Uncertainty Effects from an Asteroid Risk Assessment Perspective for the PDC25 Impact Scenario

Uncertainties in asteroid properties and entry parameters can lead to large ranges for asteroid damage and risk estimates. NASA’s Probabilistic Asteroid Impact Risk (PAIR) model uses a Monte Carlo framework to assess possible damage across these potentially wide input ranges. In this work, a value-of-information study is conducted to determine the expected benefit to risk knowledge from asteroid property and entry parameter refinements resulting from additional information sources. The 2025 Planetary Defense Conference hypothetical asteroid impact exercise is used as a case study.The study found that for every 100% asteroid property range refinement, ~70% damage radius range refinement was observed meaning, for example, for every factor of two reduction in the range of possible asteroid diameters, we obtain a factor of 1.7 reduction in the range of possible damage radii.For every 100% entry parameter range refinement, ~30% damage radius range refinement was observed. The roles reversed when looking at affected population. For every 100% asteroid property range refinement, ~30% affected population range refinement was observed. And finally, for every 100% entry parameter range refinement, ~65% affected population range refinement was observed. Overall,by 2028 in the PDC25 scenario, ~10-20% output refinement would be forfeited by forgoing asteroid property refinements from the flyby mission and ~65-75%would be forfeited by forgoing both JWST and flyby refinements. Results provide valuable context for decision makers when faced with choosing how to act.