> > Would the toilets need a slightly different design due to the > different > gravity?
You just caught me half way through "Green Mars", so I am thinking along those lines. The amount of free water is not an issue. It just needs to be melted first. There should be adequate water for a toilet. However some of the issues I can think of offhand are: Less gravity reduces the draining force of the water as it leaves the bowl. It will take more water to clean the same bowl on earth. This Aero-matic toilet bowl (TM) would also have to be wider in circumference, since water is lighter. Since nitrogen is very rare, I would expect that colonists would want to save this valuable shit for its elemental components. They may actually get paid for using the bowl. A whole new cottage industry of washroom vendors peddling people to use their hygienic facilities for free. Air pressure will also impact the toilet function, since it relies upon the outside air pressure to "power" the toilet. A differential between the sewer pipe pressure and the outside toilet could result in a pressure retrograde, thereby causing the water to either drain out of the toilet, or cause it to gush out of the toilet. Since any toilet would be housed in a closed system (a biosphere of some sort), there would be a need to cap off the sewer vent, to prevent build up of methane in the biosphere (the methane would have a lot of value, with hydro-carbons being rare on Mars as well). This would require a precise pressure valve to maintain equilibrium. If the biosphere was to suddenly lose some pressure, this could theoretically cause water to shoot out of the toilets. Those are my thoughts on it. Nerd From Hell > > And since there's not quite as much water on Mars as there is > on Earth, > would it be a good idea to design an even lower-flow toilet? Or maybe > use something other than water for waste removal? > > Julia > >
