The Space Review: The challenges of manned Mars exploration (page 1)

Why 2040 is the earliest NASA can hope to send humans to the Red Planet - by Donald Rapp

If one examines the many specific occurrences where NASA’s Exploration Systems Architecture Study (ESAS) Report mentions the word “Mars,” it is found that essentially all of them are very thin and lacking in content. It seems quite apparent that NASA has not yet made the effort to revisit the 1990s legacy of Mars human mission analysis to any depth at all, and seems to be content (at least for now) with handwaving, platitudes, and goal statements. The likely reason for this is that NASA has its hands full right now attempting to deal with lunar missions, and Mars missions have been pushed back beyond the back burner, to the point where they have fallen off the stove.