Decision Model for Potential Asteroid Impacts

Research in asteroid detection and orbital characterization has identified a new class of possible natural disaster. Asteroids are the only known type of natural disaster that could potentially destroy civilization. The societal importance of asteroid detection is assumed to be high, given the destructive capacity of Potentially Hazardous Asteroids (PHAs). This paper offers a decision analysis framework to aid in decision making regarding what to do when confronted by a particular PHA of a given size with a given probability of impact. Three decisions are modeled: (1) Study the PHA with a large telescope to further refine orbital estimates; (2) Send a small reconnaissance spacecraft to survey the PHA; and/or (3) Send a large spacecraft mission to disrupt the orbit of the PHA using nuclear explosives. INTRODUCTION: THE ASTEROID IMPACT HAZARD Asteroid impact is considered a significant hazard, with a history of small and large-scale planetary destruction (it is generally held to be responsible for the end of the dinosaurs). Potentially Hazardous Asteroids (PHA's) are defined as any near-Earth asteroid that has an orbital intersection distance of less than 0.05 astronomical units (AU) from the path of Earth. In other words, an asteroid that is expected to pass within 7.5 Million kilometers from Earth at a certain point in the future (roughly 20 times the distance from the Earth to the Moon) is defined as a PHA.