Game requirement specs are not a very good argument that the calculations are wrong... unless I'm missing a subtlety of the argument. Would you care to point out exactly where the calculations are wrong, or expand on your argument? For my part, because I did skip the presentation of a number of calculations. Volume of a sphere -> 4/3 pi r^3 Radius of kerbin: 600,000 m Pi: 3.14 (no need for more digits given we are working at the piano tuner level of analysis. I could go with 3,