Story doldrums

So, last Saturday night I finished the latest revisions on my novel Bitterwood. Then, Sunday, yardwork, then, Monday, I started my new job at the CPC in RTP. (One day, our language will consist of nothing but initials. But I digress.) Normally, after finishing a novel, I like to use some of my creative momentum to crank out a short story. I'm planning on starting another novel very, very soon, this week, I'd hoped, and when I'm working on novels I almost never write short stories. Since I have two sales to Asimov's now, and stories in a half dozen anthologies, I'd like to have more short work to keep out there on the market. Alas, this morning, everything fizzled. Some days, you sit down, and you are on fire, the words just flow. Other mornings, the well is dry, even if you have a fairly firm idea for the story. This morning I had a setting: The Scar. I know that China Mieville has a novel called the Scar, in a setting called the Scar, and maybe I'll have to rename my setting eventually, but right now I have this image of a nearly dead planet similar to the moon, only it's been smacked by a huge comet so hard the planet has a huge crack. (Maybe I'll call it the Crack instead of the scar.) Anyway, miners have swarmed to the planet and placed a shield over the surface of the Scar. Deep down in the crack, there's easy access to a zillion heavy metal and precious minerals. In the upper levels of the scar, there's oxygen and water left over from the comet impact, so human life is possible in this warren of houses carved into the cliffsides. The downside to life in the scar is that everyone works for the mine, and if you are fired by the mine, you are essentially dead. They have no legal obligation to feed you--basically you have to turn to crime since you can't work and can't afford a ticket off the rock, and even petty theft is punishable by death. My protagonist would be one of these men who've been fired and has to find a way to survive in such a hostile environment. He's been fired because he refused to carry out an execution of someone or other, I hadn't figured this out yet. Lots of times, this is all I'll need to start a story--a setting, and a character with a problem. A first sentence will come to me and I just plow ahead, letting momentum take me to places I didn't expect. Alas, I had several attempts at that first sentence, and nothing worked. The best I came up with was, "If I stayed on Earth, I wouldn't be a murderer, a thief, or a cannibal." Oh well. Maybe tomorrow.