Astronauts take a simulator to go to the bathroom in space. When a astronauts go to the bathroom in space they use air instead of water.
In the bathroom in the shuttle they use straps to keep the astronauts in place. The tube in the toilet is the main part of the toilet. The tube is used for urine and for number 2. There is a equipment that you put next to the toilet to put in toilet paper.
In the simulator toilet or the practice toilet has a little camera in the toilet and you can see your stuff in a television. When you go number 2 in space they have to separated human waste an solid waste.