Distributed space systems is an academic concept and research field dedicated to the design, coordination, and management of multiple, interconnected spacecraft operating collaboratively as a unified entity. It investigates architectures, algorithms, and methodologies for distributing tasks, resources, and decision-making across a collection of spacecraft functioning synergistically to achieve mission objectives. This approach is significant for enabling new mission capabilities, enhancing resilience, scalability, and adaptability for scientific research, exploration, and various space applications by treating the ensemble as a single, integrated system.