Robotics operations from small spaceplanes for CubeSats servicing

Worldwide successful effort in CubeSat programs promoted these platforms for educational purposes and widely spread scientific measurements of the LEO environment. The miniaturization trend will support the improvement of CubeSats’ capabilities, and will suggest the opportunity – as already attained in case of larger spacecraft - to have in orbit servicing for these smaller platforms. This paper intends to focus on the robotics related to these in-orbit servicing operations, that strongly differ from larger-scale, Canadarm-like operations typical of the Space Shuttle or ISS. The relative velocity associated with an orbital rendezvous, as well as the performance of the joint motors, do not scale together with the dimensions, so that collision risks and maneuvering should be carefully assessed differently with respect to “standard” space proximity operations. To this aim, the paper presents extensive simulations of the capture phase. The reference to a specific, even if experimental design for the spaceplane allows to understand the special requirements for the system’s mechanics, and to extract issues and considerations that apply in general to all servicing operations involving small orbiting platforms. A major result from the analysis is that the capture manoeuvre does not affect in a significant way the attitude of the chaser, so that relevant hardware should not be considered a design driver for the mission. Furthermore, the range of values for the torques required from the motors are computed, providing useful indication for the actual design of the robotic arm.