This invention solves problems associated with prior-art soft-dock mechanisms by placing all active components of a soft-dock system on the chaser side of the mechanism, leaving the target side of the mechanism completely passive (i.e., requiring no power expenditure or self-actuated moving parts to operate). In particular, the active components are supported on the end of a flexible cable attached to the probe, or chaser, side of the device. These components act as a sort of spring-loaded "trap." Once the end of the probe passes into a receptacle on the target side, the mechanism is triggered, engaging it in such a way that it can no longer be pulled out of the receptacle until it is reset. The soft-docking cable may be replaced with a rigid, semi-rigid or jointed post that is used to bring a capture mechanism into engagement with its corresponding receptacle or receiving structure. The magnetic end effector may also be implemented as an electro-magnet, which requires power to maintain the holding force, or a permanent magnet, which captures a target without power. The main target cone may be either a metallic cone: or a non-metallic cone constructed of fabric, plastic, or other flexible material.