On-board Payload Data Processing Systems

At the turn of this century, satellites which have demonstrated the feasibility of many space applications, enter in a new era. Today they have an additional mandate: they must provide a well-identified service to Users and/or to Customers. This is applicable not only to Telecommunication but also to Earth observation missions. Data products or derived information must be elaborated rapidly in order to either authorise a near real time direct dissemination of data to Users or to generate alarms (e.g. for forest fire detection). Furthermore, the amount of data produced by instruments exceeds the downlink capability, leading to the need of implementing a selection or a compression mechanism onboard. On the same line, for observatory type of science missions, on board autonomy can bring significant advantages. With respect to the points outlined here above, on-board Payload Data Processing Systems can provide a suitable solution and the necessary autonomy or intelligence. This paper focuses on Payload Data Processing Systems and in particular on their implementation based on On-board networks. Taking into account that space applications have specific requirements, no commercially available networking infrastructure could be directly used for on-board applications. Therefore, SpaceWire links, Networks and tools have been standardised and adapted to space use. This paper presents their characteristics, related devices and tools developments and new opportunities offered by their intrinsic flexibility.