The problem of this is that we don't actually know the true financial returns of basic research like this. It could have huge consequences decades down the road, that could produce a return of $billions. When Michael Faraday was asked by William Gladstone about the "practical value" of electricity, he allegedly said "Why, sir, there is every probability that you will soon be able to tax it". There is dispute over whether Faraday ever said this quote, but it says a lot about peoples expectations over economic return for scientific discoveries. Today we can not live without electricity, it affects every single aspect of our lives. The same can be said for the basic research done into radio waves, which have led to all kinds of scientific and economic applications from radio, to television.
When people claim that space exploration is a waste of money, what they are actually saying is "I don't understand science or economics"