The concepts of designing a laminated composite frangible launch tube closure are elaborated. The frangible closure is a convex shell structure of which the external failure pressure is much higher than the internal failure pressure. The frangible closure is designed in such a way that when subjected to an internal impulsive pressure of magnitude greater than certain value, the closure will be broken into several pieces in accordance with a predetermined failure pattern. A number of frangible closures of different sizes are fabricated and subjected to burst strength tests. The failure modes and the effects of some specific design variables on the burst strength of the closure are studied using the experimental results. Basically, the frangible closure can achieve the design objectives.