Characterizing the near-earth object hazard and its mitigation

Within observational constraints and analytic orbit determinations, potential NEO hazards and mitigations are characterized in terms of orbit displacements to establish (arbitrary) “safe” closest approach distances and corresponding energies that must be externally applied to achieve appropriate orbit displacements from the Earth. Required orbital velocity changes depend on projected closest Earth approach distances and time to (near) impact. Energy to achieve orbital displacement depends on NEO mass, required orbital velocity change, and the energy–momentum coupling coefficient. Errors in these parameters introduce uncertainties into hazard index and mitigation procedures. Hazard avoidance levels and mitigation indices for nine near-Earth asteroids, including 1997 XF₁₁ and 1999 AN₁₀, with non-zero Earth-impact probabilities are computed as examples of the proposed methodology, generating insight into the dilemma of predicting near impacts. This zeroth order approximation should not be construed as solving an orbital mechanics problem, nor establishing a particular set of criteria for mitigation action, but rather as a “survival index”.