Now that we've successfully proven that the Kirby Space Program is capable of both lifting a man into orbit and successfully recovering him once he lands on Kerbin again, it's time to set out sights a little higher! The obvious first choice for a more advanced mission is the Mun. It's close, it's in a tidy orbit around Kerbin, and we don't have to do anything too too crazy to get there, like leaving the local orbit of Kerbin and getting into the big leagues and establishing our own orbit around the Sun.
However, nothing is ever easy! Even with just going to the Mun, we have a lot of prep work to do. First and foremost, we have no idea about the topography of the Mun, besides what we can see by staring at it from the surface of Kerbin. Already, from there we can see it's littered with craters and valleys, which end up posing a big problem, because all the planning in the world won't help us out if we nail the delta/V and get everything right and then realize that our landing spot is on the side of a crater and at a 45 degree angle. If we try to land there, odds are we'll just tip the craft and strand anyone in the capsule on the Mun. So, it's very important that first things first, we need to send an unmanned probe to the Mun to map it for us, so we can pick a nice landing spot and look for any interesting anomalies.