PSR Section 20

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Section 20 Carbon-Carbon Radiator (CCR)
. . . Gurnie Hobbs EO-1 Carbon-Carbon Radiator
Lead
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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

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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
  -20C to 60C

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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

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Verification Matrix

• Thermal Vacuum/Balance
• four cycles, each with a minimum 4-hour soak at
  50C and -10C
• 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

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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

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Non-Conformances/Configuration ChangesAction
Items

• None

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Statement of Readiness

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