North Korea has publicly displayed what it claims to be a standardized atomic bomb that dimensional analysis indicates could weigh as little as 400 kilograms. The device displayed by North Korea is clearly a spherical implosion design—seemingly based on the same design concept that Khan sold to Libya and used by Pakistan. (If North Korea had instead sought to impress the outside world by displaying an atomic bomb that was shaped somewhat like an egg, it could have indicated an entirely different and far more advanced design.) But the payload of a missile consists of more than a warhead. Because of the extreme environments created by long-range missile reentry to the atmosphere—including temperatures in the thousands of degrees and high deceleration forces—we have assumed that 25 percent of the payload-weight of these North Korean rockets would have to be given over to a heat shield and the structure needed to hold an atomic bomb in place during deceleration. This is an intentional underestimate of the weight of the warhead assembly, to make our assessment of the Hwasong-14’s capabilities as favorable to North Korean capabilities as possible.