Ichiban made some clever points there, why spend loads of money on a multi-billion dollar experimental project that has little to no chances of being a success? Why not use the same money to help the Starvin' Marvins of Africa or cure diseases like dibaties, Aids and Cancer.
You see Ichiban, that's what Science is.... "explore" and see beyond what you can actually see with your eyes. Looking at the current condition of the Earth, you wouldn't expect this planet to be stable for another 100 years. And that means the future generations are likely to be starving for water and foods. Honey Bees are estimated to be extinct by 2022, that cuts off major production in the Honey industry thus stepping into the Food Chain. No Honey Bees means that no Honey is going to be collected the plants all go stale.
With water trials found on Mars, a possibility of human life on other planets.. why shouldn't Science explore? Everytime there has been a major problem in this planet... Science has got a way out of it... this time it's going to be no different. Although it's a very expensive project, it's just going to help the future generations... your grandchild's child whose grand daughter's child lives in 2095