When you go to the bathroom on earth,
your're lying on gravity...pretty, pretty heavily
Imagine if you're half way done and someone shut off gravity
It'd be a mess and you float out the toilet
So, when we designed our space toilet
first to a seat belt on it, to hold you down
and then, we decided to separate solids and liquids because it is easier to store that way
So, we just have tube and have air pulled to the tube