I have no clue what NASA thinks a Mars flight profile is going to look like....it is really.....odd. Their time table for SLS is so painfully slow. SLS-1 being unmanned....yeah ok, I get that. Sort of.
SLS-2 then is manned.....but two years later.
Two freaking years later until SLS flies again. Maybe. THere is some rumblings about SLS being used to throw a sample return robotic mission to Mars, but nothing certain there.
SLS-2 nobody seems to know what it will be. NASA seems ready to deorbit ISS already, I see less and less likely it will go beyond 2020. And if it is extended, by a very short amount, maybe 5 years.
NASA, if it gets its way, will construct a new small station at an L-point, that is where the off world staging will happen. I am not sure exactly how much, but also keep in mind, SLS is not going to Mars first. Its first destination will be the near-earth Asteroid that NASA wants to capture and place near the moon. The initial SLS block will be unable to support a manned flight to Mars, the whole design is to wait for the block II for that, a variant of the SLS that we may never see.
I hope we do, I hope the US will stop being pathetic, stop funding so much war and give NASA a nice budget infusion.....I hope