In-air capturing is a promising concept for recovering winged reusable launch vehicles (RLVs) using a towing aircraft (TA), without the need for any propulsion on board the RLV during descent. In this paper, the preliminary electromechanical design of an airborne device is presented, which is central to in-air capturing. The device is an autonomous system, towed by the TA, and docks with a boom attached to the nose of the RLV. A design space exploration and load analysis are performed using a simplified towing model, revealing significantly higher towing loads compared to previous estimates. The design of a probe-drogue docking mechanism is proposed, which uses a set of actuated wedges to lock the RLV boom in place. Actuator and sensor solutions are studied, aiming at a redundant and robust mechanism design. Based on reference commercial-off-the-shelf components, the size, weight, and power footprints of essential avionics are estimated, and a preliminary dimensioning of the required battery system is performed. Finally, a comprehensive, electromechanical computer-aided design model is developed, with which the overall inertial properties of the vehicle are estimated. The position of its centre of gravity is studied, revealing the need for a forward trim mass. Compared to previous design studies, the estimated total mass is increased to 175.44 kg, while the design’s overall safety factor grows to 1.51.

The space environment is ever-changing with the space structures getting larger and the orbits getting increasingly crowded with time. This creates a need for removal of large de-funct satellites to avoid the disastrous Kessler syndrome, which poses a major threat to the future of space exploration. This paper examines the dynamics and control involved in the active removal of a large space debris-Envisat. European Space Agency’s e.deorbit mission aims to de-orbit Envisat using a chaser satellite, which synchronises, docks, detumbles and deorbits it. The presence of large flexible appendages make the configuration prone to elastic perturbations leading to complex dynamics that cannot be represented using rigid body dy-namics. Therefore, a unique multibody approach based on the absolute interface coordinates in the floating frame formulation is used to model the Flexible Multibody Dynamics. The new method proves to provide a good balance between computation time and efficiency for the control application. The controllability characteristics of two phases of the e.deorbit mission are analysed using a linear PD controller and an Incremental Nonlinear Dynamic Inversion controller. For the first phase, both controllers successfully synchronise the chaser with the target debris tumbling at the rate of 3.5 ^◦ /s about all axes. However, during the detumbling phase, the large appendage (14.2 m) in the stacked configuration introduces complex dynamics, which could not be stabilised by applied controllers.