# Presentation: 171305

## Section 20

_***Section 20***_
***Carbon-Carbon Radiator***
***(CCR)***

*** ******. . . Gurnie Hobbs***
*EO-1 Carbon-Carbon Radiator Lead *

## Design Overview

***Design Overview***

***Equipment panel composed of carbon-carbon facesheets and an aluminum honeycomb core***
***Measures 28.62 x 28.25 x 1.00 in***
***Mass of 3.12 kg***
***Flight unit and spare***
***No changes since CDR***

## Performance Required

***Performance Required***

***Mass - Less than 2.5 kg***
***Stiffness - First mode frequency greater than 100 Hz when hard-mounted to the S/C***
***Strength - Inertial loading***
***Simultaneous quasi-static limit and S/C interface loads***
*15 g acceleration in any direction*
*Shear load of 16,100 N/m*
*Edge normal load of 19,500 N/m*
*Panel normal load of 1,850 N/m*
***Maximum fastener forces at the S/C attachment points***
*Maximum tension force of 25 N*
*Maximum shear force normal to panel edge of 135 N*
*Maximum shear force parallel to panel edge of 115 N*
***Strength - Thermal loading***
***On-orbit temperature variations ranging from -20°C to +60°C***

## Verification Approach

***Verification Approach***

***Structural Analysis***
***Thermal Vacuum/Balance Testing***
***Vibration Testing***
***Mass Properties Testing (Flight unit only)***
***Non-destructive examination (NDE) (radiography) conducted before and after thermal vacuum and vibration testing***

## Verification Matrix

***Verification Matrix***

***Thermal Vacuum/Balance***
***four cycles, each with a minimum 4-hour soak at +50°C and -10°C***
***mockups of the LEISA and PSE baseplates, equipped with heaters***
***CCR attached to an aluminum frame, which simulated the S/C stiffness and cross-sectional area***
***two strain gauges on the frame measured strain during thermal cycling***
***thermal balance testing for eight various conditions***
***survival heaters tested with four different voltages***
***Vibration***
***sine burst testing at 18.8 g (1.25 x limit load) in all three axes***
***low-level sine sweep before and after each sine burst test***
***mass mockups of the LEISA and PSE***
***CCR attached to an aluminum frame, which simulated the S/C stiffness***
***two tri-axial accelerometers on the CCR and on the PSE mass mockup***
***Mass Properties***
***mass measurement***
***center of gravity (cg) measurement in x- and y-axes***
***calculated cg in z-axis and moments of inertia about x-, y-, and z-axes***

## Test Results

***Test Results***

***Structural analysis showed all positive margins of safety***
***Thermal cycling loads were half those predicted, indicating that finite element model (FEM) results are conservative***
***First frequency of 89 Hz, less than 5% below the 93 Hz predicted, indicating that the FEM is reliable.  (FEM predicts a first frequency of 112 Hz for the CCR hard-mounted to the S/C.)***
***Sine sweeps indicated no structural change as a result of sine burst testing***
***NDE conducted before and after thermal and vibration testing indicated no structural damage as a result of environmental testing***

## Non-Conformances/Configuration ChangesAction Items

***Non-Conformances/Configuration Changes******Action Items***

***None***

## Statement of Readiness

***Statement of Readiness***

***Meets all subsystem- and Satellite-level requirements***
***Ready for shipment and launch***