Satellite real-time systems impose constraints on execution memory, processing power and storage space, among others. These constraints and the concern in reducing code complexity have led the Brazilian National Institute for Space Research (INPE, in the Portuguese acronym) to use low-level languages and structured programming to build custom onboard software developed from scratch for each new mission. But this is a costly and laborious approach. To improve maintainability, portability and reusability of onboard software and hence reduce development costs, INPE's Onboard Data Handling Group (SUBORD) is working on an object-oriented onboard software architecture. But object orientation (OO), by itself, does not guarantee the software reuse across missions. In order to improve reusability, SUBORD has been following as reference the ECSS Packet Utilization Standard (PUS), which describes a set of onboard services common to different missions, defined based on previous experience of many space agencies. This paper describes the lessons learned with this architecture, the benefits of using open source off-the-shelf real time operating system and development tools, the studies made concerning the applicability of OO to onboard satellite systems and our implementation of PUS services.

Nanosatellite missions are becoming increasingly popular nowadays, especially because of their reduced cost. Therefore, many organizations are entering the space sector due to the paradigm shift caused by nanosatellites. Despite the reduced size of these spacecrafts, their Flight Software (FSW) complexity is not proportional to the satellite volume, thus creating a great barrier for the entrance of new players on the nanosatellite market. On the other side, there are some available frameworks that can provide mature FSW design approaches, implying in considerable reduction in software project timeframe and cost. This paper presents a comparative survey between six relevant flight software frameworks, compared according to commonly required ‘New Space’ criteria, and finally points out the most suitable one to the VCUB1 reference nanosatellite mission.

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This paper presents the first efforts made at the Brazilian National Institute for Space Research (INPE) to increase the autonomy of its satellites through the adoption of model-based reasoning on the flight software.A prototype for an on-board, goal-oriented replanning system was developed. With the lessons learned from this prototype, we are implementing an on-board service that provides states inference, which can be used as an autonomy kernel by autonomous applications.But instead of creating one more brand new, one-of-a-kind system, we are trying to make this service fit into the European Committee for Space Standardization (ECSS) standards, which have been adopted by INPE. ECSS has not only defined an autonomy concept for space missions, but has also divided it in categories and levels.We identified a gap between two of the last autonomy levels, and propose a new intermediate level to fill it. Our Internal State Inference Service (ISIS) implements this new level.

The experiments aboard the Brazilian scientific satellites are currently thought to execute in a repetitive way, collecting, storing and sending data in a cycle that does not suffer great alterations. There are, however, scientific events of randomic occurrence which demand a fast reconfiguration in the system to collect and process the data adequately. Due to the short duration of these events and the great number of states in which a system can be at the moment of the detection, the use of classical programming techniques or the ground team intervention has shown to be inefficient, and the opportunity to analyse the event is lost. RASSO, a Resources Allocation Service for Scientific Opportunities, makes use of Artificial IntelligencePlanning & Scheduling techniques to modify onboard the current plan of operations and allows an experiment to use more computational resources when a scientific event occurs, thus improving the scientific return. This paper describes RASSO, and the safe and gradual approach foreseen to implement this replanning aboard satellites.