"Don't you need to start with the rover, how heavy it is and what its landing systems going to be and how heavy they are and if it needs an orbiter for communications and how heavy that is."<br /><br />Exactly. Any proposal has to start with the rover and base componentes (transmitter etc.). These systems have to be as low-mass as possible. <br /><br />You won't need an orbiter for communication if you land the rover on the Earth facing side of the Moon. The Moon is locked into always facing only one side to the Earth. You of course would need different relay stations on Earth to have 24 hour coverage but no orbiter around the Moon.<br /><br />"And speaking of TLI booster, are you going to use one or use an ion engine to get to lunar orbit in 3 years like SMART-1 did?<br /><br />Or are you going to try to use an unconventional method like a solar sail? "<br /><br />This is a competition that needs to stay as cost-effective as possible. Any advanced propulsion system (i.e. non-chemical) would increase mission costs and complexity. The key is to reduce the effective payload mass of your rover and base components + increase the odds for a possible mission success by using reliable technology for the TLI-burn and descent burn (that is proven chemical (storable) propellants).<br /><br />"Ion engine and solar sail have the advantage that you don't need such a big launcher to begin with."<br /><br />True, but as mentioned they also increase the complexity + you can use an ion engine like Smart-1 only for getting to lunar orbit, not to land anything on the Moon.