To be clear once and for all: I am not interested in asteroid interdiction and I will not host an endless discussion of it on my blog. Please take this conversation elsewhere.

Signed by two of my favorite scientists- Paul Spudis and Neil DeGrasse Tyson- the Aldridge commission made some interesting recommendations.

Perhaps the concepts of fundamental change and discovery-driven-vision ten years ago may be reinterpreted now in light of following developments?

The mini-sar radar that detected hundreds of millions of tons of ice on the Moon, the mounting evidence of an impact threat that is essentially random, and the realization that cosmic radiation is the showstopper for Human SpaceFlight Beyond Earth and Lunar orbit; IMO these factors change the situation from one of voluntary exploration to mandatory self-defense.

Without the ice on the Moon and with no appreciation of the impact threat, the difficulties involved in establishing a Moon base were problematic.The long ignored cosmic radiation hazards also made long duration deep space missions with humans a far more difficult enterprise.

“Greater reliance on the private sector” was to morph into the private space tourism inspired cheaper-smaller-is-better flexible path which IMO has in the public eye has certainly turned NASA into a pseudo space agency. The absolute bottom line of all this talk of profit driven private space activity is that impact crater in Mexico I mentioned in a previous comment; private space is not going to deflect any dinosaur killers on a budget.

Sending unmanned interceptors to stop doomsday is not the optimum solution considering the track record of star wars; if any mission needs a human crew it is impact deflection. Unlike a certain movie such a mission cannot be put together in a couple weeks or even months. A couple thousand megatons precisely applied several hundred million miles away will require many years of preparation. Every minute we wait is natural selection at work.

The ice on the Moon made a massive water filled cosmic radiation shield for a spaceship practical and the isolation of the Moon from the Earth’s magnetosphere makes a Moon base the only practical place to safely play with nukes for both deflection and propulsion.

What makes sense is spending money- vast amounts of money- on a Heavy Lift Vehicle with hydrogen upper stages to take us to the Moon ten times a year so we do not end up like the dinosaurs. We could get hit tomorrow and then the next day and on the scale of geologic time it would just be a blip on that convenient probability curve; but there would be no one left to say “Wow, what were the chances of that happening?” Kind of like the recent events.

Of course I have said most of this before in other comments and I sincerely thank Dr. Spudis for the opportunity to express my opinion, I do think this is important- not trivial in any sense.
Gary Church

This is one of those things we will just have to disagree about. I am not sure that the risk is sufficient to make this a high priority national goal. But for anyone convinced that it is, detection without protection is to me a complete waste of time.

The discovery rate for very large NEOs is going down, even as robotic scopes have become more numerous and more powerful. We’re running out of NEOs > 1km to discover.

With a little bit of extra money for detection over the next decade, we’ll be able to get to the 90% mark for NEOs above 100m. During that time, the risk of getting walloped by a large NEO will be almost infinitesimally small.

You’ve got to include probabilities in your mental computations.

First of all an explanation my comment dated March 23, 2013 at 9:04 am was posted before your second post was available for viewing, however your statement “So it makes sense now to put extra money into detection, not into mitigation” deserves some discussion.

To me at least to concentrate on detection only is the equivalent of proving (to your own satisfaction) that your next door neighbor intends to kill you next Tuesday and doing nothing about it except continuing to attempt to try to find out the intentions of your other neighbors.

Detection is not deflection.
NASA needs a mission- this is it. Safeguarding the human race from extinction is the penultimate moral high ground above all other calls on public funds.

This is ultimately about a base on the Moon because nuclear weapon systems to deflect impact threats are not going to be assembled, tested, and launched from Earth orbit. Survivably packaged bomb pits and fissionables for a nuclear propulsion system will have to be transported to the Moon where they can be assembled, tested, and launched.

Fortunately we have a Heavy Lift Vehicle with a powerful escape system soon to be available to transport fissionables and interceptor crews to the Moon.

Make it a multinational operation with manned interceptors from different countries and we can move all the nuclear weapons off the planet and into space. It will cost the same as fleets of bombers and nuclear submarines.

You seem to be confusing NEO detection with NEO protection.

What you say about the telescopes for finding the NEO’s is true, but without a method of diverting them there is no risk mitigation.

Mitigation against a NEO already on its way to Earth, either by blasting it or redirecting it or whatever — that’s expensive.

So it makes sense now to put extra money into detection, not into mitigation.

Watch the known NEOs accumulate at http://www.minorplanetcenter.net/iau/lists/Unusual.html at the rate of hundreds of new NEOs per year. Geologically, we are retiring NEO collision risk at breakneck pace.

And robotic telescopes to find NEOs are absurdly cheap in comparison with nuclear interceptors launched from Moon bases. If you want lower NEO collision risk, then get a few more wide-field scopes going.

All that that will cost is pocket change.