[lepton]

no useful elements in any appreciable amount;

Excuse me? Billions upon billions of tons.

There are plenty of useful elements. Now "cost-effective" is another matter.

[Prime Choice]

I wrote "appreciable amount." I should have written "appreciable concentration."

We can also turn lead into gold. What's the priority on making that "cost effective"?

[Schwaeky]

Its not a heave ho one step process to extract them or put them to tangible use, it is something that over a course of a decade or two would be completed in baby steps. once we have a colony infrastructure and an established space workforce, then it will blast off at the speed of light.