Embedded Software Development for Langmuir Probe onboard the ROMEO Satellite

The study of space plasma environments requires advanced and reliable instrumentation, particularly for in-situ measurements in harsh conditions. One such instrument is the Langmuir Probe, used to characterize electron densities and temperatures in space. This thesis addresses the development of a robust onboard software system for the Langmuir Probe instrument on the ROMEO satellite, a medium Earth orbit (MEO) mission developed by the University of Stuttgart.

The main problem tackled in this work is the design and implementation of a flexible, fault-tolerant software architecture that can operate reliably in space, manage complex measurement modes, support in-flight software updates, and comply with stringent space communication standards such as the ECSS and CCSDS protocols. Developing such a system for a scientific payload operating in a radiation-prone and resource-constrained environment presents significant technical challenges and is highly relevant for future low-cost, modular space missions. 

To address this, the system was developed in two phases. In the first phase, a complete software stack was implemented and tested on a commercial System-on-Chip (SoC) platform featuring an ARM Cortex-M7 microcontroller and a ProASIC3 FPGA, serving as a practical testbed for validating system performance under realistic conditions, as well as a COTS reference design to be tested in orbit. The second phase involved porting the system to a space-grade FPGA from NanoXplore, integrating a LEON3 softcore processor within the FPGA fabric to meet radiation tolerance requirements.

The results support the viability of a modular, RTOS-based software architecture combined with resilient in-flight update strategies (using watchdogs and restart mechanisms) and validated data-handling modules, for satisfying requirements and maintain system integrity under radiation-induced disruptions.