If we really are going to start launching manned missions to Mars then most of the payloads launched from earth are going to just be propellant. If you have a

If we really are going to start launching manned missions to Mars then most of the payloads launched from earth are going to just be propellant. If you have a failure with a used rocket that's just carrying propellant as its payload, then you're pretty much out just the cost of the propellant. This is probably oversimplifying things a bit, but still.