EFI Axial Booms Thermal Christopher Smith Thermal Engineer csmith@ssl.berkeley 510-642-2461

1. EFI Axial Booms • Thermal • Christopher Smith • Thermal Engineer • csmith@ssl.berkeley.edu • 510-642-2461

2. Axial Boom Stowed • Axial Boom (AXB) • Two units mount inside a carbon fiber tube centrally mounted on the probe • Tube attached to the top deck through an aluminum flange that is bare bolted • Bare bolted to lower deck • Two stacers, one from each unit, deploy out the tube ends AXB Mounting Tube Single AXB unit

3. AXB a/e Map • 80% Alum Foil Tape • 20% Bare Carbon Fiber VDA Tape Alodined Aluminum Bare Carbon Fiber

4. AXB Model Inputs • Optical materials • Aluminum Foil Tape • Bare Carbon Fiber • Alodined Aluminum • Thermophysical materials • Aluminum, 6061 • K13D2U Carbon Fiber • T300 Carbon Fiber • Heaters • None used at this time, though we are prepared to supply deployment heaters if needed • Conductors • Bare bolted top flange to deck: 0.612 W/C inc. bolts, flange, and adhesive • Bare bolted bottom flange to deck: 3.3 W/C each, 20 W/C total • Bare bolted AXB to Tube mount: 0.79 W/C each, 0.476 total • Power Dissipation • 0 Watts AXB Mounting Tab

5. AXB Case sets • Bottom to sun a cold case boundary condition has no eclipse • All above cases run separately with stowed boom and deployed boom

6. AXB Mechanical Unit Standard Plots - Deployed

7. AXB Mechanical Unit Sunline Plots - Deployed

8. AXB Mechanical Unit Standard Plots - Stowed

9. AXB Mechanical Unit Sunline Plots - Stowed

10. AXB Results Table

11. AXB Mounting Tube Modifications • Spacecraft was consuming too much power in the coldest, but nominal, science case ~2.2 W • To help mitigate this issue two modifications are being considered for the AXB Mounting tube • Tube construction switched from all T300 ( 5 W/mK) fiber to 4 plys K13D2U (500 W/mK) + 2 plys T300 • Tube exterior changed from blanket to a mix of Foil tape and bare carbon • Current results show the AXB unit getting too hot and we are currently exploring options to cool it down • Increase isolation between AXBs and tube • Isolate tube flange from top deck • At worst, cool the tube down by reducing the percentage of foil tape • When the design is complete it will be within limits though new temperatures may require the thermal vac hot deploy test be repeated at a new higher temperature

12. AXB Temp Map for Hottest Case

13. AXB Temp Map for Coldest Case

14. Axial Boom Deployed AXB “can” AXB PreAmp Exposed Bit After Deploy

15. AXB Geometry Model • Deployed Stacer Model

16. AXB Deployed Elements a/e Map • DAG 154 Alodined Aluminum DAG 213 Bronze

17. AXB Model Inputs • Optical materials • Acheson Coloids DAG 213 (2 part) • Acheson Coloids DAG 154 • Alodined Aluminum • Bronze • Thermophysical materials • Aluminum, 6061 • Bronze • Elgiloy • PEEK • Heaters • None • Conductors • Main Stacer to Tip Piece, 1 rivet and circumferential contact, .3 < G <.9 W/C • Tip Piece To Bronze DDAD Lock, Large threaded interface, 10 W/C • DDAD Lock to PreAmp, large threaded bolt 3.57 W/C • PreAmp to Mini Stacer, 1 rivet and circumferential contact .3< G <.8 W/C • Mini Stacer to Can, 1 rivet, 0.3 W/C • Power Dissipation • 0.07 Watts Nominal at Preamp AXB Preamp

18. AXB Deployed Elements Case Sets • Top and Bottom to sun cases after deployment are limited to no less than 11 degrees off the sun line • The Model for the Top and Bottom to Sun cases goes through a 180 min eclipse. A 100 min eclipse is the actual limit and is shown in plots

19. AXB Boom Elements Standard Plots - Deployed

20. AXB Boom Elements Sunline Plots - Deployed

21. AXB Preamp Results Table • Science operation limited to a 36 min eclipse • Current predicts show Preamp falling below the limit on the TO99 can.

22. AXB Preamp Qualification • AXB Preamp model is currently a simple lump with the proper radiative surfaces • Thermal isolation of the TO-99 from the outer shell is complicated and difficult to reliably model • Thermal Vacuum test planned determine the thermal isolation of the TO-99 from the preamp outer surface (April 12th – April 23rd) • This thermal isolation determined by test will be input into the thermal model to determine a reliable qualification temperature, still likely to be under the current qualified temp of –65

23. AXB Preamp Models

24. EFI Spin Plane Booms • Thermal • Christopher Smith • Thermal Engineer • csmith@ssl.berkeley.edu • 510-642-2461

25. SPB • 4 separate units mounted to the bottom deck • Snout pokes out the solar panel • Sphere and Preamp deploy out the snout on a wire (Half Sphere shown in picture) • Sphere and preamp separate as rotation unwinds a thin wire from a spring loaded wheel

26. SPB a/e Map • AZ 2000 IECW Inorganic White Paint Alodined Aluminum MLI

27. SPB Model Inputs • Optical materials • Germanium Black Kapton (Sheldahl 275XC Black Kapton) • Alodined Aluminum • AZ 2000 IECW Inorganic White Paint • Blanket: .01 < e < .05 • Thermophysical materials • Aluminum, 6061 • ULTEM • Heaters • None used at this time, though we are prepared to supply deployment heaters if needed • Conductors • 1/8” Ultem isolators for top deck: 0.01 W/C each, 0.04 W/C total • Power Dissipation • 0 Watts

28. SPB Case Sets

29. SPB Mechanical Unit Standard Plots

30. SPB Mechanical Unit Sunline Plots

31. SPB Results Table

32. SPB Heat Map for Coldest Case

33. SPB Heat Map for Hottest Case

34. SPB Deployed Elements • Preamp and sphere are connected by a thin wire • Preamp is connected to SPB deployment unit by another wire • Preamp is nearly identical to Axial version • Sphere is only a mechanical element Titanium Nitride DAG 213

35. Preamp and Sphere Analysis

36. SPB Sphere and Preamp Model • Nodes 3 and 4 are for the sphere hot and cold cases • Nodes 5 and 6 are for the preamp hot and cold cases • As with the axial preamp the SPB preamp falls below its limit by a bit. Qualification plan is in the works

37. SPB Sphere and Preamp Plot