The required life support systems are at best still at early stage development - projects that use novel technologies take a lot longer than expected ? it would be foolish to presume that a system to sustain human life on Mars is going to be any different.

Even if the physical basis for survival can be achieved, the psychological problems are enormous.

An update on the Mars One project, and a look at the Paragon Study

Summary specifications used in the Paragon study.

Aside from life support, there is the technolgical challenge of getting everything to Mars and setting up a long term, workable habitat

Is the Mars One project a serious attempt at a manned landing on Mars? There is little to suggest it is.

Paragon study overview, how does it measure up as an initial concept study?

Some of the issues and limitations of the Paragon Study