If a typical ICBM is in diameter, at a distance of represents a solid angle of 10−12 steradian (sr). Estimates of the dispersion angles from the Excalibur lasers were from 10−12 to 10−9. Estimates of formula_2 vary from about 10−5 to 10−2; that is, they have laser gain less than one. In the worst-case scenario, with the widest dispersion angle and the lowest enhancement, the pump weapon would have to be approximately 1MT for a single laser to deposit enough energy on the booster to be sure to destroy it at that range. Using best-case scenarios for both values, about 10kT are required.