PACS Instrument Intermediate Design Review (IIDR)

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

• Reinhard Katterloher

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
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
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
Subsystem Verification (Qualification of Units)
6
General Instrument AIV Sequence
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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
Instrument Block Diagram
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

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Thermal Mathematical Model Schematic
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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
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
Redundancy Scheme (Wiring)
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
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
H/W Deliverables (...) means not a deliverable
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Critical Areas

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

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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)

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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
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
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