This week the Skeptics Guide to the Universe featured a fascinating interview with Lawrence Krauss, author of "the physics of Star Trek. The interview was about space exploration and human space exploration in particular.
Lawrence argued I think convincingly that if we want to bring humans to Mars it should be a one way trip. Reason? Bringing the fuel for the home trip to mars and taking all necessary safety precautions to bring the humans back to earth alive would probably cost 10-times as much as it would cost to simply send them there and then provision them with all necessities for the rest of their life.
Would anyone do this? According to Lawrence it was more difficult to find a scientist who would not do it. We should not see it as sending people to their grave, rather, think of it as building a permanent human coloni of Mars, and it suddenly sounds quite cool.
Lawrence Krauss published most of these thoughts in an NY Times article in 2009 which can be found here.