Re: Competing with Soyuz...
>>The weight of this component is in the 100's of tons, could be launched in 2..3 parts on existing launchers. This sphere could of course be reused on multiple flights.
100's of tons? so that's at least 200 tons, a minimum of four Falcon launches, but that's to LEO, it costs a lot more fuel to get it past LEO.
To have any Mars mission, you need "Orbital Propellant Depots" and it's a whole new set of challenges, you'll vent a bare minimum of 3% a month (and that's the current theoretical best).
I'm really excited by Mars, but the US approach is very much a political one, employment and the big "Mars" ticket, the Chinese approach doesn't need this, so they are going to the Moon, they will be building bases and staging, perhaps harvesting He-3, I suspect that they will be on Mars while the US is still planning.