Indeed - but as I mentioned above, it depends on the quantity that they're talking about (which they never spelled out). Also, making tiny beads is very different from a large, uniformly heated crucible.
Really? I mean, we are talking about tons, hundreds of tons of "building material"
Again, the person never specified what exactly the fibers were to be for. But there's no reason you'd expect them to be the majority or even a significant fraction of the total system mass. Reinforcing fibres in concrete are generally a single digit percentage of the total mass, often in the low single digits, if that's what they were thinking of using them for. If they were thinking of using them to make sandbags, again, that's in the low single digits as a percentage.
As for the cost of sending things to Mars: Red Dragon is looking at the five figure range, possibly the low five figure range, per kilogram. ITS is looking at the lower 4 figures and ultimately even less. But let's go with $100k per kg. 1 tonne of reinforcing fiber costs $100m to get to Mars. You'd never in your wildest dreams get a flight-ready in-situ-prototype-tested system produced and deployed to Mars, along with all of its dependencies (power, cabling, mining rover(s), rock crusher, etc, etc) for that price. Even at 10 tonnes of reinforcing fiber you couldn't justify the cost. Once you start getting into the dozens, maybe. And this is assuming $100k per kilogram cost to the Mars surface.
People often tend to overestimate in their heads the cost of getting things into destinations in space and underestimate the cost of developing complete hardware systems for use in space.
What does Mars have to offer anyone traveling there?
Rocks.
No, seriously. I know it sounds silly, but look at how much people pay for rare minerals on Earth. Would your average sheikh rather tell his guests that his countertop is made from the finest agate from Italy, or that it's made of slabs of rock from freaking Mars?
If you find precious stone on Mars, all the better (and meteorites on Mars probably count in that regard, and our probes keep stumbling across those). But I'd wager you could probably get in the 5-6 figures per kilogram in low quantities for nothing more than ordinary Mars basalts and sedimentary deposits. 4-5 figures in bulk quantities. If you can keep your launch costs down, there's probably a viable market. And if you find precious minerals on Mars (especially ones that don't naturally form on Earth), the sky's the limit. How much do you think Tiffany could earn from just a single kilogram of brilliant "Marsite" cut into individual multi-carat pieces and seated in jewelry? The sky's the limit.
The structure is not "just ice", and you should really read the linked articles before you comment. The outer shell is dyneema-reinforced ETFE membrane coated in ice. The inner shell is aerogel. The habitat (inside the inner shell) is the rocket landing stage (presumably carbon fiber or aluminum).
And ice + regolith would be permafrost, not pykrete, which is based around wood fibers. And would defeat one of the main purposes, translucency.
When you say "secondary radiation", what do you mean - bremsstrahlung and (x, n) reactions? It's okay to have some heavy elements so long as you have a sufficient total cross section of light elements, esp. hydrogen. In some regards it's actually better to mix both heavy and light elements; heavy elements block X-rays/gamma rays better.
Words matter. To put it in terms familiar to Slashdotters, it's as if the other person was using the term "RAM" to mean both RAM and hard drives, using the argument that hard drives are "random access" and "memory", and thus RAM. You don't just sit there and pretend that it's okay to grossly misuse product names, particularly for products that you actually use.
For your "steel nails" analogy, it's as if the other person was calling copper nails "steel nails" on the justification there's a couple-percent iron alloying agent in it and probably some trivial amount of carbon.
It depends on what you mean by dark. If you mean "living in pitch black", no, they won't be. If you mean "living without light comparable to sunlight", then that is absolutely true.
1,4kW/m^2 at Earth in space. 1kW/m^2 on the surface on a clear day. 600W at Mars in space. A bit less on the surface on a clear day, vastly less during a dust storm.
You do need multi-kW lights per square meter because even LED lights release much more energy as heat than light, and almost any setup loses a significant amount of stray light.
It gets even worse (from an area perspective, at least) if you go PV->electricity->lights because then you need another big loss mechanism (~80% of the energy for good traditional panels, ~65% for crazy-absurdly-expensive multijunction panels)
Which apparently can magically anchor themselves without foundations into any random substance, fit into any arbitrary cave opening, and come at no mass/volume penalty and cost nothing to engineer.
Indeed. It's not even some sort of revolutionary concept; multiple computer control systems are widespread in a number of industries, and are legally required for some purposes.
You can really go crazy with the level of redundancy if you wanted to. Have enough props that you can remain stable even with the catastrophic failure of one or more (and ensure that said "catastrophic failure" won't send a piece of shattered prop into the cabin). Have multiple linear chained motors (one for each flight control system on the craft) turning each prop, each with their own integrated motor controller. So, say, 4 props & 2 FCs = 8 motors; 6 props and 3 FCs = 18 motors; etc. Get some mass production going there. Have each flight control system be fed the same input data, and have the decisions cross-referenced to look for and flag any errors that would require the system be landed and sent in for maintenance. Isolate the batteries for each motor individually and locate them as close to their corresponding motor as structural constraints will allow, to reduce the risk of any damage that could sever their connection with the motor (as well as reducing cabling mass and losses); only non-critical, lightweight cables for charging / load balancing would need to run all the way to the main body to the (non-critical) charge controller. In addition to a hard connection, each motor controller could also have a bluetooth AD encoder, paired to its associated flight controller, so that even if its control cabling is severed, it can still communicate wirelessly as backup. In a 2 FC scenario, have 2x motors per prop required for sufficient takeoff power but 1x for steady flight and landing power; in a 3FC scenario, 3x sufficient for takeoff, 2x sufficient for steady flight and landing, 1x sufficient for emergency landing. Even in a scenario where a FC goes haywire rather than failing to off, you have the other FCs running their motors independently to try to correct the RPM on the props. Have all FCs physically separated from each other. Have all electronics EM shielded.
Like I said, you can really go crazy on redundancy if you want, there's really no upper bound. You could make it so it'd be hard for even a surface-to-air missile to take one out of the sky;) The question is how much redundancy do you actually need.
Re, parachutes: Good when you have sufficient altitude, although they do take time to open. You might be able to speed it up with a spreader gun, to some extent.
It is not the definition used. "Glass fiber" refers to fibers of silicon dioxide plus various additives to lower the melting point. "Basalt fiber" refers to fiber made from basalt, without additives. These terms aren't up for debate; that's what they actually mean. That's how they're actually used. I don't give a rat's arse if basalt fiber is "a glass" from a chemical standpoint; if you go place an order on glass fiber, it will never, ever be made from basalt. If you find a place that is melting down basalt and blowing it into fibers, they will never, ever call it glass fiber. They will always call it basalt fiber. They don't evenlook similar. Without added colorants, glass fiber in its native state is pearly white. Basalt fiber in its native state looks like brass, even tarnished brass.
Please stop misusing terminology. I'm building a freaking house from the stuff, I know what I'm talking about.
And it makes a serious practical difference, too. Not just due to the higher temperature. Or the viscosity difference. Or the difference between a multiple-material source-insensitive fiber (glass fiber) versus a single-material source-sensitive fiber (basalt). Molten basalt is also optically opaque, meaning that it's harder to heat all the way through - even with traditional gas burners, let alone a solar concentrator. So while glass usually undergoes a quick melt, the basalt in basalt fiber manufacture usually undergoes a slow, multi-hour melt to ensure even melting. The fibers are also more abrasive to the bushings than glass fiber. The resulting product is stronger than glass fiber in most measures, more UV and radiation resistant, maintains its properties over a broader temperature range, and a bunch of other differences.
A "pile of plutonium" does not a nuclear reactor make. If you're talking 239Pu, a pile of plutonium is either a "pile of nothing useful" or a "pile of soon to be a nuclear disaster". If you're talking 238Pu, depending on how fast you're talking expensive to obscene proportions. And neither generally run hot enough to melt basalt, by design; you generally try to avoid meltdown.
Engineering a new nuclear reactor designed to operate in a Mars environment at temperatures hot enough to melt basalt is a project that could easily run into the lower tens of billions of dollars. Even a small conventional modular reactor programme will run you into the billions. The latter might be necessary, depending. Nobody is going to make the former. It'd be far easier just to make the latter and use an arc furnace.
bigger problem, potentially best solved by building from local materials.
In the real world, ISRU is only cheaper than shipping from Earth for simple bulk commodities. And even then it's debatable. Shipping to Mars is expensive, no question about that. But offworld mineral prospecting programmes and offworld industrial systems engineering programmes are often even more expensive. Obviously, in the long term, you want virtually everything produced by ISRU. The question is how much can you afford to do in the early stages? And the answer is generally "only the basics". Oxygen. Propellant, maybe. Water, maybe.
Yes; that's the primary point of it. You want as much material, ideally hydrogen, between you and space as you can. Water is an excellent way to do this.
I don't doubt that it's possible; it's the rate that's the issue. Not knowing what your goal is (aka, what the fibers are for), it's hard to get a sense of how rapidly you'd need to melt it, and thus how big of a system you'd have to have.
You can use terms however you want. However, to the rest of the world who deals with engineering fibers, glass fiber is made from blowing quartz, and basalt fiber is made from blowing basalt.
Because when I want a low-risk mission, I should plan to lower a multi-dozen tonne habitat into a cave on arrival, and rappel in and climb out every day?
I get the shielding appeal, but caves aren't exactly the most desirable of locations. And they also limit you to... well, wherever you can find caves. Which may not correspond with the most interesting science or the most useful mineral resources.
It might help to actually read about the proposal before commenting. Printers are used to print two concentric shells. The outer shell is ice printed onto a dyneema-reinforced EFTE membrane (inflated). This provides radiation shielding. The inner shell is translucent silica aerogel, sent from Earth. This separates the outer "staging area", which is cold but shielded and pressurized, from the courtyard area, which is warm. Inside the courtyard is the habitat itself, which is made of the landing rocket (it lands full of the aerogel, printing hardware, etc that get used, and becomes habitable once emptied).
I think the main annoying thing about "flying cars" is not that they "don't exist", but just that aircraft are still so expensive and inconvenient to use. A new low-end Cessna still costs as much as a house, and you still have to get to and from an airport to take off.
I think the solution will have to be both regulatory and technological. You need to have it permissible to take off and land from a much smaller footprint area. But to do that you're going to have to have a huge number of technologies in place. Fully automated fly by wire - no letting Jimbob and his drunk cousins sit behind a yoke and fly the thing into a house. Plus hugely redundant safety systems, highly tested. And low noise on takeoff/landing is a must.
Interestingly, I think we're finally heading in the right direction with drones - they're basically the small scale of the technology needed for practical "flying cars". If the technology and regulatory environment for drones continues to advance and maximal allowed sizes continue to scale up in correspondence with their automation and safety features, eventually you're going to hit the size where people start asking, "Um, how come we're not putting people in these things?"
Moving to electric also is a great step in this direction. Modern electric motors can have much higher power densities than modern turboprops, and can scale down to much smaller sizes. So you can use a lot more of them per vehicle. And battery packs can be divided up into independent segments with minimal mass or cost penalty. Basically, going electric makes it much easier to add in redundancy.
I haven't followed as much the progress on reduction of prop noise, so I'm not sure what the state of the art is on that.
Very good points. Note that the ice house does use a fresnel lens pattern on the outer shell to concentrate light onto the inner shell. But it's not designed to be a "farm", just a courtyard with some agricultural production potential.
Most proposals for full-scale farms on Mars these days seem to be inflatable low-pressure domes with no radiation shielding, plus artificial lighting to function as both a light and heat source. Plants can tolerate much higher radiation levels and much lower pressures than humans can. The downside to reduced pressure domes is that you have to work in space suits, but the upside is that they're much lighter; you can get a lot more acreage for the same launch mass. An interesting compromise I've seen is to grow the plants in trays/pallets that are readily movable (on carts, on rails, or whatnot), so that you can have a small "shirtsleeves" high-pressure environment at the front of each greenhouse; when you want to work with a set of plants, you bring them in, pressurize it, then you can spend as much time you need working on them without restricted movement before moving them back. I could see that working well, for example, with greenhouses laid out radially from a central habitat, so you're relocating the plants into the main habitat and back, and anything you harvest ends up right where you need it.
If the Apollo budgets had held, there's little doubt that humans would have been on Mars by 1990. It's all about where you focus your budget priorities. The US gutted NASA to pay for Vietnam.
The US isn't really at odds with the EU. But the EU spends only a pittiance on space exploration. Russia is increasingly a shadow of its former self in regards to space exploration budgets as well. If there's going to be a new space race, it'd have to be between the US and China. Or as the new president might say, "Jina".;) India might even join in the fray as well, to try to maintain technological prestige and not be too outdone by the Chinese.
Can't (realistically) beat the sun's several hundred watts per square meter. To get that much light would take multi-kilowatt spotlights every square meter**. Plus the outer ice dome is designed as a fresnel reflector to concentrate light onto the inner insulated dome.
** Offsetting this is the cosine of the angle of the sun from the horizon, and the fact that the sun provides you no light at night. But overall, it's very difficult to match the light output of the sun!
Have you seen any basalt fiber production process that actually works like that? I haven't. I would hesitate to say that it "should", because if it did, I'd expect people to use it.
As for the heating: it's hard enough to melt things like zinc with sunlight. Hot enough to melt basalt with just sunlight? On Mars? Now that's a very tall order.
Again, you keep saying "glass". Mars is basaltic, not rhyolitic. You're talking basalt fiber. And the main mechanical properties you need for most applications are tensile/yield strength and young's modulus, as well as creep and flexural behavior. And getting the desired properties means using an appropriate source material.
And I'm still not sure for what purpose you brought this up in relation to building habitats. Basalt fiber reinforced concrete is very much a real thing (I'm actually getting ready to build a basalt fiber reinforced house), but again, it'd be much simpler/cheaper/more reliable just to import your fiber from Earth, at least while one is just getting a colony established.
I assume you mean basalt fiber, not glass fiber. Quartz sand is not readily available on Mars.
Not every basalt is suitable for use in production of basalt fiber. I have no clue how well Martian regolith would suit, and I doubt anyone else does. Either way, it's a very energy intense process involving some pretty heavy hardware; you have to basically create a molten pool of basalt (aka lava) at about 1400C and blast it through tiny nozzles into air (which is extremely thin to begin with on Mars) moving at hurricane speeds.
Yes, the simulants like JSC Mars-1A are pretty poor. It's just sifted Pu’u Nene tephra. MMS is a bit better (not as weathered), but still, they just (roughly) match major elemental concentrations, they don't have any of the "Mars specific" things like hexavalent chromium, perchlorates, etc, nor do they guarantee particular mineral forms. And "roughly" is a key term to emphasize about the ratios. But for something where you're just going to be melting it down, that probably doesn't matter too much. Again, though, "Martian basalt", like basalt on Earth, is not a single universal thing; the dust from the particular site would need to be sampled and analyzed on its own.
Were you talking about fiber production for use as loose-fill reinforcing fibers (like are used in some types of concrete) or for making into cloth to make into bags? Either way it's probably just easier to send from Earth, at least in the early phases.
Slashdot Mirror
Indeed - but as I mentioned above, it depends on the quantity that they're talking about (which they never spelled out). Also, making tiny beads is very different from a large, uniformly heated crucible.
Really? I mean, we are talking about tons, hundreds of tons of "building material"
Again, the person never specified what exactly the fibers were to be for. But there's no reason you'd expect them to be the majority or even a significant fraction of the total system mass. Reinforcing fibres in concrete are generally a single digit percentage of the total mass, often in the low single digits, if that's what they were thinking of using them for. If they were thinking of using them to make sandbags, again, that's in the low single digits as a percentage.
As for the cost of sending things to Mars: Red Dragon is looking at the five figure range, possibly the low five figure range, per kilogram. ITS is looking at the lower 4 figures and ultimately even less. But let's go with $100k per kg. 1 tonne of reinforcing fiber costs $100m to get to Mars. You'd never in your wildest dreams get a flight-ready in-situ-prototype-tested system produced and deployed to Mars, along with all of its dependencies (power, cabling, mining rover(s), rock crusher, etc, etc) for that price. Even at 10 tonnes of reinforcing fiber you couldn't justify the cost. Once you start getting into the dozens, maybe. And this is assuming $100k per kilogram cost to the Mars surface.
People often tend to overestimate in their heads the cost of getting things into destinations in space and underestimate the cost of developing complete hardware systems for use in space.
Rocks.
No, seriously. I know it sounds silly, but look at how much people pay for rare minerals on Earth. Would your average sheikh rather tell his guests that his countertop is made from the finest agate from Italy, or that it's made of slabs of rock from freaking Mars?
If you find precious stone on Mars, all the better (and meteorites on Mars probably count in that regard, and our probes keep stumbling across those). But I'd wager you could probably get in the 5-6 figures per kilogram in low quantities for nothing more than ordinary Mars basalts and sedimentary deposits. 4-5 figures in bulk quantities. If you can keep your launch costs down, there's probably a viable market. And if you find precious minerals on Mars (especially ones that don't naturally form on Earth), the sky's the limit. How much do you think Tiffany could earn from just a single kilogram of brilliant "Marsite" cut into individual multi-carat pieces and seated in jewelry? The sky's the limit.
The structure is not "just ice", and you should really read the linked articles before you comment. The outer shell is dyneema-reinforced ETFE membrane coated in ice. The inner shell is aerogel. The habitat (inside the inner shell) is the rocket landing stage (presumably carbon fiber or aluminum).
And ice + regolith would be permafrost, not pykrete, which is based around wood fibers. And would defeat one of the main purposes, translucency.
When you say "secondary radiation", what do you mean - bremsstrahlung and (x, n) reactions? It's okay to have some heavy elements so long as you have a sufficient total cross section of light elements, esp. hydrogen. In some regards it's actually better to mix both heavy and light elements; heavy elements block X-rays/gamma rays better.
Words matter. To put it in terms familiar to Slashdotters, it's as if the other person was using the term "RAM" to mean both RAM and hard drives, using the argument that hard drives are "random access" and "memory", and thus RAM. You don't just sit there and pretend that it's okay to grossly misuse product names, particularly for products that you actually use.
For your "steel nails" analogy, it's as if the other person was calling copper nails "steel nails" on the justification there's a couple-percent iron alloying agent in it and probably some trivial amount of carbon.
It depends on what you mean by dark. If you mean "living in pitch black", no, they won't be. If you mean "living without light comparable to sunlight", then that is absolutely true.
1,4kW/m^2 at Earth in space. 1kW/m^2 on the surface on a clear day. 600W at Mars in space. A bit less on the surface on a clear day, vastly less during a dust storm.
You do need multi-kW lights per square meter because even LED lights release much more energy as heat than light, and almost any setup loses a significant amount of stray light.
It gets even worse (from an area perspective, at least) if you go PV->electricity->lights because then you need another big loss mechanism (~80% of the energy for good traditional panels, ~65% for crazy-absurdly-expensive multijunction panels)
What's the energy density for? People mainly want flying cars to commute to work without traffic and the like. Aka short distances.
Which apparently can magically anchor themselves without foundations into any random substance, fit into any arbitrary cave opening, and come at no mass/volume penalty and cost nothing to engineer.
Indeed. It's not even some sort of revolutionary concept; multiple computer control systems are widespread in a number of industries, and are legally required for some purposes.
You can really go crazy with the level of redundancy if you wanted to. Have enough props that you can remain stable even with the catastrophic failure of one or more (and ensure that said "catastrophic failure" won't send a piece of shattered prop into the cabin). Have multiple linear chained motors (one for each flight control system on the craft) turning each prop, each with their own integrated motor controller. So, say, 4 props & 2 FCs = 8 motors; 6 props and 3 FCs = 18 motors; etc. Get some mass production going there. Have each flight control system be fed the same input data, and have the decisions cross-referenced to look for and flag any errors that would require the system be landed and sent in for maintenance. Isolate the batteries for each motor individually and locate them as close to their corresponding motor as structural constraints will allow, to reduce the risk of any damage that could sever their connection with the motor (as well as reducing cabling mass and losses); only non-critical, lightweight cables for charging / load balancing would need to run all the way to the main body to the (non-critical) charge controller. In addition to a hard connection, each motor controller could also have a bluetooth AD encoder, paired to its associated flight controller, so that even if its control cabling is severed, it can still communicate wirelessly as backup. In a 2 FC scenario, have 2x motors per prop required for sufficient takeoff power but 1x for steady flight and landing power; in a 3FC scenario, 3x sufficient for takeoff, 2x sufficient for steady flight and landing, 1x sufficient for emergency landing. Even in a scenario where a FC goes haywire rather than failing to off, you have the other FCs running their motors independently to try to correct the RPM on the props. Have all FCs physically separated from each other. Have all electronics EM shielded.
Like I said, you can really go crazy on redundancy if you want, there's really no upper bound. You could make it so it'd be hard for even a surface-to-air missile to take one out of the sky ;) The question is how much redundancy do you actually need.
Re, parachutes: Good when you have sufficient altitude, although they do take time to open. You might be able to speed it up with a spreader gun, to some extent.
It is not the definition used. "Glass fiber" refers to fibers of silicon dioxide plus various additives to lower the melting point. "Basalt fiber" refers to fiber made from basalt, without additives. These terms aren't up for debate; that's what they actually mean. That's how they're actually used. I don't give a rat's arse if basalt fiber is "a glass" from a chemical standpoint; if you go place an order on glass fiber, it will never, ever be made from basalt. If you find a place that is melting down basalt and blowing it into fibers, they will never, ever call it glass fiber. They will always call it basalt fiber. They don't even look similar. Without added colorants, glass fiber in its native state is pearly white. Basalt fiber in its native state looks like brass, even tarnished brass.
Please stop misusing terminology. I'm building a freaking house from the stuff, I know what I'm talking about.
And it makes a serious practical difference, too. Not just due to the higher temperature. Or the viscosity difference. Or the difference between a multiple-material source-insensitive fiber (glass fiber) versus a single-material source-sensitive fiber (basalt). Molten basalt is also optically opaque, meaning that it's harder to heat all the way through - even with traditional gas burners, let alone a solar concentrator. So while glass usually undergoes a quick melt, the basalt in basalt fiber manufacture usually undergoes a slow, multi-hour melt to ensure even melting. The fibers are also more abrasive to the bushings than glass fiber. The resulting product is stronger than glass fiber in most measures, more UV and radiation resistant, maintains its properties over a broader temperature range, and a bunch of other differences.
1. That's transparent aluminum oxide, not transparent aluminum.
2. It was a Star Trek reference.
A "pile of plutonium" does not a nuclear reactor make. If you're talking 239Pu, a pile of plutonium is either a "pile of nothing useful" or a "pile of soon to be a nuclear disaster". If you're talking 238Pu, depending on how fast you're talking expensive to obscene proportions. And neither generally run hot enough to melt basalt, by design; you generally try to avoid meltdown.
Engineering a new nuclear reactor designed to operate in a Mars environment at temperatures hot enough to melt basalt is a project that could easily run into the lower tens of billions of dollars. Even a small conventional modular reactor programme will run you into the billions. The latter might be necessary, depending. Nobody is going to make the former. It'd be far easier just to make the latter and use an arc furnace.
In the real world, ISRU is only cheaper than shipping from Earth for simple bulk commodities. And even then it's debatable. Shipping to Mars is expensive, no question about that. But offworld mineral prospecting programmes and offworld industrial systems engineering programmes are often even more expensive. Obviously, in the long term, you want virtually everything produced by ISRU. The question is how much can you afford to do in the early stages? And the answer is generally "only the basics". Oxygen. Propellant, maybe. Water, maybe.
Yes; that's the primary point of it. You want as much material, ideally hydrogen, between you and space as you can. Water is an excellent way to do this.
I don't doubt that it's possible; it's the rate that's the issue. Not knowing what your goal is (aka, what the fibers are for), it's hard to get a sense of how rapidly you'd need to melt it, and thus how big of a system you'd have to have.
You can use terms however you want. However, to the rest of the world who deals with engineering fibers, glass fiber is made from blowing quartz, and basalt fiber is made from blowing basalt.
Neither are produced from clays.
Because when I want a low-risk mission, I should plan to lower a multi-dozen tonne habitat into a cave on arrival, and rappel in and climb out every day?
I get the shielding appeal, but caves aren't exactly the most desirable of locations. And they also limit you to... well, wherever you can find caves. Which may not correspond with the most interesting science or the most useful mineral resources.
It might help to actually read about the proposal before commenting. Printers are used to print two concentric shells. The outer shell is ice printed onto a dyneema-reinforced EFTE membrane (inflated). This provides radiation shielding. The inner shell is translucent silica aerogel, sent from Earth. This separates the outer "staging area", which is cold but shielded and pressurized, from the courtyard area, which is warm. Inside the courtyard is the habitat itself, which is made of the landing rocket (it lands full of the aerogel, printing hardware, etc that get used, and becomes habitable once emptied).
I think the main annoying thing about "flying cars" is not that they "don't exist", but just that aircraft are still so expensive and inconvenient to use. A new low-end Cessna still costs as much as a house, and you still have to get to and from an airport to take off.
I think the solution will have to be both regulatory and technological. You need to have it permissible to take off and land from a much smaller footprint area. But to do that you're going to have to have a huge number of technologies in place. Fully automated fly by wire - no letting Jimbob and his drunk cousins sit behind a yoke and fly the thing into a house. Plus hugely redundant safety systems, highly tested. And low noise on takeoff/landing is a must.
Interestingly, I think we're finally heading in the right direction with drones - they're basically the small scale of the technology needed for practical "flying cars". If the technology and regulatory environment for drones continues to advance and maximal allowed sizes continue to scale up in correspondence with their automation and safety features, eventually you're going to hit the size where people start asking, "Um, how come we're not putting people in these things?"
Moving to electric also is a great step in this direction. Modern electric motors can have much higher power densities than modern turboprops, and can scale down to much smaller sizes. So you can use a lot more of them per vehicle. And battery packs can be divided up into independent segments with minimal mass or cost penalty. Basically, going electric makes it much easier to add in redundancy.
I haven't followed as much the progress on reduction of prop noise, so I'm not sure what the state of the art is on that.
Very good points. Note that the ice house does use a fresnel lens pattern on the outer shell to concentrate light onto the inner shell. But it's not designed to be a "farm", just a courtyard with some agricultural production potential.
Most proposals for full-scale farms on Mars these days seem to be inflatable low-pressure domes with no radiation shielding, plus artificial lighting to function as both a light and heat source. Plants can tolerate much higher radiation levels and much lower pressures than humans can. The downside to reduced pressure domes is that you have to work in space suits, but the upside is that they're much lighter; you can get a lot more acreage for the same launch mass. An interesting compromise I've seen is to grow the plants in trays/pallets that are readily movable (on carts, on rails, or whatnot), so that you can have a small "shirtsleeves" high-pressure environment at the front of each greenhouse; when you want to work with a set of plants, you bring them in, pressurize it, then you can spend as much time you need working on them without restricted movement before moving them back. I could see that working well, for example, with greenhouses laid out radially from a central habitat, so you're relocating the plants into the main habitat and back, and anything you harvest ends up right where you need it.
If the Apollo budgets had held, there's little doubt that humans would have been on Mars by 1990. It's all about where you focus your budget priorities. The US gutted NASA to pay for Vietnam.
The US isn't really at odds with the EU. But the EU spends only a pittiance on space exploration. Russia is increasingly a shadow of its former self in regards to space exploration budgets as well. If there's going to be a new space race, it'd have to be between the US and China. Or as the new president might say, "Jina". ;) India might even join in the fray as well, to try to maintain technological prestige and not be too outdone by the Chinese.
Can't (realistically) beat the sun's several hundred watts per square meter. To get that much light would take multi-kilowatt spotlights every square meter**. Plus the outer ice dome is designed as a fresnel reflector to concentrate light onto the inner insulated dome.
** Offsetting this is the cosine of the angle of the sun from the horizon, and the fact that the sun provides you no light at night. But overall, it's very difficult to match the light output of the sun!
The ice does not prevent gas permeation; it's a dyneema (UHMWPE)-reinforced ETFE membrane that does that.
The ice certainly doesn't hurt, mind you.
Have you seen any basalt fiber production process that actually works like that? I haven't. I would hesitate to say that it "should", because if it did, I'd expect people to use it.
As for the heating: it's hard enough to melt things like zinc with sunlight. Hot enough to melt basalt with just sunlight? On Mars? Now that's a very tall order.
Again, you keep saying "glass". Mars is basaltic, not rhyolitic. You're talking basalt fiber. And the main mechanical properties you need for most applications are tensile/yield strength and young's modulus, as well as creep and flexural behavior. And getting the desired properties means using an appropriate source material.
And I'm still not sure for what purpose you brought this up in relation to building habitats. Basalt fiber reinforced concrete is very much a real thing (I'm actually getting ready to build a basalt fiber reinforced house), but again, it'd be much simpler/cheaper/more reliable just to import your fiber from Earth, at least while one is just getting a colony established.
I assume you mean basalt fiber, not glass fiber. Quartz sand is not readily available on Mars.
Not every basalt is suitable for use in production of basalt fiber. I have no clue how well Martian regolith would suit, and I doubt anyone else does. Either way, it's a very energy intense process involving some pretty heavy hardware; you have to basically create a molten pool of basalt (aka lava) at about 1400C and blast it through tiny nozzles into air (which is extremely thin to begin with on Mars) moving at hurricane speeds.
Yes, the simulants like JSC Mars-1A are pretty poor. It's just sifted Pu’u Nene tephra. MMS is a bit better (not as weathered), but still, they just (roughly) match major elemental concentrations, they don't have any of the "Mars specific" things like hexavalent chromium, perchlorates, etc, nor do they guarantee particular mineral forms. And "roughly" is a key term to emphasize about the ratios. But for something where you're just going to be melting it down, that probably doesn't matter too much. Again, though, "Martian basalt", like basalt on Earth, is not a single universal thing; the dust from the particular site would need to be sampled and analyzed on its own.
Were you talking about fiber production for use as loose-fill reinforcing fibers (like are used in some types of concrete) or for making into cloth to make into bags? Either way it's probably just easier to send from Earth, at least in the early phases.