PACS Instrument Intermediate Design Review (IIDR)

1. PACS Instrument Intermediate Design Review (IIDR) System Engineering DDVP, Model Philosophy, Critical Areas Reinhard Katterloher System Engineering

2. Status of Instrument Design • Detailed interface requirements have been finalised • Subsystem design has been finalised • Detailed system design has been finalised • Design for on-board software has been finalised • Design of EGSE and OGSE concept have been finalised System Engineering

3. Status of H/W Documentation at IIDR • All Specifications Documents related to components, subunits and units are issued • Interface Requirements Doc. and all ICDs are issued • The Instrument Requirement Doc. is issued • The Instrument Science Requirement Doc. is issued • DDVP is updated to final instrument design • Test Plan (instrument AIV and calibr.) is issued (draft) • IID-B update issued System Engineering

4. DDVP and TP Main Contents • DDVP describes the development approach according to the system level requirements, the overall qualification and verification concept at subunit/unit/ instrument level. No further issues are intended. • Individual DDVPs are issued for components, subunits and units. They contain the relevant detailed information and cover the DIV program (environmen-tal and performance) until delivery of items to MPE. • TP deals in detail with that part of DDVP which is related to all AIV activities (environmental and performance/calibration) on Instrument Level. Schedules and Test Facilities are included. System Engineering

5. Subsystem Verification (Qualification of Units) System Engineering

6. Instrument Units manufactured byPACS Consortium Partners AIV on Unit level GEN-AIV-T01 Delivery Readiness Review (acceptance tests passed at manufacturers site) GEN-AIV-T02 Delivery of Units to MPE GEN-AIV-T03 Delivery to ESA GEN-AIV-T05 Integration and Instrument Level Test (ILT-AVM/CQM/PFM/FS) Responsibility of MPE (cryovibration/functional and performance test/spectral calibrationat TBD / MPE / LENS using special test equipment at different test sites) GEN-AIV-T04 General Instrument AIV Sequence System Engineering

7. Instrument Units (Deliverables) • 1 cryogenic FPU mounted on OB • 8 warm electronics boxes mounted on SVM- 1 DPU (prime and redund.)- 2 SPU (1 prime, 1 redund.)- 4 analogue electronics boxes DEC1, MEC1 (prime), DEC2, MEC2 (redund.)- 1 analogue box BOLC • 1 preamplifier box BOLA mounted on CVV • 1 set of interconnecting harnesses System Engineering

8. Instrument Block Diagram System Engineering

9. Thermal Mathematical Model • Upgrade of TMM performed after implementation of bolometer assembly and according to design progress. • New steady state conditions and transient behavior (temperatures and heat fluxes) of all inner parts of the FPU available. • Predictions are reliable, if the PACS TMM is combined with the S/C cryostat TMM. • An FPU cooldown time of more than 5 days is expected System Engineering

10. Thermal Mathematical Model Schematic System Engineering

11. Structural Mathematical Model • Structural Analysis repeatedly performed after final FPU design. Impact of improvements on parts of FPU structure is being investigated • Resonances above 100 Hz achieved • Values for resonance amplifications will be available very soon giving final loads on individual subunits (chopper, grating, detectors, bolometer assembly, filterwheels, sources etc.) • Results under agenda point FPU Mechanics System Engineering

12. Redundancy Concept • WE units redundancy features- fully redundant: DPU, SPU, MEC- partly redundant: BOLC- not redundant: BOLA, DEC (several features to improve reliability) • FPU redundancy features (no full redundancy)- Detectors (modules, supply groups, subarrays) - neither optics nor mechanisms are redundant (redundant windings and sensors) System Engineering

13. Redundancy Scheme (Wiring) System Engineering

14. Grounding Concept and EMC/EMI • A final grounding concept has been achieved, detailed diagrams are shown in document PACS-ME-LI-006 • EMC/EMI study has started at MPE to identify and analyse critical points of system design. Modeling will provide EMC improvement. • Grounding and EMC issues will be presented under agenda point Grounding Scheme System Engineering

15. Model Philosophy • Deliverable Models to ESA are AVM, CQM, PFM, FS cold FPU (refurbished CQM) and electronics spare kits. • For qualification of warm electronics units a QM model is required. But, a specific PACS SPU QM will not be built, qualification is done within Planck Proj. • AVMs will not be returned to the PIs together with the CQM. • For the test and calibration program (ILT) on the refurbished CQM FS-FPU (and for the benefit of further S/W development), all QM WE units are needed on instrument level (missing QMs need to be replaced by AVMs). System Engineering

16. H/W Deliverables (...) means not a deliverable System Engineering

17. Critical Areas Critical Areas regarding technology issues: • CRE redesign and manufacture of complete QM-FEE (=> pretests on basic circuits) • Grating assembly performance (=> development model, investigation of dry lubricants of bearings) • Bolometer subarray manufacture • Chopper (=> lifetime model) • Black Paint (=> sampleperformance and qualification program) • Temperature Sensors (=> qualification program) System Engineering

18. Critical Areas ctd. Critical Areas with respect to AIV and schedule: • CRE redesign/manufacture/delivery loop • Detector modules and array/baffle assembly • Detector module testing (little/no margin) • Bolometer Unit AIV • ILTs (little/no margin) System Engineering

19. CRE Risk Analysis • Increased progress in CRE development makes a need for replacement of CREs by TIAs in the Photodetector Modules very unlikely • CQM detector arrays will be fitted with CREs • TIA performance proven during QM detector module pretests at MPE System Engineering

20. Impact of TIA-Arrays on PACS performance • In case the CRE performance is not adequate for PACS FM , the impact is- two 25x16 (CRE) arrays to be replaced by two 4x16 (TIA) arrays- heat dissipation 35 mW, linear 1x4 on sky • Re-definition of spectrometer calibration and observation, redesign DEC, S/W redesign DEC, SPU, DPU • TIA concept is not an alternative solution, PACS efficiency in observation time degraded System Engineering

21. Summary Slide • Redundancy Concept • Redundancy Scheme (Wiring) • Grounding Concept and EMC/EMI • Model Philosophy • H/W Deliverables (...) means not a deliverable • Critical Areas • Critical Areas ctd. • CRE Risk Analysis • Impact of TIA-Arrays on PACS performance • Summary slides • PACS Instrument Intermediate Design Review (IIDR) • PACS Instrument Intermediate Design Review (IIDR) • Status of Instrument Design • Status of H/W Documentation at IIDR • DDVP and TP Main Contents • Subsystem Verification (Qualification of Units) • General Instrument AIV Sequence • Instrument Units (Deliverables) • Instrument Block Diagram • Thermal Mathematical Model • Thermal Mathematical Model Schematic • Structural Mathematical Model System Engineering