What, precisely, is the value of the Moon? Mars?Precisely? Already we discern a misunderstanding of value. Value is not intrinsic so can never be precise.
ALL VALUE IS DETERMINED SUBJECTIVELY BY INDIVIDUAL PEOPLE
ALL WEALTH IS CREATED OUT OF NOTHING BY TRADE
So, to be as precise as is possible: The moon/mars is worth the total of what all people owning its parts are willing to sell their parts for. It has no value until people own it. No wealth is created until people trade it. This is why nothing needs to be transported from one planet to another to create wealth. Ownership can be transferred electronically. This means mars can increase the wealth of people on earth without a single gram of matter being transferred.
What about mining?