glast lat projectcdr/cd3 review may 12-16, 2003 document: lat-pr-01967section xx 1 glast large area...

GLAST LAT Project CDR/CD3 Review May 12-16, 2003

Document: LAT-PR-01967 Section XX 1

GLAST Large Area Telescope:GLAST Large Area Telescope:

LAT System EngineeringWBS 4.1.2

Dick HornSLACSystem Engineering Manager

[email protected] 926-8578

Gamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope



Topics

• LAT System Engineering Overview – D. Horn– Design Review Summary

– Key System Performance Metrics

– Configuration Management And Technical Baseline

– Risk Management

– Cost & Schedule Summary

• Requirements, Traceability & Interfaces

• System FMEA/PRA/Reliability T. Thurston

• System Verification T Leisgang



LAT System Engineering Overview



Design Maturity Summary

Fiscal Years

2000 2001 2002 2003 2004 2005 2006 2011

BeginLAT I&T

CriticalDesignReview

PDR PER

PreShipReview

LAT ReadyFor S/C I&T

FABRICATION PHASE COMMISSIONINGPHASE

Build & TestFlight Units

ObservatoryI&T

Final DesignEngr’g Models

LAT I&T

Ops.

Prelim. & Sys. Design

PDR Delta Baseline Review Subsystem CDR

Peer ReviewsSRR

Mature & Stable Requirements Since SRRInterfaces With Spacecraft Established and Reflected in CDR Design



PDR & dPDR, Peer Review RFA Closure• PDR RFA’s Submitted, xx of 57 Closed

– Working with GSFC on residual issues:• Calorimeter to grid attachment

• EMI/EMC box level acceptance test

• dPDR RFA’s Submitted, xx of 20 Closed– No design drivers identified

– LAT Initial responses under review by GSFC

• Subsystem CDR Peer Review RFA’s

Subsystem Number Of RFA’s

Status

ACD 19

Calorimeter 30

Electronics/FSW 26

Tracker 39

Mechanical 48



LAT Mass Status



LAT Power Status5-Apr-03 Estimate PARA CALC MEAS Recm'd Reserves

Item (Watts) (Watts) (Watts) (Watts) (Watts) %

ACD 9.4 2.3 3.9 3.2 1.4 15.0%

Tracker 152.4 1.5 0.0 150.9 10.8 7.1%

Calorimeter 64.9 0.0 0.0 64.9 4.6 7.1%

Trigger & Data Flow 326.2 211.5 114.7 0.0 23.3 7.1%

Grid/thermal 20.4 20.4 0.0 0.0 3.1 15.0%

Instrument Total 573.3 235.7 118.5 219.0 43.1 7.5%

Instrument Allocation 650.0

% Reserve 13.4%LAT Power

400

450

500

550

600

650

700

06-Jan-99 06-Jan-00 05-Jan-01 05-Jan-02 05-Jan-03 05-Jan-04 04-Jan-05 04-Jan-06 04-Jan-07 04-Jan-08

Po

wer

- W

atts

PDR7/30/02

I

CDR5/1/03

I

PSRR9/05

IGoals estimated using guidelines given in ANSI/AIAA G-020-1992 "Estimating and Budgeting Weight and Power Contingencies for Space Craft Systems"

PDR Reserve Was 15.2%

Goal for CDR Reserve > 10%Goal for PSRR Reserve > 5%

PARA - Best Estimate based on conceptual design parametersCALC - Estimate based on Calculated power from detailed design documentationMEAS - Actual power measurements of components



FSW Resource Usage Current Estimates

Resource Total Available Anticipated

Usage

Margin Factor

EPU Boot PROM 256 kB 128 kB 2

SIU Boot PROM 256 kB 128 kB 2

EPU EEPROM 4 MB 1.5 MB 2.7

SIU EEPROM 8 MB 1.5-2.5 MB 3-5

EPU CPU cycles 200% in 2 EPUs 30% > 6

SIU CPU cycles 100% in 1 SIU 25% 4

EPU memory 128 MB 16-32 MB 4-8

SIU memory 128 MB < 16 MB 8

Bandwidth – instrument to EPU 20 MB/sec 5 MB/sec 4

Bandwidth – EPU or SIU to SSR 5 MB/sec 40 kB/sec 112

Bandwidth – CPU to CPU 2.5 MB/sec 20 kB/sec 125



Key Science Performance Metrics



Configuration Management

GLAST Project Office433-PROC-0001

LAT ConfigurationManagement

LAT-MD-00068-01

Spectrum Astro

TrackerSLAC/UCSC

LAT-MD-00068-01

ACD/GSFCLAT-MD-00845-01

CAL/NRLLAT-MD-01486-01

LAT CM

Major Supplier CM

Italy France

LAT CM Defined By LAT MD-00068-01• Major Supplier CM defined internally• Key Subsystem Doc CM Transferred to LAT CM upon Subsystem Delivery to LAT



Management Plans



Change Control Process

Impact to requirements, cost,

schedule?

NO Need for Change

Identified

Level 4 change. Change is implemented and

DCN is distributed to LAT team.

RPE submits Change Request (CR) for manager approval.

YES

Level 2 or 3 change. RPE submits a Change Request

(CR) for CCB screening.

CR is sent to the Configuration Control Board for approval.

GSFC approval required?

YES, Level 2

CR is sent to GSFC for approval.

If approved, the change is implemented and the CR and DCN

are distributed to the LAT team.

NO, Level 3



Change Control Thresholds

Technical2 Cost3 Schedule4 Mass5 Power5

Level 16 And higher

As described in the DOE Project Execution Plan and the GLAST Mission Project Management Plan.

Level 26 DOE LAT Federal Project Manager

AND

NASA/GSFC GLAST Project Manager

Changes affecting any mission (level 2) requirement

Changes to any subsystem (level 3) allocation >$500K, or any change which causes the estimate at completion to exceed $110M

Changes which delay any level 2 or higher milestone

Changes to any subsystem (level 3) allocation which cause the total allocated mass to exceed the following thresholds:

Before PDR: 2725 kg Before CDR: 2850 kg Before launch: 2960 kg

Changes to any subsystem (level 3) allocation which cause the total allocated power to exceed the following thresholds:

Before PDR: 550 W Before CDR: 600 W Before ship: 625 W Before launch: 650 W

Level 36 LAT Project Manager

Changes affecting any LAT subsystem (level 3) requirement

Changes to any subsystem allocation; any changes > $50K

Changes which delay any level 3 milestone

Changes to any subsystem allocation

Changes to any subsystem allocation

Level 47 LAT Subsystem Manager

All changes to controlled documentation not affecting level 3 requirements

Any level 4 change <$50K which doesn’t increase subsystem cost

Any change not affecting level 1, 2, or 3 milestones

Any change within the subsystem level 3 allocation

Any change within the subsystem level 3 allocation

1 Any change to LAT baseline meeting the criteria listed in any row requires the 5 Appendix D approval of the person(s) identified in the first column 6 Level 1, 2 or 3 change requests require LAT CCB approval 2 Appendix A 7 Level 4 Cost or Schedule change requests are recorded in the 3 Appendix B Change Request log and captured in the PMCS, but require no additional 4 Appendix C review Figure 7: LAT Change Control Thresholds (from Project Management Plan LAT-00054-08)



Risk Management

Project Team Assessments

Expert Interviews

Lessons Learned

FMEA/FTA

Consolidation by PRM

Cost vs Effectiveness

Development of Mitigation

Strategy

Review by Risk Review Board

Risk Information Database

Risk Assessment

Networked Schedules

Fault Trees/Event

Trees

Monitoring of Project

Performance by

Managers/Risk Review Board

Review by Risk Review Board

Mitigation Activities

Corrective Action

RiskInformation Database

(Watch Lists, Contingency

Plans)

TPM Charts

Networked Schedules

Work Accomplished

Performance Margin

Risk Identification

Risk Analysis

Risk Planning,Mitigation

and Tracking

LAT Risk Management Defined By LAT-MD-00067-03

• Parallel Process To GSFC ….• Continuous Process Across LAT• Risk Ranked By Probability and Impact to Technical, Cost & Schedule

Low Risk (Selected Mitigation)

Moderate Risk (Selected Mitigation)

High Risk (Mitigation Required)

Risk Ranking

5 13 16 19 22 254 11 14 17 20 233 9 12 15 18 212 7 10 13 16 191 5 8 11 14 17

1 2 3 4 5Probability

Impa

ct



Top Risks

ID # Risk Rank

Risk Description Risk Mitigation Mitigation Status

Moderate

• On track

Moderate

• On track



System Requirements , Traceability & Interfaces



Specification Tree

LAT EnvironmentalSpecification

LAT-SS-00778

Mission SystemSpecification

433-SPEC-0001

ScienceRequirements

Document433-SRD-0001

LAT-SC InterfaceRequirements

Document433-IRD-0001

LAT PerformanceSpecification

LAT-SS-00010

LAT IOCPerformanceSpecification

LAT-SS-00015

ACD SubsystemSpecification

LAT-SS-00016

TKR SubsystemSpecification

LAT-SS-00017

CAL SubsystemSpecification

LAT-SS-00018

Trigger & DataflowSubsys.

SpecificationLAT-SS-00019

SASSubsystem


LOFSubsystem


PowerSubsystem


MechanicalSubsystem


Mis

sio

nL

AT

LA

T S

ub

syste

m

ScienceRqmts

MissionRqmts

Interface Rqmts

Interface Rqmts

TCS PerformanceSpecification

LAT-SS-00715

SAS DesignSpecification

LAT-SS-00505

CAL DesignSpecification

LAT-SS-00210

LAT TriggerSpecification

LAT-SS-00284

LAT TKR DesignSpecification

LAT-SS-00134

LAT OperationsFacility


Tower PowerSupplies


ACD DesignSpecification

LAT-SS-00352

Desig

n

Sp

ecif

icati

on

LAT DataflowSpecification

LAT-SS-00285

LAT Flight SWSpecification

LAT-SS-00399

LAT ReadoutElectronic


Radiator DesignSpecification

LAT-SS-00394

X-LAT PlateDesign


Grid Box DesignSpecification

LAT-SS-00775

LAT-SC InterfaceControl

Documents

Mission GroundSystem

RequirementDocuments

LAT IOC/MOC/SSC Interface

ControlDocuments



Requirements Development

Level 2 Reqts Peer Reviews (Aug. 2000)

Level 2 Reqts placed under LAT CM

LAT System Requirements Review (Sep. 2000)

Level 3 Reqts Peer Reviews (Mar.-Apr. 2001)

Level 3 Reqts placed under LAT CM

Level 4 Reqts developed by subsystems

Preliminary Design Reviews (Jan. & Jul. 2002)

Level 4 Reqts placed under subsystem CM

Line-by-line reviews of LAT and IOC Performance Specs by Subsystem Mgrs, Engineering and Science Leads

Updates require approval of LAT change control board

Top-level subsystem performance requirements were reviewed by Subsystem Mgrs and LAT Engineering and Science Leads

Updates require approval of LAT change control board

Subsystem design specifications are controlled at the subsystem level.

Level 4 requirements are managed and tracked at subsystem level.

CCB changes, document updates and test planning

Critical Design Review (May 12-16, 2003)

Reqts. docs imported and linked in DOORS

Reqts. in DOORS linked to planned tests and analyses.

Impacts from changes are flowed up or down as they are identified.



Requirements Traceability and VerificationExample of Flowdown from Science Requirements

Science R equirem ents D ocum entE ffective A rea

T racker Leve l 3 SpecificationLAT -SS-00017

LAT Level 2(b) SpecificationLAT -SS-00010

5.2.3 Peak E ffective A rea

AC D Level 3 SpecificationLAT -SS-00016

5.6 M ean T hickness

5.8 False VET O due to E lectrica lN oise

C alorim eter Level 3 SpecificationLAT -SS-00018

5.9 Low Energy T rigger S ignal

E lectron ics Level 3 SpecificationLAT -SS-00019

5.2.7 L1 T rigger D ead-tim eC ontribution

5.4.10 Event D ataflow D ead-T im e for Average O rb ita lC onditions5.11.2 Fast VET O S ignal

Latency

5.11.3 Logic VET O S ignal

5.11.4 Logic VET O S ignalLatency

5.11.5 Logic VE"T O S ignalT im ing

5.11.6 Fast VET O S ignal W idth

5.11.7 Fast VET O R ecoveryT im e for Large S ignals

5.11.9 AC D T rigger P rim itives

5.2 G am m a R ay C onvers ionE ffic iency

5.3 C onverter C onfiguration

5.5 G eom etric A rea

5.11 Self T rigger

5.12 D ata N oise O ccupancy

5.13 D ead T im e

5.10 H igh Energy T rigger S ignal



Requirements Traceability and VerificationEffective Area Requirement Flowdown

Effective Area > 8,000 cm2

Maximum (as function of energy) effective area at normal incidence. Includes inefficiencies necessary to achieve required background rejection. Effective area peak is typically in the 1 to 10 GeV range.

Verification5.2.3 The Peak Effective Area of the LAT shall be greater than 8000 cm2. SVAC Plan Measurement

S1 Fraction of Reconstructed Photons (Effective Area)

Verification5.6 The ACD, support structure, and micrometeorite shield shall absorb less than 6% of the incident

gamma radiation in the LAT field of view. Interaction Analysis, Shield/Blanket Analysis

5.8 The false VETO signal rate due to noise shall result in a rejection of no more than 1% of triggered gamma rays.

CPT (LAT-TD-01112), Step 19, 30

5.11.2 The fast VETO signal latency shall be commandable from 200-1600 ns after particle passage CPT (LAT-TD-01112), Step 44

5.11.3 A map of the tiles that produce VETO signals shall be generated for each Level 1 Trigger Acknowledge.

CPT (LAT-TD-01112), Step 8

5.11.4 The map of VETO signals shall be latched by the time the ADC's conversions are completed. GARC Functional Test

5.11.5 The logic VETO map shall represent the state of all ACD discriminators at the time of the particle passage (± 200 ns) causing the Level 1 Trigger Acknowledge.

CPT (LAT-TD-01112), Step 8

5.11.6 The fast VETO output signal shall have a commandable width of 50 - 400 nsec, after 'de-glitching' on 2 successive clock pulses. The leading and trailing edges must be synchronous with clock pulses.

FREE Functional Test (ACD-PROC-000051)

5.11.7 For a signal equivalent to 200 MIPs, the logic VETO signal shall be no longer than 10 ìs. (current design will be < 5 usec).

FREE Functional Test (ACD-PROC-000051)

SRD Requirement

LAT Level 2b Requirement LAT-SS-00010

ACD Level 3 Requirements LAT-SS-00016




Verification5.11.9 The VETO signals caused by individual PMTs will be transmitted to the LAT AEMs, where they will be

OR'ed together (for each tile or ribbon), and used by the AEMs to generate trigger primitives.N/A

Verification5.2 The TKR shall convert at least 65% of the gamma rays with energy > 10 GeV impinging upon the

device at normal incidence.SVAC Plan, Measurement S1, C13

5.2 The TKR shall convert at least 65% of the gamma rays with energy > 10 GeV impinging upon the device at normal incidence.

SVAC Plan, Measurement S1, C13

5.3 At least 25% of the gamma-ray conversions shall occur in high-Z converter foils no greater than 3.5% radiation lengths thick

SVAC Plan, Measurement S1

5.3 The remainder of the conversions shall occur in other material and converter material < or = 25% X0 thick.

SVAC Plan, Measurement S1

5.5 The TKR shall have an active area at normal incidence of at least 19,000 cm2.5.11 The TKR trigger shall be on average at least 90% efficient for the set of gamma ray conversions from

which the conversion products traverse the active areas of at least 3 consecutive measurement planes.

5.11 In the case that no charged particles or gamma rays are incident upon the TKR, the TKR trigger shall not exceed a rate of 500 Hz.

5.12 The noise occupancy in the TKR data stream shall not exceed 1 in 10,000 channels per trigger. SVAC Plan, Measurement C10

5.13 The dead-time imposed by the TKR readout shall not exceed 10% at a cosmic ray trigger rate of 10 kHz.

SVAC Plan, Measurement C27

Verification5.9 The CAL shall provide a prompt (within 2 µs of an event) low energy trigger signal to the LAT trigger

system with a detection efficiency of greater than 90% for 1 GeV gamma rays entering the CAL from the LAT field of view with a trajectory which traverses at least 6 radiation lengths of CsI.

SVAC Plan, Measurement C24, CAL Lo Discriminator

5.10 The CAL shall provide a prompt (within 2 µs of an event) high energy trigger signal with a detection efficiency of greater than 90% for 20 GeV gamma rays entering the CAL from the LAT field of view that deposit at least 10 GeV in the CsI of the CAL.

SVAC Plan, Measurement C25, CAL Hi Discriminator

CAL Level 3 Requirements LAT-SS-00018

TKR Level 3 Requirements LAT-SS-00017

ACD Level 3 Requirements LAT-SS-00016 (continued)




Verification5.2.7 The L1 trigger system shall be able to generate L1 Trigger Acknowledge signals with a minimum

spacing down to the larger of: minimum dead-time imposed by the CAL system, or minimum dead-time imposed by the TKR or 5 ms. (The latter would result in dead-time of 5% at 10 kHz rate if the CAL had no dead-time)

5.4.10 The dataflow system shall contribute < 5 % to the instrument dead-time at a L1TACK rate of 10 kHz, due primarily to background events, for average size events. Above 10 kHz dead-time shall increase to keep the throughput at 10 kHz.

Electronics Level 3 Requirements LAT-SS-00019



Requirements Traceability and VerificationExample of Flowdown from Mission System Specification

M ission System SpecificationLAT M ass < 3000 kg

Tracker Level 3 SpecificationLAT-SS-00017

LAT Level 2(b) SpecificationLAT-SS-00010

5.3.6 M ass < 3000 kg

AC D Level 3 SpecificationLAT-SS-00016

5.19 M ass < 280 kg

C alorim eter Level 3 SpecificationLAT-SS-00018

5.12 M ass < 1440 kg

E lectronics Level 3 SpecificationLAT-SS-00019

5.7.2 M ass < 220 kg

5.14 M ass < 510 kg

M echanical Level 3 SpecificationLAT-SS-00115

8.1 M ass < 345 kg



Requirements Traceability and Verification

In terface R equirem ents D ocum entC TD B shall be com pliant

w ith M IL-STD -1553B.

LAT Level 2(b) SpecificationLAT-SS-00010

5.3.4 D ata Services

E lectron ics Level 3 SpecificationLAT-SS-00019

5.3.1 Spacecraft C om m andingInterface

F light Softw are Level 4 Spec.LAT-SS-00399

5.3.1.1.1 C om m and, Telem etryand D ata Bus P rotocol

Example of Flowdown from Interface Requirements Document

• Verification of this requirement includes hardware and software components.



Requirements Traceability and Verification

• Future Work– Near term

• Incorporate all CCB-approved Level 2 and 3 changes in requirements document revisions (ECD 6/13/2003)

• Bring DOORS database up-to-date with recently released test plans (ECD 6/30/2003)

• Release reports for all requirements verified by analysis (ECD 7/31/2003)

– Long term• Prepare requirements verification table for level 2 and 3

requirements

– Link requirements to test procedures (ECD June 2004)

– Link requirements to test data packages (On-going as tests are completed. ECD June 2005)



PDR (Jan 2002)

ICD Status:TKR Draft w / 6 TBX 'sCAL Draft w / 26 TBX 'sACD Draft w / 38 TBX 's

dPDR (July 2002)

ICD Status:TKR Draft w / 16 TBX 'sCAL Draft w / 22 TBX 'sACD Released w/ 16 TBX 's

CDR (May 2003)

ICD Status:TKR Released w / 0 TBX'sCAL Released w / 0 TBX'sACD Released w / 0 TBX'sElectronic Therm&Mech Draftw / 9 TBX's

W eekly IntefaceM eetings

Frequent em ail andphone exchanges

W eekly IntefaceM eetings

Frequent em ail andphone exchanges

I/F m eetings as needed Em ail and phone

exchanges ICD 's updated as needed Conduct fina l review for

E lectronics M ech/ThermICD

In teface M eetings Em ail and phone

exchangesDraft ICD's

Interface Development



Rad

iato

rRad

iato

r

Grid Base Ass’y

CAL

TKR

ACD

X-LAT Plate

EM

I S

kir

tRadMntBkt

Electronics

Htr SwBox

Spacecraft

LV Payload Attach Fitting

EM

I Skirt

RadMntBkt

Htr SwBox

SolarArray

SolarArray

Thermal

Structural

EMI/Grounding

Accommodation

Direction of arrow signifiesdirection of reliance, structuralsupport or heat flow

Structural/Thermal Interface Overview



Electrical Interface Overview

CAL

TKR

ACD

ACD

ACD

0 1 11Tower 0

CAL

TKR

Tower 1

CAL

TKR

Tower 15

4.1.7 Data-Acquisiton

(DAQ) System

Spacecraft

LAT

VCHPHeaterControl



Interface Documentation StatusDocument Status

LAT-SC (Spectrum Astro Managed Document) 1196 EI-Y46311-000 First draft out for reviewCalorimeter

LAT-DS-00233-3: CAL-LAT Interface Definition Drawing Final draft out for subsystem reviewLAT-SS-00238-4: CAL-LAT Mech, Therm, Elec Interface Control Document Released 13 Mar 03

ACDLAT-DS-00309-1: ACD-LAT Interface Definition Drawing Final draft out for subsystem reviewLAT-SS-00363-4: ACD-LAT Mech, Therm, Elec Interface Control Document Released 17 Dec 02

TrackerLAT-DS-00851-1: TKR-LAT Interface Definition Drawing First draft in-progressLAT-SS-00138-5: TKR-LAT Mech, Therm Interface Control Document In Signature CycleLAT-SS-00176-2: TKR-LAT Elec Interface Control Document Released 27 Jan 03

ElectronicsLAT-DS-01630-1: Electronics-LAT Interface Definition Drawing First draft in-progressLAT-SS-01794-1: Elec-LAT Mech, Therm Interface Control Document First draft in-progress



LAT Internal Interfaces

Interface Structural Thermal Grounding/Shielding Accommodation

TKR Grid8 Ti flexures/bay, bolted and pinned to Grid

Cu thermal straps from TKR sidewalls dry-bolted to Grid

Slots in Grid provide race ways for TKR flex cables

CAL GridBolted tabs in CAL back plate develop shear at joint

Tab dry-joint under high bolt pre-load transfers CAL heat to Grid

Mating alum surfaces are alodined for AC/DC grounding

E-Boxes CAL4 Ti stand-offs/bay support E-Box stack off CAL module

Low-conductivity stand-offs and surface finishes minimize heat transfer

E-Box and CAL alum surfaces alodined for AC/DC grounding

E-Boxes X-LATE-Boxes support X-LAT Plate against out-of-plane deflection

Thermal straps transfer E-Box heat to X-LAT Plate

ACD GridCorner bolts and mid-side bolts/pins

Bolted dry joint and radiative coupling transfers ACD heat to Grid


TKR ACDTKR black-painted sidewalls view ACD inner CFC honeycomb facesheet

RadiatorRad Mnt

BktBolted/pinned joints carry all Radiator loads

Isolating gasket minimizes survival heat-leak from Grid

Rad Mnt Bkt

GridBolted/pinned joints carry Radiator and Switch Box loads


Grid RadiatorVCHP's mount to HP patch plate hanging from Grid

VCHP-DSHP silicone wet joint is primary heat path for Grid heat

Switch Box

Rad Mnt Bkt

Switch box bolted to Rad Mnt Bkt

Silicone wet joint removes small heat load to Rad Mnt Bkt

Shielded cables carry ground

E-Boxes EMI Skirt Skirt shields internal E-Boxes Connectors mount to Skirt EMI Skirt Grid Bolted joint Taped for EMI shielding

X-LAT EMI Skirt Bolted, pinned joint Taped for EMI shielding

X-LAT RadiatorVCHP-XLHP silicone wet joint is heat path for Elec heat off X-LAT

Interface is low risk and is f inalized

Interface design not yet f inalized or tested

Interface design is incomplete



LAT External Interfaces

Interface Structural Thermal Grounding/Shielding Accommodation

Radiator SC BusSC struts restrain Radiator against out-of-plane loads

MLI on both surfaces to minimize radiative coupling

Radiator size/position fit around SC, flexures

Solar Arrays

RadiatorCold-/hot-case SA backloading affect peak LAT temp's, survival heater needs

Cut-out in Radiator allows SA boom to pass through

GridSC

FlexuresBracket below Grid accepts bolts, pins from Flexure

Grid Bracket allows for SC attach

EMI SkirtSC

FlexuresSkirt is recessed for clearance to flexure

X-LAT SC BusMLI on both surfaces to minimize radiative coupling

Cable tie-downs to support SC cables

Interface is low risk and is f inalized

Interface design not yet f inalized or tested

Interface design is incomplete



Key Open Interface Issues

INTERFACE KEY OPEN ISSUES STATUS RESOLUTION ECD Detailed design complete Testing is underway Focused on a pinned design implemented with bolts to the Grid.

Preliminary analysis and tests confirms design meets interface requirements

ACD None Thermal design developed using vel-therm and parallel thermal paths Preliminary analysis confirms design meets interface temperature requirements.

Spectrum Astro to analyze CG impacts to ACS. LAT to further refine worst-case estimates without impacting current subsystem plans.

Hold frequent splinter meetings until issue is resolved. Status issue at weekly interface meeting.

Tracker Validating TKR-Grid copper strap thermal design.

TKR to complete thermal testing as part of Engineering Model test plan closure.

NEED DATE

Calorimeter Validating CAL Base Plate to Grid structural design.

NEED INFORMATION FROM MARC CAMPELL.

NEED DATE

Electronics Validating X-LAT Plate to Electronics box thermal joint design.

Qualification and Engineering Model testing to validate design.

6/1/03

Spacecraft LAT lateral center-of-mass requirement is being refined as part of the Spectrum Astro Attitude Control Subsystem design maturation.

LAT calculated worst-case estimates. 6/1/03

Spacecraft Finalize harness definition and routing.

Concept proposed and is being evaluated for structural interferences.

6/1/03



Summary

Weekly Telecons and Frequent Splinter Meetings have resulted in:– LAT-SC ICD released

– TKR, CAL and ACD ICD’s released and contain 0 TBX’s

– Electronics-LAT Mechanical/Thermal ICD near completion and soon to be released

– All Interface Definition Drawings released

– Key open interface issues to be resolved by June 2003




LAT FMEA/PRA/Reliability

Tim Thurston SLAC

[email protected]




System FMEA/PRA/Reliability




System Engineering Subsystem WBS: 4.1.2

Tom LeisgangLAT Systems EngineeringTest & Verification

[email protected]




Requirements Verification Process

CorrellateResults

Parse intoDOORS

IdentifyRqt.

Link toVerification

C reate V erifica tion M atrixRequirements Traceability

LAT Systems Engineering

GLAST Project

SPECIFICATIONS Test Plans

TKR

CAL

ACD

Mech

T&DF

Flt S/W

Therm al

Dynam ics

EMI/EMC

Procedures

TestReport

AnalysisReport

AnalysisReport

AnalysisReport

TestReport

TestReport

TestReport

Results

T-VAC

Funct

CPT

EMI

Dynam icsLAT IIB

LAT III

LAT IV

433-SPEC433-IRD

433-IRD

Survey &Alignm ent

W eight &CG

SV&C

LAT-MD-00466IPVP

LAT-MD-00488

A tested and certified instrument



LAT Test Plan Organization

LAT Perform ance &Operation Test P lans

Subsystem TestPlans

LAT Instrum ent Perform anceVerification Plan

LAT Integration & Test P lan

LAT Contam ination ControlPlan

Electrical Perform ance Tests

Dynam ics Tests

Instrum ent Calibration

E. Bloom

Tracker Tow er Test P lanLAT-TD-00155

Calorim eter Test P lan

ACD Test P lan

Therm al S /S Test P lan

M echanical S /S Test P lanLAT-SS-00493

TEM

GASU

SUI

EP PDU

LATTrigger &Datflow Test P lan

LAT Instrum entation P lan

W . Davis

Com ponentAliveness T ests

SubsystemIntegration T ests

LAT L im itedPerform ance

T ests

LATCom prehensive

Perform anceT ests

LAT O perationalPerform ance T ests

E. Gaw ehnM . Lovellette

L. W ai

E. Do e Couto E S ilva

M . Lovellette

J. CullinanE. Gaw ehn

EGSE W orkstation &Softw are Validation Plan

R. Claus

LAT-M D-01376

LAT-M D-01055

LAT-M D-01587

LAT-M D-00452

LAT-M D-00404

LAT-M D-00890

LAT-SS-00262

LAT-TD-00296

LAT-M D-00408

ACD-PLAN-000050

LAT Flight Softw are TestPlan

LAT-TD-00786

LAT SV&C Test P lan

E. Do Couto E SilvaT . Leisgang

LAT-M D-00446

LAT EM I/EM C Test P lan

T. LeisgangM . Lovellette

LAT Therm al Test P lan

J. W angM . LovelletteLAT-M D-01600

Therm al Tests

M . Lovellette E. Gaw ehnLAT-M D-0xxxx

LAT Dynam ics Test P lan

Y Ism aelM . LovelletteLAT-M D-01196

M echanical W eight & CG

E. Gaw ehnLAT-M D-01598

L. W ai

LAT Survey & Alignm ent

L. W ai LAT-M D-01586

LAT Survey P lan

M . NordbyL. W aiLAT-TD-00895

LAT Handling&Transportation Plan

T. Leisgang

LAT-M D-01533

No Num ber

LAT-M D-00649

No Num ber

No Num ber

LAT Beam and ParticleTest Plans

G. Godfrey

M -GSEE. Gaw ehn LAT-M D-01462

E-GSE Developm entM . Huffer LAT-M D-01533

FacilitiesL. W ai LAT-M D-01386

LAT M echanical Integration

E. Gaw ehnL. W aiLAT-PS-00676

LAT EM I Tests

M . LovelletteLAT-M D-01838

LAT-M D-0440



LAT Performance Verification

ObservatoryIntegration

Sine Vibe

T ow erIntegration

L A TIntegration

L A T T es t ObservatoryIntegration

TKR

CAL

TEM

Grid

Radiators

EP

SIU

GASU.

PDU

ACD

IntegrateE-Boxesw / Grid Delivery

Aliveness Limited

X-LAT Plate

C

CLE A

A

M assProperties

Survey

EM I/EM C

L

InstallRadiators

Acoustic

L

C

Thermal Vac

ThermalBalance

C L

C

Final M assProperties L

A

Ship toSA

F

F

F

Survey

M

M

M

L

M

O Optical M M uon

IntegrateTKR/CAL &TEM 's w ith

Grid

SurveyO

IntegrateX LAT Plate

M echanical Fit-Checks

SurveyM

M odalsurvey

E

L

Functional

Survey:

L

Interface Comprehensive

Environmental Tests

E

M

C

v C D R 4 /14/03

Htr Box

EMI Shield

IntegrateACD

IntegrateEMI Skirt, Htrsw itch boxes

SurveyO

Sine BurstL

O

M

Electrical Tests Performance



LAT Science Verification

Tracker

Qu

al

Mo

du

les

En

gin

ee

rin

gM

od

el

Ca

libra

tio

nU

nit

LA

T

Co

smic

Ray

s o

n t

he

Gro

un

d

SLAC ES-A

Positrons

Photons

Protons

Van de Graf

(17 .6 M eV )

Si Strips noisy dead

t

threshold

Calorim eterLight YieldScintillat. E ffcyPedestals (L)Energy Range (L)

Elex. GainInteg. Non;InearityD iff. Non;Inearity

Light Asym etryLight Attenuation

ACDPedestals(L)

Detection Effcy.High Threshold

Detect.

Van de Graf

(17 .6 M eV )LATAlignm ent

LATAccuracy

Dead Tim e

TrackerEfficiencyAlignm ent

SSD,Laddertray,towerinter-tower

TKRAll

Cal

Calibrations Science Verification Particle tests

E ffective A rea A bsolu te energy E nergy R eso lu tion A ngu lar D istribu tions

on and o ff axis B acground R e jection M onte C arlo S im ula tion

V a lida tion

Reconstruction Software C harged T rack

reconstruction e ffcy. C onversion

A bsolu te E nergyon and o ff axis

E ffcy. fo r track w /A C D h its

M onte C arlo S im ula tion

poin t & e ffcy.

C A L E ffcy. fo r track

Flight LAT



Subsystem Qualification Programs

RandomThermalVacuum

CPT

LPT CPT/LPT

Sine

VIBRATION

Shock**

LPTHumidity/Storage

CPT

CPT

THERMAL

Qualification Test Sequence

**As required

EMI/EMC*

FINAL

LPTCPT

LPT*

C

C

C

C

C

C

L L L L

L

L

L

L

L

I/F

I/F

*EMI/EMC Tests may be performeed anyw here w ithin the flow

EMI/EMC*

TRR

RFU



Subsystem Acceptance Test Program

ThermalVacuum

CPT

CPT

LPT

CPTCPT/LPT

Acceptance Test Sequence

Random

VIBRATION Thermal

Burn-In

CPT

FINAL

I/F I/F

TRR

RFU



Performance Verification :Thermal

ACD4 Cycles T/

V& T-Bal

Tracker12 Cycles

T/V& T-Bal

Calorim eter12 Cycles

T/V& T-Bal

Electronics12 Cycles

T/V& T-Bal

Qu

al

Pro

to-f

lig

ht

Acc

epta

nce

LA

TO

BS

LAT4 Cycles T/V& T-Bal

OBS4 Cycles T/V& T-Bal

Tracker4 Cycles

T/V

Calorim eter4 Cycles

T/V

Electronics4 Cycles

T/V

RadiatorsTBD Cycles T/V & T-Bal

Grid Box

X-LATPlates

EM IShield

Cables



Performance Verification: Dynamics

Tracker Calorim eter Electronics

Qu

al

Pro

to-f

lig

ht

Acc

epta

nce

LA

TO

BS

Tracker Calorim eter Electronics

Radiators

X-LATPlates

EM IShield

Cables

Shock

W eightCgM odal

Grid BoxStatic Load

R R R

S SB RS

ACDshell + BFA

ACD sub assy

A

A

AS

SB R

SB RSB R

SB R

SB R

SB

SB

S

S

S

S A

S SB R A

LAT

Sine SineBurst Random AcousticKEY



Performance Verification: Electronics

Pow er

Perform ance

Qu

al

Acc

epta

nce

LA

T

Pow erFull

Perform ance

Lim itedPerform ance

Pow erOperational

Perform ance

EM ICE(cm )CS(cm )

EM I

Full Suite

EM I

RE,RS,CE,CS

I/F Verification

Full Suite

I/F Verification

Full Suite

I/F VerificationIsolation

Hi-PotPwr D istCm d. D ist

FunctionalCom prehensive

A liveness

Perform ance

FunctionalCom prehensive

A liveness

Aliveness

Perform ance

Aliveness



LAT Verification Summary

• All LAT subsystems and LAT Instrument have complete requirements verification

• All MAR test requirements are performed and verified

• All Science Requirements are verified

• Systems Engineering has a “closed loop” requirements verification process in place



Systems Engineering

DRAFT

Cost/Schedule Summary



CCB Actions Affecting 4.1.2

Change Request # Description Status

LAT-XR-01395-01 Systems Engineering Manpower

Approved $2.2M



Budget, Cost, Performance

Budget vs Actuals vs PerformanceDOE + NASA Project Expenditures

4.1.2 System Engineering

0

3

6

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FY00 FY01 FY02 FY03 FY04 FY05

$M

, E

scala

ted

Do

llars

Actual Commitments

ACWPBCWP

BCWS+ Planned CommitmentsBCWS



Cost/Schedule Status

Item In k$

Budget at Complete 4,647

Budgeted Cost for Work Scheduled (a) 2,583

Budgeted Cost for Work Performed (b) 2,577

Actual Cost for Work Performed 2,880

Cost Variance -302 -11.7% of (b)

Schedule Variance -6 -.2% of (a)

• Status as of February 28, 2003:



Manpower Plan

0.0

0.5

1.0

1.5

2.0

2.5

Q3FY00

Q4 Q1FY01

Q2 Q3 Q4 Q1FY02

Q2 Q3 Q4 Q1FY03

Q2 Q3 Q4 Q1FY04

Q2 Q3 Q4 Q1FY05

Q2 Q3 Q4

FISCAL YEAR BY QUARTERS

FT

Es



Procurements

• Long-Lead Procurements

• Major Upcoming Procurements Near-Term (< 4 months)– Orbital Network Engineering

– Stellar Solutions

• Major Upcoming Procurements Long-Term (>4 months)

• Minor Upcoming Procurements



Summary

• To be provided