The problem with this is the delta-V requirement to actually send it to Mars. Even with in-orbit refueling as proposed by SpaceX you'd probably require a big ro

The problem with this is the delta-V requirement to actually send it to Mars. Even with in-orbit refueling as proposed by SpaceX you'd probably require a big rocket and/or a lot of fuel to send something really massive. Ion rockets might be used but that would make the trip take forever and would be very costly. There do exist very slow low-energy transfer orbit trajectories, but AFIAK those require you to start at various Lagrange points. So maybe it could be done but you'd have to build it at a Lagrange point, destroying the cost savings, and it would take forever to deliver to Mars.