1. University of California, Berkeley
Thermal Design
Christopher Smith
RBSP Thermal Engineer
Space Sciences Lab
University of California, Berkeley

2. Outline Requirements APL – UCB Interface Thermal Model Description
IDPU Board Level Thermal Analysis
Thermal Model Case Set Inputs
Current Predicts
Current Testing Overview

3. Spacecraft Level Thermal Requirements
Orbit: km x 30, ,250 km (EFW-7, EFW-8)
Inclination: 10 degrees +/ (EFW-6)
2 year design life, plus 60 days (EFW-1)
Spacecraft top deck pointed to sun within: degrees N/S and E/W, normal operation (EFW-201) degrees composite, normal operation (EFW-202) degrees, Safe mode (SCRD ) (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)

4. 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 (EFW-132)
Comply with Environmental Design and Test Requirements Document. APL document (EFW-136)
Comply with RBSP_EFW_SYS_301_ETM, RBSP engineering test matrix

5. 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.

6. 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.

7. Thermal Model Overview Instruments and Boundary Spacecraft
IDPU
AXBs
SPBs

8. Thermal Model Overview AXB -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)

9. Thermal Model Overview AXB -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)

10. Thermal Model Overview SPB Deployed Elements
SPB Sphere
SPB Preamp
Thick Wire
Thin Wire

11. Thermal Model Overview SPB & 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)

12. DCB Component Dissipations

13. DFB Component Dissipations

14. LVPS Component Dissipations

15. LVPS Board Distribution

16. Optical Materials
Most properties tested, used, and correlated for the THEMIS mission
Properties approved by the GSFC coatings committee July 07, 2008.

17. Thermophysical Properties
Hot Cases Use Low e* Anti-Sunward and High e* Sunward
Cold Cases Use High e* Anti-Sunward and Low e* Sunward

18. Interfaces IDPU SPB AXB Conductively mounted to spacecraft side panel.
9 #10 Bolts = 0.75 W/C each.
Radiative coupling to spacecraft interior, Black Kapton XCTape
SPB
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.

19. Power, Heaters Current power used in model
IDPU, SPB and AXB do not have any survival heaters

20. General Case Sets
APL Case Set Parameters
UCB Case Set Parameters

21. Limit Categories Science Operation Limit Operation – Out of Spec
Limits placed on an operating instrument
Specifies the range of temperatures the instrument will provide calibrated / useful science data
Operation – Out of Spec
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

22. Current Thermal Limits

23. Predicts, Deployed Case Sets

24. Margins, Deployed Case Sets
Positive Margins for all deployed cases

25. 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

26. APL and UCB Predict Comparison, Plot

27. ETU Thermal Vac Testing Completed