It's not the height, it's the speed. (Though, Virgin is trying something like this for their rocket). LEO isn't that far away, but it goes by _really_ quickly.

It's not the height, it's the speed. (Though, Virgin is trying something like this for their rocket). LEO isn't that far away, but it goes by _really_ quickly. And getting going that fast requires a lot of propellant mass, and that's judged by the tyranny of the rocket equation.