It's worth noting that SpaceX's major development change is to "hardware rich" and test often. That's something you can do launching rockets. It's something yo

It's worth noting that SpaceX's major development change is to "hardware rich" and test often. That's something you can do launching rockets. It's something you can do in orbit. And for deep space the moon is close enough (and by many measures, harder then Mars to land on) to safely yet effectively test practical systems of the type you'd want to go to Mars (consider: Mars' atmosphere is incredibly thin, so it's more Moonlike then Earth like).