System Engineering 1

PACS IIDR ESTEC 01/02 March 2001

PACS Instrument Intermediate Design Review (IIDR)

Reinhard Katterloher

System Engineering

DDVP, Model Philosophy, Critical Areas

System Engineering 2

PACS IIDR ESTEC 01/02 March 2001

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

PACS IIDR ESTEC 01/02 March 2001

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

PACS IIDR ESTEC 01/02 March 2001

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

PACS IIDR ESTEC 01/02 March 2001

Subsystem Verification (Qualification of Units)

X = test rs = warm resonance

search S = qualif. by similarity () = not a deliverable

QM

1B

OL

C/A

AV

M D

EC

/ME

C

AV

M S

PU

(+A

VM

2)

AV

M D

PU

CQ

M F

PU

(QM

2 B

OL

C/A

)

(QM

DE

C/M

EC

)

(QM

SP

U)

(QM

DP

U)

PF

M F

PU

PF

M B

OL

C/A

PF

M D

EC

/ME

C

PF

M S

PU

PF

M D

PU

FS

FP

U

FS

BO

LC

/A

FS

DE

C/M

EC

FS

SP

U

FS

DP

U

(Cryo-) Vibration X X S X X X X X X rs X X X X

Thermal Cycle X X X S X X X X X X X X X X X

Vacuum Cycle X X X S X X X X X X X X X X X

Thermal Range X X X S X X X X X X X X X X X

EMC (Instrument Level) X X X X X X X X X X

EMC (Satellite Level) X X X X X X

Physical Measurements X X X X X X X

Contamination Control X X X X X X X

Functionality/Performance X X X X X X X X X X X X X X X X X X X

System Engineering 6

PACS IIDR ESTEC 01/02 March 2001

General Instrument AIV Sequence

Instrument Units manufactured byPACS Consortium

Partners

AIV on Unit level GEN-AIV-T01

Delivery Readiness Review

(acceptance tests passedat manufacturers site)

GEN-AIV-T02

Delivery of Unitsto

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

Deliveryto ESA

GEN-AIV-T05

System Engineering 7

PACS IIDR ESTEC 01/02 March 2001

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

PACS IIDR ESTEC 01/02 March 2001

Instrument Block Diagram

System Engineering 9

PACS IIDR ESTEC 01/02 March 2001

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

PACS IIDR ESTEC 01/02 March 2001Thermal Mathematical Model

Schematic

System Engineering 11

PACS IIDR ESTEC 01/02 March 2001

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

PACS IIDR ESTEC 01/02 March 2001

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

PACS IIDR ESTEC 01/02 March 2001

Redundancy Scheme (Wiring)FPFPU

Blue Photo-conductor

Red Photo-conductor

BlueBolometer

RedBolometer

Grating

Chopper

FilterWheels

CalibrationSources

Temp.Sensors

Herschel Cryostat

MEC1

Blue DEC

Red DEC

BOLC

BOLA

DSPModule

I/FModule

Base PSU

MEC2

DSPModule

I/FModule

Base PSU

Nominal SPU

Blue SPU

Red SPU

RedundantSPU

Blue SPU

Red SPU

DPU

NominalDPU

Redund.DPU

Partially Redundant Unit

Fully Redundant Unit

S/C

System Engineering 14

PACS IIDR ESTEC 01/02 March 2001

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

PACS IIDR ESTEC 01/02 March 2001

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

PACS IIDR ESTEC 01/02 March 2001

H/W Deliverables (...) means not a deliverable

Development Models

AVM QM PFM FS

PACS

FPU

(Grating ) (Chopper ) (Detector ) (Bolometer)

Simul. CQM PFM Refurbished CQM

PACS

Warm Electronics

(DPU EQM) (DEC/MEC LM)

(SPU EM) (BOLC EM) (BOLA EM)

DPU DMC SPU

BOLC BOLA WIH

(DPU) (DMC)

(AVM2?) (BOLC) (BOLA)

DPU DMC SPU

BOLC BOLA WIH

Kit Kit Kit Kit Kit

(WIH)

System Engineering 17

PACS IIDR ESTEC 01/02 March 2001

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)

System Engineering 18

PACS IIDR ESTEC 01/02 March 2001

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

PACS IIDR ESTEC 01/02 March 2001

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

PACS IIDR ESTEC 01/02 March 2001Impact 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

PACS IIDR ESTEC 01/02 March 2001

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