LAT TVAC Test Delta-PDR 1

GLAST LAT Project

25 May 2005

LAT Environmental Test Planning and DesignLAT Environmental Test Planning and Design

Delta-Preliminary Design ReviewDelta-Preliminary Design Review

25 May 200525 May 2005

LAT T-Vac TestLAT T-Vac Test

Final version: 10 June 2005Final version: 10 June 2005

LAT Environmental Test Planning and DesignLAT Environmental Test Planning and Design

Delta-Preliminary Design ReviewDelta-Preliminary Design Review

25 May 200525 May 2005

LAT T-Vac TestLAT T-Vac Test

Final version: 10 June 2005Final version: 10 June 2005

Jack GoodmanJack Goodman

LAT TVAC Test Delta-PDR 2

GLAST LAT Project

25 May 2005 Thermal-Vacuum Test SequenceThermal-Vacuum Test Sequence

Prep Lat for TVAC

Load LAT into Chamber

Connect Instrumentation

Open Door Checkout

Chamber Pump Down

Hot OpT-Balance

Hot OpThermal Control

Hot OpPeak Power

HotPerformance

Cold SurvivalT-Balance

ColdPerformance

Cold OpT-Balance

Cold OpThermal Control

ThermalCycling (4)

Bake OutReturn to

Ambient P&T

Pre-Bake

LAT TVAC Test Delta-PDR 3

GLAST LAT Project

25 May 2005 Temperature Requirements for Simulated Sink HardwareTemperature Requirements for Simulated Sink Hardware

• Operating/Performance

– Hot at 40°C

– Cold at 0°C

• Thermal Balance

– Hot balance at 30°C

– Cold balance at 0°C

– Cold survival at -2°C

• Test Cycle

– Four TVAC Cycles, 8 Transients

• Hot soak at 40°C

• Cold soak at 0°C

• Test: EGSE Failure/Safe Hold (not relevant to orbit)

– +25°C

• Bake out

– +45°C

LAT TVAC Test Delta-PDR 4

GLAST LAT Project

25 May 2005 LAT Surfaces Requiring Thermal ConditioningLAT Surfaces Requiring Thermal Conditioning

• ACD thermal conditioning

– ACD temperature controlled by thermal sink plates electrically heated with radiation cooling to TVAC Chamber cold shroud

• Radiator and X-LAT Plate MLI Blankets (Spacecraft Bus simulator) thermal conditioning

– Spacecraft bus temperature controlled by thermal sink plates electrically heated and cryogenically cooled

• Radiator thermal conditioning – 3 options

– Thermal Control Unit sink plate system

• Radiator temperature controlled by thermal sink plates heated and cooled with Thermal Control Units

– NRL thermal conditioning system

• Radiator temperature controlled by thermal sink plates electrically heated and cryogenically cooled

– Cal Rod cage system

• Radiator temperature controlled by balance of IR heating from Cal Rods and radiation cooling to TVAC chamber cold shroud

LAT TVAC Test Delta-PDR 5

GLAST LAT Project

25 May 2005 ACD Thermal ConditioningACD Thermal Conditioning

• ACD thermal conditioning

– ACD Temperature varies: -60°C to +60°C

– Thermal sink plate requirements• Dimensions 1.8 m x 1.3 m (approx)

• Temperature -89 °C to +60 °C

• Temperature Uniformity +/- 5 °C

• Emissivity ~0.5 (Anodized Al or paint)

• Power Absorption <20W from ACD (TBD)

• Cycle none

• Quantity 5

– Heating of thermal sink plates is provided by resistive heaters• Film/strip heaters—built into the plates

• Power supplies—outside chamber with feedback control off of TC’s on plates

– Cooling of thermal sink plates is passive radiation cooling to the TVAC chamber cold shroud• TVAC Chamber Cold Shroud Temperature = -150 °C

– Thermal control• 5 independent heater circuits controlled by chamber CDACS system with feedback on TC temps

– Power requirements (includes 20% margin)• ACD +X sink plate: 985 W• ACD +Y sink plate: 625 W• ACD -X sink plate: 625 W• ACD -Y sink plate: 625 W• ACD +Z sink plate: 911 W

LAT TVAC Test Delta-PDR 6

GLAST LAT Project

25 May 2005 Spacecraft Bus Thermal ConditioningSpacecraft Bus Thermal Conditioning

• Spacecraft Bus thermal conditioning

– SC Bus temperature varies: -40°C to +25°C

– Thermal sink plate requirements

• Dimensions 1.6 m x 1.8 m (approx)

• Temperature -40 °C to +25 °C

• Temperature Uniformity +/- 5 °C

• Emissivity >0.85 (Anodized Al or paint)

• Power Absorption <25W (TBD)

• Cycle none

• Quantity 3

– Heating of thermal sink plates is provided by resistive heaters

• Film/Strip heaters—built into plates

• Power supplies—outside chamber with feedback control off of TC’s on plates

– Cooling of thermal sink plates is primarily LN2/GN2 with some radiation loss

• Active cooling supplied by LN2 solenoid valves

– Thermal control

• 3 independent heater circuits controlled by chamber CDACS system with feedback on TC temps

– Power requirements (includes 20% margin)

• SC Y-side sink plates: 2 @ TBD W

• SC top-deck sink plate: TBD W

LAT TVAC Test Delta-PDR 7

GLAST LAT Project

25 May 2005 Radiator Thermal Conditioning – Option 1Radiator Thermal Conditioning – Option 1

• Option 1 - Thermal Control Unit (TCU) sink plate system

– Radiator Temperature -13°C to +2°C (Hot Case orbit average)

– Thermal Sink Plate Requirements

• Dimensions 1.65 m x 1.85 m (approx)

• Temperature -126 °C to +4 °C (Hot transient); -95 °C to -64 °C (Cold transient)

• Temperature Uniformity +/-2.5 °C (balance); +/-5 °C transient

• Emissivity >0.85 (Anodized Al or paint)

• Power Absorption 0 W to 800 W max per Plate (includes margin)

• Cycle 92 minutes sinusoidal

• Quantity 2

– Heating and cooling of thermal sink plates is provided by 1 TCU per Radiator

– Thermal control

• 1 control zone per Radiator, controlled by TCU

– Power requirements

• TBD, rough estimate by 6/15/05

LAT TVAC Test Delta-PDR 8

GLAST LAT Project

25 May 2005 Radiator Thermal Conditioning – Option 2Radiator Thermal Conditioning – Option 2

• Option 2 – NRL Thermal Conditioning System

– Radiator Temperature -13°C, +2°C (Hot Case orbit average)

– Thermal Sink Plate Requirements

• Dimensions 1.65 m x 1.85 m (approx)

• Temperature -126 °C to +4 °C (Hot transient); -95 °C to -64 °C (Cold transient)

• Desired Temperature Uniformity +/- 2.5 °C (balance); +/- 5 °C transient

• Actual Temperature Uniformity TBD; rough estimate available by 6/1/05

• Emissivity >0.85 (Anodized Al or paint)

• Power Absorption 0 W to 800 W max per Plate (includes margin)

• Cycle 92 minutes sinusoidal

• Quantity 2

• Heater Power 5 amps per circuit (max)

– Heating of thermal sink plates is provided by resistive heaters built into panels

– Cooling is provided by active cooling supplied by LN2 solenoid valves

– Thermal control

• 1 heater/cooling circuit per Rad controlled by chamber CDACS system with feedback on TC temps

– Power Requirements

• # of circuits and power per circuit TBD, rough estimate available by 6/15/05

LAT TVAC Test Delta-PDR 9

GLAST LAT Project

25 May 2005 Radiator Thermal Conditioning – Option 3Radiator Thermal Conditioning – Option 3

• Option 3 - CAL Rod Cage System

– Radiator Temperature -13°C, +2°C (Hot Case orbit average)

– Thermal Sink Cage Requirements

• Dimensions 1.6 m x 1.8 m (approx)

• Temperature Uniformity +/- 2.5 °C (balance); +/- 5 °C transient

• Emissivity >0.38 (sandblasted stainless steel)

• Power Absorption N/A

• Cycle 92 minutes sinusoidal

• Quantity 2

– Heating and cooling

• Radiator temperature control is by balance of radiation loss to TVAC chamber cold shroud (-150 °C) and IR Heating from CAL Rod cage

• IR power from Cal-Rod resistive heating elements

• TVAC Chamber Cold Shroud Temperature = -150 °C

– Thermal Control

• 3 independent Cal-Rod circuits per Radiator controlled by chamber CDACS system with feedback from radiometers mounted in front of Radiators

– Power Requirements (includes 50% margin)

• 2400 W/cage– Radiator top: ~400 W– Radiator middle: ~ 1600 W– VCHP reservoirs: ~400 W

LAT TVAC Test Delta-PDR 10

GLAST LAT Project

25 May 2005 Trade Study - Radiator Thermal ConditioningTrade Study - Radiator Thermal Conditioning

THERMAL CONTROL UNIT SYSTEM

NRL THERMAL CONDITIONING SYSTEM

CALROD SYSTEM

Temp Control System Availability Thermal Control Unit (QTY = 2) CDACS System (QTY = 1) CDACS System (QTY = 1)

Proportional Solenoid Valves (QTY = 2) Calrod Heating Elements (QTY = 22)

Heaters (QTY = TBD, rough estimate by 6/15/05)

Thermal Sink Plates

Radiator Sink Plates/Calrod Box (QTY = 2) (QTY = 2) (QTY = 2)

Temp Uniformity Across Plate 5 °C Steady-State, 10 °C Transient 5 °C Steady-State, 10 °C Transient 5 °C Steady-State, 10 °C Transient

Pow er Absorption (total) 0 W to 800 W (max) - per Plate 0 W to 800 W (max) - per Plate N/A

Pow er Dissipation to Shroud Minimal Minimal TBD

Pow er Requirements

Max Current N/A 5 A per Circuit (max) 5 A per Circuit (max)

Pow er Supplies N/A (QTY = TBD, rough estimate by 6/1/05) (QTY = 8)

Pow er Feedthroughs N/A (QTY = TBD, rough estimate by 6/1/05) (QTY = 1)

Req'd TC's/Heat Flux Meters

LAT SupportSee Table 3 of LAT Intrumentation Plan

See Table 3 of LAT Intrumentation PlanSee Table 3 of LAT Intrumentation Plan

Test SupportSee Table 3 of LAT Intrumentation Plan

See Table 3 of LAT Intrumentation PlanSee Table 3 of LAT Intrumentation Plan

Thermcouple Feedthroughs TBD TBD TBD

Cost TCU Purchase = $84,250 each

TCU Rental = $100,000 - $120,000 for tw o

Sink Plates = estimated at $12K each; true pricing available by 6/15/05

CAL Rods: $1100 per cage for rods

Sink Plates = $7,450 each

• A trade study of the three Radiator thermal control options was done to establish the optimal solution

• The results of this show that the Cal-Rod cage system is the preferred implementation

• Baseline: Cal-Rod cage

LAT TVAC Test Delta-PDR 11

GLAST LAT Project

25 May 2005 Option 3 Cal-Rod/Baffle Sensitivity StudyOption 3 Cal-Rod/Baffle Sensitivity Study

Cal-Rod spacing = 5.6”

Cal-Rod Box Offset = 1.0”

Cal-Rod Box Height = 12”

Panel Dimensions = ~1.5 x 1.5 m (for the study)

Polished Al Frame

RadTemp (C) Per Rod Total Min Max Spread

0 55 600 -1.4 0.6 220 100 1100 18.5 21.8 3.340 153 1685 37.5 42.0 4.5

Power (W) Temperature (C) • Basis of study and boundary conditions:

– Chamber shroud temperature = -150C

– Panel internal heat gen = 300W

– Panel temp uniformity goal: 5 C

– Size system to maintain Rad temp at 0 C, 20 C, and 40 C

– Stainless steel Cal Rods, 0.25” OD

• Results: Cal-rods need 5.6” max spacing 7” set-back from Rad surface

Results of Thermal Analysis

LAT TVAC Test Delta-PDR 12

GLAST LAT Project

25 May 2005 Option 3 Cal-Rod Panel Temperature DistributionOption 3 Cal-Rod Panel Temperature Distribution

LAT TVAC Test Delta-PDR 13

GLAST LAT Project

25 May 2005 Option 3 Cal-Rod Cage Heater Circuit RequirementsOption 3 Cal-Rod Cage Heater Circuit Requirements

• Transient and steady-state thermal analyses of LAT system shows that the hot-case transient test case is the defining case for the heater system

– At one extreme of the transient, all 600 W of LAT power is radiated off of one Radiator

– The Cal-Rod cage on the opposite side of the LAT draws the most power at that time

• Max power needed: 1600 W/Radiator

• Heater cage requirements and boundary conditions

– Power: 1600 W * 1.5 margin = 2400 W/Rad

– Temp uniformity: 5 degC over surface of Radiator

– Max process power: 300 W (with Cal-Rods operating at full-power)

– Minimum of 3 control zones

– Cold shroud minimum temp: -150 C

– Low-profile/low-mass design toincrease cool-down and warm-up rates

-200-150-100-50

050

100150200250300350400450500550600650700750

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Time(min.)

Cal

rod

Tem

per

atu

re(°

C)

500 W

250 W

100 W

Calrod Dissipation

LAT TVAC Test Delta-PDR 14

GLAST LAT Project

25 May 2005 Option 3 Cal-Rod Cage Heater Circuit ImplementationOption 3 Cal-Rod Cage Heater Circuit Implementation

• Power requirements (includes 50% margin)

– 2400 W/cage

• Radiator top: ~400 W

• Radiator middle: ~ 1600 W

• VCHP reservoirs: ~400 W

• Cal-Rods

– Heated length of 60 inches

– O.D of 0.25 inches

– Emissivity >0.38 (sandblasted stainless steel)

– Resistance of at least 89 ohms

– Max operating temperature: 750°C

– Min non-operating temperature: -150°C

• Use standard NRL power supplies

– 1000 W max and 5 A max or 240 V max

– Cal-Rod cage will likely be powered by 4 supplies: one for top, one for reservoirs, and two ganged together for middle zone

Cal-Rod Heater

LAT TVAC Test Delta-PDR 15

GLAST LAT Project

25 May 2005 Summary of Heater RequirementsSummary of Heater Requirements

Area Tot Pwr4 Req'dSink Location m2 W Control

Min Max Min Max Zones

Radiator11 -77 -14 N/A N/A 3.0 2400 3

Radiator21 -77 -14 N/A N/A 3.0 2400 3ACD +X Sink -76 60 36 342 2.4 985 1ACD +Y Sink -89 25 26 217 2.4 625 1ACD -X Sink -79 25 34 217 2.4 625 1ACD -Y Sink -89 25 26 217 2.4 625 1ACD +Z Sink -82 25 31 217 3.5 911 1

SC +Y-Side Sink3 -40 25 N/A N/A 3.0 TBD 1

SC -Y-Side Sink3 -40 25 N/A N/A 3.0 TBD 1

SC Top-Deck Sink3 -40 25 N/A N/A 3.0 TBD 1Test Stand TBD TBD TBD 4

1Note: Cal Rod Cage power for Rad's calc'd based on 4C Rad temp2Note: ACD heater power based on 0.5 plate emissivity and 123K ultimate sink3Note: SC sink heater power calc'd based on cryogen temperature and flow rate4Note: Tot pwr includes 20% margin on sink plates, 50% margin on Cal-Rod cages Note: 1000W DC power supply limited to 240 volt or 5 amp

Equiv Sink Temp Htr Pwr2

W/m2deg C