A helmet system having an outer helmet, an inner helmet, and one or more orbital connectors joining the outer helmet to the inner helmet. Each orbital connector may include: a slip disc housing, a slip disc, and a post. The slip disc housing is mounted on one of the outer helmet and the inner helmet and has a first face and an opening through the first face. The slip disc has a second face abutting the first face, and the second face is movable in sliding contact with the first face relative to a spherical center. The post extends through the opening and mounts the slip disc to the other of the outer helmet and the inner helmet. The post is dimensioned to move within the opening to allow the second face to move tangentially to the spherical center in sliding contact with the first face.