Why exactly did this experiment require a satellite? For biological purposes Martian gravity is probably closer to Earth gravity than to microgravity, and all the other conditions could be reproduced for cheaper and at larger scale in a ground laboratory.
Martian gravity is lower than earth gravity, and if the test was run in earth like gravity there could be concerns that that variable would have an effect. By conducting the experiment in lower gravity than Mars's, it's hard to doubt that martian gravity would pose a problem.
As far as I understand, the basic idea is to spin the sample in such a way that over time that the forces acting on it (including gravity) average out to 0. Apparently the processes they're interested in occur slowly enough that they behave as if in free fall.
I don't know, some people are irrational about plants and farming. Sure we've grown all kinds of plants in orbit before, but maybe potatoes need to commune with the Earth in order to grow. Turns out that potatoes obey the laws of physics and chemistry as well.
This smells of a publicity stunt to me.