For a few years now, various people have postulated that possibly the best way to send a manned mission to Mars is to do away with the idea of a return to Earth, to literally go to Mars and stay there. It does away with design costs associated with having to create an entire return to earth architecture for the mission. I personally do not think it is a bad idea, for lots of reasons, but there are some major obstacles to be overcome. First, before we send a team there, we need to know a great deal more about surface conditions on Mars. There may be some extremely toxic chemical compounds there due to a different surface chemistry and surface materials reacting to Ultraviolet light which pretty much beats down on the surface worse than any bad day on the beach that you ever had. There is also the very real possibility that some form of microbial life might exist there. My gut feeling is that any life on Mars will of course be extremely tough and hardy, able to exist on not very much, and there is a possibility, albeit remote, that it might sense a human being as a very target rich environment for raw materials. Think Andromeda Strain. Older readers who remember the Viking missions might recall a very strong reaction in some of the experiments searching for life (which was later attributed to exotic Martian soil chemistry, there is still an argument about it.) We really have to conclusively establish whether or not microbes are existing at least on the surface, and if so, do they present a threat to our astronauts? If microbes do exist, we also need to establish how much of a threat we may represent to them. One celled or not, it is their planet. Then there is also the problem of contaminating Mars with Earth microbes. On a relatively short duration surface stay, it could be argued that precautions could be taken to keep Mars uncontaminated by Earth bacteria. But if an individual or groups are going there to stay, it may be much more difficult to achieve.
Then there is the entire issue of how to construct a base camp. Probably the best way to do it would be to bring the base camp with you in the form of the landing craft. We could also send up supplies on a periodic basis. That aspect of a project is a problem, as its not easy to precision land something on Mars. There is no magnetic field that will allow a compass to work, we presently don't have a GPS system for Mars, so navigating a spacecraft to a precise point on the surface is not going to be easy. In other words, your care package from Earth could land a few hundred miles away from you. We would need some kind of reliable ROV (remotely operated vehicle) to go fetch it for us. Or we will need some reliable surface or air vehicle to do it our self. It some point the camp might be able to become self sustained, indeed that should be a primary goal, but it might take time so resupply would be needed. And to be sure an added benefit of resupply from Earth would be the psychological effect of still being connected in some way to the mother planet. And make no mistake, being on Mars and knowing you are there to stay would be a psychological Mount Everest to climb. I am sure there are multitudes of people who are going to be up to the task, but since it is something beyond human experience, there is no real way to tell how a human being would deal with it. We have some experience with isolation in places like Antarctica and in space, but those people knew they had at least the possibility of return to civilization, and these explorers will have a much slimmer chance, the only possibility will come from Earth. So I believe that's going to be a monumental challenge.
Also, the equipment we take is going to have to be orders of magnitude better than anything we have used. Since spare parts are going to be several hundred million miles away, things like space suits and life support systems are going to have to operate flawlessly, and will have to be redundant on at least a factor of 3. A space suit that can operate for days on the surface instead of just brief forays from the shelter would be a good start. a portable inflatable habitat module would allow extended surface exploration, you could step inside the thing, inflate it, and at least have a survivable environment.
I also do think that the idea of sending just ONE person is foolhardy. One person who falls and breaks a leg is going to be dead. Not to mention a million other things that could happen. It would also be better to have several pairs of eyes and several brains there to observe and experience. Then there is the obvious psychological benefit of not being alone.
At any rate, the idea of a one way mission is not something we should discard for some moral discomfort. Humans have been going on one way explorations as long as there have been humans. Think where we would be if we didn't have this in us.