Wasted opportunity! The premise of this documentary and of the experiment it is based on, is that there are two twins, identical twins, that are both astronauts working for NASA. A quite fortunate confluence of events that spawns the ideal conditions to perform comparative analysis of life in space and life on earth since a control group identical to the specimen is the most ideal single-subject setup one could desire. But the movie fails us on the most important aspect. It doesn't present us the results. There's no data or information to be gained regarding the specific unique situation here portrayed. Instead, we are shown what an year in space looks like. Definitely interesting, just wasted potential. As a horizontal cut about one of humanity's greatest achievements, it's more fascinating than most of what's produced today. Just be aware that if you've already seen one of the multitudes of tours of the ISS, then you're probably already familiar with a great fraction of the content here presented.