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

2. 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

3. Technical Section

4. 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»)

5. 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

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

7. 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.

8. 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.

9. 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.