“…Nevertheless, with ever advancing computational hardware, and active research into more efficient algorithms, online optimisation has become less of a barrier to application, and there has recently been significant activity in exploiting both the ability to handle constraints and time-varying systems, whilst optimising a given performance metric in the context of spacecraft rendezvous. Examples of how MPC has been employed include: accommodating limited input authority (thrust constraints) [14]- [26]; using non-quadratic cost functions to achieve particular types of behaviour, for example sparse control actions [14], [15], [17], [20], [23], [24], [27]; enforcing line-of-sight constraints [15], [16], [18], [19], [21], [22], [26]; enforcing soft-docking constraints (the approach velocity reduces in line with with distance to the target) [18], [21]; collision avoidance (with the target and obstacles) [14], [16]- [18], [21], [26]; fault-tolerance by constraining open-loop unforced trajectories to achieve passive safety [16], [28]; accommodating time-varying prediction dynamics (such as those describing relative motion in elliptical orbits) [17], [27], [29], [30]; accommodating time-varying objectives and constraints (such as docking with a tumbling or rotating target) [18], [21]; fuel-efficient station or formation keeping [31], [32] and handling interaction between attitude and translation control [17], [22].…”