A processor transparent and cost effective on-board computer concept

This paper describes an on-going project with the aim to provide a cost-effective on-board computer concept, primarily intended for small satellite instrument payloads, using free and open source software elements, including the GNU C-compiler and the RTEMS Real Time Operating System. The project demonstrates the concept on two different processor architectures, the Thor processor from Saab Ericsson Space and the PowerPC 750 processor. Several demonstration applications are developed within the project, to provide immediate use of the support software, and to prove that the concept is viable. The paper starts with a description of the background, delineating the project framework and the reasons behind it. Then the different software developers are defined. A discussion on the advantages of open software follows. The project application domain is described, followed by a discussion of the microprocessors and software selected. The demonstration applications used are defined. Finally, a summary ends the paper.