Page 1 GLAST LAT ProjectAugust 30, 2004 GLAST Large Area Telescope: LAT Accelerometer and Thermal...

GLAST LAT Project

August 30, 2004

GLAST Large Area Telescope:GLAST Large Area Telescope:

LAT Accelerometer and Thermal Instrumentation Review

Presented by

Leonard LeeJohn KuJack Goodman

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

GLAST LAT Project

August 30, 2004

Introduction

Leonard Lee

GLAST LAT Project

August 30, 2004 Purpose of ReviewPurpose of Review

(1) Review the rationale for the quantity and location of the LAT accelerometers shown in the current revision of the LAT Instrumentation Plan (LAT-TD-00890-02) – John Ku

(2) Review the justification for the LAT thermal sensors (Flight and Test) with regard to the quantity and locations described in the LAT Instrumentation Plan – Jack Goodman

(3) Provide redlines/comments if any to update the LAT Instrumentation Plan.

GLAST LAT Project

August 30, 2004

LAT Accelerometer Review

John Ku

GLAST LAT Project

August 30, 2004 Items To Be AddressedItems To Be Addressed

• Compatibility with LAT Requirements– Purpose for Accelerometers– Selected Accelerometer Models– Sensitivity Requirements– Dimensions– Test and Flight Vacuum Compatibility– Outgassing issues

• Compatibility with NRL– Facility capability: 32 Control, 300 Response– Connector Type: Voltage Output (BNC), or Charge Output (10-32 Coax)– Cable length

• Accelerometer Locations by subsystem– ACD– TKR– CAL– Ebox– Mech

• Grid• RMB• XLAT• RAD

– SC Mount• Conclusions

GLAST LAT Project

August 30, 2004 Compatibility with LAT requirementsCompatibility with LAT requirements

• Purpose for Accelerometers

– Record acceleration vectors at key points on the integrated LAT such that natural frequency, transfer functions, and peak accelerations are captured

• Natural frequency measurements provide insight into modes and shapes (phase)• Transfer functions (response divided by input) provide information on damping• Peak accelerations ensure the LAT and subsystems are not undertested

• Accelerometer Models selected (Piezotronics brand)

ModelValidation

PerformanceVerification

355M64 – Single Axis(9.6mmW X 5.8mmT)

356M109 – Three Axis(12.0mm W X 7.0mm T)

GLAST LAT Project

August 30, 2004 Compatibility with LAT requirementsCompatibility with LAT requirements

• Sensitivity Requirements

– Based on sine vibration pre-test analysis and accelerometer location optimization routines, 10mV/g accelerometers provide needed resolution to obtain the above requirements

– Acoustic and shock environments demand higher frequency data acquisition; The accelerometers are compatible with high rate DAQ systems

• Dimensions

– Internal accelerometer placement must be carefully executed, as clearance is small. The accelerometers selected do not violate any dynamic clearance envelopes (to be confirmed when final locations are specified)

• Test and Flight Vacuum Compatibility

– Piezotronics has stated that these sealed accelerometers can withstand the vacuum of space without leaking or bursting

• Outgassing issues

– A detailed survey of all accelerometer types and associated cables has been performed to identify outgassing materials. Some problems have been identified, but steps are being actively taken to ensure no outgassing during TVAC

GLAST LAT Project

August 30, 2004 Compatibility with NRLCompatibility with NRL

• Facility capability: NRL is easily able to handle the number of accel channels we are requesting

– Vibration facility can handle 32 control accelerometers and 300 response channels

– LAT sine vibration testing requires 49 total channels (control and response designations TBD, but only a few control channels are anticipated)

– LAT acoustic testing requires 64 response channels

– No LAT shock testing performed

• Connector Type

– Positive confirmation by NRL• Voltage Output accelerometers require BNC connectors• Charge Output accelerometers require 10-32 Coax connectors

– Current accelerometers selected are ICP (Voltage) Type with BNC connectors, so they are compatible with NRL’s shaker

• Cable length

– Rough calculations show a 15 foot (~4.5 m) cable length requirement to allow routing from the LAT to NRL’s patch panel

– When the cable routing is finalized, the cable lengths will be rechecked

GLAST LAT Project

August 30, 2004 Accel Locations: ACD SubsystemAccel Locations: ACD Subsystem

500142

500599

500353

500202

Y -X

Z

Y

Y

Z500021

-X

500045Bottom Edge

Center of Panel

Z500043

-X

• Nine Accels Requested• Grid 500599, X, Y & Z• Grid 500142, X• Grid 500353, Y• Grid 500202, Y• Grid 500021, Z• Grid 500043, Z• Grid 500045, X

GLAST LAT Project

August 30, 2004 Accel Locations: TKR SubsystemAccel Locations: TKR Subsystem

• Seven Accels Requested• Grid 309282, X• Grid 315085, X• Grid 308801, Y• Grid 315185, Y• Grid 301285, Z• Grid 307082, Z• Grid 324985, Z

Z

Z

Z

X

X

Y

Y

309282

301285

308801

324985

315085

315185

307082

GLAST LAT Project

August 30, 2004 Accel Locations: CAL SubsystemAccel Locations: CAL Subsystem

• Six Accels Requested• Grid 218623, X, Y & Z• Grid 230614, X, Y & Z

218623

230614

X -Y

-Z

X -Y

-Z

GLAST LAT Project

August 30, 2004 Accel Locations: EBOX SubsystemAccel Locations: EBOX Subsystem

-Z

-Z

404665 (PDU)

406023 (GASU)

Two Accels Requested

Grid 404665, Z

Grid 406023, ZX

Z

X

Z

Z

Z

-Y

400580

401182

401618

401609

400001

Seven Accels Requested

Grid 400580, X & Z

Grid 400001, X & Z

Grid 401618, Z

Grid 401182, Y

Grid 401609, Z

GLAST LAT Project

August 30, 2004 Accel Locations: Mechanical SubsystemAccel Locations: Mechanical Subsystem

X

Z103058

104216

Two Accels Requested

Grid 103058, Z

Grid 104216, X

Y

Y 904433

902227

902264 YX

Four Accels Requested

Grid 902264, Y

Grid 902227, Y

Grid 904433, X & Y

750232

750980

Z

Z

Z

750249

X Y

Z

X Y

Z

X Y

Z

X Y

Z

Attach Accelerometersto Clevis part of RMB

Twelve Accels Requested

Grid 800565, X, Y & Z

Grid 825565, X, Y & Z

Grid 850565, X, Y & Z

Grid 875565, X, Y & Z

Three Accels Requested

Grid 750232, Z

Grid 750249, Z

Grid 750980, Z

GLAST LAT Project

August 30, 2004 SC Mount Accelerometer Locations and Overall SummarySC Mount Accelerometer Locations and Overall Summary

• Four three axis accelerometers are requested at the LAT side of the SC flexures. These accelerometers are removable prior to flight.

• The 64 total accelerometers are broken down as follows:

– ACD 9 fly-away provided by ACD

– TKR 7 fly-away provided by I&T

– CAL 6 fly-away provided by I&T

– EBOX 9 fly-away provided by I&T

– Mech 21 ground provided by NRL

– SC Flexures 12 ground provided by NRL

– 31 total Fly-away accelerometers

– 33 total Ground (removable) accelerometers

GLAST LAT Project

August 30, 2004 ConclusionsConclusions

• Design: Accelerometer models are compatible with LAT design and stayclears, and use flight qualified materials

• Analysis: The current accelerometer instrumentation list reflects all needed channels to develop a validated finite element model and verify performance of the integrated LAT

• Test: Accelerometers are compatible with NRL environmental facilities

• Integrated LAT accelerometers have been specified and meet all design, analysis and test requirements

GLAST LAT Project

August 30, 2004

LAT Thermal Instrumentation Review

Jack Goodman

GLAST LAT Project

August 30, 2004 LAT Thermal Flight instrumentationLAT Thermal Flight instrumentation

Refer To LAT Instrumentation Plan, Table No.1(Attached)

GLAST LAT Project

August 30, 2004 LAT Thermal Test instrumentationLAT Thermal Test instrumentation

Refer To LAT Instrumentation Plan, Table No.3(Attached)

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