (glasses and metals for CTE matching ) is a also a risk area, to be mitigated by early performed dedicated tests.

Design drivers & risk areas Margins for changes appear very limited, unless performing an heavy redesign and new higher level tradeoff , which would not be feasible for the scope and budget of the current phase of the PLATO programme. Scheduling is a severe constraint for any heavy design changes: To have in time mechanics detailed design, material selection & their manufacturing. For the optical materials (critical) procurement. The design optimisation shall be well oriented to the envisaged Phase C/D schedule: A suitable MAIT approach shall be defined to shorten the assembly and aligning phases: reducing DOF of lenses according to sensitivity analysis and lenses shape vs mechanical mounts; definition of tools & jigs; The procurement and verification of the identified procedures equipment, tools, might require the Phase C/D budget. Robust and effective Concurrent Engineering phase shall immediately start.

Design and Development Drivers for B/C1 phase L1 fast aspheric lens manufacturing and test Coating development & qualification Definition detailed MAIT Plan: in particular procedures, equipment & tools for lenses manufacturing « « « for TOU units assembly & alignment « « « for TOU testing BA integration  Feedback from STM to the design Remark : The EM shall finally validate the adopted design solutions, in particular with performance test at operative thermal vacuum enviroment, but the test campaign is planned in the C/D phase.