Closeout of IIDR Recommendations

1
Close-out of IIDR Recommendations

• A. Poglitsch

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
  instruments 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.

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.

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

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.

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

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

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

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

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

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

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)

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

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)

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

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