The rapid growth of the satellites in Earth orbit and the prospect of increasingly dense constellations, is reshaping the operational landscape of spaceflight. In this environment, ground-intensive approaches to fleet operations, inspection, and anomaly response become progressively less scalable. This trend motivates au- tonomous rendezvous and proximity operations as enabling technologies for routine inspection and servicing, as well as for safer and more efficient operations in space missions. At the same time, it imposes stricter requirements on onboard guidance: algorithms must be robust, constraint-aware, and computationally efficient to support repeatable operations with limited human intervention. Autonomy, however, cannot be assessed solely through nominal simulation per- formance.