Thanks a lot for the answers, TV = Terminal Velocity (saw the Acronym somewhere in the forum) Do you know How much FAR affects these maps? it shouldn't affect the values outside the atmosphere. but to scape the different planets. I get this, but I'd like to have an expected consumption and then work out how efficient was the real maneuver, and part of my enjoyment comes from understanding how did people came up with this figure (yup, I'm a nerd). I'll work with this number meanwhile. I've been working my way slowly down the list on the drawing board so I might still have some answers in there. I've been doing that, but I'd like to be able to check my design and say ok if I add fins to this rocket it will help, not just the try and error approach I've been using ("let's add fins to this thing", "yup that helped", "nope let's see, what happen if I move it up a little bit, what if I use 2 instead of 4?"), it's still fun, I'd just like to understand why it works or doesn't