Delfi-PQ: In-Orbit Performance and Lessons Learned in Developing a 3P PocketQube

Abstract

Delfi-PQ is a pioneering 3P PocketQube developed at Delft University of Technology, measuring 50x50x178 mm and weighing 545 g. Launched on January 13th 2022, it remained operational until its deorbit in January 2024, demonstrating nearly two years of sustained in-orbit functionality. Its architecture features a standardized core that supports reusable hardware and software across multiple subsystems, while an innovative structural design maximizes the limited internal volume. This paper presents results in orbit, the lesson learnt and a detailed hardware development cost analysis of a 3P PocketQube. Cost containment was a central mission objective. Using commercial off-the-shelf components, modular subsystem design, and iterative manufacturing, the Delfi-PQ team maintained tight budget control. Multiple hardware revisions allowed lessons learnt at each stage to be quickly integrated back into the design cycle. A detailed cost breakdown shows that a standardized core can substantially reduce non-recurring engineering expenses, making advanced pico-satellite development feasible within academic constraints. During its mission, Delfi-PQ encountered substantial thermal swings (up to 75◦C), yet consistently maintained full functionality. Although some limitations in battery protection arose from specific design choices, the paper documents which components performed reliably in space and how others deteriorated over time, offering critical guidance for future teams. In addition, the inclusion of a laser reflector payload designed to enhance tracking accuracy| and the structural innovations required to optimize space usage are discussed. A global network of amateur radio operators, together with the ground station in Delft, regularly received telemetry throughout the mission. This support was vital for tracking spacecraft health, investigating anomalies, and refining subsystem performance: the extended reliability of Delfi-PQ underscores the value of cost-conscious engineering, modular architectures, and strategic community partnerships to extend the service life of the mission. In summary, Delfi-PQ demonstrates that a lean yet robust satellite design based on modular principles, iterative development, and close collaboration| can reliably operate over extended mission durations. By presenting a full cost breakdown and comprehensive mission results, this paper offers practical insights for institutions aiming to deploy similarly innovative, affordable PocketQubes for advanced research and education.