I see always many people mention that the kerbin has to be 10 times more dense than the earth just becoz is 10 times smaller and has the same gravity. That is wrong... For example you are mention that the gravity is reduced but the r^2 but you dont realize this mean it doesn´t need to be the same mass to have = surface gravity. For example, lets compare Mars with Mercury. Mars: Surface gravity: 0,37 g Mass: 6,4185 × 10^23 kg Diameter: 6.794,4 km Density: 3.9335 g/cm³ Mercury: Surface Gravity: 0,38 g Mass: 3,302×10^23 kg Diameter: 4.879,4 Km Density: 5,43 g/cm3 See? Mars has 2 times more mass than mercury and it has equal or less gravity. This mean (I dont wanna make the calc right now) that kerbin only need to have aprox 20% of the earth mass to have the same surface gravity. About the change of the Kerbin Meter, you are right, but it will be difficult to us if we wanna use the unit to compare.