Abstract: A closure for a missile launch tube comprising frangible glass ribs mounted n a support ring of the tube to form a dome shaped closure. The ribs are joined to one another externally of and on the longitudinal axis of the launch tube, and a plastic or polymeric cover is mounted on and encloses the glass ribs. The external surface of the plastic cover is provided with a linear-shaped explosive charge and detonator. When the missile begins to move in the launch tube, the detonator is fired to detonate the linear-shaped explosive charge which cuts the plastic and fragments the glass ribs into small granules. The missile may then exit the launch tube without obstruction.