Hi all, I'm writing a science fiction story and I have managed to confuse myself. I have a rail line that accelerates a train in Tycho crater and tosses a heavy payload of ore to Descartes, about 1200 km, where it's supposed to land on another ramp... or something. I've used Google Earth to estimate my distance and ejection angle, then I fudged my figures into shape using this CalcTool: http://www.calctool.org/CALC/phys/newtonian/projectile Ejection angle: 9 degrees Release velocity: 2500 m/s !? g: 1.62 m/s^2 Which gives me Max height: 49488.5 m Distance traveled: 1192.2 km Time taken: 482.2 s The problem I see here is that 2500 m/s, mostly horizontal, is considerably more than the approximately 1000 m/s minimum orbital velocity of the Moon, and more than the 2380 m/s escape velocity of the Moon. It just doesn't seem right. I'm aware that this calculation fails to account for the curvature of the Moon, its rotation, mass concentrations and the tenuous atmosphere that all these rockets would eventually create. But I had *hoped* that such considerations would not be significant enough to worry about. (We also don't have to worry about such things because there is another railroad car parked across the tracks at the end of the ramp, and what we are really interested in is the size of the explosion it's going to create. Right now it looks... meteoric!) I'd really appreciate some help in restructuring my calculations and helping me to understand what's going on here. Thank you in advance for your help.