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Evaluation of Asteroid Impact Hazard, 15-9130

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Principal Investigator
Clark R. Chapman
Co-Investigators
Walter F. Huebner
Daniel D. Durda

Inclusive Dates: 03/30/99 - Current

Background - The nation and the world are on the threshold of deciding what to do about what is called Planetary Defense: how do we address the rare but horrific possibility that civilization might end because of an impact from a mile-wide asteroid or comet? Currently SwRI has several leading researchers engaged in this recently discovered threat, and it has much latent talent that could be focused on mitigating the threat when the nation decides to proceed. During this transitional year, SwRI is helping shape the decisions of federal agencies and international bodies about how to address the impact threat by engaging in several research efforts designed to advance an understanding of the impact hazard, its relationship to other natural hazards, and approaches to mitigating catastrophe should an asteroid or comet be found to be approaching Earth. At the end of this modest, one-year project, it is expected that the Institute will be well positioned to help society address this threat in a responsible way.

Approach - While plans for telescopic searches for threatening asteroids and comets are well advanced, SwRI is undertaking complementary research to identify the significance of discoveries, realistic error bars in impact or near-miss predictions, and proper methods to characterize such predictions (for example, development of a useful Impact Hazard Index, analogous to the Richter Scale for earthquakes) in order for policy- and decision-makers to respond appropriately. These research activities are being conducted in the context of SwRI’s current and invited participation in activities of the International Astronomical Union (IAU) Working Group on Near Earth Objects, the June NASA/ESA/IAU IMPACT Workshop in Torino, Italy, and the Prediction Science project sponsored by the Geological Society of America and the National Center for Atmospheric Research. The research team is also analyzing impact rates as a function of size, refining estimates of the expected environmental and societal damage due to an impact, and comparatively evaluating the impact hazard with other natural events in order for the impact hazard to be placed in a proper context within the natural hazards research community. Finally, in collaboration with Dr. Robert Gold of Johns Hopkins Applied Physics Laboratory, the team will be developing a broad, end-to-end analysis of approaches to mitigation. These approaches will be summarized in an SwRI report expected to form a widely read roadmap for how our society should deal with the impact threat. The report will emphasize analyses of how the physical properties of asteroids and comets may be understood in order to plan for possible mitigation efforts using explosive and thruster technologies.

Accomplishments - The principal investigator has completed a chapter for a forthcoming book on "Prediction Science." His chapter (Case Study) on the impact hazard will accompany chapters by experts on other natural hazards and issues in predictive science, including earthquakes, floods, and beach erosion. The principal investigator attended the Torino IMPACT conference in June and helped the International Astronomical Union develop recommendations for handling future predictions of possible impacts. He also worked with Dr. Richard Binzel (M.I.T.) and Kelly Beatty (Sky & Telescope) to refine an impact hazard index, akin to the Richter Scale. Named the Torino Scale, the index was announced in July 1999. A poster talk on the impact hazard was presented at the Asteroids/Comets/Meteors meeting in late July at Cornell University. Work is beginning on other elements of impact hazard research, while work on an end-to-end analysis of planetary defense has been deferred until later in the project period.

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