Development and Microdynamics Characterization of a Deployable Petal Assembly at Full Scale

As part of its risk mitigation efforts related to large, future space-based deployable optics such as NGST, Lockheed Martin developed, implemented, and evolved a full-scale, lightweight, deployable petal structure and associated deployment mechanisms for cryogenic and microdynamic stability testing. The test-bed features a single petal assembly for an 8-meter diameter telescope, including a flight-like mirror support structure and full-size hinges and latches. The work completed on this test-bed include: 1) Characterization of the dynamics and microdynamics response of the full-scale petal and its hinge/latch interface to low-level vibration sources down to 0.1 nanometer, 2) Evaluation of petal deployment repeatability, 3) Evaluation of the performance of simple passive damping strategies for petal vibration control at cryogenic temperatures. In all respects, including microdynamics, deployment repeatability and stability, the hardware demonstrated performance well in excess of the NGST requirements. In this paper, we summarize the development and the results of the performance testing completed during the NGST Phase I formulation, including testing of hysteresis and deployment repeatability at room temperature.