Explosive thrust-producing coupling

A separation device for separably joining two structures, comprising:

• a frangible joint comprising at least two joinder flanges, there being a joinder flange for each structure to be separably joined and a fracture region connecting the joinder flanges, the fracture region comprising frangible walls comprising fracture grooves, the walls interconnecting the joinder flanges and forming junctions therewith and defining a channel in the fracture region;
• and
• an expansion member disposed in the channel in substantial surface contact with the channel walls, the expansion member comprising a containment tube, a detonation charge, and a charge holder supporting the detonation charge within the containment tube, the expansion member comprising an expansion region proximate to each fracture groove to exert outward pressure on the channel wall upon detonation of the detonation charge to fracture the channel wall;
• there being an expansion region proximate to a wall junction to provide separation thrust upon detonation of the detonation charge.