>For instance if you want to create a space travel company, you will need funding way before you've finished your proof of concept.

There are always some ways to test concept. I've done a fair bit of indirect testing in my business, as my products take years to develop. I always found a way to test the most central aspects of them, usually in a week or two.

I don't know how you'd do it for the product these guys are trying to build, because I'm not familiar with their space. But there must be a way.