SpeckleCam Electronic Speckle Pattern
Interferometer (ESPI)
4D Technology
Tucson, AZ

The SpeckleCam™ polarization-based electronic speckle pattern interferometer (ESPI) from 4D Technology was codeveloped with NASA’s Goddard Space Flight Center in Greenbelt, MD to enable precision metrology on large flight hardware for the James Webb Space Telescope (JWST).

Certain test conditions had to be met while developing the SpeckleCam. Measurement data had to be acquired quickly in a high-vibration environment on non-reflective diffuse surface structures. Meter-class structures also needed to be measured from a distance of tens of meters in a cryogenic chamber environment. To accomplish this, 4D Technology combined its pixelated phase-sensor technology with a pulsed laser. The SpeckleCam’s acquisition time of 9 nanoseconds for a single measurement met the requirements of the test conditions, rendering the system insensitive to vibration and air turbulence.

The SpeckleCam’s instantaneous phase sensor technology enables it to aid in the detection of defects in safety critical flight hardware, and to enhance the quality control of manufactured parts. “The ESPI is a critical piece of metrology equipment needed to prove our JWST telescope technology,” Lee Feinberg, JWST Optics Manager.

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