Great fun for the technically-minded. Fast-paced if you're familiar enough with engineering to catch the clues and in-jokes, although the wealth of detail may slow readers down quite a bit if they're not. The ticking clock on everyone's survival is handled effectively, and it's honestly a surprise as to who wins through in the end and who doesn't. I was especially intrigued by this rather different take on Asimov's three laws of robotics. My biggest problem, however, was the apparent lack of psychological evaluation in hiring several of these characters. I would expect any employer who's putting people into such an isolated setting, at such enormous cost, and so very far from help and reinforcements, to use a great deal more screening than is apparent here to ensure stability and compatibility, aside from issues of competence. ( )