Why colonize Mars and not the Moon?

[lifeonmercury]

Will the Mars One mission establish the settlement near Mars' equator? Apparently the temperature there can get well above freezing.

 

[Jeroen537]

Before speculating on colonization of Mars, a note of caution. It may be that travel to Mars, let alone living on Mars, is simply no feasible option for humans.

Recently, Nature published a paper on the risk of cosmic radiation for the Central Nervous System (CNS). A summary of this and related research can be found at http://www.sciencealert.com/mars-bound-astronauts-risk-long-term-brain-damage-and-chronic-dementia. This document also contains a link to the Nature paper.

So far, no believable countermeasures to stop cosmic radiation from inflicting damage to passengers on a spaceship have been suggested, and in view of the enormous energy of cosmic radiation these may well prove unattainable. The possibility of repairing damage to the CNS on the fly is pure speculation at this point.

So, fun as it is to dream about space colonization, it is far from certain that it will ever be possible.

 

[Joshua_T]

It seems to me that the most common reason for wanting to colonize Mars is in case of an extinction level event on Earth. If all that you are trying to do is protect the human race, why not spend the money and resources developing ways to counter any extinction like event here on Earth?

It could be things like medical technology to prevent disease, anti-asteroid systems to counter asteroids, or even make orbital nuclear defense systems to defend against aliens (I doubt they exist but its good to be prepared). All of this would be a lot cheaper and happen in a much shorter time than colonizing and terra-forming Mars.

I really like Musk's work and its a great idea to colonize another planet, but I don't think that its the most practical way of protecting the human race.

Think of the Earth as a military base that you are trying to protect against a major scale attack. Wouldn't it make more sense to spend all of the resources that you have on making sure that it can withstand any attack rather than making a smaller base in the mountains as a backup in case the first is destroyed?

 

[mfb]

Is it possible to estimate the order of magnitude probability of a 500 km interstellar object getting anywhere near Earth in the next e.g. 100 million years? I have no idea how to quantify this; my intuition suggests many orders of magnitude less than other possible extinction scenarios.

500 km: extremely unlikely.
10 km: Quite likely. We have impacts of that size on average every 50 million years.

However Jupiter steers most of these away from Earth and even if it didn't, the Earth really is a very small target, much more easy to miss than to hit.

Jupiter steers as many towards Earth as it steers them away - apart from the few that hit Jupiter. It makes the orbits unstable over long timescales, so something either hits or gets kicked away after a while.

One or more satellites could be parked in an orbit around the Sun from where both Earth and Mars are contactable at these times.
It would act as a relay for signals, (so slightly greater transmission times, but that's better than no signals)

Transmission times are not the main issue. A relay satellite reduces bandwidth massively. You can't use "small spacecraft communicates with large Earth-based dish" any more, you need spacecraft - spacecraft communication over interplanetary distances. Better than no signal, but transmission will be limited to the most urgent things during opposition. This is just a 2-3 weeks period every 26 months, luckily.

Will the Mars One mission establish the settlement near Mars' equator? Apparently the temperature there can get well above freezing.

Mars One is a PR stunt, nothing more.

Recently, Nature published a paper on the risk of cosmic radiation for the Central Nervous System (CNS). A summary of this and related research can be found at http://www.sciencealert.com/mars-bound-astronauts-risk-long-term-brain-damage-and-chronic-dementia. This document also contains a link to the Nature paper.

Experiments with mice. The radiation levels for a trip to Mars are higher than in low Earth orbit, but the mission to Mars (one way flight time) is significantly shorter than the longest trips to orbit.

 

[UsableThought]

So far, no believable countermeasures to stop cosmic radiation from inflicting damage to passengers on a spaceship have been suggested, and in view of the enormous energy of cosmic radiation these may well prove unattainable.

I know nothing of the topic, but on the lowest possible level of "doing a quick Google," I find multiple hits from credible sources saying that yes, as of now it's a hard problem (and one that has been known about for many years), but nothing saying it is an insoluble problem.

E.g. see this Space.com article from 2015 which lists the 5 winning submissions for shielding/mitigation sent into a NASA prize competition for the public; the submissions don't adequately solve the problem but apparently suggest further avenues for research; and this of course is in addition to whatever else is being researched by government and/or industry: http://www.space.com/29512-mars-mission-radiation-nasa-challenge.html

Also, this 2016 Smithsonian article on the problem quotes "radiation expert Ron Turner, a senior science adviser at NASA's Institute for Advanced Concepts in Atlanta," saying that the most efficient solution might simply be a quicker trip to Mars to minimize exposure: ""The best bang for the buck is advanced propulsion, not shielding." http://www.smithsonianmag.com/science-nature/radiation-remains-problem-any-mission-mars-180959092/

 

[Al_]

It's certainly a good question, but I think there are two main reasons that people have fixated on Mars rather than the moon:
(1) Mars has a day/night cycle very close to Earth. The moon has a 4 week day/night cycle. During the two week night, it gets extremely cold, and solar power is not available for generating energy.

There is almost permanent sunlight available at the Lunar poles. Some long power cables to connect PV panels placed at different spots, and you have 24/7 power.

(2) Mars has a ready supply of water, which is essential for any human colonization. The moon might have water in permanently shadowed craters at the poles, but this has not been proven. Elsewhere on the moon is extremely dry, so water does not appear to be available.

The Moon has water, http://www.jpl.nasa.gov/news/news.php?feature=3887 and Nitrogen, and everything else. Just a bit deeper down. It also has caves. Great places for a base.
We would need to prospect the Moon just as much as Mars, and controlling robots from Earth is much easier with a 3 second delay than with the 20 minutes it takes on Mars.

 

[Gary Weller]

I'd like to see an outpost created on the Moon as a stepping stone to Mars or elsewhere. Perhaps mining the moon for whatever ingredients we can to build a larger ship that would have far less trouble launching. Of course I understand that the Moon doesn't have everything we need, not even close, but it's still a good start.

 

[Al_]

Before speculating on colonization of Mars, a note of caution. It may be that travel to Mars, let alone living on Mars, is simply no feasible option for humans.

Recently, Nature published a paper on the risk of cosmic radiation for the Central Nervous System (CNS). A summary of this and related research can be found at http://www.sciencealert.com/mars-bound-astronauts-risk-long-term-brain-damage-and-chronic-dementia. This document also contains a link to the Nature paper.

So far, no believable countermeasures to stop cosmic radiation from inflicting damage to passengers on a spaceship have been suggested, and in view of the enormous energy of cosmic radiation these may well prove unattainable. The possibility of repairing damage to the CNS on the fly is pure speculation at this point.

So, fun as it is to dream about space colonization, it is far from certain that it will ever be possible.

Personally, I wouldn't want to spend that long in space without a LOT of radiation shielding. It's really expensive to lift that much shielding stuff up from Earth, but if you take the raw materials from the Moon, it uses far less fuel. It might even be possible to launch it from the Moon by a magnetic launcher. I bet that Mars will eventually be colonised from the Moon, not from Earth! But, why would anyone want to hide themselves away down a deep gravity well like Mars, when they could stay free and make use of all those huge resources easily transportable from the small bodies with no real gravity?

 

[Al_]

I'd like to see an outpost created on the Moon as a stepping stone to Mars or elsewhere. Perhaps mining the moon for whatever ingredients we can to build a larger ship that would have far less trouble launching. Of course I understand that the Moon doesn't have everything we need, not even close, but it's still a good start.

I disagree - the Moon does have everything we need. Just a little bit underground. It's a huge moon after all!
It's way easier to go to the Moon with a bucket and a shovel than to go to Mars with a bucket and a trowel.

 

[PAllen]

500 km: extremely unlikely.
10 km: Quite likely. We have impacts of that size on average every 50 million years.

But wouldn't those 10 km impacts be almost all from objects already in the solar system? What I am wondering is the question you raised in passing: is there any way to guess, even if we can't know, about how often a substantial interstellar object passes close to earth?

 

[Gary Weller]

I disagree - the Moon does have everything we need. Just a little bit underground. It's a huge moon after all!
It's way easier to go to the Moon with a bucket and a shovel than to go to Mars with a bucket and a trowel.

Last I checked, it didn't have much carbon, which is a necessity for the production of lightweight composites. There's no petroleum for the manufacturing of plastics, which is very helpful in shielding radiation. There isn't much copper, but there's plenty aluminum and calcium, both better conductors. But that petroleum problem is a real problem.

 

[mfb]

But wouldn't those 10 km impacts be almost all from objects already in the solar system? What I am wondering is the question you raised in passing: is there any way to guess, even if we can't know, about how often a substantial interstellar object passes close to earth?

Define "in the solar system". Is the Oort cloud in the solar system?
The density of rogue objects is tiny compared to the density of objects associated with the solar system (Kuiper belt to Oort cloud).
We know how often stars pass close enough to disturb planets: at a negligible rate. We have a rough idea of the ratio of stars to rogue planets, and even with the most pessimistic estimates the chance is negligible.

The Moon has water, http://www.jpl.nasa.gov/news/news.php?feature=3887 and Nitrogen, and everything else. Just a bit deeper down. It also has caves. Great places for a base.

NASA found traces of water locked in rocks. Harvesting water from dry rocks is not very efficient. Nitrogen and carbon are challenging as well.
Caves are expected to exist on Mars as well, same as for the Moon, but we didn't find any caves yet.
The spots with 24/7 sunlight are extremely rare. How long do you want to make the power cables and water pipes if you want to combine water extraction, 24/7 sunlight and caves?
The point facing Earth would be a great anchor point for a lunar space elevator - possible with today's materials. But then you don't have 24/7 solar power.

 

[Gary Weller]

The spots with 24/7 sunlight are extremely rare. How long do you want to make the power cables and water pipes if you want to combine water extraction, 24/7 sunlight and caves?

Is it too much to say that you could setup multiple solar power stations in the most efficient areas? The nice thing about the moon is that it's loaded with Calcium and Aluminum, both great conductors (better than Copper) that could be used to transfer power over long distances. If the poles are the best locations to place solar panels, then the furthest you'd have to run lines is 1,700 miles. I've read that power can travel up to approximately 2,000 miles with minimal loss when utilizing the proper gauge conductors.

 

[dkotschessaa]

I'd like to see an outpost created on the Moon as a stepping stone to Mars or elsewhere. Perhaps mining the moon for whatever ingredients we can to build a larger ship that would have far less trouble launching. Of course I understand that the Moon doesn't have everything we need, not even close, but it's still a good start.

I thought at some point I heard that this was the plan. Probably before Elon Musk starting getting involved.

-Dave K

 

[Gary Weller]

I thought at some point I heard that this was the plan. Probably before Elon Musk starting getting involved.

I thought so too. It makes sense. I thought the progression was Moon base, space elevator, serious mining for minerals and what not, Mars or other body.

 

[dkotschessaa]

For people more knowledgeable than me, what is your assessment of Elon Musk? I know he has some science background, but I sometimes feel like he is talking out of his... business background.

-Dave K

 

[PeroK]

For people more knowledgeable than me, what is your assessment of Elon Musk? I know he has some science background, but I sometimes feel like he is talking out of his... business background.

-Dave K

I couldn't agree more. I worked on a lot of large business and Government IT projects and there was no stopping people like Musk. Entrepreneurial/consulting background, nothing is impossible, why can't we build a hospital on Mars?

The projects were never achievable and eventually what was planned for 12 months was replanned for 5-10 years and at 10 times the original budget. The Musks of this world moved on and told everyone how brilliant they'd been on their last project and what had been achieved.

Once, I actually sat in a presentation by one of his types where he was trumpeting the amazing technical virtuosity of his previous project. At that time, I was part of a "rescue squad" on that project trying to salvage something deliverable. (The client eventually took us to court on that one!).

So, it always hurts a bit when people criticize my lack of imagination, as I spent a good deal of my career trying to salvage something deliverable from the mess left by the "nothing is impossible" visionaries. But, such is life.

 

[dkotschessaa]

I couldn't agree more. I worked on a lot of large business and Government IT projects and there was no stopping people like Musk. Entrepreneurial/consulting background, nothing is impossible, why can't we build a hospital on Mars?

The projects were never achievable and eventually what was planned for 12 months was replanned for 5-10 years and at 10 times the original budget. The Musks of this world moved on and told everyone how brilliant they'd been on their last project and what had been achieved.

Once, I actually sat in a presentation by one of his types where he was trumpeting the amazing technical virtuosity of his previous project. At that time, I was part of a "rescue squad" on that project trying to salvage something deliverable. (The client eventually took us to court on that one!).

So, it always hurts a bit when people criticize my lack of imagination, as I spent a good deal of my career trying to salvage something deliverable from the mess left by the "nothing is impossible" visionaries. But, such is life.

OK, glad I'm not crazy then. In general I recognize this behavior as I have worked in companies with people with a "No excuses! We can do it!" type attitude who were usually just ignorant of what it took to make something work.

I understand that we need visionaries in this world who are "not encumbered by the thought process" sometimes. They can help push the more scientifically oriented types beyond what they might think themselves capable of. But it can get really out of hand.

Was about to say more, but I think I might spin off another thread.

-Dave K

 

[Capn'Tim]

Elon Musk is only one of many who are championing a Mars Mission concept vs going to the Moon first. I hardly would categorize Elon Musk as some fly by night visionary with no substance... His success creating PayPal, Tesla Motors, his ventures into renewable energy alone are impressive. The accomplishments of Space-Ex when viewed from the perspective that they are the first successful space rocket launch firm and contracted by NASA for payload delivery to the ISS is an amazing success so far yet still in progress of development. Yes they have had their failures, but that is the course of progress in every industry. Nothing works first time every time. Space-Ex recently re-landed a rocket booster after a launch which for all the previous history of space flight was just science fiction!
The real issue with going to Mars rather than a protracted program including the moon first is cost. Cost killed the original Apollo Program after it outlived it's usefulness during the cold war and congress had no stomach for multi-hundred billion dollar programs after that. Going direct to Mars is far cheaper over the long run than the moon first then Mars. If you want to get a program funded these days it also needs to happen over a shorter time span or it won't survive the government funding game from administration to administration... Though I would not classify the Shuttle Program (past tense) or the ISS as wasted money and science by any means, compared to the feat of going to the moon nearly 50 years ago in the pre-digital age it pales in comparison considering the time gone by and advances in technology we have today. It's time the space program stopped going around in circles and started doing what we all believed would happen fifty years ago when we watched the first Lunar landing...

 

[ProfChuck]

Ultimately, like it or not, the dominant justification for establishing a permanent human presence on the Moon, Mars, or elsewhere is economics. Making humanity a multi planet species is nice but not essential. There are industrial processes that are easier and cheaper on the Moon than on Earth. The low gravity and lack of an atmosphere enables additional options for launch to space and if asteroid mining is to become a reality it makes much more sense to operate from the Moon than Earth. As for Mars the industrial potential is less clear. Surface analysis by landers and rovers indicate that all of the raw materials for an industrial society are present so a self sustaining colony is, at least in principal, viable. Asteroid mining promises to create a new economic paradigm that will make many ventures that are currently impractical become commonplace. Technologies such as "mining" of hydrogen from the Jovian or other gas giant atmospheres could create a solar system wide economy that is as alien to us today as the semiconductor industry would have seemed in the 1930's. If we do not exploit the Moon, Mars, and other solar system bodies it will be because of a lack of imagination not for the lack of a reason to do so.

 

[Gary Weller]

For people more knowledgeable than me, what is your assessment of Elon Musk? I know he has some science background, but I sometimes feel like he is talking out of his... business background.

I find Elon Musk to be incredibly inspirational and capable. As Tim said, he's accomplished a whole lot. Some of those accomplishments were considered impossible decades, even just several years ago. I think his vision is only surpassed by his motivation and devotion to bettering Earth and mankind's well-being. Is Mars a stretch? Of course! Was the Moon a stretch? It sure was! Mars > Moon²x10². However, mankind will not survive on this planet forever; another couple billion years, maybe. Another ELE is far more likely to happen before the Sun expands, but we will eventually use up all of our natural resources or kill the planet. We will eventually have to leave the planet and there's no better time than the present to start trying to figure it out. There will be failure and we will learn from it.

For the record, Elon has the ideas. He is very smart, but also has a multitude of Scientists at his disposal who help him decide if something is possible and help him make it happen. He's not just coming up with ideas and trying them without anyone checking him on it.

I spent a good deal of my career trying to salvage something deliverable from the mess left by the "nothing is impossible" visionaries. But, such is life.

While I completely understand your statement (I contributed to Mars One when it first got started, now look where we are), I do not put Elon Musk in the same category as the rest of the "nothing is impossible" visionaries. I think Elon is a very smart person who hears someone say "it's impossible", then calculates whether it is or isn't, then decides whether to say "yes, it is" or "no, it isn't". In fact, he has said that he knows it's possible to colonize Mars. The only question is "when will we do it?" That's not to say that there will not be setbacks. I guarantee there will be and the cost will get a lot higher than initially quoted. However, I find our immigration out of Earth's atmosphere to be inevitable. Why not start trying to figure it out now?

 

[dkotschessaa]

I'll reserve judgement on Musk for now. He just sets off some alarm bells for me. My enthusiasm for technology is marred by years working on the customer service end of things. I see a world excited by 3D printing when we don't even have 2D printing that works reliably, and and a world excited by self driving cars when we still have GPS systems that instruct us to turn into brick walls. Anyway, this is a rant for another thread.

-Dave K

 

[Gary Weller]

I'll reserve judgement on Musk for now. He just sets off some alarm bells for me. My enthusiasm for technology is marred by years working on the customer service end of things. I see a world excited by 3D printing when we don't even have 2D printing that works reliably, and and a world excited by self driving cars when we still have GPS systems that instruct us to turn into brick walls. Anyway, this is a rant for another thread.

I completely understand. The way I look at that sentiment is "It's not the end of the world if my printer breaks down. My printer won't save me from the end of the world."

 

[mfb]

Is it too much to say that you could setup multiple solar power stations in the most efficient areas?

You can certainly do that, but that is a large amount of effort compared to "we'll just put them next to our base and add some storage (chemical or electric)".

Calcium has twice the resistance of copper, aluminium has a 65% higher resistance than copper. I have no idea where you got your resistance values from. Pure calcium is also not very cable-friendly: too soft, too reactive. As pure metals, silver is the only conductor better than copper. Cables over 1700 miles? While they might be easier to run over wasteland (compared to Earth), that is a gigantic effort. You would have to transform the low voltage from the solar cells up to ~1 MV, and then isolate the cables sufficiently to handle that voltage. Losses will still be relevant for realistic cable diameters.

The projects were never achievable and eventually what was planned for 12 months was replanned for 5-10 years and at 10 times the original budget. The Musks of this world moved on and told everyone how brilliant they'd been on their last project and what had been achieved.

Long text not directly related to the thread, therefore in spoiler tags:

Spoiler

Elon Musk and his brother started Zip2 with $28,000 and sold it for $37 million (only their shares) 4 years later.

The success of PayPal shouldn't need explanation. Musk's share: $10 million -> $165 million in 3 years.

SpaceX developed Falcon 1 and 9 basically from scratch for a budget ($300 million) that others use for a single rocket launch. NASA initially estimated that it would have taken them $3.6 billion, a later estimate was still at $1 billion. Source. They have the cheapest rocket on the market in that size class. They are the largest private rocket manufacturer. They are the only company to ever land an orbital rocket on the ground - something others didn't achieve in decades. Musk's investment of $100 million is now worth billions.

How many car companies did start in the last 50 years and got successful? Tesla did, mainly after Musk got involved, and it has a large impact on the market for electric cars.

SolarCity, mainly based on money from Musk (2006), now has the largest or second largest market share (depending on the source) for photovoltaics in the US.

I don't know if we talk about the same people. Musk has been extremely successful with all his companies. He multiplied his net worth by a factor 1 million in 22 years. If he announces things, he is sure they will work. Not all announced things happened at the earliest time estimate given, right. Delays in big projects are common everywhere. The only really long delay is the Falcon Heavy - but the components of the first one seem to be ready, so a first flight in 2017 is realistic.

What was the largest impact of the Apollo missions?
The rockets? Saturn V got scrapped shortly after Apollo, although some R&D was used for later rockets.
The science on Moon? Robotic sample return missions were not that worse, and we could have sent many more to many different places for the same money.
No... the largest impact was psychologically: It was a common goal of a nation. It made people work together, it made people interested in science, it produced hundreds of new things that got used elsewhere afterwards and lead to a large boost for research in general.

NASA's ROI is somewhere between 7 and 14 (depending on who you ask). NASA could finance itself easily if they would get the money for all the things they invent/make possible. It clearly makes sense to keep space exploration running - or to extend it. Even if you don't care about the results in space. But then we need something to do in space. If we stay on Earth, cut R&D budgets and so on, we'll just do business as usual until we run out of resources, and what happens then?

Mars has the best chance to build a largely self-sufficient colony as it has all the necessary resources available. Colonizing Mars would be a massive project. It would be by far the most ambitious project humans ever did. Is that a downside? I think it is an advantage. As international project, it is a goal that can unite people. The ISS contributed to improve relations between the US and Russia - but the ISS was a station used by a few experts (astronauts). A Mars colony would be for thousands or millions, and with the potential to improve international relations worldwide.
Things are working better if people are looking forward, not backward - and I think the vision of humanity making the first steps into the cosmos is a very powerful one.

 

[bobkolker]

I watched the 6-episode series called Mars this week. Elon Musk kept emphasizing that humans must spread out to at least one other planet to ensure human survival in the event of some extinction event on Earth.
Wouldn't colonization of the Moon achieve the same purpose? Seems like that would be a more viable option.

The Moon has no atmosphere so it cannot be terraformed. Mars has water from which fuel can be made. With labor and terraforming Mars could support human life independent of help from Earth. Not so, the Moon.

Even so, I think we should established habitats on the Moon and use it as a training ground for living off planet. Also the Far Side is just made for astronomy. We casn build observatories on the Far Side that far excel the light gather capacity of orbiting telescopes. There also may be HE3 on the Moon which is very crucial for attempting to generate fusion energy.

 

[Gary Weller]

Calcium has twice the resistance of copper, aluminium has a 65% higher resistance than copper. I have no idea where you got your resistance values from.

"Calcium metal has a higher electrical resistivity than copper or aluminium, yet weight-for-weight, due to its much lower density, it is a better conductor than either. Its use as such in terrestrial applications is usually limited by its high reactivity with air; however, it has potential for use as wiring in off-world applications." - Geoffrey Landis, NASA

Pure calcium is also not very cable-friendly: too soft, too reactive.

It's reactive with air. In a vacuum, not so much. And I do realized that the surface of the moon isn't a pure vacuum, but it's pretty darn close.

Cables over 1700 miles? While they might be easier to run over wasteland (compared to Earth), that is a gigantic effort.

Currently, Brazil has a power line traveling almost 1,500 miles, so it's not so far-fetched. The line drop would certainly be an issue and I agree that it makes more sense to have dedicated solar power plants in multiple locations. I was merely pointing at the possibilities.

 

[mfb]

"Calcium metal has a higher electrical resistivity than copper or aluminium, yet weight-for-weight, due to its much lower density, it is a better conductor than either. Its use as such in terrestrial applications is usually limited by its high reactivity with air; however, it has potential for use as wiring in off-world applications." - Geoffrey Landis, NASA

Per mass. Who calculates resistivity per mass? That would be interesting if you would have to launch it with a rocket, but not if it is produced on Moon.

Calcium is reactive with a lot of things. You'll need an insulating layer anyway, the thin surface is not problematic.

Brazil (and China) have long power lines because they have large rivers at places far away from their population. They cost billions even on Earth and don't scale well to lower electricity demands (half the power doesn't have half the costs). All you would save is some electricity storage, which is much easier.

 

[ProfChuck]

Ultimately, like it or not, the dominant justification for establishing a permanent human presence on the Moon, Mars, or elsewhere is economics. Making humanity a multi planet species is nice but not essential. There are industrial processes that are easier and cheaper on the Moon than on Earth. The low gravity and lack of an atmosphere enables additional options for launch to space and if asteroid mining is to become a reality it makes much more sense to operate from the Moon than Earth. As for Mars the industrial potential is less clear. Surface analysis by landers and rovers indicate that all of the raw materials for an industrial society are present so a self sustaining colony is, at least in principal, viable. Asteroid mining promises to create a new economic paradigm that will make many ventures that are currently impractical become commonplace. Technologies such as "mining" of hydrogen from the Jovian or other gas giant atmospheres could create a solar system wide economy that is as alien to us today as the semiconductor industry would have seemed in the 1930's. If we do not exploit the Moon, Mars, and other solar system bodies it will be because of a lack of imagination not for the lack of a reason to do so.

the Moon is close enough that "rescue" missions and tactical resupply are possible. The Moon and Mars are very different objectives with some very different challenges. With 1/6th Earth gravity and no atmosphere access to space is relatively easy. An electromagnetic catapult can do the job. This means that processing lunar material as well as asteroids can be done economically on Moon. Solar power is a problem because of the 14 day night but a power distribution system can be designed to deal with that. However terraforming the moon is not possible with any foreseen technology. A space "elevator" with the counterweight at the Earth-Moon la-Grange point is feasible with known tether materials but on Mars the atmosphere and the moons would pose meteorological drag and collision problems. Mars could be terraformed, at least partially but there is not enough gravitation to retain an Earth like atmosphere. Jeans escape and other mechanisms such as solar wind stripping make the maintenance of an atmosphere very challenging. Successful utilization of the Moon, Mars and other solar system bodies will require new economic structures that are driven by a space based society and culture.

 

[mfb]

Mars could be terraformed, at least partially but there is not enough gravitation to retain an Earth like atmosphere. Jeans escape and other mechanisms such as solar wind stripping make the maintenance of an atmosphere very challenging.

An atmosphere would be stable over millions of years, with an artificial magnetic field much longer. Jeans escape is a small effect.

 

[rootone]

But wouldn't those 10 km impacts be almost all from objects already in the solar system? What I am wondering is the question you raised in passing: is there any way to guess, even if we can't know, about how often a substantial interstellar object passes close to earth?

I think it's fair to say that we don't know much about substantial natural objects in interstellar space.
Accepted theories do allow for 'rouge planets' escaping their original solar system.
Also brown dwarfs, massive objects that didn't quite become a star. - now that would be serious trouble

 

[Vanadium 50]

The science on Moon? Robotic sample return missions were not that worse, and we could have sent many more to many different places for the same money

I think they were worse. More than half the Soviet Luna missions failed, and the three successes netted 0.1% of the samples of the six (of seven attempts) Apollos. I agree with your overall conclusion - just not the part about the rocks.

 

[rootone]

China is sounding serious about returning robotically 2kg or so of moon rock this or next year.
Probably more PR than science though.
https://en.wikipedia.org/wiki/Chang'e_5

 

[Gary Weller]

That would be interesting if you would have to launch it with a rocket, but not if it is produced on Moon.

It is abundant on the moon, as is Aluminum. Copper is not. Therefore, instead of lugging however much Copper you'd need from Earth to the Moon, it makes a boatload more sense to utilize the abundant materials ON the Moon for such things instead. If cost is the biggest obstacle, which many would agree that it is, then I think that's the best option.

 

[Vanadium 50]

China is sounding serious about returning robotically 2kg or so of moon rock this or next year.

Sounding serious is not the same as being serious. Being serious is not the same as being successful.

 

[mfb]

I think they were worse. More than half the Soviet Luna missions failed, and the three successes netted 0.1% of the samples of the six (of seven attempts) Apollos. I agree with your overall conclusion - just not the part about the rocks.

I don't say one robotic mission is as good as one manned mission. What about 100 robotic missions vs. 1 manned mission? Even if half of them fail (unlikely if you can study the common failure modes in detail), you get samples from 50 different locations of your choice, probably with rovers to look for the most interesting samples. The Soviet sample return missions didn't get a high priority because we had the Apollo samples.

China's sample return mission is expected for this year. They are serious. Success: We'll see.

It is abundant on the moon, as is Aluminum. Copper is not. Therefore, instead of lugging however much Copper you'd need from Earth to the Moon, it makes a boatload more sense to utilize the abundant materials ON the Moon for such things instead. If cost is the biggest obstacle, which many would agree that it is, then I think that's the best option.

No one suggested to bring a lot of copper. Using materials found on the moon is interesting, but you don't find the best material there (copper). That was my point. Both aluminium and calcium are very reactive and need a lot of energy to produce, and pure calcium doesn't make good cables.

 

[Al_]

No one suggested to bring a lot of copper. Using materials found on the moon is interesting, but you don't find the best material there (copper). That was my point. Both aluminium and calcium are very reactive and need a lot of energy to produce, and pure calcium doesn't make good cables.

The absence of Oxygen as a gas means that raw metals are just lying around on the surface from meteorites. Drag a magnet through the dust and you'll soon get all the Iron you need. Your robot can hammer/weld that into a conducting cable, make it thicker than a copper cable to compensate for less conductivity. Wrap it in basalt fibres for insulation.
Or filter the Lunar soil electromagnetically to pick up the other metals, Al, Cu, Ag, Au, Pt etc.

Prospecting with robots is relatively easy on the Moon compared to some other space missions.
If we find a vein of whatever ore on the Moon, it doesn't matter that it's rare over the Moon as a whole, because we will have plenty for our immediate purposes right there. By the time the colony grows so big that it's used up all the ore, there will be other ways to get more.

 

[mfb]

Oxygen doesn't have to be a gas to react with other elements. The Earth formed without an oxygen atmosphere, and most rock formation happens in the absence of oxygen gas even today. By mass (and even more by number of atoms), oxygen is the largest component of lunar regolith, for example.

If we find a vein of whatever ore on the Moon, it doesn't matter that it's rare over the Moon as a whole, because we will have plenty for our immediate purposes right there.

Moon is lacking the chemical activity to nicely separate the elements. We'll have to do that, which needs a lot of energy and chemistry.

 

[Al_]

Harvesting water from dry rocks is not very efficient. Nitrogen and carbon are challenging as well.
Caves are expected to exist on Mars as well, same as for the Moon, but we didn't find any caves yet.
The spots with 24/7 sunlight are extremely rare. How long do you want to make the power cables and water pipes if you want to combine water extraction, 24/7 sunlight and caves?

Water is not going to be needed in large amounts. The base will be sealed, all the air, water and food will be recycled or grown. We will need just enough to replace leakage, or when expanding the colony.

The fact that the Moon is solid right down to the core, means that mines can be dug way deeper than on Earth. Go deep enough, and the natural pressure will allow volatiles to exist as liquids and gases. They will move through the rocks, and pool in places where the layers block them.

Many cave entrances have been photographed from orbit. "An analysis by an instrument on Chandrayaan-1 revealed a 1.7-km long and 120-metre wide cave" http://www.siliconindia.com/shownews/Cave_in_moonBase_station_for_astronauts-nid-79567-cid-2.html

I don't suggest any water pipes across the surface. No need. At first, the electric cable only needs to go from one side of a hill to the other, at the pole where the sun circles a peak. As the colony expands, it grows away from the pole in all directions, and builds a ring-circuit just long enough to link all the new habitats.

If we find a cave near the pole, great. But if not we can get a robot to dig a mine at the pole.
Alternatively, there are some neat ways to store power using Moon materials. One of the best is a flywheel made from spun lunar basalt fibre, mounted on magnetic bearings made from lunar metals.

 

[Al_]

Last I checked, it didn't have much carbon, which is a necessity for the production of lightweight composites. There's no petroleum for the manufacturing of plastics, which is very helpful in shielding radiation.

We can use alternative materials for a lot of the purposes that we would normally use plastics or hydrocarbons for.
But, where we do need plastics -
Hydrocarbons can be made by a simple process: Fischer–Tropsch_process https://en.wikipedia.org/wiki/Fischer–Tropsch_process
The fact that the Moon is solid right down to the core, means that mines can be dug way deeper than on Earth. Go deep enough, and the natural pressure will allow volatiles to exist as liquids and gases. They will move through rocks, and pool in places where the layers block them.
I'm aware that the Moon has much, much smaller fraction of these materials than Earth, but we only need to find places where these substances are collected. We don't need more than a tiny, tiny fraction of the Moon's mass in this form, even for a large colony.

 

[Al_]

Moon is lacking the chemical activity to nicely separate the elements. We'll have to do that, which needs a lot of energy and chemistry.

It does have some chemical activity. And deep down, where the pressure is high enough, there can be volatiles moving through the rocks.

 

[mfb]

100% recycling, no waste at all? Good luck.

The fact that the Moon is solid right down to the core, means that mines can be dug way deeper than on Earth.

Mines on Earth are not limited by the rock getting liquid. They are limited by temperature and logistics. What is the temperature gradient inside the Moon?
By the way, the Moon has a small layer that is partially liquid, but it is so deep down that it is not relevant.

The moon was once liquid - I don't see how volatiles in relevant quantities would be trapped anywhere.

As far as I understand the original source, they didn't find a cave, they found something that is expected to be an intact lava tube. Might need drilling to get in.

It does have some chemical activity.

Nothing compared to Earth, or even Mars.

 

[Al_]

To bring it back to the original question, why colonise Mars and not the Moon?
I think the English-speaking public, for a generation or more, have taken the initial Apollo findings that the Moon is barren, and written the Moon off as a potential site for a colony.
These ideas are deeply embedded in the scientific and technical world, even though, over the years, the evidence has been slowly swinging back in the Moon's favor.
The Chinese, and others, not having quite the same outlook or culture, have recently taken a keen interest in the Moon. We may soon find a colony growing there rapidly while the U.S. is still trying to make the long, difficult and dangerous voyage to Mars. And once a Moon colony is established it makes a really great launch pad to go everywhere else, Mars included.

Let's colonise the Moon first.

 

[mfb]

The Chinese have their Moon program for the same reason the US had the Apollo program. To show that they can do it, to test manned spaceflight beyond LEO, and to have a good near-term goal to look forward to.
The US did all that already. Launching a second Apollo program ("we'll land on the Moon again within this decade!") wouldn't help. The next goal is Mars.

Both projects are not colonies, however, those are beyond the scope of existing programs.

Launching things from the Moon is not necessarily cheaper. Building anything factory-like there would cost a huge amount of money, not all of it for R&D. Access to space will probably get much cheaper soon with reusable rockets - and building things on Earth is much easier than building them on the Moon.
But even if launching things from Moon stays cheaper for some reason, you don't need a full colony there to do so.
I had a look at the mice irradiation study linked a while ago. They irradiated the mice with dose rates between 0.05 and 0.25 Gy/min, for a total dose of 0.05 to 0.3 Gy. That is a total dose ~10 times the dose expected for humans on the way to Mars - but in a single minute instead of 6 months. What do we learn from that study? If you irradiate mice at 1 million times the rate expected on a trip to Mars, they can have issues with memory and other brain functions. Yeah... okay. So what? That's like testing an acceleration of 1 million g and then claiming that humans could struggle on Earth with 1 g.

 

[Al_]

99.999% recycling means you need very, very little input. Why would you vent used air or used water, or throw out fertilizer? Life support requires these things.

Mines on Earth are not limited by the rock getting liquid. They are limited by temperature and logistics. What is the temperature gradient inside the Moon?
By the way, the Moon has a small layer that is partially liquid, but it is so deep down that it is not relevant.
The moon was once liquid - I don't see how volatiles in relevant quantities would be trapped anywhere.

I concede that you are right. The temperature gradient is not known, but can be estimated with some simple calculations. I expect that volatiles are rare, on a planetary scale.
But we're not looking to fill an ocean. Just looking for the odd little places where a teeny tiny bit is collected together, say 100 tons or so. Miniscule.
Similarly with the chemistry. Rare, deep, historic, different, but enough.

 

[Al_]

Yes, they are similar programs, and not about colonisation, as you say.

At least not initially.

But just because the U.S. didn't take the next step to capitalize on it's Apollo success, doesn't mean the Chinese will stop at the same point. Especially now that the Moon looks a lot more enticing than it did in the Apollo years.
It would be kind of embarrasing for the U.S. to have to race back to the Moon. Almost an admission that they left stuff not finished. Maybe ESA will have to be the ones to ensure the Chinese don't have a monopoly.

There are technical challenges to manufacting in vacuum, but there are many compensating advantages.
Building a factory on the Moon would be very expensive, now. But when a Moon colony is esablished, less so. Eventually, the difference will be irrelevant next to the question: from where can move the most stuff to a destination further out in space?

Launching from the Moon is physically much, much, easier. Reusable rockets will work there, too. Making things on Earth is easier, at the moment, but getting them into space is always going to be harder than from the Moon, however cheap Elon's rockets are.

 

[mfb]

99.999% recycling means you need very, very little input. Why would you vent used air or used water, or throw out fertilizer? Life support requires these things.

No one wants to vent air or all used water. But what do you do with the most toxic waste? Do you expect to squeeze the last hydrogen atom out of everything?

The Chinese are looking at Mars already - it will be their next step after the current Moon program. They plan to go to Mars without a Moon colony.

Reusable rockets will work on Moon, but they are high-tech. The very last thing a colony will be able to manufacture on the way to get self-sufficient. You can launch them from Earth to Moon, but then you can directly use them from Earth as well.

 

[Ophiolite]

Apologies if I am repeating a point already made. I have not yet read the entire thread.

Evolution has gifted homo sapiens with an urge to explore and expand. That's why some of us left Africa. It's why we went, albeit briefly, to the moon. It's why our surrogates have visited every planet (and former planet) in the system. Regardless of the logic of colonising Mars our natures will compel us to attempt to do so, probably marginally before it is technologically practical.

 

[mheslep]

...got successful? Tesla did,

Successful in several ways, growing sales, growing revenue, and being innovative, but Tesla is nonetheless a business and has always lost money. Last year Tesla lost a billion dollars.

 

[mheslep]

Why not colonize say, the deep ocean instead of a lifeless moon or remote planet with the associated low gravity and high radiation problems? The exploration, the challenge factors are all there as well, and would be orders of magnitude easier and more feasible.

 

[clope023]

Why not colonize say, the deep ocean instead of a lifeless moon or remote planet with the associated low gravity and high radiation problems? The exploration, the challenge factors are all there as well, and would be orders of magnitude easier and more feasible.

Nothing that says you can't do both; Space Colonization is in general more exciting and finding unknown life in the oceans is still going to be 'simply' undiscovered Earth Life, while the possibility of finding truly Alien life will be a monumental moment in scientific history.