TOU Team PLATO Consortium Campi Bisenzio, 12 Dec 2016
Thermal – Elastic Analysis Radiation Effects Glasses Procurement Optical Design Mechanical Design Optics Mass Trade-Off Thermal – Elastic Analysis Radiation Effects Glasses Procurement Campi Bisenzio, 12 December 2016 PLATO Consortium
Optical Design D. Magrin, M. Munari, R. Ragazzoni, A. Brandeker, D Optical Design D. Magrin, M. Munari, R. Ragazzoni, A. Brandeker, D. Greggio Campi Bisenzio, 12 December 2016 PLATO Consortium
optical baseline PLATO-INAF-TOU-ML-001-i2.1-Baseline.zmx Reference ZEMAX File (cold environment): PLATO-INAF-TOU-ML-001-i2.1-Baseline.zmx 24 N-TOUs 2 F-TOUs Campi Bisenzio, 12 December 2016 PLATO Consortium
optical baseline Main Drivers: Performance + Mass Budget (cold environment) Campi Bisenzio, 12 December 2016 PLATO Consortium
optical baseline Optical elements parameters (cold environment) Campi Bisenzio, 12 December 2016 PLATO Consortium
optical baseline Lenses cut Mass before cut = 5578.5 g Mass after cut = 5217.7 g Mass cut = 360.8 g (6.5%) Lenses cut Campi Bisenzio, 12 December 2016 PLATO Consortium
optical baseline Window - The main purposes of the entrance window are to shield the following lenses from possible damaging high energy radiation and to mitigate the thermal gradient that the first optical element will experience during the launch from ground to space environment. In contrast, the presence of the window increases the overall mass by a non-negligible quantity (586 g). Campi Bisenzio, 12 December 2016 PLATO Consortium
optical baseline L1 aspheric surface (cold environment) Campi Bisenzio, 12 December 2016 PLATO Consortium
Wavelength cut off vs. FoV optical baseline Filters: Deposited on window internal surface. Environment Surface Flatness Wavelength cut off vs. FoV Flat Field Uniformity Cost/Risk TOTAL Window surface 1 - + ++/--- surface 2 ++++/- L1 -- +++/--- L3 surface 1/2 L6 +/----- N-TOUs: cut wavelengths below 500 nm. Campi Bisenzio, 12 December 2016 PLATO Consortium
optical baseline Filters: F-TOUs transmissivity pass-band filters examples F-TOU Blue: 500-675 nm F-TOU Red: 675-1000 nm The filter coating will consist of radiation resistant TiO2 and SiO2 layers that can be combined to produce a wide range of filter functions while being radiation resilient at the same time. Campi Bisenzio, 12 December 2016 PLATO Consortium
performances Image quality: goal criteria is the 90% polychromatic enclosed energy in 2×2 pixels2 with respect to centroid at nominal working temperature (-80°C) and pressure (0 atm) and a depth of focus of ± 20 µm on the FPA. Campi Bisenzio, 12 December 2016 PLATO Consortium
performances Field of View: about 1037 degrees2 for N-TOUs, about 619 degrees2 for F-TOUs N-TOUs F-TOUs Campi Bisenzio, 12 December 2016 PLATO Consortium
performances Field distortion: about 3.84% on the FoV edge Campi Bisenzio, 12 December 2016 PLATO Consortium
performances Vignetting: Mechanical 3.63%, Natural (View factor, Pupil distortion) 10.48%, Total about 14.1% Campi Bisenzio, 12 December 2016 PLATO Consortium
performances Transmissivity: internal transmissivity + AR coatings BOL-EOL Transmissivity (coating 0.98) BOL-EOL Transmissivity (coating 0.985) ADOPTION BOL-EOL Transmissivity (coating 0.985+window 0.97) BOL-EOL Transmissivity (coating 0.99) BOL-EOL Transmissivity (coating 0.987) BOL-EOL Internal Transmissivity Campi Bisenzio, 12 December 2016 PLATO Consortium
performances PSFs: HR and LR Campi Bisenzio, 12 December 2016 PLATO Consortium
Ghost and Straylight Analysis Ghosts Straylight Analysis STEP model TOU+FPA imported in ASAP Campi Bisenzio, 12 December 2016 PLATO Consortium
Optical tolerances Manufacturing and alignment tolerances: Mimic the current foreseen optical alignment procedure. Analysis on cold environment model. Campi Bisenzio, 12 December 2016 PLATO Consortium
Optical tolerances Manufacturing and alignment tolerances: MF is RMS spot radius Campi Bisenzio, 12 December 2016 PLATO Consortium
Optical tolerances Manufacturing and alignment tolerances: 90% Enclosed Energy Campi Bisenzio, 12 December 2016 PLATO Consortium
Optical tolerances Manufacturing and alignment tolerances: 90% Enclosed Energy through focus Campi Bisenzio, 12 December 2016 PLATO Consortium
Optical tolerances Manufacturing and alignment tolerances: 90% Enclosed Energy through focus full FoV 90% of the detected energy from a star shall fall within the following areas: - 30 x 30 arcsec2 (2x2px) for 50% of the nominal FOV; - 37.5 x 37.5 arcsec2 (2.5x2.5px) for 95% of the nominal FOV; - 45 x 45 arcsec2 (3x3px) for 99.8% of the nominal FOV. Campi Bisenzio, 12 December 2016 PLATO Consortium
Mechanical Design D. Piazza and UBE team Campi Bisenzio, 12 December 2016 PLATO Consortium
Mechanical Design Campi Bisenzio, 12 December 2016 PLATO Consortium
Mechanical Design Campi Bisenzio, 12 December 2016 PLATO Consortium
Mechanical Design Campi Bisenzio, 12 December 2016 PLATO Consortium
Mechanical Design Campi Bisenzio, 12 December 2016 PLATO Consortium
Mechanical Design Campi Bisenzio, 12 December 2016 PLATO Consortium
Optics Mass Trade Off Campi Bisenzio, 12 December 2016 PLATO Consortium
Optics Mass Trade Off Item N-TOU #1/#4 N-TOU #2/#3 F-TOU All TOU's on S/C CBE [g] Nominal [g] Lenses 4,632 5,558 Structure 4,382 5,040 Baffles 1,265 1,518 1,350 1,620 1,155 1,386 Thermal HW 240 288 Tot. per TOU 10,519 12,404 10,604 12,506 10,409 12,272 Quantity per S/C 14 2 Tot. per S/C 147,266 173,657 148,456 175,085 20,818 24,544 316,540 373,286 Baffles weight estimation baseline is the one presented at the SRR. At the moment it shall be considered an upper limit. Thermal H/W weight from TOU URD Total made for 24+2 TOU units Campi Bisenzio, 12 December 2016 PLATO Consortium
Optics Mass Trade Off Mass Trade off: MASS D MASS [g] [%] BASELINE 5217.7 N/A UPPER LIMIT 5946.8 729.1 14.0% EDGE VIGNETTING ×2 5103.6 -114.1 -2.2% EDGE VIGNETTING ×3 4999.1 -218.6 -4.2% PUPIL 5% 5188.8 -28.9 -0.6% PUPIL 10% 5139.6 -78.1 -1.5% FOV (13.00. 13.00) 4960.3 -257.4 -4.9% FOV (12.71, 12.71) 4851.9 -365.8 -7.0% FOV (12.71, 12.71) + VIGNETTING 4772.8 -444.9 -8.5% L6 SUPRASIL 5312.5 94.8 1.8% Campi Bisenzio, 12 December 2016 PLATO Consortium
Optics Mass Trade Off Mass Trade off: The assumptions taken on the modified optical design were studied in details, with the aim to consolidate the mass saving estimate of glasses and supplement it with a mass saving estimate of the TOU mechanical structure. From this study, it turned out that the mass saving of glasses had been overestimated and was quantified to about 266 g. For the mechanical structure, a mass saving of about 40-50 g was estimated. In conclusion, at this working level, for the studied case the overall mass saving was estimated to be around 300 g per TOU. Campi Bisenzio, 12 December 2016 PLATO Consortium
Mass Trade Off Mass Trade off: Relaxing manufacturability, coating, mounting and gluing Physical Aperture w.r.t. Clear Aperture > 3mm (radius) Central thickness > 8 mm Edge thickness > 5 mm Mass before cut = 6372.2 g Mass after cut = 5946.8 g Mass cut = 425.4 g (6.7%) w.r.t. baseline + 729.1 g + 14.0% (<20%) Campi Bisenzio, 12 December 2016 PLATO Consortium
Thermal-Elastic Analysis S. Rockstein, S. Becker, D. Magrin Campi Bisenzio, 12 December 2016 PLATO Consortium
Thermal-Elastic Analysis Thermal-Elastic analysis with: Simplified model (thermal maps) (materials CTEs, refractive indexes, curvature radii) MultiPAS model (-80C steady state, ongoing) (Thermal model, Structural model, Optical model) Campi Bisenzio, 12 December 2016 PLATO Consortium
Thermal-Elastic Analysis AA7075 CTE 23.60 53.9324 16.5440 13.5074 22.9690 22.9827 23.5181 ATi6AI4V CTE 8.37 13.9908 10.4630 5.2951 25.6013 5.2921 RSA 905 CTE 19.00 61.8805 8.9417 34.2537 RSA 443 CTE 13.50 40.4214 22.9786 9.9910 96.3410 42.4605 21.9746 T = -80°C P = 0 atm 70.9407 2.3847 11.9952 0.6148 Invar 36 CTE 1.30 CTE 1.60 SiC CTE 4.00 Si STOP FPA WINDOW L1 L2 L3 L4 L5 L6 Suprasil CTE 0.51 S-FPL51 CTE 13.10 N/KZFS11 CTE 6.56 Lithotec CAF2 CTE 18.41 S-FTM16 CTE 9.00 BK7 G18 CTE 7.00 9.0000 23.0000 2.0000 26.3282 7.0000 55.1982 23.6000 66.3131 15.6000 14.9094 110.0511 4.0000 23.6036 12.2921 3.4415 23.7373 AlBeMet CTE 12.68 Invar 36 - Polyacetal CTE 0.00 (Preloaded) CTE 9.30 ZrO2 0.9991 11.4940 Model: PLATO-INAF-TOU-ML-001-i2.1-Baseline-ThermalModel-i2.0 Campi Bisenzio, 12 December 2016 PLATO Consortium
Thermal-Elastic Analysis AA7075 CTE 23.60 54.0597 16.5649 13.5187 23.000 ATi6AI4V CTE 8.37 RSA 443 CTE 13.50 23.0119 23.5378 14.0000 10.4763 5.2995 25.6499 5.3021 RSA 905 CTE 19.00 61.9589 8.9492 34.2999 40.4726 22.9978 10.0000 96.4631 42.4960 21.9900 T = 20°C P = 1 atm 71.0000 2.3850 11.9971 0.6150 Invar 36 CTE 1.30 CTE 1.60 SiC CTE 4.00 Si STOP FPA WINDOW L1 L2 L3 L4 L5 L6 Suprasil CTE 0.51 S-FPL51 CTE 13.10 N/KZFS11 CTE 6.56 Lithotec CAF2 CTE 18.41 S-FTM16 CTE 9.00 BK7 G18 CTE 7.00 9.0005 23.0301 2.0754 26.3737 7.0046 55.2633 23.6434 66.3759 15.6204 14.9136 7.0063 110.1814 7.0049 4.0069 23.6191 12.3147 3.4460 23.7587 AlBeMet CTE 12.68 Invar 36 - Polyacetal CTE 0.00 (Preloaded) CTE 9.30 ZrO2 1.0000 11.4940 Model: PLATO-INAF-TOU-ML-001-i2.1-Baseline-ThermalModel-i2.0 Campi Bisenzio, 12 December 2016 PLATO Consortium
Thermal-Elastic Analysis Thermal maps A B C D CCD Node T [°C] at t = 0 hrs T [°C] at t = 14 hrs T [°C] at t = 3 mths +Y B TUBE 2000010 -79,9796 -79,9706 -79,9550 +Y C 2000020 -79,7792 -79,7685 -79,7579 +Y D 2000030 -79,6565 -79,6430 -79,6208 +X B 2000100 -80,1509 -80,1310 -80,0966 +X C 2000110 -79,8690 -79,8510 -79,8272 +X D 2000120 -79,7112 -79,6928 -79,6620 -Y B 2000190 -80,0454 -80,0308 -80,0057 -Y C 2000200 -79,8276 -79,8138 -79,7984 -Y D 2000210 -79,6788 -79,6629 -79,6366 -X B 2000280 -79,8900 -79,8863 -79,8801 -X C 2000290 -79,7375 -79,7304 -79,7266 -X D 2000300 -79,6240 -79,6128 -79,5950 +Y A 2000600 -81,3489 -81,3085 -81,2510 +X A 2000630 -81,8754 -81,7991 -81,6813 -Y A 2000660 -81,4589 -81,4013 -81,3160 -X A 2000690 -80,7189 -80,7035 -80,6905 -Y CCDs 2001510 -78,4645 -78,4259 -78,3533 +X 2001520 -78,4713 -78,4336 -78,3624 +Y 2001530 -78,4315 -78,4001 -78,3405 -X 2001540 -78,4291 -78,3971 -78,3365 Campi Bisenzio, 12 December 2016 PLATO Consortium
Thermal-Elastic Analysis Nominal t = 0 hrs t = 3 mths t = 14 hrs Campi Bisenzio, 12 December 2016 PLATO Consortium
Thermal-Elastic Analysis Campi Bisenzio, 12 December 2016 PLATO Consortium
Thermal-Elastic Analysis Nominal -80C, -16 µm refocused Campi Bisenzio, 12 December 2016 PLATO Consortium
Radiation effects F. Borsa, M. Ghigo Campi Bisenzio, 12 December 2016 PLATO Consortium
transmission loss estimates as of 21/01/2016 Radiation & Glass Darkening transmission loss estimates as of 21/01/2016 CNES method takes into account L2 radiation spectrum as incident on the lenses, which is not the real case: the lenses (beside window) are inside the “tube” We agree in principle with CNES method, weighting krads on the spectrum of the incident radiation. But cannot exclude completely losses >10% at low wavelengths Campi Bisenzio, 12 December 2016 PLATO Consortium
Update on Radiation Analysis from OHB - 08 Sep 2016 Radiation & Glass Darkening Update on Radiation Analysis from OHB - 08 Sep 2016 Top+bottom irradiation values (8 years) Radiation for 5 different lens zones Not possible to have incident proton spectrum, but propagation inside lens Campi Bisenzio, 12 December 2016 PLATO Consortium
Radiation & Glass Darkening New darkening analysis using the new values Considering worst case position of telescope Considering a “mean” radiation on the lens: -mean value for each lens -5 different EOL transmission values Always considered a 2x margin Campi Bisenzio, 12 December 2016 PLATO Consortium
Radiation & Glass Darkening EOL transmission loss using L2 spectrum for darkening Campi Bisenzio, 12 December 2016 PLATO Consortium
Radiation & Glass Darkening How to make a more accurate analysis: estimating the radiation environment inside the tube (still preliminary) SPENVIS analysis, using ESA L2 radiation environment and 1mm Al shielding Fluence Energy [MeV] SHIELDOSE2 + inside-tube spectrum Local dose for SiO2 L2 spectrum Inside-tube spectrum Mean dose for SiO2 Campi Bisenzio, 12 December 2016 PLATO Consortium
Radiation & Glass Darkening Preliminary: using ALWAYS a 2X radiation margin With spectrum inside-tube, literature s-fpl51 data WL (nm) 500 600 700 800 900 1000 Loss (%) -14.0% -6.7% -1.9% -0.5% 0.0% With spectrum inside-tube, (confidential) new s-fpl51 data WL (nm) 500 600 700 800 900 1000 Loss (%) -3.3% -1.8% -0.8% -0.5% 0.0% Campi Bisenzio, 12 December 2016 PLATO Consortium
Radiation & Glass Darkening Irradiation tests to be made: N-KZSF11 - data on equivalent glass S-FTM16 - no proper data in literature S-FPL51 - most sensible glass, to be verified AR coatings still not considered Campi Bisenzio, 12 December 2016 PLATO Consortium
Glasses Procurement Campi Bisenzio, 12 December 2016 PLATO Consortium
Glasses Procurement Our experience is based on THALES-SESO glasses procurement for the prototype: They had a delay on L1 glass procurement (S-FPL51) because at that time there was no blank of the required size available off-the-shelf. It was required to wait for a new melting. No other particular problem was experienced BUT no radiation-hard version of the glasses are implemented in the prototype. For Flight Models, the current baseline foresee B-K7 G18 for L6 and Suprasil (radiation resilient) for the window. Note: We required the measurement of the optical and mechanical constants (CTEs, refractive indexes in the nominal working conditions: T =-80C and P=0 atm). Campi Bisenzio, 12 December 2016 PLATO Consortium