Re: Make them an offer?
>The other issue is: Where is the fuel coming from? If it's coming from Earth, what are you saving by sending the fuel & vehicle up separately?
Mars is very far. You need a lot of provisions to get there, and Delta-V when you arrive. GTO is pretty much the halfway point to anywhere in the solar system in terms of Delta-V.
It makes sense to boost as much ship and supplies as you can on one rocket, and fuel on others. A fully fuelled ship that can lift off Earth, departing from orbit is just better.
Since the fuel ships are fully reusable and can make many flights, and the fuel is practically free, it can be much more economical that designing a vast ship that must launch its own weight as well as huge supplies of fuel from the ground. That excess fuel capacity from Earth liftoff isn't going to be helpful on the long journey.