1. PACS IIDR ESTEC 01/02 March 2001 System Engineering 1 PACS Instrument Intermediate Design Review (IIDR) Reinhard Katterloher System Engineering DDVP, Model Philosophy, Critical Areas

2. PACS IIDR ESTEC 01/02 March 2001 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

3. PACS IIDR ESTEC 01/02 March 2001 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

4. PACS IIDR ESTEC 01/02 March 2001 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.

5. PACS IIDR ESTEC 01/02 March 2001 System Engineering 5 Subsystem Verification (Qualification of Units)

6. PACS IIDR ESTEC 01/02 March 2001 System Engineering 6 General Instrument AIV Sequence Instrument Units manufactured by PACS 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 Integration and Instrument Level Test (ILT-AVM/CQM/PFM/FS) Responsibility of MPE (cryovibration/functional and performance test/spectral calibration at TBD / MPE / LENS using special test equipment at different test sites) GEN-AIV-T04 Delivery to ESA GEN-AIV-T05

7. PACS IIDR ESTEC 01/02 March 2001 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

8. PACS IIDR ESTEC 01/02 March 2001 System Engineering 8 Instrument Block Diagram

9. PACS IIDR ESTEC 01/02 March 2001 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

10. PACS IIDR ESTEC 01/02 March 2001 System Engineering 10 Thermal Mathematical Model Schematic

11. PACS IIDR ESTEC 01/02 March 2001 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

12. PACS IIDR ESTEC 01/02 March 2001 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)

13. PACS IIDR ESTEC 01/02 March 2001 System Engineering 13 Redundancy Scheme (Wiring)

14. PACS IIDR ESTEC 01/02 March 2001 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

15. PACS IIDR ESTEC 01/02 March 2001 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).

16. PACS IIDR ESTEC 01/02 March 2001 System Engineering 16 H/W Deliverables (...) means not a deliverable

17. PACS IIDR ESTEC 01/02 March 2001 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 (=> sample performance and qualification program) Temperature Sensors (=> qualification program)

18. PACS IIDR ESTEC 01/02 March 2001 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)

19. PACS IIDR ESTEC 01/02 March 2001 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

20. PACS IIDR ESTEC 01/02 March 2001 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

21. PACS IIDR ESTEC 01/02 March 2001 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) 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