 What likely happens to Val and Ron after the story ends?
The great atomic wars of the late 20th Century had used up much of the supply, but the amount used to blow up half the great cities of the world hardly compared with the amount we needed to put them back together again. And that started the chain of events that led Val and me to end up as a madman's prisoners, on Mars. But there wasn't forty or fifty years' worth of raw stuff to tide us over until then. In a decade or so, our power would be just about gone. It's a stopgap effort, just to keep things moving until Project Sea-Dredge starts functioning.
 They stay on Mars for their contract and then move on to a different project
 They stay on Mars for their contract and then move on to a different project  They go back to earth to make sure Ledman gets the care he needs  They decide to stay on Mars forever  They stay on Mars for a few more weeks before heading back to Earth