Quote from: meekGee on 01/19/2019 10:11 pmOr, work the Sprung on making pressurized domes. The overall design will be different, but the devil's in the details and they have a lot of real-life experience.Yes, Sprung, capital-S, the company, might have the skills to design a pressure vessel suitable for Mars. But it won't be based on the "sprung" spans, little-s, that their existing buildings are based around. The second sentence was the point I was trying to make.People have a tendency to point at a picture of pretty much any novel Earth-structure and shout "on Mars!" But it's meaningless if you don't look at how that structure works on Earth, look at the problem it's trying to solve, and ask whether that's at all related to the completely different requirements you need on Mars. There's nothing about Sprung's self-supporting buildings, or geodesic domes to bring it back to the topic, or domes in general, that makes them suitable for Mars just because they vaguely resemble the sci-fi images we all know and love.Does Sprung (the company) have the engineering skills to design a Mars-hab? Maybe. Does their experience with building clever compressive structures on Earth give them any more insight that any other company with structural engineering experience on Earth? No.
Or, work the Sprung on making pressurized domes. The overall design will be different, but the devil's in the details and they have a lot of real-life experience.
What would it take to be able to manufacture glass on Mars to avoid transporting from earth? Natural gas (Methane) for melting the silicone can be made for rocket fuel and maybe some used to manufacture glass. Can it be made like safety glass on car windshields on Mars? Making the glass panels small and double pane to interlock in a geodesic dome or tunnel would allow for easier repair without depressurizing the habitat.
Glass and ceramicsMars clays should enable the manufacture of ceramics, while silica, ubiquitous, will allow producing glass. One problem though: the Martian silica will be obtained from a sand rich in Fe2O3 iron oxide (hematite) that we must get rid of if we want to get a good optical quality glass. This can be done by reducing Fe2O3 with carbon monoxide and segregating the iron thus obtained. From glass, we can also manufacture glass fiber, useful for elaborating composites.
Energy to Produce Glass per KG(from sand, etc): 18-35 MJ (5 to 9.7 KWhrs)
Electric melting of glass is not efficient, electric heat is not efficient in general, at least on earth. A gas furnace can melt glass easier, unless solar can be concentrated directy on the silicone, or directly on iron, aluminum etc and can get hot enough. The plant you referenced got the water to 550° C. Pretty hot, but silicone melts at 1,400° C, while aluminum is 660° C. Can a reflective solar plant on Mars get as hot as it does on earth?
A light furnace can heat things as hot as the thing that emits the light, which in this case is the surface of the sun, so 3500°C.
Making glass from raw materials is a complex process, requiring enough chemicals and purification steps, many which will need to be different enough on Mars, that picking a heat-source will be the smallest issue to solve.
Quote from: spacenut on 01/20/2019 05:59 pmElectric melting of glass is not efficient, electric heat is not efficient in general, at least on earth. A gas furnace can melt glass easier, unless solar can be concentrated directy on the silicone, or directly on iron, aluminum etc and can get hot enough. The plant you referenced got the water to 550° C. Pretty hot, but silicone melts at 1,400° C, while aluminum is 660° C. Can a reflective solar plant on Mars get as hot as it does on earth?I think you mean silica (silicon dioxide)
Quote from: Paul451 on 01/20/2019 11:45 pmMaking glass from raw materials is a complex process, requiring enough chemicals and purification steps, many which will need to be different enough on Mars, that picking a heat-source will be the smallest issue to solve.Glass can be pure silica,
flotation glass method (liquid glass on liquid metal bed), and here the gravity may even help because normally molten glass spreads until it's 6mm thick. We may find the gravity lets it settle at 1.8mm thick.
I missed a point. Yes, methane and oxygen can be probably separated/combined from the existing atmosphere and water in quantities sufficient for rocket fuel, but I doubt that sufficient can be obtained to make glass. It may even turn out that hydrolox is the only reasonably efficient rocket fuel. Any way you figure it, it will be quite a while before sufficient energy is available to make glass of reasonable quality for any purpose. Just off the top of my head, I suspect that thicknesses of frozen water will make the best windows for quite some time, as well as providing good radiation protection. We might want to take along some surface films to reduce deliquescence and/or evaporation.
Quote from: Lampyridae on 01/21/2019 12:12 pmQuote from: Paul451 on 01/20/2019 11:45 pmMaking glass from raw materials is a complex process, requiring enough chemicals and purification steps, many which will need to be different enough on Mars, that picking a heat-source will be the smallest issue to solve.Glass can be pure silica,Except even high quality sand is not pure silica.Getting from sand to silica is a complex, chemical hungry process. With enough steps (remembering that you have to make everything else you use) that the step "heat the purified silica until it melts" is such a trivial step, it can be ignored or treated as solved in a thread like this one. It's everything else that needs to be fleshed out.
Quote from: Lampyridae on 01/21/2019 12:12 pmflotation glass method (liquid glass on liquid metal bed), and here the gravity may even help because normally molten glass spreads until it's 6mm thick. We may find the gravity lets it settle at 1.8mm thick.What's the reasoning for the latter? I would assume the minimum thickness is a function of gravity and surface tension. Less gravity, the greater the effect of surface tension and so the thicker the glass panes (without further rolling/stretching.)