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Thermal Design. Christopher Smith RBSP Thermal Engineer Space Sciences Lab University of California, Berkeley. Outline. Requirements APL – UCB Interface Thermal Model Description IDPU Board Level Thermal Analysis Thermal Model Case Set Inputs Current Predicts Current Testing Overview.

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Thermal design

Thermal Design

Christopher Smith

RBSP Thermal Engineer

Space Sciences Lab

University of California, Berkeley


Outline
Outline

  • Requirements

  • APL – UCB Interface

  • Thermal Model Description

  • IDPU Board Level Thermal Analysis

  • Thermal Model Case Set Inputs

  • Current Predicts

  • Current Testing Overview


Spacecraft level thermal requirements
Spacecraft Level Thermal Requirements

  • Orbit: 500-675 km x 30,050 - 31,250 km (EFW-7, EFW-8)

  • Inclination: 10 degrees +/- 0.25 (EFW-6)

  • 2 year design life, plus 60 days (EFW-1)

  • Spacecraft top deck pointed to sun within: 25 degrees N/S and E/W, normal operation (EFW-201) 27 degrees composite, normal operation (EFW-202) 33 degrees, Safe mode (SCRD 3.10.4.4) (Was 47)

  • S/C spin rate (about top deck):

    4 to 6 RPM, normal and safe modes (EFW-9)

    3 to 15 RPM, instrument commissioning (EFW-203)

  • S/C shall survive 112 minute eclipse (Derived EFW-6, EFW-7, EFW-8)


Efw thermal requirements
EFW Thermal Requirements

  • Conductive external surfaces with 105 Ohms/Sq. (EFW-133)

  • Contamination: 100,000 class (EFW-132)

  • Instruments to operate within specification with -25 to +55 spacecraft boundary conditions. (EFW-76, EFW-77)

    • -25 to +65 for top deck interface, new since PDR

  • Instruments to survive without damage with -30 to +60 spacecraft boundary conditions. (EFW-79, EFW-80)

    • -30 to +70 for top deck interface, new since PDR

  • Comply with contamination control plan. APL document 7417-9007. (EFW-132)

  • Comply with Environmental Design and Test Requirements Document. APL document 7417-9019. (EFW-136)

  • Comply with RBSP_EFW_SYS_301_ETM, RBSP engineering test matrix


Engineering test matrix
Engineering Test Matrix

  • 7 total cycles per instrument, 5 at component level, 2 at suite level.

  • Pre-Amps cycled separately due to larger temperature swing.

  • No need for thermal balance as all instruments are conductively coupled to the spacecraft.


Apl thermal modeling interface
APL Thermal Modeling Interface

  • Berkeley maintains a Thermal Desktop model of the EFW instrument and a boundary node definition of the spacecraft.

  • APL Maintains a TSS geometry and SINDA network model of the spacecraft.

  • APL integrates Berkeley geometry via Thermal Desktop TSS export.

    • Provides environmental heat flux data to instruments.

  • APL integrates Berkeley SINDA network model into the SINDA spacecraft network model.

    • APL specifies spacecraft connection nodes.

  • APL runs integrated model and provides temperature predicts back to Berkeley.

  • Design cycles as necessary.

  • APL is responsible for producing high fidelity temperature predicts.


Thermal model overview instruments and boundary spacecraft
Thermal Model OverviewInstruments and Boundary Spacecraft

IDPU

AXBs

SPBs


Thermal model overview axb stowed
Thermal Model OverviewAXB -Stowed

Sphere / Preamp in Caging Mechanism

(Clear Alodine, GeBK Blanket)

Sphere / Preamp

(DAG 213)

Rod to Stacer Hinge

(DAG 213)

Mounting Tube (M55J)

Stacer

(Elgiloy)


Thermal model overview axb deployed
Thermal Model OverviewAXB -Deployed

Stacer

(Elgiloy)

Sphere

(DAG 213)

DAD

(AntiSun: Clear Alodine)

(Sun: Clear Alodine / GeBk Tape mix)

Sphere Caging Mechanism

(AntiSun: Clear Alodine)

(Sun: GeBk Blanket / Clear Alodine mix)


Thermal model overview spb deployed elements
Thermal Model OverviewSPB Deployed Elements

SPB Sphere

SPB Preamp

Thick Wire

Thin Wire


Thermal model overview spb idpu
Thermal Model OverviewSPB & IDPU

SPB - Deployed

IDPU

(Mostly Black Kapton XC Tape, Some Gold Alodine)

(Black Kapton XC Tape)

(Clear Alodine)

SPB - Stowed

(Black Kapton Blanket, Shown in Green)






Optical materials
Optical Materials

  • Most properties tested, used, and correlated for the THEMIS mission

  • Properties approved by the GSFC coatings committee July 07, 2008.


Thermophysical properties
Thermophysical Properties

  • Hot Cases Use Low e* Anti-Sunward and High e* Sunward

  • Cold Cases Use High e* Anti-Sunward and Low e* Sunward


Interfaces
Interfaces

IDPU

  • Conductively mounted to spacecraft side panel.

  • 9 #10 Bolts = 0.75 W/C each.

  • Radiative coupling to spacecraft interior, Black Kapton XCTape

    SPB

  • Conductively mounted to spacecraft side panel.

  • 4 #10 Bolts = 0.75 W/C each.

  • Deployed elements are completely isolated from the spacecraft by wire.

  • Low radiative coupling to spacecraft interior, Clear Alodined Aluminum

    AXB

  • Conductively mounted to the top and bottom spacecraft deck.

  • 6 #8 Bolts at each end = 0.75 W/C each.

  • Radiative coupling somewhat isolated from major portions of the spacecraft since the mechanical units are stowed inside a carbon fiber tube which is also stored inside a spacecraft carbon fiber tube.

  • Deployed elements are isolated from spacecraft influence by stacer.

  • Caging mechanisms conductively mounted to top deck, 4 #8 Bolts = 0.75 W/C each.


Power heaters
Power, Heaters

  • Current power used in model

  • IDPU, SPB and AXB do not have any survival heaters


General case sets
General Case Sets

APL Case Set Parameters

UCB Case Set Parameters


Limit categories
Limit Categories

  • Science Operation Limit

    • Limits placed on an operating instrument

    • Specifies the range of temperatures the instrument will provide calibrated / useful science data

  • Operation – Out of Spec

    • Limits placed on an operating instrument

    • May represent a wider range that is survivable but may be out of spec

    • Temperatures beyond Science Op Limit need not be calibrated to

  • Non-Operation

    • Limits placed on a non operating instrument

  • Pre-Deployment Limit

    • Limits placed on a mechanical system before it is actuated

  • Deployment Limit

    • Limits placed on a mechanical system at the time of actuation

  • Post-Deployment Limit

    • Limits placed on a mechanical system after it has executed its one-time deployment




Margins deployed case sets
Margins, Deployed Case Sets

  • Positive Margins for all deployed cases


Apl and ucb predict comparison table
APL and UCB Predict Comparison, Table

  • Each case set compared at a specific time and a representative node

  • All case sets agree to within 1.5 degrees





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