There has been much discussion about the extended space flight to mars, and how the astronauts will have to face, possible years of no gravity. This could be detrimental to their health. This is most likely true of course.. The question is, why on earth would you be so stupid to spend all that time in zero gravity? Simply rotate the spacecraft so you have the same amount of gravity on board as you do here at home? This is a very simple solution to solve the problem, which shouldn't even be mentioned anymore.
We are doing all these fantastic tests to see if plants grow in zero gravity.. Seems neat, but pointless if you ask me. In the future, people will be flying through space using some form of artificial gravity anyways, so I think it's not very useful info. They are currently doing tests to test mice at mars type gravity, I think this makes more sense if you ask me, since the trip there and back will be like sitting at home..
Just my two cents..