Got a serious problem. I simply fall through the ground on Mars. Not a single area on that planet has any clipping, I flew around and checked different places. Contact with the ground, even at 1m/s causes anything to fall through and explode instantly, ships, unmanned craft, land vehicles, kerbals. I haven't tried other planets, but I have a hunch that if its some kind of scaling issue then I just can't land anywhere in the solar system other than Kerbin.
Also, the ocean on Kerbin has a deceiving sealevel; because when i drop into the sea, i 'land' and splash several meters above the visible water.
Don't know how to fix any of it.