The thesis 'The dynamics of tethers and space-webs' investigates the motion of the Motorized Momentum Exchange Tether (MMET) on an inclined orbit, and while deploying and retracting symmetric payloads. The MMET system is used as a basis for examining the stability of space-webs using a triangular structure of tethers while rotating. The motion of small robots is introduced as they move on the space-web, and their motions are found to influence the behaviour of the structure. Several methods of limiting the destabilising influences of the robots are considered, and are found to stabilise the web in most circumstances. A structured method for describing the rotations of a tether system is outlined, and different rotational systems are compared. This lays the foundation for the further chapters examining MMET dynamics on an inclined orbit and while deploying and recovering the payloads. Lagrange's equations are generated for the three cases, and are solved using standard numerical integration techniques. To emphasise the practical uses of the MMET system, several missions are analysed by using the system as a re-usable launcher for micro-satellite payloads.