July 18, SPP-FIELDS Thermal Path to TRL 6 M. Diaz-Aguado

July 18, 2013 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 –BOL/EOL solar absportivity/emissivity, Nb 2

July 18, 2013 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 °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 3

July 18, 2013 Back Up Slides 4

July 18, 2013 Resistivity at High Temperatures 5

July 18, 2013 Thermal Conductivity at High Temperatures 6

July 18, 2013 Absorptivity vs. Emissivty Ni C103 CNES, Solar Furnace Odeillo APL 7

July 18, 2013 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) 8

July 18, 2013 Weight Loss Test 9

July 18, 2013 Thermal Choke TTM Whip Disk Whip Choke Choke Water Cooling

July 18, 2013 Thermal Shield TTM Shield Clamp Bracket Stub Water Cooled

July 18, 2013 Choke Thermal Balance TC# LocationMin 17 Day 2ModelΔT (°C)Min 72 Day 1ModelΔT (°C) 1Shield Shield Antenna-Shield Antenna-Choke Choke Antenna Base Clamp Cooling plate Cooling plate B.C.

July 18, 2013 Shield Thermal Balance TC #Location Min 27 Day 1 ModelΔT (°C) 1Shield Shield 2Bad-- 3Bracket-Shield Bracket-Away Shield Antenna Base-Shield426*4242 6Antenna Base-Away Shield383*3758 7Antenna Base-Camp Clamp63 0 B.C.

July 18, 2013 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

July 18, 2013 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 C103 Tube2: –Pre to final –Pre to mid –mid to final TaW Tube 2: –Pre to final –Pre to mid –mid to final