The Mid-Infrared Advanced Chemical Laser (MIRACL) antimissile system is currently being developed by the US Army. Its aim is to destroy incoming missiles with lasers. This paper determines that there is a maximum of 10 minutes preparation time (assuming the missile is fired from at least 10 minutes flight time away), and it would take a 1 MW laser about 0.82 seconds to destroy a typical missile made of aluminium. It does not however cover the practical difficulties involved with implementing such a system