glast large area telescope lat pre-shipment review thermal vacuum test jesse armiger

Thermal Vacuum Test 1

GLAST LAT Project September 15, 2006: Pre-Shipment Review

Presentation 8 of 12

GLAST Large Area TelescopeGLAST Large Area Telescope

LAT Pre-Shipment Review

Thermal Vacuum Test

Jesse ArmigerThermal Vacuum Test Director

Stanford Linear Accelerator Center

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




AgendaAgenda

• Test Overview and Major Test Event Log

• Compliance To Requirements

• Correlation Results

• Thermal Test Observations

• Summary




Test PictureTest Picture




Test OverviewTest Overview

LAT Thermal-Vacuum Test Timeline

-15.0

-10.0

-5.0

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Time (days)

Tem

pera

ture

(deg

. C)

RIT Temp

Extreme Tracker Temp

TCS

Hot-Plateau 2

Hot-Cold Trans

Cold-TB

Cold-Hot Trans

Pre-TV Perf Test

Hot-TB

Peak Load Test

Final-Perf TestHot-Perf

TCS

Cold-Perf

Hot-Plateau 3

Cold-Plateau 2

Hot-Plateau 4

Cold-Plateau 1 Cold-Plateau 3Start: 30 July 2006

Hot-Cold Trans

Hot-Cold Trans

Hot-Cold Trans

Cold-Hot Trans

Cold-Hot Trans

Cold-Hot Trans

Cold-Plateau 4

Surv-TB




Compliance to RequirementsCompliance to Requirements

• LAT successfully completed Thermal Vacuum Testing– 40 day test was successfully completed with only EGSE

issues– Successfully tested LAT at Proto-Qual levels

• Verified thermal subsystem performance– Heaters– Heat pipes– Temperature sensors– Thermal Interface/Unit Mounting

• Thermal analysis correlation– No abnormal observations– Complete by October 30




Heater System VerificationHeater System Verification

• Survival heater system maintained all temperatures within limits during Survival Thermal Balance – Unregulated and regulated feeds at minimum voltage

• Unregulated feed at 25v and regulated feed at 27v – Grid heaters cycled at primary set points – Radiator Antifreeze heater duty cycle under review

• Demonstrated primary VCHP heaters could close Radiators at 70% power

• Functionally demonstrated all primary and redundant Radiator antifreeze and Grid heaters

• Demonstrated TCS could maintain RIT at all operational levels




Heat Pipes and Thermal InterfacesHeat Pipes and Thermal Interfaces

• Heat Pipes– All Heat Pipes functioned normally

• DSHP and XLATs operated as expected• VCHPs opened/closed Radiators as designed

• Interfaces– No baseplate outliers




Unit Temperature DistributionUnit Temperature Distribution

Hot Thermal Balance

20.1 21.0 21.2 20.520.9 22.3 22.4 21.821.1 22.1 22.3 21.720.0 20.8 21.2 20.6

11.0 12.6 12.7 11.413.7 15.3 15.3 14.013.7 15.2 15.3 13.911.7 12.2 12.3 15.0

11.9 14.0 14.2 12.717.2 15.3 15.6 15.515.8 15.1 16.0 13.314.5 14.0 14.1 11.3

TKR+Z

CAL Base

TEM+Z




• Test results show good correlation between sink temperature predictions and input Watrod power

• ACD model received from GSFC uncorrelated – ACD MLI effectiveness needs evaluation

• ACD temperatures have impact on LAT correlation– Generally ACD tile temperatures higher than predictions

(>5o C) in all cases– Higher tile temperatures lead to higher tracker temperatures

• Grid heaters need to be modeled with individual thermostat set points for each circuit

Preliminary Correlation 1/2Preliminary Correlation 1/2




• Hot Case - Temperatures generally lower than predicted

• Cold Case –– Temperatures generally higher than predicted– Radiator Anti-freeze and grid survival heaters off– VCHP heaters

• 9.7 watts to maintain RIT between -6oC and -5oC (23% duty cycle)• Locked on to maintain RIT between -1oC and 0oC

• Survival Mode– Temperatures generally higher than predicted– Radiator Anti-freeze and grid survival heater use about 7 amps– Heater Power use higher than predicted

Preliminary Correlation 2/2Preliminary Correlation 2/2




Test Predictions vs. ActualsTest Predictions vs. Actuals

Component

Cold Survival Limits

Cold Operating

Limits

Hot Operating

LimitsHot T.B. Predict

Hot T.B. Actual

Hot T.B.Delta

Surv. T.B.

PredictSurv T.B.

ActualSurv T.B.

DeltaCold T.B. Predict

Cold T.B. Actual

Cold T.B.Delta

Cold T.B. Predict

Cold T.B. Actual

Cold T.B.Delta

TKR(SSD) -15 -15 30 25 23.9 1 -10.3 -4.4 -6 -1 6 -7 4 2.7 1CAL BP -30 -15 25 17.8 15.7 2 -4.4 -3.3 -1 0.2 1.6 -1 5.5 4.9 1EPU* -40 -30 45 15 17 -2 -5 -0.9 -0.6 0 3.4 3.4 0GASU* -40 -30 45 12.7 18.3 -6 -5 -3.6 -1 0.2 5.1 -5 4.8 7.8 -3PDU* -40 -30 45 9.8 18.4 -9 -5 -3.6 -1 0.7 6.2 -6 5.1 10.1 -5SIU* -40 -30 45 15 17.7 -3 -5 -3.3 -2 -0.8 0 -1 3.5 4.4 -1TPS* -40 -30 45 15.7 19.1 -3 -5 3.2 4.5 -1 8.1 8.3 0TEM* -40 -30 45 22.2 18.4 4 -5 -3.8 -1 3 1.6 1 7.9 4.9 3ACD BEA -30 -15 30 15 11.7 3 -4.8 1.3 -0.6 2 6.5 2.9 4ACD TDA -40 -30 35 21.5 19.7 2 -12.2 -3.4 -9 -1.9 10.3 -12 1.7 11.3 -10RIT -6 0 15 9.1 6.9 2 -5.7 -6.7 1 -5.6 -6.8 1 0.4 -3 3All temperatures are in degrees CTemperatures shown are for the hottest/coldest extremity of the subsytem, except as indicatedTemperature predicts are from model without any marginBased upon the latest Power Summary of 536 Watts LAT disipation, not including the thermal subsystem(*) Temperatures shown are for the box interface to its heat sinkTemperatures measured for all electronics except TEM are internal, not at box interface




• ACD temperature sensor exceeded its red alarm limit of 40C (unit proto-qual = 40C) – This sensor reached a maximum of 42C; the temperature

excursion may have been caused by sensor malfunction– This was not unexpected because the ACD is bounded by a

thermal blanket on one side and Tracker Towers with goal temperatures of 40-45C

– The ACD project manager has indicated that this temperature poses no risk to the ACD

– Recommend an ACD red limit of 45C for the observatory test

Thermal Test ObservationsThermal Test Observations




• LAT start up sequence from cold survival NCR #?– The normal start up sequence involves incrementally

powering up the LAT in a manner which does not exceed the power budget

– The planned sequence involved powering up the TCS last but it turned out that this step had to be performed earlier in order to stay within the budget

– This minor change will be documented and implemented in the normal turn on sequence to be performed during observatory level testing

Thermal Test ObservationsThermal Test Observations




• The LAT thermal vacuum test was accomplished ahead of schedule and without any major incident. Three thermal balances (hot, cold and survival) and four thermal cycles were performed.

• Thermal data readout by VSC was very noisy and inaccurate; this caused hardship during the test.

• Minor incidents were corrected efficiently.

• Complete LAT Thermal Vacuum test report by October 31.– Include thermal model correlation

SummarySummary




Major Thermal Vacuum Test Events Major Thermal Vacuum Test Events 1/21/2

Performance Testing

Hot Operational TestingHot Thermal Balance 8/4 @ 9:33pmRIT Testing 8/5 @ 1:05am 8/6 @10:10amHot Performance Testing 8/6 @10:10am 8/9 @ 1:50pm

Cold Survival TestingRadiator & Grid Survival Heater Testing (1st attempt) 8/11 @ 11:18pm 8/14 @ 7:00amCold Survival Thermal Balance 8/14 @ 7:00amVCHP/Survival Heater Margin Test 8/14 @ 11:52am 8/14 @ 7:00pmRadiator & Grid Survival Heater Testing (2nd attempt) 8/14 @ 11:19pm 8/15 @ 12:45pmConfigure for Cold Performance Testing/Turn-On 8/15 @ 12:46pm 8:15 @ 11:40pm

Cold Operational TestingCold Performance Testing 8/15 @ 11:57pm 8/18 @ 12:16pmTCS-to-End Testing 8/18 @ 12:18pm 8/19 @ 6:30amCold Thermal Balance 8/20 @ 7:30amTCS RIT Testing (cold environment) 8/20 @ 11:20am 8/20 @ 3:50pm




MajorThermal Vacuum Test Events MajorThermal Vacuum Test Events 2/22/2

Thermal Cycling

Thermal CyclingTransition to Hot Plateau 2 8/20 @ 4:23pm 8/22 @ 1:31amHot Plateau 2 8/22 @ 1:38am 8/22 @ 1:26pmTransition to Cold Plateau 2 8/22 @ 1:35pm 8/23 @ 11:30amCold Plateau 2 8/23 @ 11:30am 8/23 @ 11:22pmTransition to Hot Plateau 3 8/23 @ 11:30pm 8/25 @ 10:00amHot Plateau 3 8/25 @ 10:00am 8/26 @ 1:09amTransition to Cold Plateau 3 8/26 @ 1:09am 8/27 @ 10:00amCold Plateau 3 8/27 @ 10:00am 8/27 @ 11:40pmTransition to Hot Plateau 4 8/27 @ 11:52pm 8/29 @ 9:00amHot Plateau 4 8/29 @ 9:00am 8/30 @ 5:45pmTransition to Cold Plateau 4 8/30 @ 5:45pm 9/1 @ 1:52amCold Plateau 4 9/1 @ 1:52am 9/2 @ 11:20pm

Transition to AmbientTransition to Hot Plateau 9/2 @ 11:20pm 9/4 @ 9:30pmLAT Powered Off 9/5 @ 10:10amChamber Recovery 9/5 @ 10:10am 9/7 @ 9:00am

glast large area telescope lat pre-shipment review thermal vacuum test jesse armiger

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