The toilet on the shuttle dumps urine overboard but keeps feces in a tank. They just float around in there. There is a mechanism that gets actuated once or tw

The toilet on the shuttle dumps urine overboard but keeps feces in a tank. They just float around in there. There is a mechanism that gets actuated once or twice during flight which spins a net attached to an arm through the tank, to catch all the feces, and then smashes them up against a wall of the tank. The mechanism to run the net can break. It has broken during flight before. At that point you have to put on an arm-length glove, stick your hand in the tank, then smash all the feces up against the wall of the tank manually. You need to do this because at a certain point if you open the toilet to use it there's a very good chance you'll get something floating _out_ of the toilet. Free floating zero-g human waste is an absolute nightmare.