GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 1
GammaGamma--ray Large ray Large Area Space Area Space TelescopeTelescope
GLAST Large Area Telescope:GLAST Large Area Telescope:
Systems Overview WBS: 4.1.2
Tim ThurstonStanford Linear Accelerator CenterSystems Engineering Manager
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 2
TopicsTopics
• System Key Requirements• Technical Trades• Systems Overview• LAT Design Heritage - Highlight• System Performance • Systems Engineering & Configuration Management• Schedule/Milestones
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 3
LAT Key Science RequirementsLAT Key Science RequirementsLevel II(b) Specification No: LAT-SS-00010-01
Parameter Range Requirement PDR
Energy Resolution 20MeV-100MeV < 50%, Normal Incidence 9% @ 100 MeV
100 MeV - 10 GeV <10%, Normal Incidence 8% @ 10 GeV
10 GeV - 300 GeV <20%, Normal Incidence < 15%
Energy > 10 GeV <6% Incidence > 60º <4.5%
Effective Area 1, 10 GeV (peak within range) > 8000 cm2 10,000 cm2 @ 10
GeV
Field of View > 2 sr 2.4 sr
Single Photon Angular Resolution - 68% 100 MeV < 3.5º/6º
(front/back) 3.37º/4.64º (front/total)
10 GeV - 300 GeV < 0.15º/0.3º (front/back) .086º/.115º (front/total)
Pointing knowledge < 7 arcsecond 5 arcsecond
Dead Time < 100 µs/event 20 µsec
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 4
LAT Key Design RequirementsLAT Key Design RequirementsLevel II(b) Specification No: LAT-SS-00010-01
Parameter Requirement PDR
Orbital Period 90 minutes 90 minutes
Instrument Mass < 3000 kg 2614 kg
CG Constraints < 0.246 m 0.180 m
Envelopex: < 1.8 my: < 1.8 mz: < 3.15 m
x: 1.794 my: 1.794 mz: 1.044 m
Static Load Thrust +6.0 +/- 0.6 g (See SI/SC IRD)* comply
Lateral +/- 4.0 g (@ Liftoff) comply
Average Power (orbit average) < 650 watts 528 watts
Peak Power < 1000 watts 603 watts
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 5
LAT Technical Trade Studies LAT Technical Trade Studies • Many Studies Complete prior to Nov ’99 proposal• Studies completed since selection
– Tracker SSC size, pitch instrument footprint, mass• SSD spec finalized, prototypes made and evaluated
– Tracker radiator thickness distribution– Grid Material: Al vs. CFC
• Aluminum selected– ACD Segmentation
• 104 segments selected– Grid Pitch
• Pitch increased 1 mm– SAA protection scheme
• PMT current limit in addition to SAA alert protective action– Optimized I&T, calibration and verification test plans
• Ongoing Studies– ACD Skirt – Hardware Triggers/Onboard Filter – Optimized on-board processors– Thermal Control System
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 6
LAT System Overview (Continued)LAT System Overview (Continued)Instrument Configuration – Major Mechanical & Thermal Components
Thermal/micro-meteorite shield (MLI and ceramic blankets)
Anticoincidence Detector (ACD) surrounds TKR
Trackers (TKR) mount to top flange of Grid
Grid support structure (aluminum)
Radiators mount to Grid and Spacecraft (SC)
Calorimeters (CAL) inside Grid
Electronics mount to CAL bottom platesHeat pipes on top of
GridSpacecraft mount points (4x)Radiator
(aluminum)
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 7
LAT System Overview (Continued)LAT System Overview (Continued)
Instrument Configuration Major Electrical Components
Anticoincidence Detector• 5 sided, composed of segmented plastic
scintillator tiles• 194 photo multiplier tubesTracker• 16 Modules• 8.8 105 channels (18 layers/module) Si Strip Det.Calorimeter• 16 Modules• 8 x 12 CsI bars x 2 channelsData Flow & Electronics• 16 Tracker/CAL Electronics Modules (TEM)• 2 Spacecraft Interface Units (1 box - SIU)• 2 ACD-Electronics Modules, 2 Global Triggers
modules ( 1 box - GASU)• 5 Processor Modules• 2 Power Distribution Units (1 box –PDU)
DAQ EM DAQ EM DAQ EM DAQ EM
DAQ EM DAQ EM DAQ EM DAQ EM
DAQ EM DAQ EM DAQ EM DAQ EM
DAQ EM DAQ EM DAQ EM DAQ EM
TKR
TKR
TKR
TKR
TKR
TKR
TKR
TKR
TKR
TKR
TKR
TKR
TKR
TKR
TKR
TKR
ACD
spare
EP-3
T / C PS T / C PS T / C PS T / C PS
T / C PS T / C PS T / C PS T / C PS
T / C PS T / C PS T / C PS T / C PS
T / C PS T / C PS T / C PS T / C PS
EP-RESEP-1 EP-2
spare spare
EP-4
CAL CAL CAL CAL
CAL CAL CAL CAL
CAL CAL CAL CAL
CAL CAL CAL CAL
SIU Pwr Dist. Box
GASU
- ACD
-TKR
- CAL
- TEM
- T/C PS
- GASU, EP, PDU, SIU
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 8
LAT Operating ModesLAT Operating Modes
Launch Mode
Early Orbit Mode
Observatory Verification
Mode
Normal Operations
Mode*
Re-entry Mode
Safe Mode
Software Mode
Hardware Mode
Survival Mode
Safe Mode Recovery
Standby/ Engineering
Mode
* Science Operations
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 9
LAT Design LAT Design -- Flight HeritageFlight Heritage
Examples of Flight Experience & Heritage Application• Balloon Flight Experiment
– Successful implementation and flight tested a prototype tower consisting EM units from ACD, Tracker, Calorimeter, and DAQ
– Demonstrated Trigger and data & command communications along with on-board data storage
• Thermal Subsystem– Heat Pipes & Thermal Control: Designed by Lockheed Martin with
flight heritage from MILSTAR, Classified, Iridium and CommercialRemote Sensing (CRSS)
• Structural– Tracker Tower: Engineering support Hytec Inc., provider of
advanced composite frames and materials for flight programs such as STEREO and FORTE
• Processor– British Aerospace RAD750 radiation hardened PowerPC, a follow-
on to the flight proven RAD6000 family
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 10
System Design Complexity ComparisonSystem Design Complexity ComparisonElectrical DesignBaBar vs. LAT BaBar LAT
Main Physics Detector Systems 5 3Tracker
Detector Technology Si Strip Si StripChannels 100,000 850,000Signal Processing 7 bit 1 bit
Radiation Hardness > Mrad <10 KradCalorimeter
Detector Technology Cesium Iodide Cesium IodideChannels 14,000 1,500Dynamic Range 18 bit/diode 15 bit/diodeDigitization Rate 4 MHz < 10 KHzFE Electronics Servicable No No
3rd Detector System (DIRC/ACD)Photo Multiplier Tube Channels 11,000 200Pulse Processing Height+(2ns)Time+Charge Height
Trigger & Data FlowTrigger Input Channels 14,000 800 CAL/TKR Layer OR's
L1 Trigger Rate 2 KHz < 10 KHzTKR Trigger Processing curve fitting simple 3-in-a-rowCAL Trigger Processing energy sum simple 3-in-a-rowDeadtime after Trigger 2 µsec 20 µsecSystem Dead-time < 0.5 % at 2 KHz 20% at 10 KHz
Event ProcessingReal Time Event Processors 240 4Event Data Size 30 kb 1-2 kb
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 11
Systems Performance Budget (1)Systems Performance Budget (1)Mass Budget (Kg)
13-Dec-01 Estimate Recm'd ReserveItem (Kg) (Kg) %ACD 228.1 33.0 14.5%
Tracker 504.9 15.1 3.0%
Calorimeter 1,466.3 98.8 6.7%
Trigger & Data Flow 184.4 42.2 22.9%
Grid/thermal 230.0 63.5 27.6%
Instrument Total 2,613.7 252.7 9.7%
Instrument Allocation 3,000.0
% Reserve 14.8%LAT Mass
24002500260027002800290030003100
06-Jan-99
06-Jan-00
05-Jan-01
05-Jan-02
05-Jan-03
05-Jan-04
04-Jan-05
04-Jan-06
Mas
s - K
G
Instrument Allocation: 3000 kg Instrument Reserve at PDR: 14.8%
Goal for PDR Reserve > 9.9% Goal for CDR Reserve > 5.4%
Goals estimated using guidelines given in ANSI/AIAA G-020-1992 "Estimating and Budgeting Weight and Power Contingencies for Space Craft Systems"
Proposal SRR I-PDR I-CDR Ship Inst . Launch
Current
Trigger
A llocat ion
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 12
Systems Performance Budget (2)Systems Performance Budget (2)
Power Budget (Watts)30-Nov-01 Estimate Recm'd Reserves
Item (Watts) (Watts) %ACD 12.3 2.2 18.1%
Tracker 168.9 15.2 9.0%
Calorimeter 77.2 12.4 16.1%
Trigger & Data Flow 244.9 44.3 18.1%
Grid/thermal 24.5 2.2 9.0%
Instrument Total 527.8 76.4 14.5%
Instrument Allocation 650.0
% Reserve 23.1%LAT Power
400450500550600650700
06-Jan-99
06-Jan-00
05-Jan-01
05-Jan-02
05-Jan-03
05-Jan-04
04-Jan-05
04-Jan-06
Pow
er -
Wat
ts
Instrument Allocation: 650 Watts Instrument Reserve at PDR: 23.1%
Goal for PDR Reserve > 15% Goal for CDR Reserve > 10%
Goals estimated using guidelines given in ANSI/AIAA G-020-1992 "Estimating and Budgeting Weight and Power Contingencies for Space Craft Systems"
Proposal SRR I-PDR I-CDR Ship Inst . Launch
Current
Trigger
A llocat ion
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 13
Systems Engineering&
Configuration Management
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 14
Systems EngineeringSystems Engineering
System Design
RequirementManagement
4.1.2.1
LAT SystemConfigurationManagement
4.1.2.6
DocumentManagement
Risk/Reliability
System Analysis4.1.2.3
Science Analysis
StructuralAnalysis
Thermal Analysis
CyberDoc
DOORs
Level II/III ChangeControl BoardPower Budget
Mass Budget
LAT Systems EngineeringTim Thurston(WBS 4.1.2)
Interface Control
Database
FMEAs
SystemVerificaiton
System Validation
IV&V Support
Verification Plan
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 15
Requirements FlowRequirements Flow
LAT - ACD Spec. LAT-SS-00016
LAT - TKR Spec. LAT-SS-00017
LAT - CAL Spec. LAT-SS-00018
LAT - T&DF Spec. LAT-SS-00019
Leve
l IPr
ojec
t Sp
ecifi
catio
nsLe
vel I
I(a) S
yste
m
Leve
l III
Subs
yste
m S
peci
ficat
ions
LAT Operations Facility Spec.
LAT-SS-00021
ProgramRequirements
Leve
l II(b
) Ele m
ent
LAT – ACD ICDMech: LAT-SS-00241Elec: LAT-SS-00363
LAT SAS Spec. LAT-SS-00020
LAT InstrumentPerf. Spec. LAT-SS-00010
MOC Functional Reqs Document
433-RQMT-0001
LAT IOCPerf. Spec.LAT-SS-00015
Leve
l II S
yste
m S
peci
ficat
ions
LAT Power Subsystem Spec.
LAT-SS-00136
LAT Mech. Spec. LAT-SS-00115
Other Element Specifications
Ops Concept Document
433-OPS-0001
LAT Mission Assurance Reqs
433-MAR-0001
Mission System Specification433-SPEC-0001
Science ReqsDocument 433-SRD-0001
Design Standards
LAT-SC IRD433-IRD-0001
LAT – CAL ICDMech: LAT-SS-00273Elec: LAT-SS-00238
LAT – TKR ICDMech: LAT-SS-00138Elec: LAT-SS-00176
GLAST Project Specification LAT Instrument Specification LAT IOC Specification
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 16
System Requirements Flow Down & TrackingSystem Requirements Flow Down & TrackingGLAST Mission & LAT Project have selected Telelogic DOORS® requirements management tool
Systems Engineering
DOORS
Level 4Test Plans
Level 4Performance
Specifications
Level 3Performance
Specifications
Level 3Test Plans
Level 2Performance
SpecificationsLevel 2
Test Plans
Level 2LAT
Requirements
Level 2Test
Requirements
VerificationMatrix
Level3LAT
Requirements
Level 4LAT
Requirements
Level 3Test
Requirements
Level 4Test
Requirements
Requirements Management:• Tracking• Flowdown• Verification
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 17
LAT Configuration ManagementLAT Configuration Management
Online Access for Status Reporting and Real-Time Inquiries
BaselineDocuments
CIDL
CISelection
ProposedChange
ChangeApproval
(Manager or CCB)
ChangeVerification
ConfigurationAudits
Online Access to LAT Team
Configuration Change ControlConfiguration Change Control
Configuration IdentificationConfiguration Identification Configuration Status Configuration Status AccountingAccounting
Configuration Configuration VerificationVerification
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 18
CCB ProcessCCB Process
Need for ChangeIdentified
Responsible Project Element(RPE) submits Document Change
Notice (DCN) for managerapproval
Impact to requirements,cost, schedule?
Class III changeChange is implemented and DCN
is distributed to LAT team
Class I or II changeRPE submits a Change Request
(CR) for CCB screening
CR is sent to the ConfigurationControl Board for approval
GLAST Project Office (GPO) approval required?
CR is sent to GPO for approvalIf approved, the change is
implemented and the CR and DCNare distributed to the LAT team
CLASS DEFINITIONSClass I - MissionClass II - IPOClass III - Subsystems
NO, Class II
YES, Class I
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 19
System Requirements & Analysis
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 20
System Requirements Tracking (Example)System Requirements Tracking (Example)LAT Level IIb Requirements
Parameter Constraint Predicted Performance
(PDR)
Requirement Goal Verification Spec Ref
630 cm2 to Sim,ground BT (>10,000 TPT, 20±5 MeV, NI )2000 cm2 Sim,(being worked) BT (> 5000 TPT, 100±10 MeV, NI)
1, 10 GeV (peak within range)
>10,000 cm2
@10 GeV> 8000 cm2 > 12,000 cm2 Sim,
BT (> 1000 TPT, 1±0.1 & 10±1 GeV, NI) 5.2.3
8,000 - 10,000 Sim,cm2 BT (> 1000 TPT, 10±1 GeV, extrapolate)
1 TeV TBD > 9500 cm2 Sim 5.2.1TBD Sim (every 10 MeV),
BT (see cases above)
TBD Sim (every 10 MeV from 50 to 90 MeV, then see cases above),BT (see cases above)
100 MeV
300 GeV
Aeff 20 MeV > 300 cm2 > 1000 cm2
> 6400 cm2 5.2.1
5.2.1
> 3000 cm2 > 8000 cm2 5.2.1
5.2.4
50 – 300 MeV < 25 % < 10 % 5.2.4
Aeff
knowledge (1σ)
20 – 50 MeV < 50 % < 20 %
Comments:
TPT – tagged photon trigger
For 300 GeV data:
BT – beam test
NI – normal incidence
Simulations must match measured backsplash rates to better than 10% – earlier measurements must be reviewed and, if necessary, another set of measurements must be made.
Effective Area vs. Energy
0
5000
10000
15000
0.01 0.1 1 10 100 1000
Energy (GeV)
Aef
f (cm̂
2) SpecGoalPDR
Single point from SRD
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 21
FMEA & Reliability RequirementsFMEA & Reliability Requirements
As described in the MAR
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 22
Probabilistic Risk Assessment CategoryProbabilistic Risk Assessment Category1 >10% (<90%)
None
None
2 <10%>1% (>90% <99%)
None
None
3 <1% (>99%)
None
4 Failure Unlikely - No Known failure, Large Margins
None
Prob
abili
ty o
f Occ
urre
nce
(Mis
sion
Suc
cess
)
5 Failure Not Credible- Specific mitigation action
None
5 No Effect
4 Loss of non critical function a. not needed, b. backup available
3 Degraded Mission (meets minimum science mission)
2 Loss of Science (does not meet minimum science mission)
1 Total Loss of Mission
Criticality - Consequence of Failure
Risk High Medium Low
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 23
Reliability AllocationReliability AllocationMission Elements Systems Subsystems
Launch Vehicle
??%(Pf = .??)
Mission70%
(Pf = .3)
GSE??%
(Pf = .??)
Space Craft85%
(Pf = .15)
Observatory85%
(Pf = .15)
GBM85%
(Pf = .15)
LAT85%
(Pf = .15)
Elec/DA96%
(Pf = .04)
Mechanical/ Thermal
99%(Pf = .01)
CAL96%
(Pf = .04)
TKR96%
(Pf = .04)
ACD96%
(Pf = .04)
Reliability is defined as the probability of successfully meeting mission objectives at end of life. Pf is probability of failure.
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 24
Operability AllocationOperability AllocationSystems Subsystems
LAT85%
Elec/DA90%
Mechanical/ Thermal
100%
CAL90%
TKR90%
ACD98.5%
Operability is defined as the fraction of the component or subsystem required to be operational in order for the instrument to meet minimum mission performance at end of life.
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 25
Risk & Risk MitigationsRisk & Risk Mitigations• Power & Mass
– Established Power & Mass Review Board to control the power growth
• Trigger/Background Filtering– Flexible compute/software architecture– Trigger/Filtering studies underway
• Thermal Control System Ground Testing– Enhanced validation program– Additional concepts being studied
• Calorimeter: Diode/Crystal optical bonding– Pre-production testing program– Optional non-bonded pin diode configuration
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 26
Level III Milestones (1)Level III Milestones (1)vDE Activity
DescriptionStartDate
FinishDate
ND AV
Instrument Project Office (Level 3ACD Subsystem Requirements Review 03/20/01A 2 6
Tracker Subsystem Requirements Review 03/22/01A 2 4
Calorimeter Subsystem Requirements Review 03/28/01A 2 5
Science Analysis Software Requirements Review 04/20/01A 2 D
Electronics & DAQ Subsystem Requirements Review 04/25/01A 2 7
Mechanical Subsystem Requirements Review 05/02/01A 2 8
IOC Requirements Review 05/03/01A 2 B
Flight Software Requirements Review 05/30/01A 2 7
Tracker PDR 06/19/01A 2 4
Anticoincidence Detector PDR 07/25/01A 2 6
Calorimeter PDR 07/27/01A 2 5
Mechanical Systems PDR 08/15/01A 2 8
Electronics & DAQ PDR 08/16/01A 2 7
Flight Software PDR 08/16/01A 2 7
IOC PDR 08/17/01A 2 B
FY01 FY02 FY03 FY04 FY05 FY06
© Primavera Systems, Inc.
Run Date 11/19/01 14:26 *** DRAFT *** Sheet 1 GLAST-LAT ProjectProject Milestones
Level 3
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 27
Level III Milestones (2)Level III Milestones (2)Activity
DescriptionStartDate
FinishDate
ND AV
Instrument Project Office (Level 3)Science Analysis Software PDR 08/17/01A 2 D
Sub System Qual Readiness Review-ACD 1/2/03 2 6
Sub System Qual Readiness Review-TRKR 6/12/03 2 4
Sub System Qual Readiness Review-CAL 3/3/03 2 5
Sub System Qual Readiness Review-MECH 4/3/03 2 8
Sub System Qual Readiness Review-ELEC 12/5/03 2 7
Sub System Qual Review-ACD 3/31/03 2 6
Sub System Qual Review-TRKR 8/8/03 2 4
Sub System Qual Review-CAL 9/18/03 2 5
Sub System Qual Review-MECH 9/29/03 2 8
Sub System Qual Review-ELEC 1/22/04 2 7
Sub System Production Readiness Review-CAL 2/21/03 2 5
Sub System Production Readiness Review-TRKR 8/4/03 2 4
FY01 FY02 FY03 FY04 FY05 FY06
© Primavera Systems, Inc.
Run Date 1/7/03 17:05 *** DRAFT *** Sheet 2 GLAST-LAT ProjectProject Milestones
Level 3
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 28
Level III Milestones (3)Level III Milestones (3)vDE Activity
DescriptionStartDate
FinishDate
ND AV
Instrument Project Office (Level 3Mechanical Systems CDR 05/22/02* 2 8
Tracker CDR 05/29/02* 2 4
Calorimeter CDR 06/05/02* 2 5
Flight Software CDR 06/12/02* 2 7
Electronics & DAQ CDR 06/20/02* 2 7
Anticoincidence Detector CDR 06/26/02* 2 6
Science Analysis Software CDR 09/04/02* 2 D
IOC CDR 12/04/03* 2 B
FY01 FY02 FY03 FY04 FY05 FY06
© Primavera Systems, Inc.
Run Date 11/19/01 14:26 *** DRAFT *** Sheet 3 GLAST-LAT ProjectProject Milestones
Level 3
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 29
System Engineering CostSystem Engineering Cost
4.1.2
0
0.1
0.2
0.3
0.4
. . . . . . . . . . . . . . . . . . . . . . . .
FY00 FY01 FY02 FY03 FY04 FY05 FY06
$M
M & S ( no Travel )
Labor
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 30
System Engineering Cost & CommitmentsSystem Engineering Cost & Commitments
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 31
Systems EngineeringSystems Engineering
Supporting Materials
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 32
System Science Requirements (Continued)System Science Requirements (Continued)LAT Level IIb Requirements
Parameter Constraint Predicted Performance
(PDR)
Requirement Goal Verification Spec Ref
9% at 100MeV Sim (TKR front and back separately, 20, 50, 100 MeV),BT (TPT from 5.2.1)
100 MeV – 10 GeV
8% at 10 GeV Sim (TKR front and back separately, 0.1, 0.2, 0.5, 1, 2, 5, 10 BT (TPT from 5.2.1)
<15% Sim (TKR front and back separately, 10, 50, 100, 300 GeV),BT (TPT from 5.2.1)
> 10 GeV <4.6% < 6% < 3 % Sim (60°, at 10, 50, 100, 300 GeV)
> 60° off-axis (Aeff > 10% that of NI)
(Aeff > 10% that of NI)
BT – beam test
NI – normal incidence
5.2.2
<= 10% < 8% 5.2.2
Energy Resolution
20 – 100 MeV <= 50%
5.2.2
5.2.2
10 – 300 GeV <= 20% < 15%
Comments:
TPT – tagged photon trigger
Energy Resolution vs. Energy
0
0.1
0.2
0.3
0.4
0.5
0.6
0.01 0.1 1 10 100 1000
Energy (GeV)
Ener
gy R
esol
utio
n (d
elta
E/E
) SpecGoalProposalPDR
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 33
System Science Requirements (Continued)System Science Requirements (Continued)LAT Level IIb Requirements
Parameter Constraint Predicted Performance
(PDR)
Requirement Goal Verification Spec Ref
3.37º Sim,BT (photons as in 5.2.1)
4.64º (Total) Sim,BT (photons as in 5.2.1)
.086º Sim,BT (photons as in 5.2.1)
.115º (Total) Sim,BT (photons as in 5.2.1)
Single Photon Angular Resolution (SPAR) – 95% On-Axis
2.1x/2.6x (front/back)
< 3x SPAR 68% On-Axis
< 2x SPAR 68% On-Axis
Sim (see cases for 68% On-Axis), BT (see Comments)
5.2.6
Single Photon Angular Resolution (SPAR) – 68% Off-Axis at 55°
1.6x < 1.7x SPAR 68% On-Axis
< 1.5x SPAR 68% On-Axis
Sim (averaged over f and at f = 0, 30, 45° ), BT (see Comments)
5.2.7
Single Photon Angular Resolution (SPAR) – 68% On-Axis
Comments:
10 – 300 GeV TKR Front
100 MeV TKR Front
5.2.5
< 0.3º
100 MeV TKR Back
10 – 300 GeV TKR Back
< 0.1º 5.2.5
< 0.15º < 0.07º
SPAR 68% Off-Axis at 55° – Bins of energy, angle, impact position and conversion layer TBD. This test drives the photon beam
SPAR 95% On-Axis – Need a factor > 20 statistics, or > 20k events in each energy/angle bin studied. This parameter must be carefully studied on the ground, as it parameter must be carefully studied on the ground, as it will be difficult to extract on-orb
BT – beam test
5.2.5
< 6.0º < 5.0º 5.2.5
< 3.5º < 3.0º
Angular Resolution vs. Energy
0.01
0.1
1
10
100
0.01 0.1 1 10 100 1000
Energy (GeV)
68%
On-
Axi
s C
onta
inm
ent A
ngle
SpecGoalPDR
LAT Front Only
LAT Back Only
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 34
System Science Requirements (Continued)System Science Requirements (Continued)LAT Level IIb Requirements
Parameter Constraint Predicted Performance
(PDR)
Requirement Goal Verification Spec Ref
Field of View (FOV) 2.4 sr > 2 sr > 3 sr Sim (same points as BT), BT (at least one energy in range 1 – 5 GeV at > 5 angles from 0 – 80°, using > 1000 TPTs in each bin
5.2.8
Source Location Determination
Source flux 10-7 ph cm-2 s-
1, E > 100 MeV, high gal. lat. source, spectral index -2 above flat background, no cutoff to 10 GeV and no s/c effects, 1 year survey
<0.4 arcmin < 0.5 arcmin (1σ radius)
< 0.3 arcmin (1σ radius)
Analysis (see Comments) 5.2.9
Point Source Sensitivity
> 100 MeV at high gal. lat., 1 year survey
< 3x10-9 cm-2 s-
1 < 6x10-9 cm-2
s-1 (5σ detection)
< 3x10-9 cm-2
s-1 (5σ detection)
Analysis (see Comments) 5.2.10
Time Accuracy TBD < 10 µsec < 2 µsec BT (20±5 MeV, 100±10 MeV, 10±1 GeV photons or electrons)
5.2.11
Comments:
BT – beam tes t
Analys is us ing m easured, param eterized Aeff and SPAR functions with sky s im ulation.
Tim e Accuracy – Measure (event tim e s tam p – beam clock) dis tributions
Comments:
BT – beam testTPT – tagged photon trigger
Note: FOV is defined here as integral of effective area over solid angle, divided by peak (on-axis) effective area.
Relative Area vs. Angle of Incidence
0
0.2
0.4
0.6
0.8
1
1.2
0 20 40 60 80
Angle of Incidence (°)
Effe
ctiv
e A
rea
/ On-
Axi
s Ef
fect
ive
Are
a Proposal
PDR
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 35
System Science Requirements (Continued)System Science Requirements (Continued)LAT Level IIb Requirements
Parameter Constraint Predicted Performance
(PDR)
Requirement Goal Verification Spec Ref
Dead Time <20 µsec < 100 µsec < 10 µsec Cosmic Ray Test (reducing CAL and TKR trigger thresholds to raise L1 rate to 10 kHz)
5.2.13
BT (electron and photon events from 100 MeV to 10 GeV and multi-electron events with effective energies up to 300 GeV)
Background Rejection
See Comments < 10% diffuse < 10% < 1% Sim (using best current background flux model), BT (TBD)
5.2.12
GRB Location Accuracy On-Board
Within LAT FOV, > 100 reconstructed photons with E > 1 GeV in 20 secs
TBD < 10 arcmin (1σ radius)
< 1 arcmin (1σ radius)
Analysis (see Comments) 5.2.14
GRB Notification Time to Spacecraft
After detection of burst with characteristics as in 5.2.14
TBD < 5 sec < 2 sec Instrument/spacecraft simulator 5.2.15
AGN Location Accuracy On-board
Within LAT FOV at high gal. lat., with ∆F > 2x10-6 ph cm-2 s-1 (E > 100 MeV) for more than 1000 secs
TBD < 2° (1σ radius)
Analysis (see Comments) 5.2.16
AGN Notification Time to Spacecraft
Within LAT FOV at high gal. lat., with ∆F > 2x10-6 ph cm-2 s-1 (E > 100 MeV) for more than 1000 secs
TBD < 1 min (after recognition)
Instrument/spacecraft simulator 5.2.17
Analysis using measured, parameterized Aeff and SPAR functions with sky simulation.
Background Rejection – evaluated as contamination of observed high lat. diffuse flux (1.5x10-5cm-2s-1sr-1) in any decade of energy (> 100 MeV), photon spectral index of -2.1 with no spectral cutoff
Comments:
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 36
System Science Requirements (Continued)System Science Requirements (Continued)LAT Level IIb Requirements
Parameter Constraint Predicted Performance
PDR
Requirement Goal Verification Spec Ref
GRB Location Accuracy On-Board
Within LAT FOV, > 100 reconstructed photons with E > 1 GeV in 20 secs
Comply < 10 arcmin (1σ radius)
< 1 arcmin (1σ radius)
Analysis (see Comments) 5.2.14
GRB Notification Time to Spacecraft
After detection of burst with characteristics as in 5.2.14
Comply < 5 sec < 2 sec Instrument/spacecraft simulator 5.2.15
AGN Location Accuracy On-board
Within LAT FOV at high gal. lat., with ∆F > 2x10-6 ph cm-2 s-1 (E > 100 MeV) for more than 1000 secs
Comply < 2° (1σ radius)
Analysis (see Comments) 5.2.16
AGN Notification Time to Spacecraft
Within LAT FOV at high gal. lat., with ∆F > 2x10-6 ph cm-2 s-1 (E > 100 MeV) for more than 1000 secs
Comply < 1 min (after recognition)
Instrument/spacecraft simulator 5.2.17
Comments:
Analysis using measured, parameterized Aeff and SPAR functions with sky simulation.
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 37
System RequirementsSystem RequirementsLAT Level IIb Requirements - Launch
Parameter Constraint Predicted Performance
(PDR)
Requirement Goal Verification Spec Ref.
Instrument Mass Excl. SI/SC I/F hardware
2673 kg < 3000 kg none Mass Properties Measurements
5.3.6
CG Constraints Measured from I/F plane
0.180 m < 0.246 m none Measure reaction torque with LAT on its side in integration fixture
5.3.7
Envelope Delta II Payload Planners Guide
x: 1.794 my: 1.794 mz: 1.044 m
x: < 1.8 my: < 1.8 mz: < 3.15 m
none Survey LAT 5.3.8
Static Load Launch config. comply See SI/SC IRD* none Structural analysis and inspection/ func. test after exposure
5.3.12.4
Random Vibration Launch config. comply GEVS Table D-6* none Structural analysis and inspection/ func. test after exposure
5.3.12.5
Acoustic Loads Launch config. comply GEVS Table D-3* none Structural analysis and inspection/ func. test after exposure
5.3.12.6
Shock Launch config. comply GEVS Table D-8 or D-9 as appl.**
none Structural analysis and inspection/ func. test after exposure (S/C-level test)
5.3.12.7
Launch Temperature Launch config. comply 0° < T < 30° C none T/V and thermal modelling
5.3.12.8
Launch Pressure Launch config. comply Tolerate launch pressure profile in Delta II PPG, Sec. 4.2.1
none Venting Analysis 5.3.12.9
Comments:*Pending change**Levels attenuated to LAT-SC interface values
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 38
System Requirements (Continued)System Requirements (Continued)LAT Level IIb Requirements – Flight Operations
Parameter Constraint Predicted Performance
(PDR)
Requirement Goal Verification Spec Ref.
Instrument Life Time on-orbit > 10 years > 5 years > 10 years Reliability Analysis 5.3.2
Science Data Interface
comply MIL-STD-1553 none Interface test with S/C simulator
5.3.3
SI/SC Communications
comply MIL-STD-1553 none Interface test with S/C simulator
5.3.4
Operating Modes comply See MSS, Sec. 3.1.13 (accommodate mission modes: sky survey, pointed observation, safe, load shed)
none LAT operational and T/V tests
5.3.5
Average Power Averaged over 24 hrs. 528 watts < 650 watts none Power consumption measurements and analysis
5.3.10.1
Peak Power 602 watts < 1000 watts none Power consumption measurements and analysis
5.3.10.2
Peak Power Duration Per orbit comply < 10 minutes none Analysis 5.3.10.3
Heat Dissipation comply Dissipate all internally generated heat in addition to thermal flux
none T/V and thermal modelling. T/B test.
5.3.11.1
Heat Load from S/C Excl. radiated heat from S/C to radiators
comply Dissipate up to 5 watts conducted heat from S/C.
none Thermal analysis 5.3.11.2
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 39
System Requirements (Continued)System Requirements (Continued)LAT Level IIb Requirements – Flight Operations
Parameter Constraint Predicted Performance
(PDR)
Requirement Goal Verification Spec Ref.
comply Earth IR: 265 W/m2 (hot) 208 W/m2 (cold)
comply Albedo factor: 0.40 (hot) 0.25 (cold)
Solar Thermal Flux Environment
Any operational mode, LAT radiator temperatures
comply 1419 W/m2 (hot) 1286 W/m2 (cold)
none T/V and thermal modelling
5.3.12.10.2
Solar Panel Backloading
Any operational mode, LAT radiator temperatures
comply TBD W/m 2̂ on +Y or –Y side of LAT. One side exposed at a time.
none T/V and thermal modelling
5.3.12.10.3
Radiator Sun Exposure
Any operational mode, LAT radiator temperatures within operational
comply Up to 5 degrees view angle to the sun from radiator. One side exposed at a time.
none T/V and thermal modelling
5.3.12.10.4
Survival Solar Thermal Flux
Powered off, prolonged exposure on any
comply 1419 W/m2 (hot) 1286 W/m2 (cold)
none T/V and thermal modelling
5.3.12.10.5
Meteoroid and Debris Flux
Any operational mode
comply to 0.001 Tolerate impact by meteoroids/debris with probability of impact of 0.001 and above. See MSS, Sec
none Probabilistic risk analysis and shield impact damage analysis
5.3.12.12
5.3.12.10.1Earth IR and Albedo Flux Environment
Any operational mode, LAT radiator temperatures within operational
none T/V and thermal modelling
GLAST LAT Project DOE/NASA Baseline-Preliminary Design Review, January 8, 2002
Document: LAT-PR-00403 Section 5.0 Systems Overview 40
System Requirements (Continued)System Requirements (Continued)LAT Level IIb Requirements – Ground Operations
Ground Temperature - Unpowered
Powered off comply* Tolerate 0 < T < 40 °C
none thermal cycle test, monitor temperatures, func. test after extended storage and transport.
5.3.12.3.1
Ground Rel. Humidity -Unpowered
Powered off comply* Tolerate 20% < R.H. < 55%
none monitor humidity, func. test after extended storage and transport.
5.3.12.3.2
I&T Temperature Any operational mode comply* Tolerate 15 < T < 25 °C
none thermal cycle test, monitor room temp. and func. test at ambient
5.3.12.3.3
I&T Rel. Humidity Any operational mode comply* Tolerate 35% < R.H. < 55%
none monitor room humidity and func. test at ambient
5.3.12.3.4
Ground Temp. Rate of Change**
Any operational mode comply* Tolerate up to 5° C/hour
none thermal cycle test 5.3.12.3.7
Launch Vehicle Temp.
Any operational mode comply* Tolerate 13° < T < 27° C
none Included in thermal cycle test range
5.3.12.3.5
Launch Vehicle Rel. Humidity
Any operational mode comply* Tolerate 40% < R.H. < 55%
none Included in thermal cycle test range
5.3.12.3.6
*Will comply by design or procedure. The instrument must tolerate this environment or the LAT project must develop procedures and equipment to protect the instrument during ground operations.**To protect the CsI logs.
Comments: