First there's the annoying part where everyone says it was a year but the actual flight time was less than a year. It is only a year in the sense that they launched and landed in March.
But getting past that, I am having trouble deciphering all the media to understand exactly what they were studying that hasn't already been studied or proven in some way before.
First, there was the flight by the Russian cosmonaut that actually lasted for more than a year. We already know that it's physically possible. So what were we studying in that respect and why not try to beat his record instead of undercutting it substantially? Just more thorough data collection that we have available with today's technology? What does that get us?
Expanding on that we know that your body degrades from the lack of exercise required in microgravity but lack of exercise also degrades your body no matter how much gravity you are subjected to. And we know and have proven that the cure is to exercise. So was it more about trying to find the best/minimal exercise routine/equipment that works in microgravity?
The psychological aspect has been mentioned a lot too yet we have done numerous studies involving isolation in recent years and have already lived through the practicality of it through the use of boats and submarines.
Then there is the effects of radiation and microgravity on DNA replication. We have already seen radiation effects in nuclear disaster zones like Chernobyl and have done studies sending seeds and animals to orbit to expose them to these types of conditions.
And then there is whatever else I'm not thinking of at the moment. So in conclusion, what science did we gain from this expedition that helps us get to Mars?