Actually, the USA is worse than broke. If private enterprise can’t finance space exploration, the government certainly can’t fund it. We are going to struggle under the weight of tens of trillions of dollars of debt for generations just trying to pay for Obama Care. There will be nothing left for the military, much less NASA.
If we had an international treaty stating that extraplanetary land and resources can be claimed by any private person or company, or country for that matter, who personally claims and stakes the territory, we’d create free market incentives to go to mars and other places. As it stands, the treaties don’t allow this.
Hm. Well, no. The economics of space exploration in general are not at all interesting to private enterprise.
Private enterprise is built on the idea that investors will get a reasonable return on their investment within a reasonable time.
There are sectors of the space business where the time and profit factors are positive: Communucations satellites are an obvious example and, increasingly, so is space-based imaging.
But space exploration on the "going to Mars" model has absolutely no profit potential over a 10-year time span, and probably not even over a 50-100 year time span.
It requires far too much infrastructure, and for manned space that sort of thing is intrinsically extremely costly.
And once you get to Mars.... what is there at Mars that could turn a profit? What could be done or gotten there that cannot be done or gotten more cheaply here?
The simple economic truth is that private enterprise is not going to be at the forefront of solar system space exploration until some entity that is not profit-driven provides the necessary infrastructure. What that means, of course, is that "government" of some sort will have to build it.