Actually, it would be mandatory if we want Jeb to come back from the 'Kluna' (would personally prefer the Kearth also to be a moon of another planet ). It would be possible to get enough fuel to achieve lunar orbit, and come back, but landing... bringing all the fuel needed for the trip back to the moon surface, and back up to its orbit - some heavy cheating will have to be involved. Much easier to first have possibility to dock and undock from objects, put fuel storage on lunar orbit, and leave it there while we play with the lunar crash... err... lander. You know, like it was done 42 years ago Some game saving system would also be nice... no to redo the whole mission, when we crash to the fuel tank coming back from Kluna surface Sending Kerbals to their moon is a fun project, but for it to happen we need a lot of other content in this game.