Publications

Abstract not provided.

Abstract not provided.

Micro Nano Technology-Based Systems (MNT-Based Systems) are expected to provide unprecedented capabilities for aerospace applications. However we have not sufficiently addressed the reliability of such systems for a number of reasons. For example, our foundational understanding of such systems is incomplete at the basic physics level and our understanding of how individual subsystems interact is much less than we originally assumed. In addition the manner in which we operate during the product realization cycle has large implications for the ultimate reliability we can expect to achieve. Currently it is quite difficult to determine the reliability of MNT-Based Systems and is in fact borne out by a number of estimates we have seen that are unsatisfactory. We shall discuss a number of issues that at present have slowed our progress in developing NMT-Based Systems and have detened us from effectively ascertaining the true "reliability" of such systems.

Over the last decade the successful design and fabrication of complex MEMS (MicroElectroMechanical Systems), optical circuits and ASICs have been demonstrated. Packaging and integration processes have lagged behind MEMS research but are rapidly maturing. As packaging processes evolve, a new challenge presents itself, microsystem product development. Product development entails the maturation of the design and all the processes needed to successfully produce a product. Elements such as tooling design, fixtures, gages, testers, inspection, work instructions, process planning, etc., are often overlooked as MEMS engineers concentrate on design, fabrication and packaging processes. Thorough, up-front planning of product development efforts is crucial to the success of any project.

Abstract not provided.

We have designed and fabricated a system using micromachining technologies that represents the first phase of an effort to develop a miniaturized or micro trajectory safety subsystem. Two Surface Micromachined (SMM) devices have been fabricated. The first is a device, denoted the Shuttle Mechanism, that contains a suspended shuttle that has a unique code imbedded in its surface. The second is a mechanical locking mechanism, denoted a Stronglink, that uses the code imbedded in the Shuttle Mechanism for unlocking. The Stronglink is designed to block a beam of optical energy until unlocked. A Photonic Integrated Circuit (PIC) fabricated in Gallium Arsenide (GaAs) and an ASIC have been designed to read the code contained in the Shuttle Mechanism. The ASIC interprets the data read by the PIC and outputs low-level drive signals for the actuators used by the Stronglink. An off-chip circuit amplifies the drive signals. Once the Stronglink is unlocked, a laser array that is assembled beneath the device is energized and light is transmitted through an aperture.

This paper discusses the design, fabrication and testing of a surface micromachined Counter-Meshing Gears (CMG) discrimination device which functions as a mechanically coded lock, A 24 bit code is input to unlock the device. Once unlocked, the device provides a path for an energy or information signal to pass through the device. The device is designed to immediately lock up if any portion of the 24 bit code is incorrect. The motivation for the development of this device is based on occurrences referred to as High Consequence Events, A High Consequence Event is an event where an inadvertent operation of a system could result in the catastrophic loss of life, property, or damage to the environment.