Feature-Based Assessment of Passive Spacecraft Dynamics During Removal Missions

One of the key functionalities required in a mission for removing a noncooperative spacecraft is the assessment of its kinematics and inertial properties. In a few cases, this information can be approximated by ground observations. However, a reassessment after the rendezvous phase is of critical importance for refining the capture strategies. This paper proposes a set of measurement methods to estimate the location of the center of mass, the angular rate, and the moments of inertia of a passive object. These methods require the chaser spacecraft to be capable of tracking a few known features of the target through passive vision sensors. They can be applied considering a chaser spacecraft flying close to the target for a time long enough to complete the measurement. Because of the harsh lighting conditions of the space environment, feature-based methods should tolerate temporary failure in detecting features. The principal works on this topic do not consider this important aspect, making it a distinctive element of the proposed methods. The proposed techniques do not depend solely on state observers. However, methods for recovering missing information, like compressive sampling techniques, are used for preprocessing input data to support the efficient usage of state observers. Simulation results showed accuracy properties that are comparable to those of experimentally tested methods already proposed in the literature