Inspection of Space Rider with a 12U CubeSat: Ensuring Safety and Efficiency

With the advance of technology development, CubeSats potential is increasing steadily. Within this scenario, the Space Rider Observer Cube (SROC), a 12U CubeSat, that is being developed to carry out several in-orbit proximity operations, including an inspection, around Space Rider. The observation phase is carried out using the Walking Safety Ellipse (WSE) described in this paper. This particular trajectory is characterized by an out-of-plane elliptic periodic relative path around the target spacecraft, characterized by a high degree of safety thanks to the out-of-plane component. The desired trajectory is achieved using two different impulses, the first one is part of the Out-of-Plane Approach (OPA) manoeuvre that brings the chaser spacecraft from a waiting point, called Hold Point, to the WSE insertion point, where the second impulse takes place, starting the actual inspection phase. Given the number and variability of parameters in the WSE design, an iterative method based on several nested cycle has been selected. The process analyses different WSE iterating the Hold Point duration, the WSE starting position and the OPA duration. The geometry of the WSE starts from a predefined one, based on relative orbital parameters, such as the relative inclination, eccentricity and argument of perigee, calculated or given as an input. These values are then modified during the run of the simulation to guarantee the satisfaction of the several constraints. The output of the analysis is the desired WSE which, in this case, lasts 3 hours satisfying the observation constraints for approximately 0.75 hours.