High-Level Strategies for the Rapid Development of an AOCS Simulator for a Student-Designed CubeSat Mission

This work presents the strategies adopted and lessons learned during the development of an Attitude and Orbit Control System (AOCS) simulator for a CubeSat mission designed by students. The case study focuses on the ELECTRA mission, developed by the CubeSat Team PoliTo, and selected for the "ESA Fly Your Satellite! Design Booster 2" programme. The AOCS development, specifically, brought together a sub-team of students with heterogeneous academic backgrounds and different levels of education. Working collaboratively, the team designed and implemented an AOCS simulation tool with a hierarchical architecture to support system design and validation. The simulator was implemented leveraging Simulink's integration capabilities alongside Matlab functions and toolboxes, with support for code generation aimed at onboard rapid prototyping. A top-down design approach was adopted to decompose the system into its main components, with algorithms, sensors, actuators, and plant blocks at the higher level. This resulted in a multi-layered simulation architecture, where upper layers manage mission-level inputs and outputs, while lower layers manage navigation and control algorithms, system and hardware characteristics, and attitude and orbital dynamics. This modular structure enhances scalability, facilitates debugging, and improves system awareness, while also enabling efficient task allocation according to the students' expertise. To accelerate development in a student-driven environment, several simplifications were introduced, such as the use of pre-built functions and simplified models. The high-level input-output structure allows for rapid performance benchmarking against validated external tools, notably System Tool Kit, supporting verification and validation process. The initial version of the simulator was completed within approximately six months in a volunteer-based student environment. Extensive algorithm testing has been conducted, integrating all blocks and verifying compliance with mission objectives and requirements. Future developments will focus on extending the simulator toward hardware-in-the-loop testing and onboard software integration, thereby establishing a reusable framework for educational and research applications in small satellite design.