It turns out this is not that big deal for the Mun due to such low gravity, and close proximity to Kerbin (still within Kerbin's gravity well). There is the potential to save a little bit of fuel, since it is not necessary to land and re-orbit the fuel required for the return trip (and thus, also, the extra fuel required to move the fuel).Why an Apollo style mission? Here are some weak, advantages and disadvantages for an Apollo style, two-ship system: Effort is placed on only using parts that are on the early and mid tier levels of the technology tree, with only a few exceptions, discussed individually below.Only stock parts allowed on the rocket.It should be designed to get to the Mun comfortably, with a reasonable margin of extra fuel, but no more. While the rocket design is not minimal, it shouldn't be wasteful either.The rocket should get the job done comfortably, and have carry enough fuel to cover a margin of error, in case things don't go according to plan, or modifications need to be made to the flight plan.The science equipment must also land on the Mun and be returned to Kerbin.Get three kerbals and a bunch of science items to the Mun, in an Apollo style mission: such that two kerbals (and science) land on the surface, one remaining in orbit.The following are the rocket's design goals: This post illustrates an example of KSP rocket design.