Meeting the long term needs of the remote sensing community requires the development of large aperture space-based optical systems to achieve dramatic improvements in resolution and sensitivity. It is possible that ultralarge apertures will be obtained using deployable thin film mirror technology, yet many technological barriers must be overcome to make this approach viable. This paper summarizes an initial research effort into the development of piezoelectric thin film mirrors that can be actively shaped using electric fields applied by an electron flux at selected locations. Recent progress is described in the key areas of mirror figure sensing methods, electron gun excitation, and shape control algorithm development.

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We investigate the reliability of a rechargeable battery acting as the energy storage component in a photovoltaic power supply system. A model system was constructed for this that includes the solar resource, the photovoltaic power supply system, the rechargeable battery and a load. The solar resource and the system load are modeled as siochastic processes. The photovoltaic system and the rechargeable battery are modeled deterministically, and an artificial neural network is incorporated into the model of the rechargeable battery to simulate dariage that occurs during deep discharge cycles. The equations governing system behavior are solved simultaneously in the Monte Carlo framework and a frrst passage problem is solved to assess system reli,ibility.

This paper summarizes the development and testing of an actively damped boring bar for mitigation of selfexcited chatter vibrations. PZT stack actuators are integrated into a commercially available bar to provide vibration suppression both normal and tangential to the workpiece surface. Biaxial control is proven essential to obtaining good performance over the normal range of tool mounting variability. Cutting tests performed at various speeds and depths of cut on a hardened steel workpiece illustrate the bar's effectiveness toward eliminating chatter vibrations.

An actuation technique suitable for controlling bending vibrations in thick beams and plates is described. This work is motivated by vibration problems encountered in manufacturing that require greater control authority than can be obtained using surface mounted PZT patches or PVDF films. Instead, PZT stack actuators mounted in material cutouts are used to induce bending moments in the host structure. Experimental results are provided for the case of a cantilevered bar and a lithography platen used in the manufacture of integrated circuits. Good coupling between the extensional motion of the actuators and the bending deformation of the host structures is illustrated, and significant increases in first mode damping are achieved in both examples using a positive position feedback compensator.