James L. Cambias, whose story "Balancing Accounts" is the cover story of the February 2008 issue of F&SF, said in an interview that the story is about a small-time independent robotic space tug called Annie who is hired by a mysterious client for a voyage between two of Saturn’s moons.  "During the voyage Annie learns the true nature of her cargo and must fight off pursuers determined to capture or destroy what she’s carrying," Cambias said.

"Balancing Accounts" is Cambias’s attempt to update an old space-opera trope: the scruffy, hand-to-mouth space merchant crew. "I tried to make it work without violating physical laws or realistic economics," he said. "That meant it had to be within the Solar System (no faster-than-light drives) and couldn’t involve a human crew."

The protagonist, Annie, is a robot rocket tug who hauls cargo among the moons of Saturn.  "She’s autonomous and ‘incentivized’ — her purpose is to generate income for her owners back on Earth and Mars, and can more or less do whatever she chooses in order to do so," Cambias said. "But Annie has learned that there’s more to life than just earning micrograms of Helium-3; she works just as hard to accumulate ‘non-quantifiable assets’ like the goodwill of her fellow robots, a reputation for honest dealing, and what a human might call friendship."

This was the most "number-crunchy," hard-SF story Cambias has written, he said. "I did the math for everything — designing Annie’s performance parameters, figuring travel time, even fuel consumption," Cambias said. "Since the whole point was to write a story with no ‘magic’ or rubber science, I felt honor-bound to make everything as accurate as I could."

As research, Cambias made extensive use of Winchell Chung’s superb "Atomic Rockets" Web site. "Every SF writer should have [that site] bookmarked," Cambias said.

Lately, Cambias has become interested in how one can be moral without a supernatural or religious framework defining what is good, and so that factored into the story as well. "In the story I try to show that being a good person works for Annie as a purely self-interested logical machine," he said. "Good works."

Cambias reports that he a blast writing "Balancing Accounts," and is planning to write a sequel. But first, readers can look forward to his "The Dinosaur Train," which should be appearing in a forthcoming issue of F&SF sometime soon.

The February 2008 issue of F&SF is on sale now.