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The Economic Viability of Mars Colonization (1998)

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Re: The Economic Viability of Mars Colonization (1998)

#11

Post by thatcherc »

LeifCarrotson wrote: post #9

> Assuming complete coverage of the planet with photosynthetic plants, it would take about a millennia to put the 120 mbar of oxygen in Mars' atmosphere needed to support human respiration in the open...Assuming the whole planet is covered with machines converting sunlight to electricity at 30% efficiency, and all this energy is applied to releasing oxygen from metallic oxides...atmosphere could be created in about 3…

It's kind of an unsatisfying argument, but what I've heard (back in high school biology) is that the reason you see the relatively low efficiency is because that's all the plants need. In the course of evolution there was either not a great enough reward for more efficient photosynthesis, or no mechanism developed that was able to utilize something like 30% of incoming sunlight.

It's also important to remember that plants evolved to reproduce and spread as effectively as possible, not to be as photosynthetically efficient as possible. Engineered machines, however, can be designed with energy efficiency as the main goal.

Re: The Economic Viability of Mars Colonization (1998)

#12

Post by Pica_soO »

Nokinside wrote: post #10

In the end it depends on the economic incentives, or lack of them. The potential economic value for space exploration comes from satellites orbiting earth (communication, sensors), mining near earth asteroids for rare and expensive minerals and possibly even energy generations. Moon is possible destination because it could serve Earth. From the point of financing the effort Mars is just a sink. First spend hundreds o…

It would make for a great book, the tale written by the last colonist on mars, in a slowly collapsing infrastructure - almost cut off from earth, out there nothing but howling winds and the gravestones of all the others.

"..sometimes at night, when i cant sleep, i rise and open the hatch too look out. There on the horizon it hangs, like a small blueish star- far away.

Earth.

Its in bad shape as it was when we left. Wars, global heating- and still, the most garbage strewn beach, the most abandoned dessert under blue sky, the peak of Mount Everest- i would give anything and everything to be there, not half an hour away from any voice of reason ..."

Re: The Economic Viability of Mars Colonization (1998)

#13

Post by LeifCarrotson »

Nokinside wrote: post #10

In the end it depends on the economic incentives, or lack of them. The potential economic value for space exploration comes from satellites orbiting earth (communication, sensors), mining near earth asteroids for rare and expensive minerals and possibly even energy generations. Moon is possible destination because it could serve Earth. From the point of financing the effort Mars is just a sink. First spend hundreds o…

> The potential economic value for space exploration comes from ... mining near earth asteroids for rare and expensive minerals

As the article describes, mining asteroids for rare and expensive minerals is more viable from Mars.

Earth is in an incredibly deep gravity well: it's remarkable that we made it out with just chemical rockets, an Earth just 1.5x larger in diameter would need a stack of something like 20 Saturn Vs to get one ton to LEO, instead of the 120 tons that a single rocket could do on Earth.

Mars is half the diameter of Earth. To lift fuel to an asteroid from Mars takes a rocket 1.7% the size of an equivalent rocket from Earth.

Asteroid miners will need fuel, water, food, metals, and other supplies that could be manufactured on Mars. It is many, many times cheaper to launch these from the surface of Mars than to do so from the surface of Earth.

You end up with a three-way triangle of trade between high-tech components like microchips and turbopumps from Earth, supplies from Mars, and precious metals aerobraking down into Earth's gravity well.

> Moon is possible destination because it could serve Earth.

I don't want to mirror previous stupid decisions on Earth of undervaluing potential colonies, but the Moon has very little it can offer Earth...the geology can't support the production of fuel, water, food, and metals like Mars is capable of.

Re: The Economic Viability of Mars Colonization (1998)

#14

Post by AnimalMuppet »

LeifCarrotson wrote: post #9

> Assuming complete coverage of the planet with photosynthetic plants, it would take about a millennia to put the 120 mbar of oxygen in Mars' atmosphere needed to support human respiration in the open...Assuming the whole planet is covered with machines converting sunlight to electricity at 30% efficiency, and all this energy is applied to releasing oxygen from metallic oxides...atmosphere could be created in about 3…

But not all of the plant's absorbed energy goes into releasing oxygen.

Re: The Economic Viability of Mars Colonization (1998)

#16

Post by ElBarto »

LeifCarrotson wrote: post #9

> Assuming complete coverage of the planet with photosynthetic plants, it would take about a millennia to put the 120 mbar of oxygen in Mars' atmosphere needed to support human respiration in the open...Assuming the whole planet is covered with machines converting sunlight to electricity at 30% efficiency, and all this energy is applied to releasing oxygen from metallic oxides...atmosphere could be created in about 3…

Note that converting sunlight to electricity (what the 30% figure is about) is also quite different from using sunlight to convert CO2 to glucose (what the 6% figure is about).

Apparently the first stage of photosynthesis effectively does convert sunlight to electricity and does that with 90% efficiency, which is far beyond what our technology can achieve.

Source: https://www.economist.com/the-economist-explains/2014/12/03/...

Re: The Economic Viability of Mars Colonization (1998)

#18

Post by TeMPOraL »

LeifCarrotson wrote: post #13
Nokinside wrote: post #10

In the end it depends on the economic incentives, or lack of them. The potential economic value for space exploration comes from satellites orbiting earth (communication, sensors), mining near earth asteroids for rare and expensive minerals and possibly even energy generations. Moon is possible destination because it could serve Earth. From the point of financing the effort Mars is just a sink. First spend hundreds o…

> The potential economic value for space exploration comes from ... mining near earth asteroids for rare and expensive minerals As the article describes, mining asteroids for rare and expensive minerals is more viable from Mars. Earth is in an incredibly deep gravity well: it's remarkable that we made it out with just chemical rockets, an Earth just 1.5x larger in diameter would need a stack of something like 20 Satu…

> You end up with a three-way triangle of trade between high-tech components like microchips and turbopumps from Earth, supplies from Mars, and precious metals aerobraking down into Earth's gravity well.

AFAIK it makes even more sense to try and lift manufacturing out to LEO and beyond, rather than sending raw resources downwell. Earth has plenty of natural resources that aren't extracted because there's no need, but which would be still cheaper to tap into than having them sourced from space.

This is why it's fashionable now to talk about "cislunar economy". Instead of sending raw material planetside, you'd "reinvest" extracted metals and volatiles into supporting and expanding space-based capability, ultimately leading to a small and somewhat self-sustaining economy, which could then maybe trade with Earth, offering products that benefit from being manufactured in microgravity (optical fiber is one example of such product today). I imagine such space-based economy would end up being the primary trade partner for Mars, just by virtue of being upwell.

> I don't want to mirror previous stupid decisions on Earth of undervaluing potential colonies, but the Moon has very little it can offer Earth...the geology can't support the production of fuel, water, food, and metals like Mars is capable of.

Not like, but enough to matter, at least in term of fuel and raw resources. Food, well... we have to figure out how to grow it in space anyway, so this doesn't make Moon farm any less likely than an orbital farm. Point being, Moon is a pretty useful destination. It's close and has resources, which puts it in a position of being key element in expanding space-based manufacturing and operations.

Re: The Economic Viability of Mars Colonization (1998)

#19

Post by TeMPOraL »

maxxxxx wrote: post #7
fosk wrote: post #4

Earlier quoted context omitted.

I would assume that a colony on Mars will have to rely on materials found on Mars for construction in order to be viable. Therefore after the few initial buildings built with materials shipped from Earth, there will need to be a great push to find new materials on Mars and perhaps new construction techniques to grow the colony.

I would like to see more prototyping of techniques that could be used on Mars to create materials. It seems there is a lot of handwaving but not much real-world engineering. Before we haven't run a long-term trial for surviving in some desert on earth it would be irresponsible to fly to Mars.

There is some prototyping, but not nearly enough IMO, and it doesn't hit the news that much.

I agree about desert trials (or better yet, somewhere dry and cold near the pole). I'm not sure why this isn't done - whether it's just a money issue, or there's less benefit to be had from such test than we think?

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