The risk from large impactors that we can do nothing about is greater than the cumulative risk from small impactors below 1 km. NASA is making good progress on large impactors > 1 km which retires roughly 90% of the risk we can do something about. The 10 to 25 % of the total risk we can't do anything about requires advances in space technology that are only likely if human spaceflight beyond LEO is pursued, not to mention the eggs out of one basket approach. In case you can't do the math that means that only 7.5 to 9 % of the total risk is due to small impactors and at least three projects are already underway to retire a large portion of that risk. DCT is fully funded for completion in 2011 and can readily find 90% of objects > 300 m and make big strides with even smaller objects. Work has started on Pan-STARRS and LSST which can finish a > 100 m survey within a few decades. Other options have been listed by astronomers to do the job within 10 years and none of these are CAPS and cost 1 to 10% of that. These numbers are based on peer reviewed scientific studies not a book by some nut who doesn't even include references.

If you had ever actually read the reports you so often mention you would be a manned spaceflight supporter for the synergies with your main area of interest instead of constantly trying to promote a false conflict. These reports clearly detail that we can do nothing about the comet threat due to their darkness and the short warning for long period comets. They also make clear that even small NEAs can be detected without CAPS. CAPS was not promoted outside of Langley because the scientists doing actual searches saw no need for it and wanted something that was reasonable enough to actually get built.

Regards,
Mark