Overall, the main problem with this story is that it’s one missed opportunity after another. It all climaxes with yet another very boring “time is running out to do something about the bomb” situation, and what they do about the bomb is so amazingly improbable that Dr. Science’s acid reflux started acting up again. Jack Colvin’s flunkies are operating under the delusion that their crimes on the moon will work wonders for their careers. Steve never thinks to tell them that they have already killed hundreds of people and will probably end up killing millions before they’re done. There may not be a United States to come back to, and they’ll certainly never see the money Colvin promised them.
But if we must have this nonsense of a megaton bomb that can’t be moved because of a fluid motion sensor, Marie spotted the obvious solution. They’ve gone on and on about the dark side of the moon being at absolute zero and punched a hole from the surface into the mine shaft to freeze Steve’s bionics via a long steel rod. (That’s ten shades of Dr. Science having a headache, so we won’t go into how they’re keeping their artificial underground environment stable with an open borehole to the surface…) Why didn’t they just freeze the fluid in the sensor when they had a hole to the freezing surface right there?
I’d like to not be too critical, because this is for kids, and there’s some science that children can use and bring back to school Monday morning, but the rest of this is just painfully silly! Ah, well, Colvin does a good job playing the calculating and emotionless villain… even if he is pretty blasted wrong to calculate that he’ll return to Earth a rich scientific hero, he comes pretty close to getting away with it.