Note: Petey's mass, according to Captain Tagon, is "a few million tons." It would be more accurate to say "a few hundred million metric tons." It's difficult to be more precise without enumerating starting conditions -- how much neutronium is in each of the Annie-Plants, how far along is the reconstruction of bays three and four, and so forth.

In the spirit of challenging the reader, here's an easy one: If Petey displaces as much water as a heavier-than-water sphere of 1000 meters diameter, what's the LEAST he can weigh? (And don't give me any excuses along the lines of "things in space don't weigh anything." If he's displacing water, we can safely assume he's not in space. Think Earth-normal gravity, you bozos.)

If that problem's not difficult enough for you, here's a hard one: Extrapolate Petey's blueprints and superstructure from the drawings in the comic, estimate the mass of the hypertensile materials with which he's constructed, average out the mass of his fittings and crew, and tell us all how much of the rest of his mass is neutronium.

Show your work.