For a rotorcraft lander sampling system, ALTEN Technology delivered comprehensive avionics hardware and software development across the aerospace and robotics domains. The team worked in an Agile model with Jira kanban tracking and NPR 7150.2D Class C compliance, collaborating with the client through weekly sub-team meetings spanning hardware, software, FPGA, QA, electrical, and mechanical disciplines. ALTEN developed a complete flight software architecture built on a custom publish and subscribe design with a CCSDS packet interface, UML-based module design, a custom Interface Transfer Frame, and DevOps automation for builds, testing, and code generation, with rigorous verification through unit testing, system verification, and performance analysis. Key results included six PCBs taken from design through testing with EEE-INST-002 radiation-hardened components, a flight software framework of 24 modules paired with a digital twin simulator, a lander simulation in OpenC3 COSMOS for commands, communications, and telemetry, and reliability features such as EDAC memory scrubbing, I/O CRC, and a journaled filesystem, all delivered with comprehensive documentation for client handoff. The team drew upon Quality Assurance, Electrical, Systems, and Software Engineering and Project Management, leveraging Altium Designer, a LEON3FT processor, Python, Ruby, C, RTEMS OS, and CCSDS, with TSIM, GRMON, GitLab CI/CD, and OpenC3 COSMOS for testing.