How cost-effective are efforts to detect near-Earth-objects?

Near-Earth-objects (NEOs) include asteroids and comets with orbits that bring them into close proximity with Earth. NEOs are well-known to have impacted Earth in the past, sometimes to catastrophic effect.2 Over the past few decades, humanity has taken steps to detect any NEOs on impact trajectories, and, in doing so, we have significantly improved our estimate of the risk that an impact will occur over the next century. This report estimates the cost-effectiveness of such detection efforts. The remainder of this section sets out the context of the report...