Children do not learn in a vacuum. The children who aspire to be engineers and scientists need to have hope that projects - to Mars, and beyond, will await them when they finish university education.
Further, we have today, an amazing resource of scientists such as Dr. Carolyn Porco, and Dr. Steve Squyres who will be the mentors to this next generation.
We cannot afford to lag behind in space science exploration. Humanity is relying on us.
We need to sustain, and grow this effort into a national will. It could create demand for jobs, for knowledge, and for a sense of national direction.
And finally, I do not believe that the amount saved is anything but a drop in the bucket from other spending..