MSFC CSiC Preliminary Cryogenic Optical Testing Data Review

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MSFC CSiC Preliminary Cryogenic Optical Testing
Data Review

• James Hadaway, Joseph Geary, Patrick Reardon,
  Bruce Peters, Phil Stahl, Ron Eng, Barry Hale,
  Jeff Kegley Mark Baker
• The University of Alabama in Huntsville
• Marshall Space Flight Center
• May 9, 2001

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Outline

• Optical Testing System
• Early Results
• Early Conclusions

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General System Layout
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PhaseCam Pallet

• PhaseCam instantaneous phase-shifting
  interferometer with F/33 diverger.
• Reference sphere for subtraction of instrument
  errors.
• Intelliwave software.
• Leica Disto Pro distance meter.
• Located on 5-DOF platform.

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Definitions

• Total or Raw Results - basic Wavescope output
  that has piston, tilt, focus removed.
• Zernike Fit - fit of first 36 terms.
• Residual - difference of Total Zernike Fit.

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PV Cryo Deformation vs. Temperature
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RMS Cryo Deformation vs. Temperature
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PV Residual Cryo Deformation vs. Temperature
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RMS Residual Cryo Deformation vs. Temperature
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CSiC Ambient Cryo Figure
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CSiC Cryo Deformation
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Observed PhaseCam Repeatability

• Performed two measurements (average of 50 frames)
  at each temperature.
• Performed difference of two measurements at each
  temperature in order to look at repeatability in
  the operational environment.
• Average difference/repeatability seen during this
  test was ?/33 PV ?/400 rms (HeNe).
• In process of conduction more rigorous accuracy
  repeatability characterization.

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Conclusions

• In process of analyzing data from first cryo test
  of IABG CSiC mirror at MSFC.
• Effort has led to early development of PhaseCam
  measurement procedures in advance of AMSD testing.

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Contacts

• hadawayj_at_email.uah.edu
• phil.stahl_at_msfc.nasa.gov