LAT-PR-01967-01Section 8.2 – Structural Design1 GLAST LAT Project CDR/CD3 Review, May 12-16 2003...

LAT-PR-01967-01 Section 8.2 – Structural Design 1

GLAST LAT Project

CDR/CD3 Review, May 12-16 2003

15 Apr 2003

Martin Nordby [email protected]

With contributions from:With contributions from:

Youssef Ismail John Ku

Mike Foss Rich Bielawski

Michael Lovelette Jim Haughton

Eric Gawehn Larry Wai

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

LAT Structural SystemsLAT Structural Systems


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 AgendaAgenda

• Design Overview

– LAT design

– Design and interface changes since Delta PDR

– CCB actions, trade studies, and open issues

• Peer Review RFA’s and requirements

• Structural analysis model development

• Structural analysis results

– LAT modal analysis

– Distortion analysis

– Interface loads extraction

• Environmental test plans

– Integration and test flow

– Modal survey testing

– Sine vibe and sine burst testing

– Acoustic testing

– Optical and muon surveying

• Summary and conclusions

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Mechanical Design OverviewMechanical Design Overview

LAT OverviewLAT Overview

Anticoincidence Detector (ACD)

Mass 270.1 kg (Mar 2003 est)Size 1806 mm w x 1081.5 mm hInterfaces Grid bolted joint, shear pins

Electronics

Mass 199.3 kg (Mar 2003 est)Size 1417 mm sq x 222 mm hInterfaces Stand-off to CAL; thermal joint

to X-LAT Plate

Grid/X-LAT Plate/Radiators

Mass 329.3 kg (Mar 2003 est)Size 1580 mm sq x 236 mm hInterfaces Four-point mount to SC

flexures

LAT Structural Design Parameters

Design Spec

Mass 2679.4 kg <3000 kg

Center of Gravity 149.3 mm <185 mm

Width 1806 mm <1820 mm

Height 1081.5 mm 1100 mm

LAT Mass Budget and Current Estimates (kg)

Estimate Budget

TKR 504.9 510.0

CAL 1375.8 1440.0

ACD 270.1 280.0

Mech 329.3 345.0

Elec 199.3 220.0

LAT Total 2679.4 3000Source: LAT-TD-00564-6 “LAT Mass Status Report Mass Estimates for Mar 2003”

Calorimeter (CAL)

Mass 1375.8 kg (Mar 2003 est)Size 364 mm sq x 224 mm hInterfaces Grid bolted friction joint

Tracker (TKR)

Mass 504.9 kg (Mar 2003 est)Size 372 mm sq x 640 hInterfaces Grid Ti flexure mount and

Cu strap

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 System Block DiagramSystem Block Diagram

TKR ModuleCFC tray, side walls

Gridmonolithic alum structure

CAL Modulesalum bottom plate

Elec. Boxesalum electronics box

MLI InsulationMLI surrounding underside of LAT

ACDBase Elec Ass’y alum frame

LAT Radiatorson +/- Y sides of LAT Grid

SpacecraftLAT mounting structure

SpacecraftSC bus structure

Solar ArraysS.A. mount

MLISurrounding ACD

LAT Block DiagramLAT Block Diagram

X-LAT Platemonolithic alum structure

Radiator Mnt BktSupport Radiators at corners of Grid

EMI SkirtShields E-Boxes, supports X-LAT Pl

Htr Switch BoxesOperate Radiator heaters


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 LAT Design DetailsLAT Design Details

Grid corner detail showing heat pipes, purge grooves; corner chamfer and bottom flange for ACD

Radiator Mount at Grid corners. Note mid-side Grid Wing

Reverse-angle view of VCHP S-bends and DSHP connection TKR mid-side and corner flexures

Copper thermal straps

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 LAT Interface DetailsLAT Interface Details

Grid Wing with SC mount bracketEMI Skirt cut-outs around SC stay-clear

LAT inside LV fairing static stay-clear

PAF, per Boeing PPG

SC proposed interface stay-clear on top of octagonal SC volume

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003LAT Underside Design DetailsLAT Underside Design Details

Upside-down view of a Grid Y mid-side, showing DSHP’s, Grid Wing, and EMI Skirt

Detail of TEM, TPS, and EPU box stack

Empty boxes

EPU boxes

PDU box

GASU box

SIU boxes

TPS (16x)

TEM (16x)

LAT Underside View of LAT Underside View of Electronics BoxesElectronics Boxes

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003LAT Design Changes Since Delta-PDRLAT Design Changes Since Delta-PDR

• Subsystem changes affecting system performance

– TKR bottom tray re-work: strengthens CC tray in high-stress corner regions

– TKR flexure re-design: accommodates updated bottom tray design and provides for stiffer cantilever mode for TKR

– ACD mass growth: accommodates larger tile overlaps and increase in structural stiffness and strength

• LAT internal interface changes

– Integrated Grid Wing into bottom flange• Incorporated Wing into machined Grid (no longer a bolt-on part)• Tapered wing into a full bottom flange around Grid perimeter to reduce stress concentrations at

SC mount and heat pipe cut-outs

– Changed TKR thermal interface to thermal straps• Copper straps provide compliant joint to Grid

– Stiffened TKR flexure connection to Grid• This was part of TKR bottom tray re-design• Effect was to increase TKR first-mode natural frequency

– Moved Electronics Box structural mount to CAL back plate• Boxes now hard-mounted to CAL plate by way of moment-bearing stand-offs• Cleaner structural design simplifies analysis and test plans for CAL and Electronics groups• Forces on the X-LAT Plate are reduced to just inertial loads of the plate

– X-LAT plate thermal connection changed to V-Therm cloth• Test program underway

– CAL-Grid bolted joint modified to include pins• Development program underway to finalize pinned joint design• Design incorporated into CDR analysis


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003LAT External Interface Changes Since Delta-PDRLAT External Interface Changes Since Delta-PDR

• Finalized Radiator dimensions and interface

– Modified Radiator aspect ratio at request of Spectrum

– Agreed on final width, based on reduction in spacing between Radiators that was requested by Spectrum

– Agreed on final height, based on final positioning of LAT and PAF stay-clear agreements with Boeing

– Resulting radiator area is 2.78 m2

• Finalized Radiator mount location to SC

– Moved mount location down at request of Spectrum

– This reduced Radiator first-mode natural frequency, but margin to 50 Hz requirements is still large

• Modified LAT-SC mount region

– Finalized bolt pattern and pad size to accommodate Spectrum’s flexure design

– Agreed to final LAT and SC stay-clear geometry around flexure


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Design Changes Since Delta PDR (cont)Design Changes Since Delta PDR (cont)

LAT Delta PDR Design LAT Delta PDR Design July 2002July 2002

LAT CDR Design LAT CDR Design Mar 2003Mar 2003

Radiator panels widened and shortened, reducing thermal efficiency

Panels cut-out locations fixed

SC-LAT mount region still in work

VCHP S-bends

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Change Control Board Changes Since Delta-PDRChange Control Board Changes Since Delta-PDR

• ACD mass growth

– Added structural mass to increase design margins

– Added mass in scintillating tiles to increase size of tiles and overlap between tiles

• Mechanical Systems mass growth

– Added mass for Grid box additions: Grid Wing, bottom flange, EMI Skirt stiffening, X-LAT thermal straps

– Added mass for slightly increased Radiator area

• Calorimeter mass de-allocation

– Decreased mass allocation to reflect reduction in size of CsI logs

– Log size was reduced to accommodate tolerance stack-up within CFC box structure

• Power allocation update (pending)

– Updated power allocations based on current measured values

– Already using updated allocations in thermal analysis


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003LAT Mechanical System Schematic DiagramLAT Mechanical System Schematic Diagram

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

LAT Schematic DiagramLAT Schematic Diagram


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Trade Studies Since Delta PDRTrade Studies Since Delta PDR

• Moved Electronics Box structural mount to CAL back plate

– Boxes now hard-mounted to CAL plate by way of moment-bearing stand-offs

– Cleaner structural design simplifies analysis and test plans for CAL and Electronics groups

– Forces on X-LAT Plate are reduced to just inertial loads of the plate

• Radiator panel top profile

– Modified panel to a stepped top profile

– Radiator area is maximized, while providing good access volume under the ACD


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Structural Interface Open IssuesStructural Interface Open Issues

• CAL-Grid structural joint

– Issue: joint has recently been changed from an all-friction joint to a pinned joint, but analysis and development testing are not yet complete

– Closure plan• Structural analysis underway• Joint testing is underway• Process development work underway

• X-LAT Plate to Electronics box thermal joint

– Issue: thermal strap design was recently abandoned in favor of V-Therm carbon fiber cloth, with much testing yet to be done

– Closure plan• Materials testing• Contamination studies and testing• Thermal properties testing• Joint design and tolerance study

• Radiator-SC strut angle

– Issue: Spectrum proposes to angle the Radiator support struts


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Structural RFA’s from Peer ReviewStructural RFA’s from Peer Review

UPDATE

ID # Status RFA Description RFA Response/Closure Plan


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003LAT Requirements Flow-DownLAT Requirements Flow-Down

Mission SystemSpecification

433-SPEC-0001

ScienceRequirements

Document433-SRD-0001

LAT-SC InterfaceRequirements

Document433-IRD-0001

LAT PerformanceSpecification

LAT-SS-00010

ACD SubsystemSpecification

LAT-SS-00016

TKR SubsystemSpecification

LAT-SS-00017

CAL SubsystemSpecification

LAT-SS-00018

Trigger & DataflowSubsystem

SpecificationLAT-SS-00019

SASSubsystem


LOFSubsystem


PowerSubsystem


MechanicalSubsystem


Mis

sio

nL

AT

Su

bs

ys

tem

ScienceRqmts

MissionRqmts

Ground System Rqmts

InterfaceRqmts

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

De

sig

n S

pe

cif

ica

tio

n LAT DataflowSpecification

LAT-SS-00285

LAT Flight SWSpecification

LAT-SS-00399

LAT ReadoutElectronic


LAT IOC/MOC/SSC Interface

ControlDocuments

Radiator DesignSpecification

LAT-SS-00394

X-LAT PlateDesign


Grid Box DesignSpecification

LAT-SS-00775

LAT-SC InterfaceControl Document

LATEnvironmentalSpecification

LAT-SS-00778

LAT IOCPerformanceSpecification

LAT-SS-00015

Legend GLAST Mission Spec’s LAT Spec’s Subsystem Spec’s


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Key LAT Configuration and Structural RequirementsKey LAT Configuration and Structural Requirements

Parameter Requirement Design Margin ComplyVer.

MethodDriving Req.

LAT ConfigurationLAT mass allocation < 3000 kg 2679.4 kg 320.6 kg Y MLAT vertical center of mass above LIP < 185 mm 149.3 mm 35.7 mm Y MLAT lateral center of mass off Z-axis < 20 mm 1.26 mm 18.74 mm Y MLAT moment of inertia about X-, Y-axes < 1500 kg-m2 1058 kg-m^2 442 kg-m^2 Y ALAT moment of inertia about Z-axis < 2000 kg-m2 1340 kg-m^2 660 kg-m^2 Y AMax Radiator area (#) < 5.88 m^2 5.57 m^2 0.31 m^2 Y IConfigured as 2 separate Radiators OK Y IRadiator max width (#) < 1.903 m 1.896 m 7 mm Y IPositioned according to IRD App. A (#) > 1.84 m sep 1.863 m 22.6 mm Y IMount point for SC support as shown in IRD Appendix A (#)

1.177 m below LIP

OK Y I

Structural, LoadsFixed-base first-mode > 50 Hz 11% Y TTKR alignment during normal LAT operation

< 7arc-sec 1s radial

4.1 arc-sec peak-to-peak

2.9 arc-sec + 5s

Y T, A

Capable of exposure to static-equivalent launch loads

OK Y T, A

Capable of exposure to sinusoidal vibration launch loads

OK Y T

Capable of exposure to acoustic launch loads

OK P T

UPDATE:

Origin of Req


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003LAT Integrated Structural FEA ModelLAT Integrated Structural FEA Model

• LAT structural model moved to NASTRAN

– Changed FEA software from ANSYS to NASTRAN to make it more compatible with GLAST project office

– Re-built model to improve dynamic analysis capabilities

– Model is used to generate system structural response and interface limit loads

• Subsystem models updated

– New TKR model from Hytec—including bottom tray and flexure design modifications

– Updated ACD model from GSFC—with new mass baseline

– Incorporated reduced CAL model from NRL

– New Radiator model from LM—including size and mount point modifications

– Re-built electronics—new model based on current E-Box and interface designs

– Grid Box model modified—integrated wing and X-LAT Plate modifications have been included

LAT Finite Element ModelLAT Finite Element Model

NEW FEA

Model


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003

Subsystem Check TKR CAL ACD Elec Rad XLAT Grid Comments Evaluation CriteriaSubsystem FEA reviewUnits check metric used; units consistent yes/noOrientation/coord sys correctly oriented in LCS yes/noMesh size size suitable for LAT modelMesh resolution, qlty resolution error is acceptable est mesh density error < 20%Review report report and model agree yes/noSubsystem FEA check runsFree-free evaluate mechanisms, DOF's no mechanisms; 6 DOF'sTranslation check unit translation, rotation no groundingGravity check reaction force check forces sum to mass

Temperature checktemp increase to check for grounding, conductivity

no grounding; thermally conductive

Mass compare to mass estimate FEA mass within 5% of estCenter of mass compare to mass estimate FEA c.g within 5 mm of est

Modal analysischeck against subsystem detailed model and report

Mode shapes, freq's agree with subsystem report to 2 Hz

Subsystem FEA Model Quality ChecksSubsystem FEA Model Quality Checks

• Subsystem model evaluation

– Review model—units, orientation/coordinate system, size, mesh resolution

– Review delivery report—do the report and model agree

• FEA model check-runs

– Free-free modal analysis—check model for mechanisms

– Translation check—check model for inadvertent grounding

– Gravity check—check that inertial loads are reacted only at boundaries

– Temperature check—check that structure is free to expand/contract

• Analysis comparison runs

– Mass, center of mass—compare with subsystem estimate

– Modal analysis—check against subsystem detailed model and report

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003LAT FEA Model Boundary ConditionsLAT FEA Model Boundary Conditions

• Accelerations

– Used LAT center-of-mass accelerations from LAT Environmental Spec. for structural load cases

• SC mount boundary condition mimics flexure-type connection

– X-Side SC mount: LAT restrained in the Y- and Z-directions

– Y-Side SC mount: LAT restrained in the X- and Z-directions

• Radiator mounting

– Radiators mounted to Grid through Radiator Mount Bracket beams

– SC boundary condition fixed in Y-direction (out-of-plane) only

LAT F.E.A. Properties and Current LAT EstimatesLAT F.E.A. Properties and Current LAT Estimates

Source: LAT-TD-00564-06 “LAT Mass Status Report, Mass Estimates for Mar 2003,” 7 Mar 2003

LAT Static-Equivalent Design AccelerationsLAT Static-Equivalent Design Accelerations

Source: LAT-SS-00778-01 “LAT Environmental Specification,” March 2003

LAT F.E.A. Model MetricsLAT F.E.A. Model Metrics

LAT F.E.A. Current LAT Est.Subsystem Mass

(kg)Center of

Gravity (m)Mass (kg)

Center of Gravity (m)

TKR 520.1 261.85 505 230.0CAL 1375 -138.55 1376 -148.8ACD 268 348.00 270 318.2Radiators 71.67 -1034.30 77 -1368.6Grid Box 250.3 -231.00 253 -218.0Elec. Boxes 199.6 -348.25 199 -352.9Total 2685 -60.53 2679 -86.9

Model Feature Number

Nodes 56,458Total elements 64,091Point elements 448Shell elements 47,819Beam elements 15,160

LAT Design Unit

Launch EventLift-Off/ Airloads

MECO

Lateral 5.1 0.2 gAxial (Z) +4.1/-1.4 +6.8 g

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003LAT FEA Model Quality ChecksLAT FEA Model Quality Checks

• FEA model check-runs

– Free-free modal analysis—check model for mechanisms

– Translation check—check model for inadvertent grounding

– Gravity check—check that inertial loads are reacted only at boundaries

– Temperature check—check that structure is free to expand/contract

• Analysis comparison runs

– Mass—compare model mass with LAT estimate

– Center of mass—compare model center of mass with LAT estimate

– Modal analysis—compare subsystem modes in LAT model against fixed-base results

LAT Model Check TKR CAL ACD Elec Rad XLAT Grid Comments Evaluation CriteriaFree-free evaluate mechanisms, DOF's no mechanisms; 6 DOF'sTranslation check unit translation, rotation no groundingGravity check reaction force check forces sum to mass

Temperature checktemp increase to check for grounding, conductivity

no grounding; thermally conductive

Mass compare to mass estimate FEA mass within 5% of estCenter of mass compare to mass estimate FEA c.g within 5 mm of est

Modal analyisiscompare subsystem modes to fixed-base results

Modes, freq's consistent w/ subsystem results


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Launch and Thermal Load Case DefinitionsLaunch and Thermal Load Case Definitions

LAT Structural Analysis Load CasesLAT Structural Analysis Load Cases

Launch Load Case X Y Z Configuration/Comments

Modal on SC Mount Flight config. Supports fixed in Z and hoop, free radiallyLift-Off/Airloads 1 +5.1g 0 g +4.1g Flight config. LAT is +X/-X symmetricLift-Off/Airloads 2 0 g +5.1g +4.1g Flight config. LAT is +Y/-Y symmetricLift-Off/Airloads 3 +3.6 g +3.6 g +4.1 g Flight config. Diagonal lateral accelerationLift-Off/Airloads 3 -3.6 g +3.6 g +4.1 g Flight config. Diagonal lateral accelerationLift-Off/Airloads 1 +5.1g 0 g -1.4 g Flight config. Lift-Off/Airloads 2 0 g +5.1g -1.4 g Flight config. Lift-Off/Airloads 3 +3.6 g +3.6 g -1.4 g Flight config. Diagonal lateral accelerationLift-Off/Airloads 3 -3.6 g +3.6 g -1.4 g Flight config. Diagonal lateral accelerationMECO +0.2 g 0 g +6.8g Flight config. MECO 0 g +0.2 g +6.8g Flight config. MECO + 0.14 g + 0.14 g +6.8g Flight config. Diagonal lateral acceleration

UPDATESubsystem Temperature

Thermal Load Case TKR CAL ACD Elec Rad XLAT Grid Configuration/CommentsOn-Orbit Thermal Cases

Cold Survival Soak -30 -30 -40 -40 -67 -40 -40Cold survival soak. Temp's imposed on structural model

40 C bake-out soak 40 40 40 40 40 40 40Hot survival soak. Temp's imposed on structural model

Hot survival soak 50 50 45 60 60 40 40 Subsystem surv tempsHot-case Temps mapped from thermal model resultsCold-case Temps mapped from thermal model resultsThermal Transient Temps mapped from thermal model results +/- 3C/95 min period

I&T Thermal CasesChill-bar cooled 3-pt mid-side mount; chill bars on X-sidesT-Vac cold-case Temps mapped from thermal model results 3-pt mid-side mount on T-Vac stand

Temps mapped from thermal model results 3-pt mid-side mount on T-Vac stand


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Integration and Test Load Case DefinitionsIntegration and Test Load Case Definitions

I&T Load Case X Y Z Configuration/Comments

IntegrationIntegration 1 0 g 0 g +1 g 4 corner mounts in GPR. No Rad, X-LAT, or ACDIntegration 2 +1 g 0 g 0 g 4 corner mounts in GPR, rotated 90 deg. No Rad, X-LAT, or ACDIntegration 3 0 g 0 g -1 g 4 corner mounts in GPR, upside down. No Rad, X-LAT, or ACDIntegration 4 0 g 0 g +1 g 4 corner mounts in GPR. No Rad, with X-LAT, ACDIntegration 5 +1 g 0 g 0 g 4 corner mounts in GPR, rotated 90 deg. No Rad, with X-LAT, ACDIntegration 6 0 g 0 g -1 g 4 corner mounts in GPR, upside down. No Rad, with X-LAT, ACDSurvey 1 0 g 0 g -1 g 3-pt mid-side support, in GPR. No RadSurvey 2 +1 g 0 g 0 g 3-pt mid-side support, rotated 90 deg in GPR. No RadCrane lift 1 2 GPR corner supports carrying entire load. No RadCrane lift 1 2 GPR corner supports carrying entire load. With RadModal survey M 4-pt mid-side support on modal survey stand. No RadTransport 1 M 4 corner mounts in GPR on transport stand. No RadTransport 2 -1 g 4 corner mounts in GPR on transport stand. No RadSine vibe 1 Flight interface to vibe test stand. No RadAcoustic 1 1 g Flight interface to acoustic test stand. With RadT-Vac 1 1 g 3-pt mid-side flight mount to T-Vac stand. Sideways. With Rad

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 Modal Analysis ResultsModal Analysis Results

• 10 modes below 75 Hz

– 1 significant LAT modes

– Multiple ACD panel, BEA vibration modes

– Multiple Radiator modes and mode combinations

• LAT drumhead mode

– 65.9 Hz at 2679 kg estimate

– 63 Hz at 3000 kg allocation

First 10 LAT ModesFirst 10 LAT Modes

LAT Drumhead ModeLAT Drumhead Mode

# Freq. Effective Mass Fraction Mode Description

1 56.4 9.4% UX, 5.4% UY ACD lateral mode2 58.8 1% UZ ACD mode3 60.6 6.6% UX, 9.8% UY LAT lateral mode at 45 degrees4 62.3 0.1% UY -Y side Radiator out-of-plane mode5 64.1 .16% UY +Y side Radiator out-of-plane mode6 65.9 42% UZ, 26% RX, 26% RY LAT drumhead mode7 67.2 0.1% RZ ACD anti-symmetric mode8 67.4 0.6% RX -Y side Radiator asymmetric mode9 68.7 0.2% UY +Y side Radiator asymmetric mode

10 73.8 1% UX, 3% RY X-axis LAT rocking mode

Parameter Req Design Margin Comply

LAT natural frequency > 50 Hz 56.4 Hz 6.4 Hz Y

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Deflections Due to Launch LoadsDeflections Due to Launch Loads

• Grid Deflection

– 6.8 g thrust load at MECO produces maximum Grid bowing

– Grid deflections• -0.41 mm at the center of the Grid• -0.09 mm at corner of the Grid

LAT Deflected Shape PlotLAT Deflected Shape Plot

UPDATE

Load Case Name:Grid center UzGrid corner UzGrid center UxTKR gap closingACD-TKR gap closingRadiator UxRadiator out-of-planeAll dimensions in millimeters


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 Interface Load RecoveryInterface Load Recovery

• The LAT Environmental Specification is the collection point for interface loads for subsystem design and test

• Current load tables in the LAT Environmental Specification contain results from the Delta-PDR structural model (also being used for the current CLA cycle)

– Some interface limit loads were generated by LAT static-equivalent analyses

– Some limit loads were gleaned from the preliminary CLA, completed in December, 2001

• The goal of CDR analysis is to generate updated loads, based on the CDR design, and compare with Delta-PDR design values

– Include results for all load cases to assure that worst-case loads have been captured

– Identify interfaces and load cases where CDR analysis shows higher predicts than earlier analysis develop action plan to resolve these issues

– Identify interfaces where loads have come down considerably investigate reducing limit loads in the Environmental Specification, to increase design margin

LAT Mech PDR Structural AnalysisAug, 2001

LAT PDR Structural AnalysisJan, 2002

Prelim CLA Results OutDec 2001-Mar, 2002

Deliver Mech PDR LAT FEA (Sep,

2001)

LAT Delta-PDR Structural AnalysisAug, 2002

Deliver Delta- PDR LAT FEA (Sep,

2002)

LAT CDR Structural AnalysisMay, 2003

LAT Env SpecMar, 2003

SC Study II Struc Models

Deliver CDR LAT FEA

(Jun, 2003)

Spectrum Proposal

Struc Model

Mission PDR CLA Results OutMay, 2003

LAT Env SpecJun, 2003

Spectrum PDR Struc

Model

Mission CDR CLA Results OutSep, 2003

LAT Env SpecOct, 2003

LAT Structural Analysis Flow-down ScheduleLAT Structural Analysis Flow-down Schedule


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003TKR Interface Load RecoveryTKR Interface Load Recovery

• TKR Flexure joint

– Flexures isolate the carbon-fiber TKR structure from thermal strains of the Grid

– All flexure normals point to the center of a TKR module

– The 8 flexures are not a kinematic mount

• TKR Flexure force recovery

– Nodal forces are retrieved by isolating nodal forces at the TKR Flexure beam elements

– All forces are expressed in local cylindrical coordinates, with the module centerline the z axis

– Shear forces in theta-increasingdirection have the same sign. Shear forces sum to zero.

– Design limit loads are the maximaof the TKR module loads

• Limit loads identified for peakcompressive, tensile, and shear load

• Peak loads all occur in corner bays

TKR-Grid Flexures Design Accept Qual Unit

Launch EventLift-Off/

TransonicMECO

Mid-Side FlexuresShear 2266 2061 2266 2832.5 NTension/Compress. 391 291 391 489 N

Corner FlexuresShear 1,003 80 1,003 1,254 NTension/Compress. 1,277 1,193 1,277 1,596 N

Source (2) (4)

Flexure Limit LoadsFlexure Limit LoadsDelta PDR Analysis ModelDelta PDR Analysis Model


UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003CAL Interface Load RecoveryCAL Interface Load Recovery

• CAL-Grid tab joint

– Pins carry all shear load at joint

– Bolts carry pull-out and prying loads

• Load recovery

– Tab loads separated into shear tabs and bolted tabs

– All tabs designed to peak limit loads

Tab Limit LoadsTab Limit LoadsDelta PDR Analysis Model Delta PDR Analysis Model


CAL Design Load Cases Acceptance Test Qualification TestTabs LC1 LC2 LC3 LC1 LC2 LC3 LC1 LC2 LC3 Unit Comments

F(x) 4373 1140 -3302 4373 1140 -3302 5467 1424 -4128 N Across tab in plane of plateF(y) 206 2994 1414 206 2994 1414 258 3742 1767 N Along tabF(z) -195 -11 654 -195 -11 654 -244 -14 817 N Out of plane of plateM(x) 1.39 -0.05 -6.09 1.39 -0.05 -6.09 1.74 -0.06 -7.61 N-m Around x-axisM(y) 0.45 -1.28 0.22 0.45 -1.28 0.22 0.56 -1.60 0.27 N-m Around y-axisM(z) 20.98 4.58 -14.86 20.98 4.58 -14.86 26.22 5.73 -18.57 N-m Around z-axisSource (6) (6) (6)Scale 1 1 1 1.25 1.25 1.25Notes: Interface loads are for CAL tab thickness of 7 mm

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003ACD Interface Load RecoveryACD Interface Load Recovery

• ACD Base Electronics Assembly (BEA) to Grid Joint

– Bolted connection at 4 corners of BEA carry z-direction (thrust) loads only

– Bolted and pinned connections at the center of each of the 4 sides

• Interface load recovery

– Interface loads evaluated by retrieving nodal forces at rigid extension from Grid to BEA

– Loads shown are the maximum of predicts from ACD subsystem and LAT level analysis

ACD-Grid Mount Design Accept. PFQ Unit CommentCorner Mounts

Shear 0 0 0 N RSS of X, Y max shearTens/Compression 1787 1787 2234 N Parallel to LAT Z-axis

Mid-Side MountsShear 4402 4402 5503 N RSS of X, Z shears in plane of Grid wallTens/Compression 2223 2223 2779 N Normal to Grid wall

Source

ACD Limit LoadsACD Limit LoadsDelta PDR Analysis Model Delta PDR Analysis Model


UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Electronics Interface Load RecoveryElectronics Interface Load Recovery

• Electronics Box joints

– Rigid stand-offs to the CAL carry z-direction (thrust) loads, and lateral loads and moments

– Flexible connection to the X-LAT Plates allow transverse motion while providing compressive pre-load

• Interface load/deflection recovery

– Limit loads extracted from model

– Max relative motion at X-LAT Plate interface also tracked, for use in finalizing the bolted joint design

E-Box Stand-Off Design Accept. Qual UnitTension 3,750 3,750 4,688 NCompression 2,625 2,625 3,281 NShear 1,288 1,288 1,609 NBending Moment 19.3 19.3 24.1 N-m

Electronic Box Limit LoadsElectronic Box Limit LoadsDelta PDR Analysis Model Delta PDR Analysis Model


UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Structural Analysis Summary and Further WorkStructural Analysis Summary and Further Work

• Summary

– Subsystem structural models have been updated to reflect Peer Review designs

– First look at mode shapes and frequency show that the LAT has margin with respect to its frequency requirement

– Structural model re-work is still in process

• Further Work

– Verify subsystem model integration

– Complete all load cases with LAT CDR model

– Update subsystem interface loads, based on CDR model

– Deliver model to GLAST PO for next CLA cycle

– Incorporate acoustic analysis results into limit load analyses

– Revise “LAT Environmental Specification” with these results

– Start pre-test analysis runs• Dynamic analyses to size accelerometers• STE structural analyses

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 Verification Test OutlineVerification Test Outline

• Integration and Test flow

• Qualification and verification flow

– Strength qualification test flow

– Vibroacoustic test flow

• Dynamic test plans (see LAT-MD-01196, “Dynamics Test Plan”)

– Modal survey

– Sine vibration

– Sine Burst

– Acoustic

• LAT survey plans (see LAT-MD-00895, “LAT Instrument Survey Plan”)

– Optical survey

– Cosmic-ray muon survey


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 Integration and Test FlowIntegration and Test Flow

ObservatoryIntegration

Sine Vibe

TowerIntegration

LATIntegration

LAT Test ObservatoryIntegration

TKR

CAL

TEM/TPS

Grid

Radiators

EPU

SIU

GASU

PDU

ACD

IntegrateE-Boxesw/ Grid

Htr Box

Delivery

AlivenessTests

LimitedPerformance

X-LAT Plate

C

CLE A

A

MassProperties

EMI/EMC

L

InstallRadiators

Acoustic

L

C

Thermal Vac

ThermalBalance

C L

C

Final MassProperties

Pre-ShipSurvey

L

A

Ship toSA

F

F

F

EMI SHIELD

Survey Survey

M

O M

L

M

O Optical M Muon

IntegrateTKR/CAL &TEM's with

Grid

SurveyO

Integrate ACD

SurveyO

Integrate EMISkirt, Htr Switch

Boxes

Mech Fit-Check

SurveyM

Modalsurvey

E

L

FunctionalTests

Survey:

L

ElectricalInterfaceTests

ComprehensivePerformance

Environmental Tests

E

M

C

v CDR 3/14/03

Integrate X-LAT

LAT Integration and Test FlowLAT Integration and Test Flow

UPDATE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Strength Qualification Test FlowStrength Qualification Test Flow

ACD Sub-Ass’ySine Burst

A

TKR QMSine Burst, Static Load

QACD Shell + BFASine Burst

QCAL QMSine Burst

QTEM/TPS QM’sSine Burst

QE-Box PF QM’sSine Burst

PGrid Box Ass’yStatic Load

PRadiatorStatic Load

P

LAT Ass’ySine Burst

P

GLAST ObsSine Burst

P

Subsystem Qual Tests

Subsystem Acceptance

Tests


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 Vibroacoustic Test FlowVibroacoustic Test Flow

• LAT and GLAST vibroacoustic test plan

– LAT modal survey—without Radiators, while at SLAC

– LAT sine vibration—without Radiators; includes sine sweep signature

– LAT acoustic—without Radiators

– GLAST Observatory sine vibration—with Radiators but without solar arrays (TBR); includes sine sweep signature

– GLAST Observatory acoustic—with Radiators but without solar arrays (TBR)

– GLAST Observatory shock—shock event applied at PAF separation plane

ACD Sub-Ass’ySine Vibe, Random Vibe

A

ACD Sub-Ass’yAcoustic

A

TKR Qual ModuleSine Vibe, Random Vibe

Q

TKR Flt ModulesSine Vibe, Random Vibe

A

ACD Shell + BFASine Vibe, Random Vibe

Q

ACD Shell + BFAAcoustic

Q

CAL QM’sSine Vibe, Random Vibe

Q

CAL FM’sRandom Vibe

A

TEM/TPS QM’sSine Vibe, Random Vibe

Q

TEM/TPS FM’sRandom Vibe

A

E-Box PF QM’sSine Vibe, Random Vibe

P

Grid Box Ass’y

P

RadiatorSine Vibe

P

RadiatorAcoustic

P

LAT Ass’yModal Survey, Sine Vibe

P

LAT Ass’yAcoustic

PGLAST ObsSine Vibe

PGLAST ObsAcoustic

P

Subsystem Qual Tests

Subsystem Acceptance

Tests

GLAST ObsShock

P


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 LAT Modal SurveyLAT Modal Survey

• Test goals

– Validate the LAT structural finite element analysis (FEA) model by correlating with test results

– Measure all primary modes of the LAT/Grid structure.

– Measure the first mode, and all modes predicted to have high mass participation, for every subsystem

– Measure as many natural frequencies of the LAT up to 150 Hz as practical

– Test results will be used to evaluate the predicted expected modal frequencies and mode shapes, and used to modify the structural FEA, if needed.

– Finalize test environments and notching plans for sine vibration testing

• Configuration

– Fully integrated, except the Radiators are not mounted

– Supported off of its spacecraft (SC) mount brackets,

– +Z-axis point vertically up

– LAT powered off during testing

• Specialized test equipment requirements

– LAT supported by the Vibe Test Plate which provides a rigid support of each mount point

– Vibe Test Plate sits on a massive base-isolated table, to damp high-frequency base noise being transmitted to the structure

– Excited using two stingers, located under the LAT


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 LAT Modal Survey (cont)LAT Modal Survey (cont)

• Instrumentation

– High-precision accelerometers mounted to the LAT and test stand

• Outstanding technical issues

– Establish excitation levels

– Finalize accelerometers for test, based on predicted test levels

LAT +X

LAT+Y

TKR (z = 640 mm)

CAL (z = -27 mm)

X-TKR

Y-TKR

Grid ( z = 0 mm)

X-TKR

X-TKR X-TKR

XYZ-CAL

XYZ-CAL

XYZ-CAL

XYZ-CAL

Z-TKR

Z-TKR

Z-TKR

Z-TKR

Z-TKR

Z-TKR

0 1 2 3

4

Y-TKR

Y-TKR

Y-TKR

Y-TKR

765

1098

1514

13

12

11

XYZ-Grid

XYZ-Grid

XYZ-Grid

XYZ-Grid

XYZ-Grid

XYZ-GridXYZ-Grid

XYZ-Grid

XYZ-Mnt XYZ-Mnt

XYZ-MntXYZ-Mnt

Y-TKR

X-TKR

X-TKR

X-axis Accel

Y-axis Accel

Tri-axis Accel

Z-axis Accel

Source: LAT-MD-01196-01, “LAT Dynamics Test Plan,” March 2003

LAT +Y

LAT +Z

ACD: outer surfaceof honeycomb

Tri-axis Accel

Out-of-PlaneAccel

LAT +X

Y-ACD

Z-ACD

X-ACD

Y-ACD

XYZ-ACD

XYZ-ACDXYZ-ACD

XYZ-ACD

X-ACD

LAT +X

LAT+Y

Elec (z = -500 mm)

CAL (z = -251 mm)

0123

47 6 5

10 9 8

15 14 13 12

11

X-axis Accel

Y-axis Accel

Tri-axis Accel

Z-axis Accel

PDU

SIU

SIU

EPU EPU

EPUMTY MTY MTY

MTY MTY

GASU

XYZ-CALXYZ-CAL

XYZ-CAL

XYZ-CAL

XYZ-CAL

XYZ-CAL

XYZ-Elec

XYZ-Elec

XYZ-Elec

XYZ-Elec

XYZ-Elec

ACD Accelerometer ACD Accelerometer PlacementPlacement

CAL Bottom and E-Box Accelerometer PlacementCAL Bottom and E-Box Accelerometer PlacementTKR, CAL, and Grid Accelerometer PlacementTKR, CAL, and Grid Accelerometer Placement


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 LAT Sine Vibration TestLAT Sine Vibration Test

• Test goals

– Verify the LAT’s ability to survive the low frequency launch environment

– Test for workmanship on hardware such as wiring harnesses, MLI, and cable support and strain-reliefs which will not have been fully verified at the subsystem level

– Interface verification test for subsystem structural interfaces to the LAT Grid

• Configuration

– Fully integrated, except the Radiators are not installed

– Supported off of its spacecraft (SC) mount brackets, on the Vibration Test Stand

– The LAT is tested in all three axes, X, Y, and Z independently, requiring re-configuration between tests

– The LAT is powered off during sinusoidal vibration testing, and the E-GSE cable harnesses removed


– The Vibe Test Stand must support the LAT at the SC interface with flight-like connections

– The Stand must allow for reconfiguration to alternate axes, with the LAT attached, to avoid unnecessary handling


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003LAT Sine Vibration Test (cont)LAT Sine Vibration Test (cont)

• Instrumentation

– Accelerometers mounted to the LAT and test stand, to cover the entire dynamic range predicted for the LAT and subsystems


– Accelerometer sensitivity—pre-test dynamic analysis will indicate the level of precision and dynamic range needed for this test

– Finalize LAT degrees of freedom at STE connection (simulating a “fixed” connection or a flexure)

– Establish test levels based on Observatory CLA, without exceeding interface limit loads

LAT +X

LAT+Y

TKR (z = 640 mm)

CAL (z = -27 mm)

Grid ( z = 0 mm)

XYZ-CAL

XYZ-CAL

XYZ-CAL

XYZ-CAL

XYZ-TKR

0 1 2 3

4 765

1098

15141312

11

XYZ-Grid

XYZ-Grid

XYZ-Grid

XYZ-Grid

XYZ-Grid

XYZ-GridXYZ-Grid

XYZ-Grid

XYZ-Mnt XYZ-Mnt

XYZ-MntXYZ-Mnt

X-axis Accel

Y-axis Accel

Tri-axis Accel

Z-axis Accel

XYZ-TKRXYZ-TKR XYZ-TKR XYZ-TKR

XYZ-TKR XYZ-TKR XYZ-TKR

XYZ-TKR XYZ-TKR XYZ-TKR

XYZ-TKR XYZ-TKR XYZ-TKRXYZ-TKR

LAT +X

LAT +Z

Radiator Inner Facesheet

Tri-axis Accel

Y-axis Accel

Source: LAT-MD-01196-01, “LAT Dynamics Test Plan,” March 2003

TKR, CAL, and Grid Accelerometer PlacementTKR, CAL, and Grid Accelerometer Placement

Radiators Accelerometer PlacementRadiators Accelerometer Placement

Qualification Sine Vibration Test LevelsAxis Freq. (Hz) Test levels Sweep Rate

Thrust 5 to 7.4 1.27 cm (0.5 in.) double amplitude 2 octaves/min7.4 to 50 1.4 g (zero to peak)

Lateral 5 to 6.2 1.27 cm (0.5 in.) double amplitude 2 octaves/min6.2 to 50 1.0 g (zero to peak)

LAT Sine Vibration Minimum Test LevelsLAT Sine Vibration Minimum Test Levels


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 LAT Sine Burst TestLAT Sine Burst Test

• Test goals

– Complete qualification of the LAT interface to the SC, and surrounding regions

• Configuration

– Same configuration as the sine vibe test


– Same requirements as the sine vibe test

• Instrumentation

– Same instrumentation as the sine vibe test


– Establish test levels with pre-test analysis, to develop proto-qual level interface loads


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 LAT Acoustic TestLAT Acoustic Test

• Test goals

– Verify the LAT’s ability to survive the acoustic launch environment

– Test for workmanship on LAT hardware, especially that hardware which responds to acoustic loading

– Validate the acoustic analysis

• Configuration

– LAT is fully integrated, including the Radiators

– Mounted to STE using the flight-configuration bolted joint

– LAT +Z-axis vertical, and with Radiators integrated to the Grid as well as to the STE at the SC strut mount points

– LAT is powered off during acoustic testing, and the E-GSE cable harnesses removed


– The Vibe Test Stand must support the LAT in the same degrees of freedom as the SC flexures, to avoid over-constraining the Grid and Radiators

– The STE fills the volume between the Radiators, so must approximate the acoustic behavior of the SC

• Instrumentation

– Accelerometers mounted to the LAT and test stand

– Microphones mounted around the LAT


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 LAT Acoustic Test (cont)LAT Acoustic Test (cont)


– Establish acoustic fill and response requirements of STE to adequately bound response of SC

– Define post-test modal signature test to verify that LAT dynamic response matches baseline

– Finalize accelerometer and microphone placement

– Perform pre-test acoustic analysis

Acoustic Loading

100

105

110

115

120

125

130

135

140

145

150

10 100 1000 10000Frequency (Hz)

So

un

d P

ress

ure

Lev

el (

dB

)

Accept Tes t (dB)

Qual Tes t (dB)

LAT Acoustic Test LevelsLAT Acoustic Test Levels

Source: LAT-SS-0077801, “LAT Environmental Specification,” March 2003


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 LAT SurveyingLAT Surveying

• Survey program goals

– Verify as-integrated interface stay-clears

– Verify LAT alignment requirements

– Verify science performance requirements • Validate analytical thermal-mechanical analysis models• Develop correlation functions for thermal-mechanical distortion• Predict the expected on-orbit precision of the instrument

• Survey program description

– Optical surveying• Subsystem inspection measures position of survey retro-reflector balls with respect to physical

features and active elements of subsystem module• After integration, laser tracker measures bearing and distances to balls on the LAT and in the

integration room• Data reduction of measurements produces position location information for all balls relative to

room coordinate system, and prediction of measurement precision• This will establish location of subsystem surfaces and features in their as-integrated positions,

providing a verification check during integration

– Muon surveying• Uses naturally-occurring cosmic-ray muons• Muons generate straight-line tracks through TKR modules• Mis-alignments between modules will show up as a step in the reconstructed track• With muons generating enough cross-tower tracks, the relative locations of tower can be

measured• This will be used to precisely establish the locations and attitudes (and changes) of TKR modules


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 LAT Surveying (cont 1)LAT Surveying (cont 1)

1A: 1-Toweroptical survey

Integrate Towers Int. ACD Ship/Vibe T-Bal/T-Vac

1B: 4-Toweroptical survey

2A,B,C: LAT baselinemuon survey

1C: 16-Toweroptical/muon survey

3A: Pre-T-Vacmuon survey

4A,B,C: T-Vac muonsurvey at temp

# Goal When/Where Orient. Method Support/Configuration Cooling Temp

1AVerify SS stayclears, TKR alignment accuracy

SLAC, after 1st TKR module is integrated

+Z Up Optical4 corners on GPR; 1 TKR/CAL/ TEM tower integrated. LAT off

None RT

1BVerify SS stayclears, TKR alignment accuracy

SLAC, after 4 TKR modules are integrated

+Z Up Optical4 corners on GPR; 4 TKR/CAL/ TEM towers integrated. LAT off

None RT

1CVerify SS stayclears; establish baseline position of all TKR's

SLAC, before ACD integration

+Z HorizOptical/

Muon3 mid-sides on GPR; ACD not on LAT on. Push on 4th mid-side.

Elec: forced air; Det: conduction

17 C

2A Verify ACD stay-clearsSLAC, after ACD and X-LAT Plate integration

+Z Up Optical4-corners on GPR; ACD integrated. LAT off.

None RT

2BEstablish baseline position of TKR's with ACD on

SLAC, after CPT +Z Horiz Muon 3 mid-sides on GPRElec: forced air; Det: conduction

17 C

2CCharacterize gravity effect on TKR position w/ ACD

SLAC, after CPT +Z Up Muon 3 mid-sides on GPRElec: forced air; Det: conduction

17 C

3ARe-baseline TKR positions after transport, vibe

NRL, after vibe and before T-Vac pump-down

+Z Horiz Muon 3 mid-sides on T-Vac STEElec: forced air; Det: conduction

17 C

4ACharacterize thermal effects on LAT at min temp

NRL T-Vac Chamber +Z Horiz Muon 3 mid-sides on T-Vac STEElec: X-LAT Pl, Det: conduction

-5 C

4BEstablish baseline position of TKR's at nom operating temp


8 C

4CCharacterize thermal effects on LAT at max temp


17 C

LAT Optical and Muon Surveys During Integration and TestLAT Optical and Muon Surveys During Integration and Test

Source: LAT-MD-00895 “LAT Instrument Survey Plan”


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 LAT Surveying (cont 2)LAT Surveying (cont 2)

• Instrumentation

– Laser tracker—measurement precision of instrument is less than 10 microns, but actual precision is more a function of room temperature stability, reflector ball location precision

– Tracker—measurement precision and instrument calibration will be verified with Calibration Unit beam tests at SLAC


– Room temperature controlled to within 5 oC (TBR)

– LAT and GSE/STE temperature stable to within 2 oC (TBR)

– Support stands allow for leveling the LAT to within 0.2 degrees to ensure proper functioning of heat pipes

– Chill plates provide a heat sink for the Grid during in-air testing


– Investigating the use of inclinometers during thermal-vacuum testing

– Thermal-mechanical model of LAT in test configuration has not yet been done—this is needed to establish precision and stability requirements for STE


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003Summary of Structural Test Issues and Closure PlansSummary of Structural Test Issues and Closure Plans


GLAST LAT Project

CDR/CD3 Review, May 12-16 2003 Summary and ConclusionsSummary and Conclusions

• UPDATE

• Structural Analysis Summary

• Verification Test Summary

• Conclusions

• Summary

– LAT Dynamics Test Plan has been written and is ready for initial release

– LAT Thermal Test Plan has been written and is ready for initial release

– LAT Survey Plan has been written, with final pieces coming together for release before CDR

– Test instrumentation and levels are understood

• Further work

– Perform pre-test analysis to finalize instrumentation and STE requirements

– Expand test plans with results of pre-test analysis

– Complete test implementation plans

LAT-PR-01967-01Section 8.2 – Structural Design1 GLAST LAT Project CDR/CD3 Review, May 12-16 2003...

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