Well, I am quite familiar with Ludicrous Speed, so I think I have to speak up for this one (Sorry. I just had to do that). Seriously, even at 75 km/s, you wouldn't entirely "skip" the atmosphere, unless you happen to be running KSP at one frame per second (at which point I would congratulate you for getting a ship that lags your computer down to 1 FPS up to 75 km/s). Even if you are running KSP at 30 FPS, 60 being the maximum on most screens, 75 km/s would mean that you would have at least 30 frames of deceleration if you entered Kerbin's atmosphere vertically. Less, of course, on Duna, but still, my point stands. To fully "skip" the atmosphere, you would have to go 30 times 75 km/s, or 2250 km/s, at 30 FPS. At either speed, though, you would be obliterated by reentry heat, g-forces, and just plain old hitting the ground. In any case, Kerbin's atmosphere does way too much slowing as it is. Here's some experiments: http://imgur.com/a/SN5gr With a command pod with a greater drag coefficient. http://imgur.com/a/K0GLn#0 Didn't press F1 fast enough to get screenshots of actual reentry on either experiment. Still, I spent a significant amount of time in the actual atmosphere, just as MarvinKitFox did. In both experiments, I was slowed far more than could possibly happen in real life. So, the atmospheric physics did their job a bit too well as far as I'm concerned. To sum it up, to fully skip the atmosphere you would have to go so insanely fast that you are likely using K-drives or otherwise actively abusing the physics engine, at which point realistic aerodynamic physics would barely slow you anyways. EDIT: Did some more experiments with FAR installed. trying to reenter at these speeds caused KSP to glitch out in some very fun ways, including causing my command pod turn fully around and head back out of the atmosphere without hitting the ground (probably due to the way it simulates body lift).