SPP-FIELDS Thermal Path to TRL 6

1. SPP-FIELDSThermal Path to TRL 6 M. Diaz-Aguado

2. Material Characterization at High Temperatures • Outgassing studies (tested at NASA Glenn) • Small (4%) mass losses observed at 1600°C, higher than expected temperatures for three closest perihelion passes • Thermal distortion (tested at SRI) • Less than .06” on a 16” tube – total alignment error budget is 2° for which 0.77° is allocated for thermal distortion (measured was 0.2°) • Future testing (8/2013) at VPE to check thermal distortion longer test article • Electrical resistance (tested at APL, SRI) • Sapphire, alumina and Nb C103 (1e-4 Ωcm) • Thermal conductivity (tested Odeillo, PROMES chamber) • Tested with model at temperature with alumina • Total hemispherical optical properties (tested Odeillo & APL) • BOL/EOL solar absportivity/emissivity at temperature of Nb C103 (a/e=1.8) @Odeillo • BOL/EOL solar absportivity/emissivity, Nb C103 @APL

3. Thermal Model and Model Verification • Thermal design studies of shield configuration • Shapes, layers • Thermal Test Model (TTM - 1,2 tested Odeillo) • Verified thermal design at high temperatures (~1000°C - 1500°C) • Issues with silver coated bolts and titanium parts • Testing at VPE to ensure Titanium behaves as expected w/o silver coating on bolts (7/2013) • Thermal test model (TTM – 3, test at Harvard SAO) • Shield shape test and other updates (9/2013), up to 1000°C with 2 light sources • Test margins • Maximum temperature from modeling is 1500°C • Currently using a/e of Nb C103 of 2.1, measured a/e=1.8 (translates to 100°C margin) • Post TRL-6 Testing (TTM- 3, test at Harvard SAO) • Shield shape test and high temperature conductance (date?) with 6 light sources

4. Back Up Slides

5. Resistivity at High Temperatures

6. Thermal Conductivity at High Temperatures

7. Absorptivity vs. Emissivty Ni C103 • CNES, Solar Furnace Odeillo • APL

8. E-Field Antenna Development • Niobium sheet and tube stock required for development • Candidate flight material • Tantalum-Tungsten (Ta-W) sheet and tube in stock • Back up candidate material • Thermal Modeling updates • Change heat shield design to lower max temperature and maintain max preamp temp < 70°C (chevron shape) • Added shield and thermal isolation to hinge and preamp • Material Thermal Testing • C103 and Ta-W do not have mass loss issue • Testing of TML < TBD%, CVCM <TBD% (in previous missions TML<1%, CVCM<0.1%) • High temperature optical properties testing • Verified other high temperature properties, e.g. thermal conductivity, resistance • Design • Replaced fluid hinge damper with mechanical damper that is more temperature tolerant • Hinge will be cycled and tested (reminder that hinge will deploy once to a locking position before getting close to Sun)

9. Weight Loss Test

10. Thermal Choke TTM Whip Disk Whip Choke Choke Water Cooling

11. Thermal Shield TTM Shield Clamp Bracket Water Cooled Stub

12. Choke Thermal Balance B.C. B.C.

13. Shield Thermal Balance B.C. B.C.

14. TTM Shield Lessons Learned • Re-crystalization of Titanium • Has no observed effect on bracket • Melting of silver coating on bolts • Might create gaps on joints • Rapid heating • Probably deformed shield

15. Antenna Tube Deflection • Below are the measurements in inches that were made in Photoshop based on the images captured at the tip of these three tubes at 1400 °C, for 40 min. • C103 Tube1: • Pre to mid 0.040 • C103 Tube2: • Pre to final 0.060 • Pre to mid 0.056 • mid to final 0.004 • TaW Tube 2: • Pre to final 0.021 • Pre to mid 0.012 • mid to final 0.009