In the movie The Martian, a giant spacecraft known as the Hermes is used to ferry astronauts from Earth orbit to Mars' orbit.
Once in Mars orbit, the astronauts take a Mars descent vehicle to a pre-assembled hab, pre-fueled MAV,
and two large rovers waiting on the surface.
I remember that Mars Direct called for a Earth Return Vehicle to be fueled on the surface of Mars via a series of chemical reactions, similar to that in the Martian.
Putting all economic obstacles aside with building the Hermes and sending tens of tons to Mars, are there any major flaws in the Martian Mars Architecture that would prohibit a manned mission to Mars from happening? Are there any design flaws with any of the vehicles used to transport the humans, or with any life support systems?