* NASA is not funded for such a project.
* Congress would not allow the U.S. to foot the bill for this.
* Congress would not allow the U.S. to lead such an expensive project.
* There are cheaper ways to go about this in unmanned LEO, rather than manning and recycling a station on, or near, the Moon.

The importance of Impactor detection is enormous -- actually Universal, as far a life on Earth is concerned. The matter, however, is not in the hands of the few who realize this fact. It's in the hands of the many voters who cannot properly grasp it, or simply do not care. They have far more important daily chores to take care of, rather than being concerned whether their grandkids, kids, or they themselves survive through the years that follow.

I'm afraid it may well require a devastating hit to impress upon the world as a whole just how fragile our existence really is.

Dan