Abstract. This paper presents an analysis of the unit testing approach developed and used by the Core Flight Software (CFS) product line team at the NASA GSFC. The goal of the analysis is to understand, review, and reconunend strategies for improving the existing unit testing infrastructure as well as to capture lessons learned and best practices that can be used by other product line teatns for their unit testing. The CFS unit testing framework is designed and implemented as a set of variation points, and thus testing support is built into the product line architecture. The analysis found that the CFS unit testing approach has many practical and good solutions that are worth considering when deciding how to design the testing architecture for a product line, which are documented in this paper along with some suggested innprovennents.

This paper presents an analysis of the unit testing approach developed and used by the Core Flight Software System (CFS) product line team at the NASA Goddard Space Flight Center (GSFC). The goal of the analysis is to understand, review, and recommend strategies for improving the CFS' existing unit testing infrastructure as well as to capture lessons learned and best practices that can be used by other software product line (SPL) teams for their unit testing. The results of the analysis show that the core and application modules of the CFS are unit tested in isolation using a stub framework developed by the CFS team. The application developers can unit test their code without waiting for the core modules to be completed, and vice versa. The analysis found that this unit testing approach incorporates many practical and useful solutions such as allowing for unit testing without requiring hardware and special OS features in-the-loop by defining stub implementations of dependent modules. These solutions are worth considering when deciding how to design the testing architecture for a SPL

In January 2015 the NASA Goddard Space Flight Center (GSFC) released the core Flight System (cFS) as open source under the National Aeronautics and Space Administration (NASA) Open Source Agreement (NOSA) license. The cFS is based on flight software (FSW) developed for 12 spacecraft spanning nearly two decades of effort and it can provide about a third of the FSW functionality for a lowearth orbiting scientific spacecraft. The cFS is a FSW framework that is portable, configurable, and extendable using a product line deployment model. However, the components are maintained separately so the user must configure, integrate, and deploy them as a cohesive functional system. This can be very challenging especially for organizations such as universities with minimal FSW development experience that are building CubeSats. This paper describes the OpenSatKit [2] that was developed to address the cFS deployment challenges and to serve as a cFS training platform for new users.OpenSatKit provides a fully functional out-of-the box software system that includes NASA's cFS, Ball Aerospace's command and control system COSMOS, and a NASA dynamic simulator called 42. The kit is freely available since all of the components have been released as open source. The kit runs on a Linux platform, includes eight cFS applications, several kit-specific applications, and built in demos illustrating how to use key application features. It also includes the software necessary to port the cFS to a Raspberry Pi and instructions for configuring COSMOS to communicate with the target. All of the demos and test scripts can be rerun unchanged with the cFS running on the Raspberry Pi.OpenSatKit can serve two significant architectural roles that will further help the adoption of the cFS and help create a community of users that can share assets. First, the kit is being enhanced to automate the integration of applications with the goal of creating a virtual cFS 'App Store'. Second, a platform certification test suite can be developed that would allow users to verify the port of the cFS to a new platform. This paper will describe the current state of these efforts and future plans.

No abstract

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.