SatNOGS-COMMS is an open-source, open-hardware communications subsystem for CubeSats, developed by the Libre Space Foundation in collaboration with the European Space Agency (ESA). This innovative system combines advanced hardware and software to meet the challenges of CubeSat missions while promoting accessibility and flexibility through an open ecosystem.

The subsystem features an STM32H743 microcontroller as its main processor, complemented by a ZYNQ-7020 FPGA accelerator for computationally intensive tasks. SATNOGS-COMMS is built on Zephyr RTOS, with the firmware written entirely in C++17. Notably, its hardware control interfaces follow a platform-agnostic architecture, enabling users to adapt the firmware to their preferred RTOS with minimal effort.

This presentation will delve into the software engineering decisions, challenges encountered, and the advantages of an open-source approach for CubeSat missions and space exploration. Key topics include: * The benefits of using C++ in embedded systems, particularly in the context of resource constraints. * How the use of exceptions improves firmware safety and reliability. * Fault-tolerant mechanisms designed to ensure reliable operation in the harsh environment of space. Additionally, we will highlight our approach to enabling user-defined code integration without modifying the original codebase, comparing it with other commercial and non-commercial solutions.

The complete project, including hardware designs, software, simulations, and documentation, is freely available at the project’s GitLab repository: https://gitlab.com/librespacefoundation/satnogs-comms.