SUMMARYAerospace remote-sensing payloads are continuing to advance to higher speeds and increasing the demands of on-board intra-satellite networks. These payloads include synchronous continuous mode and asynchronous event-driven sensor data requiring real-time transfer with deterministic latency to capture sensor data. The networked satellite payloads include combinations of: uplinks, downlinks, sensors, processors, formatters, storage devices (recorders), and payload controller. Advanced systems planned for development in the next few years require data rates of 1-10 Gbps. An effective aerospace data-handling network must supply real-time data that is fault tolerant and able to withstand the rigorous conditions of launch as well as the harsh space environment. The IEEE1393-1999 Standard for spaceborne fibre-optic data bus (SFODB) has established the design requirements for the interconnection of these on-board aerospace subsystems. Programs involving NASA Goddard Space Flight Center, the Air Force Research Laboratories, Space Photonics Incorporated, the University of Arkansas, and others, are in the process of developing components necessary for the implementation of the SFODB. SFODB utilizes fibre-optic components for subsystem interconnect and eliminates cable-to-cable and box-to-box EMI, significant reductions in size, weight, and power are among the achievable characteristics that are desirable for aerospace applications. This paper discusses SFODB characteristics and the status of implementation programs.
Spectral and radiometric requirements of optical filters for space applications are always more demanding. Multispectral bandpass filters require very steep edges, a high accuracy in the central wavelength position, a high average transmittance as well as a very good level of blocking outside of the bandpass region.Realization of such filters implies to design the layer stacks in a way that reduces sensitivity to the production deviations and to be able to properly control the coating conditions in the machine.In order to optimize the design, a pre-production error analysis can be performed, to assess the weight of each layer in the global filter properties and therefore modify the design until a good stability level is achieved. We discuss different insitu optical monitoring strategies and process conditions depending on the coating technology. The realization phase needs a precise control of the coating machine such as well-characterized deposited materials, stable deposition rates, a reliable layer thickness monitoring system in addition to a good coating uniformity over all the coating positions inside the machine.We present design strategies and means of pre-production error analysis for typical multispectral bandpass specifications as well as transmittance curves.
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