...like us, it's a hard pill to swallow, but there is nothing out there of commercial value, at least for the forseeable future. There IS immense scientific value, which will eventually convert to new products, industries and profits, but it is hard to predict the payoff, so it is of little interest to private investors. This is not to say there is no role for the private sector in space, for example, I expect private enterprise will soon be able to launch comsats cheaper than governments do, using surplus hardware and the efficiencies inherent to the free market. But these applications will be highly specialized and of little help in conquering the solar system.

Back in the 19th century, astronomers knew that the sun would have burned out in just a few thousand years if its source of energy was simple combustion. There had to be some other source of energy that coud produce that much energy over the long time frames geologists and biologists had demonstrated. One astronomer, Jeans or Eddington, even made a speculative remark about energy "issuing from matter like steam from boiling water at temperatures above 20 million degrees". Some scientists had a suspicion that the newly-discovered radioactivity might have something to do with it, but no one could guess what was really going on.

Intense study of the sun and other stars by astrophysicists eventually revealed the mechanism of hydrogen fusion, a perfect example of how pure basic research can have totally unexpected practical benefits. Who would have guessed that the otherworldly curiosity of a few university long-hairs would lead to the H-bomb and atomic power. No entrepreneur would have invested cold hard cash in astrophysics in the hope of creating a thermonuclear industry.

The funny thing about it is that eventually it WAS private funding that financed the great telescopes of the late 19th and early 20th centuries, but it wasn't investment capital. It was philanthropic contributions from tycoons and financiers that paid for those observatories. But it wasn't investment, it was charity.

Space travel will eventually turn up something financially worth our while, it can't help but do so, we have a whole universe to learn about. But when it comes, it will be totally unexpected and a complete surprise. In the meantime, we need government funding, military activity, private philanthropy, public funding, even spoiled millionaires who want to play spaceman, anything to keep the ball rolling until we make that breakthrough.

The Heinlein-type businessman bravely putting his cash on the line (usually against evil government conspiracies determined to shut him down) is a pathetic fantasy. After all, that's what Heinlein wrote, science fiction for juveniles.