Yup, the heavier the rocket, the harder it is to take of and get into orbit. That\'s because the heavier the rocket the more thrust it needs to take-off, therefore, more fuel is needed to feed the engines, making the rocket heavier. Smaller rockets may seem pathetic, but as long as the rocket can get into orbit and still have enough fuel to burn to the moon, land, get back into kerbin orbit, and retro-burn (your lander should have enough fuel for that), you can, well, land on the Mun (and even Minus)! BTW: First post!