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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Systems-of-Systems (SoS) often support critical domains. They must be trustworthy, i.e., they must keep their operation in progress, being not subject to failures, as they can cause potential damages and hazards to human integrity. Simulations are a recurrent approach in SoS development, as they can anticipate potential failures, consequently increasing the level of trustworthiness and quality exhibited by a SoS. Nevertheless, simulation is still software and demands engineering. Moreover, many simulation formalisms are not trivial of specifying, sometimes tangling software an hardware details to program an executable simulation. Thus, the aim of this paper is contributing for software engineering of SoS by externalizing two patterns for the conception of SoS simulations. We evaluated our patterns by applying them in a case study in two different domains. For both, patterns were successfully applied during automatic generation of functional code, supporting the execution of SoS simulations and prediction of SoS behavior at design-time.

Research of automatic solutions for space operations is a real need for all space agencies in order to reduce space mission costs. Nowadays, a significant parcel of satellite operation activities at the National Institute for Space Research (INPE) is still performed manually. Thus, finding automated alternatives for the satellite operation activities at INPE is of capital importance, in order to maintain the currently satisfactory performance of these activities, despite the scarcity of financial resources. This paper proposes the architecture of an Intelligent Planning System for the automatic generation of satellite flight operation plans (PlanIPOV). The proposed system employs temporal planning techniques of artificial intelligence (IA) in the automatic flight operation plans (FOP) generation for a satellite routine operational phase, with the aim of opening the way toward a higher degree of automation for satellite operation activities of INPE. The main reason for the application of the planning system in the routine operational phase of the satellite lifespan is that this phase is composed of very repetitive and well defined tasks which have lower programming costs. In addition, this phase is the longest comprising practically the entire lifespan of the satellite. The PlanIPOV system uses the Planning Domain Definition Language (PDDL2.2) to model the knowledge base of INPE satellite operations. It is based on the automatic generation of problem files, i.e., the initial state of the satellite control environment and the goal to be reached by executing the generated FOP timeline. The system uses information extracted from the following files: tracking knowledge domain; prediction of future satellite passes of the involved ground stations; and configuration parameters of the satellites and the ground stations. This paper also presents a prototype of the proposed planning system. This prototype was implemented using the PDDL2.2 language and LPG-TD planner (Local Search for Planning Graphs -Time Initial Literal and Derived Predicates). It was tested for the tracking domain of the satellites currently being controlled by INPE (SCD1, SCD2 and CBERS2). These results are presented along with the limitations that have been observed in the planning technique application. The solutions adopted to overcome these limitations are outlined. The obtained results may be considered satisfactory.

 This paper provides a case study of a real aeronautical safety-critical software development project under the DO-178C processes, where the COCOMO II method was applied as an estimation technique for the required software development effort. The main goal and contribution of the case study is to support the research on software effort estimation and provide software practitioners with useful data based on a real project. We collected the actual required effort for the project and then compared to the estimated values. The rationales for each scale factor and effort multiplier selection were also described in details. We found a Magnitude of Relative Error (MRE) of 31% and provided alternatives for future work in order to increase the effort estimation accuracy in safety critical software projects.

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