the body. Depending on how the body disrupts, the effect on Earth could, in some circumstances, be worse overall than if disruption were not attempted. Alternatively, disruption might lead to less total damage to Earth but more damage to, for example, a particular populated location. With the uncertainty in the present understanding of fragmentation and disruption, the committee does not now endorse disruption as a mitigation strategy, but it suggests that further study of this issue should be an important part of any research program into mitigation of the NEO hazard. (See Chapter 6.)
Finding: The mitigation of the threat from NEOs would benefit dramatically from their in situ characterization prior to mitigation if there is time.
Finding: Changing the orbit of an NEO given the current level of understanding is sufficiently uncertain that, in most cases, it requires an accompanying verification. This is easy to implement with many slow-push techniques, but it would require considerable additional effort for other techniques.
Recommendation: If Congress chooses to fund mitigation research at an appropriately high level, the first priority for a space mission in the mitigation area is an experimental test of a kinetic impactor along with a characterization, monitoring, and verification system, such as the Don Quijote mission that was previously considered, but not funded, by the European Space Agency. This mission would produce the most significant advances in understanding and provide an ideal chance for international collaboration in a realistic mitigation scenario.
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