Changing the subject:From what we have learned from IAC speech, we can probably safely assume that:(a) ITS won't be carrying ready-made tuna can habitats to Mars (there is no pod-dropping)(b) There is no need to carry ready-made habs (wedge, or any other shape) because the ITS itself can serve as a temporary hab on Mars(c) Habitat components will be delivered flat-packed for assembly on Mars (like all other cargo)These assumptions lead to the conclusion that the very first humans on Mars (on a long-stay mission) will be building habitats. Agree / disagree with this conclusion? What kind of amazing, spacious habitats can we envision? What selection of habitat building components would you want in your flat-packed containers?
Hmm. You will build your habitat only where you can find lots of easily accessible water. Like a glacier with thick ice you can drill, heat and pump. And if you do that anyway, melting caverns and tunnels into the ice would be the easiest way to build habitats from Mars resources. There are glaciers with ice up to half a mile thick and stretching for tens of miles, this would give you not only lots of propellants but also lots of room to live in. You'd need insulation to keep the warmth in and the ice from melting but this is much easier than building pressure vessels. Gives perfect radiation shielding too.Actually building your habitat on the surface isn't going to scale very well. You will only be able to build quite small habitats, interconnected with lots of airlocks just to make sure that a single leak doesn't seal your fate. Makes lots and lots of stuff you will have to bring along and to maintain and to care for.Glaciers will be structurally sound, so you have much more freedom in fitting them out and using them long-term. And once the machinery is in place you can continue to expand your habitats for a long time and use your cargo capacities to bring more useful stuff than pressure vessels (or components of pressure vessels).
What is the structure made of that supports the weight of the regolith cover. I can't see a giant window like that being remotely practical, it can't be transported or installed without some huge equipment and how it can be sealed effectively is a huge issue.
Quote from: Impaler on 10/11/2016 05:31 amWhat is the structure made of that supports the weight of the regolith cover. I can't see a giant window like that being remotely practical, it can't be transported or installed without some huge equipment and how it can be sealed effectively is a huge issue.The structure is made from panels that are strong in tension.The weight of 2 m of regolith is about 2 tonnes per m2 on Mars, the internal pressure of the habitat is 100 000 kPa, or just about 10 tonnes per m2. So the building is not crushable. It rather tends to explode!The window is built as a group of panes, exactly like the main window of the ITS Spaceship. Whatever works for it will work for the house.The whole thing is shipped flat, and assembled Ikea fashion at Mars.It could be assembled on site and should keep its shape, rather like a geodesic dome. Then an airtight membrane is added to the inside, like rolls of vapor barrier here on Earth. Pressure is added to the minimum breathable and the whole think is leak tested. Then you can add a first layer of regolith on top.Pressure is increased to full Earth normal, and the rest of the regolith is added.The building is always under tension, never under compression.Here is a more detailed version. I've decided to do without the awning for this one. Kids are just warned not to play all day beside the big window :-)At 5 kg/m2 it would weigh about 3 tonnes, including the floor.The main limit to how big this design can be is the angle of repose of the regolith (ends up looking like a pyramid pretty fast as it gets taller) and the safe tension loading of the structure. Using light pipes, you can extend it lengthwise pretty much forever, but there probably is an optimum size for a volume on Mars versus the risk of catastrophic failure.I wonder about the behavior over time? Tension structures are fragile in some ways and creep may be an issue? The water and oxygen will take their toll as well.The regolith might be tailing from the water mines? Depends if the water can be found in clean sheets or if ot is bounded with other materials, I expect
Quote from: lamontagne on 10/11/2016 01:08 pmQuote from: Impaler on 10/11/2016 05:31 amWhat is the structure made of that supports the weight of the regolith cover. I can't see a giant window like that being remotely practical, it can't be transported or installed without some huge equipment and how it can be sealed effectively is a huge issue.The structure is made from panels that are strong in tension.The weight of 2 m of regolith is about 2 tonnes per m2 on Mars, the internal pressure of the habitat is 100 000 kPa, or just about 10 tonnes per m2. So the building is not crushable. It rather tends to explode!The window is built as a group of panes, exactly like the main window of the ITS Spaceship. Whatever works for it will work for the house.The whole thing is shipped flat, and assembled Ikea fashion at Mars.It could be assembled on site and should keep its shape, rather like a geodesic dome. Then an airtight membrane is added to the inside, like rolls of vapor barrier here on Earth. Pressure is added to the minimum breathable and the whole think is leak tested. Then you can add a first layer of regolith on top.Pressure is increased to full Earth normal, and the rest of the regolith is added.The building is always under tension, never under compression.Here is a more detailed version. I've decided to do without the awning for this one. Kids are just warned not to play all day beside the big window :-)At 5 kg/m2 it would weigh about 3 tonnes, including the floor.The main limit to how big this design can be is the angle of repose of the regolith (ends up looking like a pyramid pretty fast as it gets taller) and the safe tension loading of the structure. Using light pipes, you can extend it lengthwise pretty much forever, but there probably is an optimum size for a volume on Mars versus the risk of catastrophic failure.I wonder about the behavior over time? Tension structures are fragile in some ways and creep may be an issue? The water and oxygen will take their toll as well.The regolith might be tailing from the water mines? Depends if the water can be found in clean sheets or if ot is bounded with other materials, I expectA couple of minor points that may be good for consideration; 1. Build the actual structural framework inside of the pressure envelope. This would make the whole operation simpler, and could use lower pressure to do the leak checking. 2. Use Bigelow style pressure envelopes. The wall thickness will minimize puncture potential, add additional radiation protection, and minimize envelope creep. 3. The windows could be reinforced with clear Plexiglas panes, between panes of the aluminum glass. Pressure could then be reduced more gradually between the inner panes and outer panes, thus dissipating the pressure stress between the inner and outer window surfaces. The Plexiglas would also help reduce radiation coming in from outside. (On a side note; the space between panes could also be filled with a O2 and CO2 sensitive polymer gel that would be clear, but harden if exposed to either O2 or CO2. this could prevent pressure leaks through the windows).
1. Hollow out hole in glacier.2. Spray urethane foam to insulate and air tight seal.3. Install door and window.Done
Quote from: rsdavis9 on 10/11/2016 04:00 pm1. Hollow out hole in glacier.2. Spray urethane foam to insulate and air tight seal.3. Install door and window.DoneDo glaciers not move, even on Mars??? what I mean, here on Earth Glaciers do creep.. slowly, so there might be a problem with structural integrity.edit for clarification...
... it will should be fine if you do not dig to deep - you will have to go below 29 m before the pressure even overcomes 1 atm of hab pressurization.
According to Wikipedia you need about 50 m of ice on Earth before the pressure becomes great enough for it to start deforming. As you noted there is likely not much flow on Mars which combined with the lower gravity and the much lower average temperature means that it will should be fine if you do not dig to deep - you will have to go below 29 m before the pressure even overcomes 1 atm of hab pressurization.