Close-out of IIDR Recommendations

1. Close-out of IIDR Recommendations A. Poglitsch IIDR Close-out

2. IIDR Board Conclusions • The Board notes with satisfaction that at subsystem level very good progress has been made in the design and identification of critical areas and congratulates the PACS team for their efforts. • The Board is confident that with the implementation of its recommendations PACS will arrive at the required status for the next review, which will mark the start of the instrument’s detailed design and development phase. • Although the Board does not consider the Review objectives formally fully met, it does not see the need for a delta Review. IIDR Close-out

3. Board Recommendations • R1: The Board fully supports PACS’ desire to review and consolidate urgently their model philosophy, test sequences and schedule in conjunction with the Prime Contractor and ESA and strongly asks PACS to ensure, as part of the consolidation, proper AIV sequence and instrument characterisation. The main goals will have to be to ensure the required delivery dates for the CQM and PFM, to reduce the number of items on the critical path and to ensure adequate schedule margins, while still allowing adequate time for properly characterising and calibrating the instrument on the ground. • This is still ongoing work; it is clear, however, that proper characterisation and calibration on the ground are incompatible with original (IID-A) schedule. Final assessment requires consolidated schedule for satellite from Prime which has to be achieved yet. IIDR Close-out

4. Board Recommendations • R2: The Board asks PACS to proceed without delay in the resolution of the identified open issues, being telescope optical prescription and straylight, black paint and connector qualification and instrument product assurance. • Closed – • telescope optical prescription agreed between instruments, ESA, and Prime • black paint qualification at ESTEC • connectors through CPP • PA established • Open – telescope straylight model from Prime IIDR Close-out

5. Board Recommendations • R3: The Board urges PACS to carry out a failure analysis at system and subsystem levels and to provide a FMECA. • Closed. IIDR Close-out

6. Board Recommendations • R4: The Board asks PACS to review their thermal analysis of the FPU and the validity of the underlying assumptions. The Board sees an expertise exchange between PACS and SPIRE as very profitable and asks PACS to liaise with SPIRE. PACS must deliver a proper thermal model including the bolometer array. • Closed – thermal model delivered • Open – thermal analysis; can only be done at system level! Results urgently needed as manufacture of FPU has started and changes will lead to delay and cost increase IIDR Close-out

7. Board Recommendations • R5: The Board asks PACS to optimise their FPU mechanical design with the aim to reduce the loads on the chopper. • Closed • change in FPU structural design has reduced loads on chopper to accepted value • RfW for notching pending IIDR Close-out

8. Board Recommendations • R6: The Board acknowledges that PACS clearly identified their critical areas as being the CREs, the grating mechanism, the SPU, and the bolometer arrays, and asks PACS to follow these closely to arrive at a mature design. • Progress – • CRE performance according to specs demonstrated in most parameters, QM chips manufactured, small optimisations for FM run identified • SPU H/W design according to PACS requirements settled • grating drive and position readout bread-boarded • QM bolometer arrays manufactured, performance tests done so far are within specs IIDR Close-out

9. Board Recommendations • R7: The Board urges PACS to validate the new design for the BOLA with the reduced dissipation. Before deciding on the desirability of ‘designing away’ the BOLA unit, the impact of mission lifetime must be assessed in connection with ESA. • Closed – BOLA with reduced dissipation is baseline • Problem: BOLA minimum operating temperature may be above CVV temperature; needs clarification on short timescale IIDR Close-out

10. Board Recommendations • R8: The Board sees the interdependence of the SPU and REBA (LFI) requirements as unhealthy and asks PACS to make a detailed analysis of the SPU requirements and closely follow the SPU programme (see also R9 and R10). • Closed – design of both units has been upgraded to meet PACS SPU requirements IIDR Close-out

11. Board Recommendations • R9: The Board sees the need to directly involve the SPU and DPU contractors in programmatic and technical discussions and asks PACS to consider the participation of representatives of CRISA (contractor for SPU) and Gavazzi (contractor for DPU) in the PACS team. • Closed for DPU – regular progress meetings between system engineering, IFSI, and Gavazzi • Open for SPU – interaction lacks sufficient support from IAC/CRISA IIDR Close-out

12. Board Recommendations • R10: The Board asks PACS to urgently review the needed on-board data processing and compression needs for all foreseen operating modes in the view of consolidating the requirements for the implementation of this critical subsystem. • Closed – basic needs for all operating modes have been defined to the extent needed for H/W design. • Remark: more detailed definition at the border between requirements and implementation is still necessary (ongoing work) IIDR Close-out

13. Board Recommendations • R11: The Board asks PACS to consolidate the data compression requirements with the SPU design. The Board urges PACS to review with IAC as a matter of urgency all aspects of the SPU programme, i.e. technical issues (e.g. processor speed, memory requirements), cost and schedule impacts, SPU model philosophy, etc. • Closed • agreed design following PACS requirements • schedule compatible with PACS master schedule • SPU AVM not form-fit-function IIDR Close-out

14. Board Recommendations • R12: The Board asks PACS to bring its documentation to the standard required for the start of its phase C/D. All documents should be at Issue 1 (or higher), properly signed and put under formal Configuration Control. As a matter of priority the following documents must be updated: • DDVP • Product Tree • Work Breakdown Structure • Documentation Tree • ICDs • Closed with IBDR • Remark: DDVP replaced with 2 new documents • general instrument AIV (without tests) • test plan (including AIV) IIDR Close-out

15. Board Recommendations • R13: The Board takes note of the increase of the FPU mass budget and urges PACS to trace their budgets and clearly identify the drivers. • Closed – FPU mass budget • after FPU design review and change request new and final masses accepted by Project • Open – electrical power budget • PACS “on” mode above allocated 100 W per instrument • ongoing discussion with Prime on actual total power budget as all 3 instruments do not need to be “on” simultaneously IIDR Close-out

16. Board Recommendations • R14: The Board urges PACS, together with SPIRE and the Science Team, to provide a schedule how to settle the “parallel” mode issue before the end of the year, identifying the (currently missing) knowledge required to make a decision. • Progress – Evaluation Note on parallel mode byM. Griffin and A. Poglitsch sent to Project Scientist on 08 Jan 02 IIDR Close-out