Impact Deflection of Potentially Hazardous Asteroids Using Current Launch Vehicles

Nuclear explosions, and a wide variety of technologies not yet realized, have been proposed to deflect asteroids away from collision with Earth. In contrast, this article presents realistic models for simple kinetic energy impact deflection, using the actual orbital elements of 795 catalogued Potentially Hazardous Asteroids, and impactor masses launched to intercept trajectories by Atlas V HLV rockets or equivalent. The authors take asteroid diameter, density, cratering characteristics, and Earth-collision lead time as parameters whose influence is to be investigated. Assuming asteroids of rocklike density, the article finds deflection off of Earth-collision to be achievable given 5-year lead time with a single kinetic energy intercept for 100% of 250 m diameter PHAs, 20-year lead with a single intercept for 93% of 500 m PHAs, 20-year lead with 5 and 10 intercepts, respectively, for 55% and 94% of 1 km PHAs, or 100-year lead with 1 and 2 intercepts, respectively, for 55% and 94% of 1 km PHAs. Considering likely future lead times for Near-Earth Objects, simple impact deflection using current launch vehicles is therefore a viable strategy for up to kilometer-diameter asteroids. This method has important advantages over other proposals: it requires no new technologies, would not require development or testing of nuclear warheads, and would likely be the least costly, least risky, and fastest to effect.