A forward closure system includes a cylindrical frame. A pair of lune-shaped base sections are mounted to an inside surface of the frame. First and second opposed lune-shaped shell assemblies, each assembly including at least an outer shell section and an inner shell section, are rotatably mounted independently of each other at opposed ends along the rotation axis, the inner section and base sections of each shell assembly nested within the outer section when the forward closure system is in an open position, mating edges of the outer sections abutting one another when the forward closure system is in a closed position. An actuator is coupled to each outer shell section.