Studying zero gravity is all very nice but if you want to travel in space for long periods of time you design a spaceship that can spin to simulate near earth conditons. We and the russians have spent billions on studying the effects of weightlessness on humans, only to learn that we dont like it very much. So stop wasting our precious dollars on such stuff and spend it on designing a craft that has the ability to carry humans safely in space. Most all we needed to know about weightlessness was learned on Mir, which was that humans need to limit time weightless to be healthy. Say you want to fly to Mars, you design a method of teathering your human capsule to a spent fuel tank, spin it and off you go.

George, excellent point. We need not spend money on studing effects of weightlessness on the human body. I say we take that money, channel it into building spacecraft that spin to their destination, and study micro-gravity effects on crew members of the ISS (which won't be spinning). There is no law that requires us to travel to Mars without gravity, its easy to accomplish compared to other technical obsticals.

Is it just me or you guys missing the point....
I think they are studying how Mars gravity will
effect mice.....not weightlessness....

GK, true, but we already know that 0 g's is harmful for any significant amount of time. I believe the average person loses about an ounce of muscle mass per month of weightless even with heavy excercise. Being exposed to .3 g's would only slow down that rate and maybe the final muscle lose bottom limit would be higher.
Im just saying, we have detailed information on this subject already, the risks don't justify not going.

I believe the station does not produce any artificial gravity in order to study a mars gravity setting or situation. That would be and is why we are trying to go back to the moon. Moon diameter 3,476km while the Mars is 6,788km granted the moon is small but that is as close to a natural body as we can get, the earth is 12,756km just for reference.