= RTEMS Centre = As of 2010, the RTEMS Centre is inactive. On-board software applications are becoming a more and more important contributor to the overall cost of the on-board space systems. This is a consequence of the increasingly complex tasks assigned to software applications and the implicit risks associated to them. The ever-developing software technologies, engineering standards, methods, tools and techniques outside the space community could certainly allow the production of better and lower cost space software. However, effort needs to be put on the study of these technologies and on the learning of how they can be used with advantage on the engineering of on-board systems. One of these areas concerns compilers and run-time systems. In this particular case, we consider only the real-time operating systems. Clearly, these form an important building block of an on-board embedded system, because of the strict requirements in terms of real-time execution, dependability, reliability and availability. Until recently, the solution adopted for the RTOS has been to use a commercial and proprietary one. Because the space community is comparatively small, the maintenance and support to proprietary RTOSs for use on board satellites constitutes a recurring cost to ESA, its contractors and community in general. The use of open source software, and specially, an open source RTOS, is a possibility to reduce overall costs or at least the initial technology access cost barrier. Open source solutions are being slowly introduced. In addition to the cost reduction, the use of open source software ensures long-term maintenance and independence from the market (in the worst case the source code is available) and allows the space community to benefit from the developments within the overall user's community. The RTOSs dependency has been identified by ESA (On-Board Software Harmonisation meeting, March 2003) as one of the two areas where dependency is greater, being the other the control algorithm modelling tools. Hence, developing competences and implementing the processes for offering support and maintenance in one specific open source RTOS within the ESA members brings important advantages from two points of view: (1) a sustainable use of open sources as RTOS building block for on-board space systems and improving the overall cost-effectiveness of the Agency; (2) the reduction of the technological dependence from the proprietary tools vendors. [http://rtemscentre.edisoft.pt RTEMS Centre] is a project under the European Space Agency - Portugal Task Force aiming to develop a support and maintenance centre for the RTEMS operating system. The project objectives can be summarized in two main streams, first one related to design, development, maintenance and integration of tools to augment and sustain RTEMS operating system and second stream linked to the creation and maintenance of technical competences and support site to RTEMS operating system in Europe, special interest would be for the cost minimization of incorporation/integration of airborne and space applications in this RTOS. RTEMS/Support tools are envisaged to be covered by this project, timeline tools for analysing application time utilisation, OS management/visualisation tools for configuration and resources status visualization (e.g., stack checking, RTEMS managers status, CPU allocation, etc), maintenance of flight board supported packages (TBC) and maintenance of flight c-libs (TBC). Considerations on ARINC 653, DO-178B and ECSS E-40 for the RTEMS OS could be provided to RTEMS community. The development of a RTEMS complementary support platform (website) to make public the technical know-how and developments produced in this project. Website intends to include mailing lists for technical support, user forums for extended/dedicated technical support and debate of ideas, FAQs for the frequently asked questions, software repository for the software produced within this project, bug reporting tools and links for the RTEMS community websites.