To do much on Mars, just must send a lot of robots.  The robots have to be relatively autonomous if only because the time for radio communications is so long.  Sending a lot of suicidal people is not so good.  One reason is have a lot of dead people up there could in some respects corrupt the site under study.<p>Generally, if we are going to do much in exploration on rocks other than earth, then we need some good autonomous robots.  So, we might as well get with building the robots.<p>For sending humans to Mars, we really will be very interested in getting them back safely.  One way to have confidence that we can is what I outlined:  Let robots do essentially all of the needed work first so that by the time humans go they are really just guests of the robots that have long since been very successful -- lots of trips back and forth with no mistake-ys.