There are two moons now - the first one orbits Kerbal (the planet) at about 11.4 million kilometers. The second one is much further out. It's not as difficult to reach that altitude as you'd think - what's difficult is actually managing to be in the same place at the same time as the moon. You don't just click the moon and it drives you there - you have to figure out a way to hit what is essentially a pinprick in millions of kilometers of empty space. It's pretty damn cool.
