Pat Flannery wrote:

the plan is for a manned Mars _fly-by_ by 2020; not a landing...and I
can think of few things more useless and frustrating than a manned Mars
fly-by with no landing.

Couldn't agree more. If it's about science, it's a waste of money to
send guys to fly past, if it's about exploration, a fly-by accomplishes
nothing. I can't even see it serving as a stepping-stone - there are no
legitimate questions that this answers.

Land, or send unmanned probes. The intermediate solution is a loser
in any case.

Brett