 What is ironic about Ledman's quick departure to Mars?
But no; she blamed it all on me somehow: So we were out walking on the spongy sand of the Martian desert. No, we had decided together to come to Mars—the way we decided together on everything. Maybe we shouldn't have come to Mars after all. I watched her, sleeping peacefully, a wayward lock of her soft blonde hair trailing down over one eyebrow, and it seemed hard to believe that we'd exchanged Earth and all it held for us for the raw, untamed struggle that was Mars. I thought I knew everyone on sparsely-settled Mars. And that started the chain of events that led Val and me to end up as a madman's prisoners, on Mars. So, Mars.
 Inventors discovered a way to create prosthetics using atomic power
 Victims of the Sadlerville blast received a large settlement and were culturally recognized as heroes  Inventors discovered a way to create prosthetics using atomic power  In hunting Geigs, Ledman is killing the only people with the power to help him walk again  He needs uranium in order to survive and went to a place where there is scant uranium