US National Science and Technology Council on Impacts of Near-Earth Objects

The Trump Administration has been broadly indifferent to advice from the scientific community, a stance underlined by its long delay in filling the statutory post of science adviser to the President. The Administration has sought to scale back government funding of research in many areas of science and technology, notably on climate change. An exception to these cuts, apparently justified by a potentially more dramatic connection to homeland security, is the case of impact risks of near-earth objects (NEOs). In June 2018, a working group of the National Science and Technology Council issued a brief report, titled National Near-Earth Object Preparedness Strategy and Action Plan, setting out US goals for detecting and tracking NEOs, developing deflection technologies, and recovering from impacts. (The actual work envisaged is seen as largely being undertaken by the National Aeronautics and Space Administration, which has had a long-running program on NEOs.) Initial sections of the report are reprinted below. The report offers estimates of the number and size distribution of NEOs thus far detected, in a chart that also marks the three best-known actual impacts: Chelyabinsk (20m), Tunguska (50m), and Chicxulub (10km). For American readers, it helpfully transposes Tunguska to New York City. It does not estimate average impact intervals or compare expected fatalities with other risks of death. This was done in a National Research Council report from 2010 (see the Documents section of PDR 36, no. 4). A Tunguska-level event might be expected every 2000 years or so, a Chelyabinsk every century or two. Expected deaths per year-admittedly a highly skewed distribution-were around 100, an order of magnitude greater than those from shark attacks but three orders less than from earthquakes.