Bob Zubrin’s not enamored with NASA’s Mars proposal:

The kindest thing that can be said about this quintuple rendezvous plan is that it is probably the unplanned product of the pathology of bureaucracy, rather than the willful madness of any individual. For a fifth of its cost, NASA could fly five simple direct sample return missions, each of which would have (at least) five times its chance of mission success. So it’s hard to imagine any sane person inventing it on purpose.