Deflection and Disruption of Asteroids on Collision Course with Earth

Use is made of a gravitationally-bound, hard-sphere model to simulate the effect of surface-detonated nuclear explosive. Regardless of the elasticity of the component rocks, the regimes of intact deflection and total dispersal appear to be separated by about two orders of magnitude in explosive energy. The shatter-free velocity that can be imparted to an asteroid consisting of ~ 10 equal-sized components is about twice that which can be imparted to an asteroid of the same diameter consisting of ~ 100 components. If the component rocks are so inelastic as to convert all of their collisional relative kinetic energy into heat, about an order of magnitude more energy is required to obtain the same fracture characteristics as if the components were perfectly elastic.