The future of space development has been examined in the context of the infrastructure necessary support it. It is concluded that the selection of propulsion systems for in-orbit transportation requires the development of general computer codes capable of simulating the use of a wide range of propulsion systems on near-Earth missions. It is also concluded that, even if limited infrastructural development occurs, polar orbiting spacecraft will be an important feature of future space activities. Replacing current single-use polar spacecraft with extended-life serviceable platforms is attractive. However, the very limited manned access polar orbits in the mid-term future suggests that such platforms will only be possible if remote telerobotic/autonomous servicing can be carried out. To this extent polar platforms are considered to provide a useful driver and first testbed for the development of technologies designed to extend human capability in those regimes where direct mediation is not possible. Options for such remote servicing are examined, the concept of performing nodal transfers by enhanced differential nodal drift is introduced and the application of electric propulsion to this discussed. Low-thrust orbital manoeuvres are analyzed in this context and the conditions for optimum nodal transfer defined. Particular service vehicle configurations are then defined against a projected infrastructure and baseline polar platform constellation. A model for the service vehicle is defined and its performance investigated using a number of electric propulsion systems. Simulations of transfer manoeuvres; have been carried out and the effects and relative importance of the various orbit perturbations identified. It is concluded that a service vehicle propelled by a Xenon ion system offers the capability required and two final configurations are identified characterising different servicing mission upload schemes.

This thesis addresses visual tracking of a non-cooperative as well as a partially cooperative satellite, to enable close-range rendezvous between a servicer and a target satellite. Visual tracking and estimation of relative motion between a servicer and a target satellite are critical abilities for rendezvous and proximity operation such as repairing and deorbiting. For this purpose, Lidar has been widely employed in cooperative rendezvous and docking missions. Despite its robustness to harsh space illumination, Lidar has high weight and rotating parts and consumes more power, thus undermines the stringent requirements of a satellite design. On the other hand, inexpensive on-board cameras can provide an effective solution, working at a wide range of distances. However, conditions of space lighting are particularly challenging for image based tracking algorithms, because of the direct sunlight exposure, and due to the glossy surface of the satellite that creates strong reflection and image saturation, which leads to difficulties in tracking procedures. In order to address these difficulties, the relevant literature is examined in the fields of computer vision, and satellite rendezvous and docking. Two classes of problems are identified and relevant solutions, implemented on a standard computer are provided. Firstly, in the absence of a geometric model of the satellite, the thesis presents a robust feature-based method with prediction capability in case of insufficient features, relying on a point-wise motion model. Secondly, we employ a robust model-based hierarchical position localization method to handle change of image features along a range of distances, and localize an attitude-controlled (partially cooperative) satellite. Moreover, the thesis presents a pose tracking method addressing ambiguities in edge-matching, and a pose detection algorithm based on appearance model learning. For the validation of the methods, real camera images and ground truth data, generated with a laboratory tet bed similar to space conditions are used. The experimental results indicate that camera based methods provide robust and accurate tracking for the approach of malfunctioning satellites in spite of the difficulties associated with specularities and direct sunlight. Also exceptional lighting conditions associated to the sun angle are discussed, aimed at achieving fully reliable localization system in a certain mission.