Investor Engineering Discussions

[2daMoon]

Atmospheric pressure on Mars is way too low for that.

The existence of some atmospheric pressure may lead to application of a suit uniquely designed for use on Mars. Temperature might be another variable that has more variation on Luna than on Mars. Gravity differences will play into the design for a suit's mass as well.

With this in mind, a Mars suit may be designed that has less mass, is more flexible, etc. than what would be required on the moon.

Do you find this unlikely as a possibility worthy of any consideration by those living and working on Mars?

 

[mongo]

The existence of some atmospheric pressure may lead to application of a suit uniquely designed for use on Mars. Temperature might be another variable that has more variation on Luna than on Mars.

With this in mind, a Mars suit may be designed that is lighter, more flexible, etc. than what would be required on the moon. Do you find this unlikely as a possibility worthy of any consideration by those living on Mars?

The Martian atmosphere is 0.088 psi (13 psf) or 0.006 of Earth's. Even given 100% oxygen EVA suits that operate at 4.3psi 0.29 atm, it is only a 2% reduction in differential pressure.

 

[wipster]

I believe Bosch developed one in the 1980s, it was demo'd on a Lexus and was just amazing. Patent probably has expired on it by now.

Then there are "water balloon" based suspensions, which are very old, which are also fantastic.


Not sure what the TAM for something like that would be, however.

I believe that was Bose, not Bosch, at least originally. See below:

 

[bkp_duke]

I believe that was Bose, not Bosch, at least originally. See below:

Thanks, that was the video I recall that spurred me to do a little reading.

 

[Oil4AsphaultOnly]

Terraforming is an engineering problem. I was mostly addressing the bolded bit, below.



Any choice of "other places than Earth for humans" will include immense challenges. Any choice, in the case of a major setback on Earth, will be in a better position to preserve technology, knowledge, and hopefully continued growth for the human race.

Possibly, this cache of tech and knowledge could be used to help the survivors of an Earth catastrophe to rebuild, once the effects of any such event stabilize. Whether that opportunity is immediate or requires some significant time before a response is possible, this option of colonizing a nearby planet seems advantageous. Particularly, when compared to kicking the can down the road and taking no action to arrange for an alternative to preserve humanity's accomplishments, intact.

At this point it isn't about duplicating Earth's total environment on another planet, it is more like putting some essentials in a safe deposit box, or, keeping an off-site backup. Doing so will preserve the key factors needed for humanity to continue on, rather than start over from, depending upon the severity of the cataclysm, a stone-age reset.

Waiting to put the backup off site until after we have the tech to terraform an entire planet doesn't seem as prudent as doing it now, rather than later. Living in a bubble city and developing manufacturing and industry there while working toward making it as good as we can offers greater potential for race survival at our current level of technology and capabilities.

Mars is a better choice than Luna because it has higher gravity and an atmosphere. Higher gravity will likely be easier on the human form from both biological and functional aspects. An atmosphere reduces the complexity needed to work outside by not requiring a vacuum suit. There are other advantages to Mars over Luna, but these seem most significant.

With the realization that any attempt at terraforming Mars would yield only temporary results at best, it seems that a space colony solution (in any of the LaGrange points) would make far better (at the very least more permanent) uses of limited resources than either Mars or the Moon. The need for a backup civilization doesn't dictate that Mars is our best option.

 

[wipster]

With the realization that any attempt at terraforming Mars would yield only temporary results at best, it seems that a space colony solution (in any of the LaGrange points) would make far better (at the very least more permanent) uses of limited resources than either Mars or the Moon. The need for a backup civilization doesn't dictate that Mars is our best option.

After watching "The Expanse" and a few other shows, it seems quite obvious that because of the difference in gravity, while it would be difficult for an Earth-born human to travel back to Earth after being on Mars for a while, it would be very, very difficult, if not impossible, for a Mars-born human to travel to Earth for any length of time. An object or person on Mars weighs 37.83% of its weight on Earth. Conversely, a person is 62.17% 164% heavier on Earth than on Mars, so a person that weighs 100 lbs on Mars would weigh ~260 lbs on Earth... that would be a beatch!

However, it would be fun to go to Mars just to check it out! Where's my Mars CyberTruck?

 

[Oil4AsphaultOnly]

After watching "The Expanse" and a few other shows, it seems quite obvious that because of the difference in gravity, while it would be difficult for an Earth-born human to travel back to Earth after being on Mars for a while, it would be very, very difficult, if not impossible, for a Mars-born human to travel to Earth for any length of time. An object or person on Mars weighes 37.83% of its weight on Earth. Conversely, a person is 62.17% heavier on Earth than on Mars, so a person that weighs 100 lbs on Mars would weigh ~260 lbs on Earth... that would be a beatch!

However, it would be fun to go to Mars just to check it out! Where's my Mars CyberTruck?

The Cybertruck is celestial-body-agnostic. It can literally work anywhere (as long as the batteries are warm enough and the atmosphere isn't highly corrosive).

 

[Knightshade]

With the realization that any attempt at terraforming Mars would yield only temporary results at best, it seems that a space colony solution (in any of the LaGrange points) would make far better (at the very least more permanent) uses of limited resources than either Mars or the Moon. The need for a backup civilization doesn't dictate that Mars is our best option.

A space station wouldn't have any natural resources available to it at all, so it's not much of a backup option once the supplies from earth stop showing up.

Mars has quite a bit in the way of resources (aluminum, iron, lithium, water, etc)- and while it'd be a good while before it could be self-sufficient long term, it's at least possible.

 

[Oil4AsphaultOnly]

A space station wouldn't have any natural resources available to it at all, so it's not much of a backup option once the supplies from earth stop showing up.

Mars has quite a bit in the way of resources (aluminum, iron, lithium, water, etc)- and while it'd be a good while before it could be self-sufficient long term, it's at least possible.

A mass driver on the moon should be able to send enough raw materials to build a pretty sizeable space colony without the need launch everything from earth. Follow up with mass drivers on one of the rocks in the asteroid belt, and you'll have trillions of tons of matter slow-boated to a LaGrange point for further expansion.

Edit: for those who don't know. Mass drivers are electromagnetic "railguns" that throw mass down a linear track. You don't need much track, since lunar escape velocity is only a few m/s. If it's on an asteroid, simply point it opposite of where you want to go, and Newton's second law (and a LOT of time) will take care of the rest.

 

[Knightshade]

I guess I'm not seeing how having to go to multiple OTHER places in space to constantly bring in resources- plus produce your own gravity by spin- makes much sense for a long-term survival backup.....over a single planet that already has all that stuff locally.

 

[Oil4AsphaultOnly]

I guess I'm not seeing how having to go to multiple OTHER places in space to constantly bring in resources- plus produce your own gravity by spin- makes much sense for a long-term survival backup.....over a single planet that already has all that stuff locally.

You only need to go to multiple other places to build additional colonies. Once a colony is established, it's self-sufficient with recycling and solar power (from being significantly closer to the sun). Mars, with its leaking atmosphere and lack of a magnetic field is constantly in need of maintenance (not to mention needing a nuclear power plant, since the solar insolation is barely 1/3 that of earth's).

 

[Knightshade]

You only need to go to multiple other places to build additional colonies. Once a colony is established, it's self-sufficient with recycling and solar power (from being significantly closer to the sun).

So you're never, ever, going to need "more" of anything that wasn't already shipped there? And your recycling of literally every resource and material is 100% efficient so you're not losing anything cycle over cycle ever? For generations into the future with a growing population?


I'm gonna need to see the math on that.

Mars, with its leaking atmosphere and lack of a magnetic field is constantly in need of maintenance (not to mention needing a nuclear power plant, since the solar insolation is barely 1/3 that of earth's).

Mars of course has a BIT more surface area than any station you intend to build to populate with panels.

Granted you'll need to keep the dust off, but there's way more than plenty enough land to actually grow your power infrastructure as population grows- and to mine new resources as needed in the future- And to actually have a TON more space for actual growing populations to live in-- unlike the station idea of yours where whatever is there after construction, assuming a collapse of earth since that's the scenario we are discussing, is all you'll ever have.

 

[mongo]

So you're never, ever, going to need "more" of anything that wasn't already shipped there? And your recycling of literally every resource and material is 100% efficient so you're not losing anything cycle over cycle ever? For generations into the future with a growing population?


I'm gonna need to see the math on that.

That is the Elon given definition of a self sustaining colony. If it can't do that, it's not increasing species survivability.

 

[mongo]

Now we are talking.
View attachment 870244

Understatement of the month: "Carports" (four carports to be precise)
1200 Amp * 480V three phase = 1MW grid connection.
2MW solar
4 pedestals = 4-5MW peak
Guessing 1-2 2-hr Megapacks or 2-4 4-hr version

 

[Oil4AsphaultOnly]

So you're never, ever, going to need "more" of anything that wasn't already shipped there? And your recycling of literally every resource and material is 100% efficient so you're not losing anything cycle over cycle ever? For generations into the future with a growing population?


I'm gonna need to see the math on that.





Mars of course has a BIT more surface area than any station you intend to build to populate with panels.

Granted you'll need to keep the dust off, but there's way more than plenty enough land to actually grow your power infrastructure as population grows- and to mine new resources as needed in the future- And to actually have a TON more space for actual growing populations to live in-- unlike the station idea of yours where whatever is there after construction, assuming a collapse of earth since that's the scenario we are discussing, is all you'll ever have.

Yes, as long as the population size stays under the rated capacity of the station. Aluminium, steel, and copper are infinitely recyclable, while glass is nearly so. And plastics are recyclable given a large enough supply of cheap energy. Organic matter shouldn't need any explanation.

Also did you miss the part about "build additional colonies"? Unlike celestial bodies, you don't just try to fill every nook and cranny. If you want to support population growth, you'll have to build additional colonies, but population growth takes years, something that can be planned for. The moon mass driver can support building a colony every few years, while the asteroid delivery yields trillions of tons of matter at a time.

Contrast that to Mars, where even a jumpstart of 1,000 inhabitants would require a huge shipment of material and infrastructure. And as discussed earlier in this thread, smelting requires a HUGE amount of energy! Something that solar panels alone, producing at 1/3 of their normal output, would have tremendous difficulty to support (in addition to O2 generation, water recycling, colony-air heating, and lighting). An entire self-sustaining Mars colony (complete with habitat, machine shop, farms, and recycling plants) would have to be dropped in before it could be considered "viable". But that's millions of pounds of finished products (because of the solar panels and recycling plants). More solar panels will have to be shipped in, EVERY time energy needs grow (because silicon smelting is even more energy intensive than bauxite refining).

In contrast, solar thermal smelting is relatively easy when you're close enough to the sun. Heat, although we see it as a waste product in this time of severe climate change, is a necessary requirement for life. And heat is something Mars doesn't have much of.

 

[Knightshade]

Yes, as long as the population size stays under the rated capacity of the station.

If it's all that is left of humanity that's a pretty flat out non-starter as a limiting condition.

Mars on the other hand can expand, not infinitely, but vastly beyond the capacity of any L point station in population.

Also did you miss the part about "build additional colonies"? Unlike celestial bodies, you don't just try to fill every nook and cranny. If you want to support population growth, you'll have to build additional colonies, but population growth takes years, something that can be planned for. The moon mass driver can support building a colony every few years, while the asteroid delivery yields trillions of tons of matter at a time.

Sure as long as you always have ships, fuel, etc to move things all around the solar system.

Which still seems tons more work than just doing everything on a planet where everything is already in the same gravity well (and HAS a gravity well so you don't need to bring your own at each living habitat)

Contrast that to Mars, where even a jumpstart of 1,000 inhabitants would require a huge shipment of material and infrastructure. And as discussed earlier in this thread, smelting requires a HUGE amount of energy! Something that solar panels alone, producing at 1/3 of their normal output, would have tremendous difficulty to support (in addition to O2 generation, water recycling, colony-air heating, and lighting).

Why?

Mars has, compared to an L-point station, near infinite space for more panels. Certainly WAY more than 3x as many to make up for the distance from sun.

An entire self-sustaining Mars colony (complete with habitat, machine shop, farms, and recycling plants) would have to be dropped in before it could be considered "viable".

Yup. Elon has addressed that very point giving estimates of the mass/number of starship trips required.

But that's millions of pounds of finished products (because of the solar panels and recycling plants). More solar panels will have to be shipped in, EVERY time energy needs grow (because silicon smelting is even more energy intensive than bauxite refining).

With enough infrastructure you can make your own panels using local power. Doing so is in fact the point.

Plus- your "expand to making more stations in future years" idea would ALSO require that, but without having the materials locally to do it so now you'll need the time, energy, and fuel to extract it elsewhere and bring it to the stations.

 

[Oil4AsphaultOnly]

Mars on the other hand can expand, not infinitely, but vastly beyond the capacity of any L point station in population.

Which still seems tons more work than just doing everything on a planet where everything is already in the same gravity well (and HAS a gravity well so you don't need to bring your own at each living habitat)

Mars has, compared to an L-point station, near infinite space for more panels. Certainly WAY more than 3x as many to make up for the distance from sun.

With enough infrastructure you can make your own panels using local power. Doing so is in fact the point.

Ugh. Okay, let's get your head around the vast amounts of heat required for a foundry so that you'll see why simply having "more solar panels" isn't going to do the trick.

a single 400-watt 1 sq meter solar panel on earth only produces 150-watts on mars. Therefore a single panel on Mars would produce ~750wh per day (martian day is only 37 mins longer than an earth one). To recycle (at industrial scale, while micro foundry would need more energy) Al takes 390wh for each kg of Al. Smelting Al takes 6kwh/kg. So to "grow" just the living space, you'll need 9 sq meters of additional solar cells to make 1kg of Al per day and more additional panels to run the machines to turn the Al into sheet goods. SpaceHab (the habitation module of the ISS) weighs 5,000 kgs and is mostly aluminium.

Producing silicon wafers (pre-requisite for making photovoltaic cells) takes 340wh per sq cm, and another 1.5kwh to turn that into a solar cell. So to produce a single solar panel (ignoring the energy it took to extract and mine for those raw materials and the production of clean water to run the process) a day, it would take 18.4 mwh of energy, or 30,700 panels (not to mention the conduits, conductors, and dc-dc converters to connect all those panels together). And you'll need batteries to buffer that power too. So just to double the size of the solar field to produce 2 solar panels a day instead of just 1, you'll need that field of panels dedicated to the task for over 80 years (MUCH longer in reality, because I still didn't calculate for the energy needed to keep the panels clean and water and other chemicals and minerals in the fabrication process). That field of panels will have stopped working well before they could even build their replacement panels!

Space isn't the issue (whether on mars or in space), lack of heat is!

As for the lack of gravity, that actually helps industrial processes and is a benefit for space colonies. I get that people need gravity, but that "should" be solvable through centripetal acceleration (space colonies have very large diameters, so vertigo "shouldn't" occur). I've put the "should" in quotes, because it's only true in theory, but yet to be verified in practice.

 

[Oil4AsphaultOnly]

one more tid bit of info just to demonstrate how something as trivial as how close we are to the sun helps/hurts the survival chances. That same 400-watt panel that only produces 750wh of electricity daily on mars (and requires cleaning) would produce 9.6kwh of electricity daily as a solar shield for a space colony.

 

[mongo]

Ugh. Okay, let's get your head around the vast amounts of heat required for a foundry so that you'll see why simply having "more solar panels" isn't going to do the trick.

a single 400-watt 1 sq meter solar panel on earth only produces 150-watts on mars. Therefore a single panel on Mars would produce ~750wh per day (martian day is only 37 mins longer than an earth one). To recycle (at industrial scale, while micro foundry would need more energy) Al takes 390wh for each kg of Al. Smelting Al takes 6kwh/kg. So to "grow" just the living space, you'll need 9 sq meters of additional solar cells to make 1kg of Al per day and more additional panels to run the machines to turn the Al into sheet goods. SpaceHab (the habitation module of the ISS) weighs 5,000 kgs and is mostly aluminium.

Producing silicon wafers (pre-requisite for making photovoltaic cells) takes 340wh per sq cm, and another 1.5kwh to turn that into a solar cell. So to produce a single solar panel (ignoring the energy it took to extract and mine for those raw materials and the production of clean water to run the process) a day, it would take 18.4 mwh of energy, or 30,700 panels (not to mention the conduits, conductors, and dc-dc converters to connect all those panels together). And you'll need batteries to buffer that power too. So just to double the size of the solar field to produce 2 solar panels a day instead of just 1, you'll need that field of panels dedicated to the task for over 80 years (MUCH longer in reality, because I still didn't calculate for the energy needed to keep the panels clean and water and other chemicals and minerals in the fabrication process). That field of panels will have stopped working well before they could even build their replacement panels!

Space isn't the issue (whether on mars or in space), lack of heat is!

As for the lack of gravity, that actually helps industrial processes and is a benefit for space colonies. I get that people need gravity, but that "should" be solvable through centripetal acceleration (space colonies have very large diameters, so vertigo "shouldn't" occur). I've put the "should" in quotes, because it's only true in theory, but yet to be verified in practice.

1. Are your numbers starting from room temp with no heat recapture? Or are they based on 1 pound? My Googling says Al melting is 600kWh/ton so 600Wh/kg. Smelting from bauxite is 13-15kWh/kg
2. Foundary can use, at least in part, lenses at much higher efficiency rather than solar->electric heat.

 

[Oil4AsphaultOnly]

1. Are your numbers starting from room temp with no heat recapture? Or are they based on 1 pound? My Googling says Al melting is 600kWh/ton so 600Wh/kg. Smelting from bauxite is 13-15kWh/kg
2. Foundary can use, at least in part, lenses at much higher efficiency rather than solar->electric heat.

1. I took the numbers from this industry report (pg 28): https://www1.eere.energy.gov/manufacturing/resources/aluminum/pdfs/al_theoretical.pdf
Its energy consumption was on the low end, but it serves the purpose for illustrating the point.

2. Solar lensing would be more energy efficient, but the amount of heat you get drops significantly from solar occlusion (even a light dust storm would inhibit it, and there are MANY on Mars). Solar panels and an electric furnace would be more consistent for a foundry.