Given the poor track record so far for successful unmanned Mars missions (26/55, less than half), and the fact that a manned mission would have to use yet another descent method, let alone a whole lot of newly developed equipment, what would the chances for success of a first mission really look like?
Are there any studies available on how to assure mission success and crew safety? What would alternative scenarios look like for such a mission? What would possible consequences look like in the event of a breakdown?
I'm not looking for vision documents and the like I'm looking for cold hard facts.