Im not talking about fuel, because it doesnt much matter as we can get the fuel from earth! im talking about the spacecraft and astronauts going there!
Think of Delta-V budget as the money you need to spend for energy to reach specific destination in space. if any astranaut or spacecraft want to go to moon it needs to spend 16km/s Delta-V budget from earth, do you agree with this? so this doesnt make any difference if it refuels in moon because you still have to spend 16km/s Delta-V budget for it if you want to go to the moon! now if you want to refuel in moon and send the same spacecraft to mars or asteroids you will need to spend another 4km/s Delta-V budget so in total you need 20km/s Delta-V budget to go from earth to mars via moon. but it will only take you 12 kms/s Delta-V budget to go straight from earth to mars! so which one do you think is cheaper?! in fact fuel made in moon is gonna be more expensive than in earth so the price of launch is much higher than double that amount!!.. regardless of what you do, you have to spend money on two things: Rocket & spacecraft + Fuel. since we use the same spacecraft to refuel in moon the cost of rocket doesnt change, but fuel in here is more doubled! so this way of launch is much more expensive than straight from earth travel.
unless of course we use a smaller rocket from earth to send astranauts to moon while a bigger "moon made" rocket & spacecraft is waiting for them to take them from moon to mars and beyond, then yes it will be cheaper IF making rocket & spacecraft in moon is same price as making them on earth! ... anyway these are just cost terms, i still havent talked about complexity of doing it this way! imagine making a rocket factory in moon!
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