A document discusses a mechanism that uses flex-pivots in a parallelogram arrangement to provide frictionless motion with an unlimited lifetime. A voice-coil actuator drives the parallelogram over the required 5-cm travel. An optical position sensor provides feedback for a servo loop that keeps the velocity within 1 percent of expected value. Residual tip/tilt error is compensated for by a piezo actuator that drives the interferometer mirror.

This mechanism builds on previous work that targeted ground-based measurements. The main novelty aspects include cryogenic and vacuum operation, high reliability for spaceflight, compactness of the design, optical layout compatible with the needs of an imaging FTS (i.e. wide overall field-of-view), and mirror optical coatings to cover very broad wavelength range (i.e., 0.26 to 15 μm).

This work was done by Jean-Francois L. Blavier, Matthew C. Heverly, Richard W. Key, and Stanley P. Sander of Caltech for NASA’s Jet Propulsion Laboratory. NPO-47317


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Optical-Path-Difference Linear Mechanism for The Panchromatic Fourier Transform Spectrometer

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This article first appeared in the May, 2011 issue of NASA Tech Briefs Magazine.

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