Picometer-scale edge sensing and actuation for ultra-stable mission concepts

The 2020 decadal survey presents a clear message of the grand astronomy goals of the next decade and beyond, and of the urgent need for technology maturation that will enable the next flagship observatory to observe potentially habitable exoplanets. For a segmented implementation of a large ultra-stable telescope, low TRL areas such as segment sensing and control at the picometer scale have been identified as critical areas for significant technological improvements to accomplish the survey's grand goals. We present exciting results on picometer scale sensing and actuation in certain temporal and spatial bandwidths as key advances towards addressing this technology gap. We have designed and demonstrated a capacitive testbed for informing different edge sensing architectures, and qualified our novel ultra-fine stage actuator using an optical distance measuring interferometer. We have also integrated the capacitive sensor and our ultra-fine stage actuator for an integrated demo with few picometer noise floor, sensing and actuator resolution. These key results will roll into the design of subscale demonstrations of these components in a future flight-like layout.