That is really an interesting question.I was wondering about it too,so I have made a little research about it online, and I found out,that a mission to Mars is rather a complex one,than anyone can imagine.The technology development plays an important role in it,and we have not achieved the level yet to send humans to the Mars.There is still not available a spacecraft large enough to hold humans and to transport them to the Mars.There are several impediments for humans to land on the Mars:the atmosphere is very thin,there is not a vehicle to lift off humans from the Mars,so it may take a long time till we have a developed technology to realize this dream.It is a dream for many astronauts, to conquer the Mars too and become part of other legendary astronauts, like:Neil Armstrong,Buzz Aldrin etc.