Dynamic Testing and Automatic Repair of Reconfigurable Wiring Harnesses

摘要

In order to be viable, spacecraft must mass relatively little, while being capable of surviving the G-forces and vibration of launch. In space, they must withstand extreme temperatures, hard vacuum and high levels of radiation for years without maintenance. Conventionally, spacecraft wiring harnesses are built with architectures that are fixed at the time of manufacture. They must therefore be designed to endure the lifetime of the mission. Reducing the mass of a spacecraft's wiring harness, without compromising reliability, is highly desirable. Recent advances in MEMS-based switching have made it possible to consider the construction of reconfigurable manifolds - essentially, wiring harnesses that behave like macroscopic FPGA routing networks. Redundant wiring can be shared between many signals, thereby significantly reducing the total amount of cable required. Reconfigurability has a significant further benefit, in that it also allows adaptation to mission requirements that change over time, while also significantly reducing design time. The US Air Force has been moving toward a responsive space paradigm which aims to reduce the time from design concept to launch (currently several years) to less than one week; a parts-bin driven, plug-and-play approach to satellite construction will become essential. It must be possible to choose a satellite chassis of a size appropriate to the task, then bolt everything together and have the resulting satellite just work. We present an approach that allows such a reconfigurable manifold to be automatically self-configured, then dynamically tested in-situ, such that signals are automatically rerouted around non-functioning wires and switches as soon as faults are detected. Make-before-break switching is used in order to allow wires to that are currently in use to be rerouted transparently from the point of view of subsystems that are interconnected by the manifold, whilst also making it possible to achieve near-100% testability.