Concurrent design of miniaturised spacecraft: tools for supporting the system definition and sizing

This work is framed within the Systems Engineering domain, and in particular in the area of approaches and methodologies for the early design stages of space systems and missions. This thesis aims at defining a set of tools for enabling the design and sizing of space missions developed by nanosatellites. The tools will support the design from phase 0 through phase B of the life cycle, making use of the MBSE (Model Based System Engineering) and Concurrent Design approaches. The Model-Based Systems Engineering (MBSE) is an approach currently used in the industry to improve the efficiency and effectiveness of the design and development process. The implementation of MBSE in the Concurrent Design concept allows to have a rapid and efficient development of conceptual design. To understand what potential benefits or challenges could arise from this approach, it was first necessary to review the current state of the art. While several facilities, mainly located at space agencies and large companies, already exist for supporting the early design of “traditional” space missions, very few examples are available for small missions and systems. The idea at the basis of the present work is to develop some tools useful for the implementation of the concurrent design approach to small-scale missions and systems. In particular, two main elements have been developed: • A database of CubeSat-like technology. Data on CubeSat components were grouped together in a single Excel® document, some coming from the literature, others from ESA’s and NASA’s State-of-the-Art, and other data already available in the research team from past projects • A set of spreadsheets to carry out the conceptual to preliminary sizing of the system and subsystems. The spreadsheets guide the designer through the development of the design solution and allow the generation of various systems budget, such as Power Budget, Energy Budget, Mass budget and Link budget of the satellite to be sized. The tools were validated through application in the SPEISAT (Spei Satelles) project, a telecommunications mission with two main objectives: •The primary mission is to bring into orbit a "Nanobook", a miniaturized chip encoded in binary code that contains a message of hope by Pope Francis, first shared on March 27, 2020 during the COVID pandemic and known as Statio Orbis. •The secondary mission is to collect data to characterize the behaviour of the spacecraft and of the space environment, using a sensing suite equipped with an inertial measurement unit, magnetometers and temperature sensors. The developed tools are compliant with respect to the ESA’s Concurrent Design Facility (CDF), and they could be integrated within it without major modification. Most important, these tools are part of the upgrade of the CubeSat Concurrent Engineering System (CES), a design facility that is used at PoliTO for supporting both research and educational activities.