. CASE FOR MOON FIRST - 14 Summary of the vision

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SUMMARY OF THE VISION

Here are some of the main points again, to review some of the material covered above:

• The Moon is turning out to be far more interesting than most realized. We are at the same stage there as the very first Antarctica explorers, setting foot on a continents sized land mass that we know little about first hand.

• So we have to be careful when exploring Mars, also Europa and Enceladus and anywhere likely to have alternative exobiology. Why start our new phase of human exploration in space by sending humans with our microbe hitchhikers to the one place in the inner solar system that is most vulnerable to introduction of Earth microbes?

• Robots and humans work well together. Our robots are our collective sense organs in the universe, and they can go to places humans can't go.

• We have potential for superpositive outcomes of great value for humanity from the search for life in our solar system from discoveries of origins of life, earlier forms of life, or alternative exobiology. And life on Mars can be vulnerable to Earth life.

• So we have to be careful when exploring Mars, also Europa and Enceladus and anywhere likely to have alternative exobiology. Why prioritize a mission with our microbe hitchhikers to the one place in the inner solar system that is most vulnerable to them?

• Space development can be of great benefit to Earth through new discoveries, also moving heavy industry into space, providing solar power from space etc.

• Most successful colonization of Earth has been of places already occupied by humans, for the last thousands of years and there have been many failed colonizations. If you focus just on the ones that succeed you get only a partial picture, which may be over optimistic.

• Mars is far more like the Moon than it is like Earth. It's more inhospitable than deserts and Antarctica and we don't colonize those places.

• So, I think that space settlement in early stages at least would be like an Antarctic base - where you are there because you are doing something of value to Earth.

• Yes we might get future tech that lets us build self sufficient habitats on Mars. But before then we'd be able to reverse desertification, build self sufficient sea colonies far more easily than on Mars, and do many other things.

• Yes, we can build human settlements in space using resources from space. But the reasoning of the 1970s is still valid - that the most abundant and easiest resources to access in space in the early stages, are those on the Moon and in the asteroids.

• Settlements on the Moon or using materials from the asteroids are likely to be easier to support economically - because it's much easier to export materials, to sell on Earth.

• We don't yet know how humans tolerate artificial gravity, or what the gravity prescription is . The problem is that though we can simulate the physics easily, we can't simulate the human body, but can only find out with experiments in space.

• We haven't yet attempted a self sufficient habitat in space. Several ground experiments suggest it may be possible, but though this works on the ground, this has not yet been tested in space.

• So before developing grand visions of the future of humans in space, we need to look closely at those two points. And do them in a location where we can do it safely. The key to Apollo was to do things on a step by step fashion, first showing that humans can survive a few days in zero g, which was not known at the start of the program, then building up to longer and more demanding missions. What we do next may depend on what we find out in the process.

• We are bound to have fewer people in space than on Earth in the near future. It doesn't matter how valuable the materials are that are returned from space, what matters is how many people on Earth are needed to support you there.

• Earth is the best place for a backup and to rebuild civilization for those that worry about end of the world disasters. That's because no disaster could make Earth as uninhabitable as Mars, because the Earth surface is much better protected from cosmic disasters than Mars, and some humans would survive anything that is likely to happen.

• As for self created problems, again we can't escape from them in space. In my view again, if technology is our problem, escaping into space to set up an even more highly technological society is not likely to be our solution.

• A future with large numbers of humans in space with high technology is not necessarily the best thing to aim for. You can't restrict it to just the "good guys" whoever you think they are if you have millions in space.

• Space settlement is neutral just like settlement anywhere - could be good or bad. It could be hugely positive if done well. It could be very harmful if it goes wrong. And the details of how we do it could swing it either way.

• Mars has turned out to be a much more likely habitat for present day life than previously thought Though it is so cold and inhospitable for humans, and extremely dry, yet it may have habitats for microbes and even lichens capable of surviving in extreme conditions.

• It is tricky to explore places with life without introducing Earth life. We are still figuring out how to explore the subglacial lakes in Antarctica, and wouldn't send humans there.

• A human crash on Mars putting debris all over the planet would introduce Earth microbes and has to be avoided. We don't yet have the technology to build 100% reliable spacecraft, and even a 1 in 100 chance of a crash, which some volunteers might be willing to take on as a personal risk, is far higher than the 1 in 10,000 probability that's often used for planetary protection.

• There is no urgency to send humans to the Mars surface. Even if we send humans there, it is best to understand Mars better first. The best way to do it for planetary protection is to send robots, either controlled from Earth or from Mars orbit.

• It is not at all clear that we can terraform Mars, and if it is possible, with current technology, it's a thousands of years, or perhaps a 100,000 year megatechnology project. Are we confident that this is what our descendants a thousand years from now will want us to do for them? With our clumsy early attempts, we may close off future options for Mars that our descendents would prefer.

• Introducing life to Mars as a result of a human crash or landing on Mars is likely to be biologically irreversible. You could create a new geological era on Mars, marked by the presence of Earth lifeforms brought to the planet by twenty first century humans. Introducing Earth life before you study Mars in depth is closing off options for the future. While keeping it free of Earth life leaves all your future options open.

• We can do a lot more in situ exploration of Mars from Earth than we can currently. The main bottleneck at present is not the light speed time delay, but the bandwidth.

• The search for life on Mars is also best done in situ at present. It is more practical, can study many different regions at different depths over the rover's exploration region, and we do have many space capable instruments now for sensitive searches for life in situ, which we didn't have as recently as a decade ago.

• We don't have any prior experience of containing exobiology returned from another planet in our labs. It will be much easier to do this safely if we know what is there first, at least in a preliminary way.

• Then humans in Mars orbit would be an exciting mission, psychologically good for the crew, like orbiting in the ISS but above another world. Controlling avatars on the surface via telepresence, with binocular vision, binaural sound if you like, haptic feedback, and digitally transformed vision so you can experience the surface with bright colours as if lit by a midday sun, even a blue sky if you like.

• As for exploring a galaxy, robots are far safer. We should start with robots and think very carefully before considering setting up new colonies of humans. Because uncontrolled self replication is an issue in the galaxy whether the self replicators are robots or humans.

• Generally, sending humans into space is something new, that humans have never done before. We are capable of making mistakes, even huge ones, and this could even cause our extinction. Or it could have hugely beneficial consequences. We need to be able to look ahead and need to be adaptable.

• Grand plans such as terraforming ideas, and ideas for ways that humans might be able to survive on Mars long term are well worth studying as we find out more about how planets work, learn about other potential futures for Mars, may help with studies of exoplanets, and help us understand how Earth works, and it may have many other benefits. Many of the ideas will be of benefit early on for robotic exploration and human missions closer to Earth. But anything that closes off other options for all future time needs to be approached with caution at this stage, until we know more, whether on Mars or anywhere else in space.

• For all these reasons our human and robotic space exploration strategies should be open ended and capable of being changed quickly and easily based on new discoveries. They should also involve long term future thinking to avoid mistakes that we could make by rushing in "where angels fear to tread".

• The best place to start surely is the Moon and the Earth Moon system - where we know that we can do it, with minimal risk of contamination, and the maximum of safety for humans.

WHAT ABOUT ALL THE PEOPLE WHO RESEARCH SPACE EXPLORATION BECAUSE THEY ARE EXCITED BY THE PROSPECT OF MARS EXPLORATION?

This is one of the questions I was asked on the SpaceShow on 27th May 2016 (one hour and twenty minutes in).

So first, many of the things developed for Mars are also useful for the Moon. One example, the suitport, to keep dust out of the habitat. Also Dava Newman's counter pressure spacesuit.

The same approach can be used on the Moon. Also the ideas for making fuel on the Mars surface for feedstock hydrogen from Earth - we can use it for fast telepresence rovers exploring the surface, and for robotic avatars which might be quite energy guzzling to start with. SpaceX's supersonic retropropulsion could be used to land multi-ton robotic missions on Mars.

Then there are many ideas for exploring Mars with robots, and we'll need more ideas there. Requires just as much invention to explore it robotically. The jumping cave bots, flying entomopters (fly like a bumble bee in the thin atmosphere), and so on, see my Soaring, Buzzing, Floating, Hopping, Crawling And Inflatable Mars Rovers - Suggestions For UAE Mars Lander

And the in situ search for life on Mars will revitalize the whole field of astrobiology. Astrobiologists have been designing instruments to send to Mars since before Viking, to search for life in situ. We have an extraordinary array of instruments designed over the last decade, and maybe at last they will get a chance to fly them.

Indeed, keeping the surface of Mars free of Earth life, of maximum interest for science, is the best way, I think, to make sure we have a long term interest in the planet, rather than a short term mission like Apollo that starts and then almost immediately stops.

And meanwhile we'd be doing really exciting things closer to Earth. For instance, things like the human factors research in LEO. Astronauts find this sort of research very interesting, to be taking part in experiments to learn how to survive better in space long term.

And I think if we went very quickly to Mars, necessarily without any lifeboats, that there's a strong possibility of a disaster like Apollo 13, that doesn't have such a happy ending, which could really be a downer for human spaceflight. I think we need a step by step approach, as for Apollo. We might make such rapid progress that we feel we are ready for a humans to Mars mission early on, but if our "shake down cruises" closer to Earth, in LEO or at L2 turn up problems, maybe we shouldn't do it for some time until we sort out whatever the problems are. A triply redundant system is not much good if all three copies of it have similar problems.

So in short, some of the research can be used for the Moon. Some for Mars robotic exploration. And some for human missions to Mars orbit and flybys. And by the time we've done all that, if we are not in too much of a hurry, maybe we've learnt enough about Mars to make more informed decisions about what to do next.

COMMERCIAL VALUE FOR MARS

This section originated as a Quora answer

• Could colonizing Mars be a lucrative or potentially profitable venture?

It was run by Forbes magazine as

• Is There A Fortune To Be Made On Mars?

The debate about going back to the Moon focuses on the commercial value of the Moon, for exports to LEO, to Earth or to other locations in outer space, see The Moon is resource rich. But what about Mars, does it have any commercial value for exports to Earth or anywhere else? This is relevant whether or not we send humans to the Mars surface, so let's forget about planetary protection issues for this section. If there is anything of great commercial value on Mars then either

• You mine it telerobotically or robotically, humans remain in orbit around Mars - nobody visits the surface, Instead, they live in orbital colonies and control robot-like avatars on the surface. (For more on this, see my To Explore Mars With Likes Of Occulus Rift & Virtuix Omni - From Mars Capture Orbit, Phobos Or Deimos)

• Or you mine it with humans on the surface

Elon Musk has said several times that he doesn't think there will be anything material from Mars that would be worth transporting back to Earth.

"I don't think it's going to be economical to mine things on Mars and then transport them back to Earth because the transport costs would overwhelm the value of whatever you mined, but there will likely be a lot of mining on Mars that's useful for a Mars base, but it's unlikely to be transferred back to Earth. I think the economic exchange between a Mars base and Earth would be mostly in the form of intellectual property"

Elon Musk interview on the future of energy and transport - and more quotes like this from him.

Robert Zubrin covers this in more detail:

"Another alternative is that Mars could pay for itself by transporting back ideas. Just as the labor shortage prevalent in colonial and 19th century America drove the creation of Yankee Ingenuity's flood of inventions, so the conditions of extreme labor shortage combined with a technological culture and the unacceptability of impractical legislative constraints against innovation will tend to drive Martian ingenuity to produce wave after wave of invention in energy production, automation and robotics, biotechnology, and other areas. These inventions, licensed on Earth, could finance Mars even as they revolutionize and advance terrestrial living standards as forcefully as 19th Century American invention changed Europe and ultimately the rest of the world as well."

I discuss this in the next section, Would a space colony survive with only exports of intellectual property to pay for imports?. So will set it to one side for now and look at the other suggestions.

Elon Musk is skeptical about space mining generally thinking it probably won't be possible to export from the asteroids - "I'm not convinced there's a case for taking something, say, platinum, that is found in an asteroid and bringing it back to Earth." Of course many think that this will be possible. Myself I just don't know, I've heard the arguments on both sides and remain on the fence here.

Anyway Elon Musk doesn't go into any more detail about the case for or against material exports. Robert Zubrin however has discussed this in a paper "The Economic Viability of Mars Colonization " in the Journal of the British Interplanetary Society from 1995, and later on in the Interplanetary Commerce section of Case for Mars. He first outlines the need for exports to make a Mars colony viable:

"A frequent objection raised against scenarios for the human settlement and terraforming of Mars is that while such projects may be technologically feasible, there is no possible way that they can be paid for. On the surface, the arguments given supporting this position appear to many to be cogent, in that Mars is distant, difficult to access, possesses a hostile environment and has no apparent resources of economic value to export. These arguments appear to be ironclad, yet it must be pointed out that they were also presented in the past as convincing reasons for the utter impracticality of the European settlement of North America and Australia."

..."While the Exploration and Base building phases can and probably must be carried out on the basis of outright government funding, during the Settlement phase economics comes to the fore. That is, while a Mars base of even a few hundred people can potentially be supported out of pocket by governmental expenditures, a Martian society of hundreds of thousands clearly cannot be. To be viable, a real Martian civilization must be either completely autarchic (very unlikely until the far future) or be able to produce some kind of export that allows it to pay for the imports it requires."

..."Mars is the best target for colonization in the solar system because it has by far the greatest potential for self-sufficiency. Nevertheless, even with optimistic extrapolation of robotic manufacturing techniques, Mars will not have the division of labor required to make it fully self-sufficient until its population numbers in the millions. It will thus for a long time be necessary, and forever desirable, for Mars to be able to pay for import of specialized manufactured goods from Earth. These goods can be fairly limited in mass, as only small portions (by weight) of even very high-tech goods are actually complex. Nevertheless, these smaller sophisticated items will have to be paid for, and their cost will be greatly increased by the high costs of Earth-launch and interplanetary transport. What can Mars possibly export back to Earth in return?"

(emphasis mine)

So according to his ideas, the Mars colony is supported on the basis of outright government funding for the early stages of exploration and base building. He thinks that in these early stages you need something over and above ISRU (In Situ Resource Uitilization) for a commercial case unless the base is autarchic - a word which usually refers to individual liberty and governing oneself - but in this context I think he must mean, producing everything it needs, independent of Earth.

So it is rather similar to Elon Musk's idea except that in Elon Musk’s vision, the settlement is supported by private funding from Earth in the early stages rather than government funding. I will discuss that later in this section (under the idea of using the free return flight in an empty BFR to sustain the colony).

Robert Zubrin's idea of it being paid by the government initially would work. But it's a huge outlay of probably many trillions of dollars (or a very small colony of maybe a half dozen people) and what US government or any government is going to commit to that?

If they do, how do you know they will continue to do so through the next presidency, with the US feeling the pinch as a result of spending so much on trying to set up a Mars colony? Especially with e.g. high profile crashes and a 100 people dying on Mars with Elon Musk's idea of transporting 100 at a time to Mars? However much one president who really got on board this project might enthuse the US population, after the first few humans on Mars they may well yawn and lose interest in the project with the next president.

Zubrin then discusses the possibility of ores on Mars, and we'll come back to this later in this section:

..."Mars may have concentrated mineral ores, with much greater concentrations of ores of precious metals readily available than is currently the case on Earth due to the fact that the terrestrial ores have been heavily scavenged by humans for the past 5000 years. It has been shown that if concentrated supplies of metals of equal or greater value than silver (i.e. silver, germanium, hafnium, lanthanum, cerium, rhenium, samarium, gallium, gadolinium, gold, palladium, iridium, rubidium, platinum, rhodium, europium, etc.) were available on Mars, they could potentially be transported back to Earth at high profit by using reusable Mars-surface based single stage to orbit vehicles to deliver the cargoes to Mars orbit, and then transporting them back to Earth using either cheap expendable chemical stages manufactured on Mars or reusable cycling solar sail powered interplanetary spacecraft. The existence of such Martian precious metal ores, however, is still hypothetical."

In his section on Interplanetary Commerce in “Case for Mars” page 239 and following he also suggests deuterium as an export. I'll look at that below, between the section on geological products and the section on fuel exports.

He then goes on to suggest that Mars may play a crucial role for supply of ores and other exports to the asteroid belt once we have humans living there. He suggests Phobos and Deimos may also be valuable as a staging post on the way to the asteroid belt. Which may be true, but that's a rather later stage. I'm interested here in the earlier stages before we have large numbers of humans in the asteroid belt.

Do correct me if anyone knows of any other papers with detailed discussions of possible exports from Mars. That's all I've been able to find so far.

However it is discussed a fair bit online in places like Reddit, and the various Mars forums and spaceflight forums, and enthusiasts have suggested many other ways that they think a Mars colony could become profitable. So what I present here is based on that, as well as some thoughts of my own.

So, let's look at this a bit more closely, is there anything physical that could be worth exporting, (apart from the science value of the search for life and the information returned). Also is there anything worth exporting at a reasonably early stage such as the first few decades of a human exploration of Mars either on the surface or telerobotically from orbit?

• Samples of Mars dust and rock. The first samples could be worth billions of dollars per kilogram to start with, at least that's how much they plan to spend for Curiosity's successor's sample return

However, the price would go down quickly as we get more samples from Mars of the order of tons of material. You'd only return as much as was needed for the scientific research you need to do due to the high price of return of material from Mars.

Also, individuals might want to buy Mars rocks at high prices, but only for as long as they are rare. This would be like supporting a lunar mission by returning and selling Moon rocks. The first few rocks could be valuable to collectors, and if they were issued with a certificate of authenticity as the first rocks to be returned from Mars or the Moon maybe the first few rocks would retain their value. But longer term, how many people would want to buy into something of continually reducing value?

The only reason to buy Mars rocks would be because you want to study them scientifically or - for the kudos of being one of the first people to own a Mars rock. You know that this rock you paid a million dollars for will soon be worth only a thousand dollars. Even with a certificate of authenticity as one of the first Mars rocks returned TO Earth, it's value is still likely to go down by a few orders of magnitude as they become more common - like "Interesting, but so what". But if you are a billionaire it may still be worth the extra bragging rights that you had a Mars rock before anyone else. It might get a few takers but not nearly enough to support a colony.

• There are also the products of past life. On the surface - all of that has been pretty much completely destroyed by cosmic radiation. But - could there be deposits set down by ancient life below the surface, like our oil and gas and oil shale deposits.

You'd think they must be rare or we would have spotted them on the surface. There's no sign at all of outcrops of oil shale. But on the other hand - cosmic radiation is very damaging. Would there be anything left of a surface oil shale deposit after billions of years?

It's an exponential process so you get very rapid reductions. Every 650 million years you get a 1000 fold reduction in the concentrations of small organic molecules such as amino acids on the surface because of cosmic radiation. So that's a million fold reduction every 1.3 billion years.

Cosmic radiation has little effect over time periods of years, decades, centuries or millennia. But over time periods of hundreds of millions of years the effects are huge. After 1.3 billion years, a thousand tons of amino acids gets reduced to a kilogram, with the rest converted mainly to gases like carbon dioxide, water vapour, methane and ammonia. After 2.6 billion years it's down to a microgram (millionth of a gram) and after 3.9 billion years you are down to less than a picogram (a millionth of a microgram) of your original thousand tons deposit.

So, I don't think absence of these deposits on the surface, at least ones easy to see from satellites, really shows that they don't exist below the surface. There could be millions of tons of organics from past life ten meters below the surface, and our rovers so far would probably not spot a thing. The organics of course also have to be there in the first place (surely likely to be patchy, in some places more than in others) and buried quickly - if it took several hundred million years to bury them, much of the organics would be gone also.

Oil itself is surely not worth the trouble of mining to return to Earth. But if there was some unique biological product on Mars that we don't have on Earth - which you could mine to find there, maybe that could be worth returning to Earth.

• Ordinary Earth life on Mars, e.g. vegetables, fruit, decorative flowers or whatever. Perhaps Mars could be a "garden planet" to export food to orbit and space colonies.

Mars could potentially be competitive with Earth for export of food for use on spacecraft and other space colonies due to the much lower launch cost, provided that the costs of growing the crops on Mars are also comparable to Earth's (quite a big if in the early stages).

But what about greenhouses in space? It would also have to compete with those. This would require it to be much easier to build a greenhouse on the surface than in space. Since it's a near vacuum and also has such huge diurnal swings in temperature, I'm not sure that it has much by way of advantages over, say, Phobos or Deimos, or indeed the Moon which has much less delta v than Mars. Even for export to Mars orbit, it could be as economical or more so to export from the Moon for foodstuffs that can keep for months long transport journeys. See section above: Greenhouse construction - comparison of the Moon and Mars

It could be more economical to export from Mars to Mars orbit rather than from the Moon perhaps for food that can spoil quickly, though this is not a net export from the Mars system. Another thought, if the natural Mars gravity was an advantage, and for some reason, easier to use than artificial gravity, perhaps it could be worthwhile.

It could also be worth doing if conditions on Mars let you produce unusual food or decorative plants more easily. As an example, it could be worth doing, if you can grow rare flowers on Mars that are very expensive to grow elsewhere, or similarly unusual and tasty rare new food stuffs that grow best on Mars for some reason, perhaps genetically designed for Mars conditions. This is related to the next topic:

Continuing to

• Products of present day life. If Mars has interestingly different biology, maybe RNA based, maybe XNA, or not a DNA type chemical basis at all - you might find it worthwhile to grow Mars micro-organisms in greenhouses or special habitats on Mars designed to make conditions conducive for them. Then these might make products useful for Earth.

• Or genetically engineered biology that grows best in Mars conditions for some reason (actually responds well to the near vacuum, and extreme swings of temperature for instance)

Products you could export could include

• Medicines, if Mars life produces products of value for human health

• Spices and special foods - if the extraterrestrial biology is especially tasty and is safe to eat but can't be grown on Earth.

• Chemicals, e.g. if Mars life consists of XNA and the XNA is valuable, you could make large quantities on Mars to export to Earth. Similarly for any proteins, enzymes or other chemicals that are easier to make on Mars.

• Nano structures - makes products that are unusual and useful on the nanoscale.

For this to work there must be some reason they can't be grown on Earth

• Needs Mars conditions of near vacuum, huge temperature differences from day to night, high UV levels, or cosmic radiation and solar storms, and it's easier to grow on Mars than simulate Mars conditions on Earth. (I don't know why life might need solar storms or high levels of UV radiation but just added that for completeness, given that it may be a totally alien exobiology and we don't know what it can do or how it works in detail - those are sources of energy that could potentially be used by exobiology in theory).

• Can't be grown on Earth at all for safety reasons - e.g. photosynthetic life that's more efficient than any Earth based photosynthetic life, or perhaps it depends on symbiotic microbes that would be harmful to the environment of Earth if returned here. Perhaps what we return from Mars is the product of such microbes rather than the microbes themselves.

• E.g. if it is based on XNA then it might not be safe to set up an XNA based ecosystem on the Earth to grow these products, because of the risk of escape and competition with DNA based ecosystems, and if they are also very valuable that could be a reason for growing them on Mars.

• Can grow on Earth but easier to grow on Mars.

This case might also be another reason to be really careful not to contaminate Mars with Earth life, so that you can continue to grow the native Mars life there without interference from Earth life to make unique products that can only be produced easily from the native Mars life.

However, even if you can't grow the products safely on Earth, at some point you'd have the capability to grow them in Stanford Torus type habitats, biologically isolated from Earth and designed to mimic Mars conditions. Still, by the time that's feasible, export costs from Mars could go down at the same time that prices of such habitats go down, so keeping Mars competitive with them.

This does seem a potential early export that may continue to be commercially viable for quite some time, maybe even indefinitely. But it depends entirely on what we find as we search for life on Mars and also on how easy or safe it is to grow them on Earth, the Moon or elsewhere.

• Geological deposits With the dry ice, low atmospheric pressure, cosmic radiation, things will be different from Earth in some respects. For one clear example, its salt deposits are made up of sulfates and perchlorates rather than chlorides as on Earth. Not that those are worth returning, but could it have other more valuable deposits that we don't have on Earth, or rarely find here? Which leads to the next idea, could it have unique rare gemstones for instance?

• Opals from Mars. In 2013, the Mars Reconnaissance orbiter found evidence of large deposits of opals (hydrated silica) on Mars. Now most of that won't be gemstones, just deposits of silica modified by water. But could it have valuable gemstones there? Might the opals have markings unique to the way they formed on Mars? This orbital discovery was backed up by discovery of trace amounts of opal in a Mars meteorite in 2015.

Raw opal found in Andamooka South Australia - photo credit CR Peters

Mars is different from asteroids or the Moon here, so it could have unique deposits. It's the only place we know of with deposits formed in ancient seas billions of years ago and its past and present climate is unique too. It might have unique minerals of decorative value.

What about:

• Gold from Mars (or substitute platinum, or titanium, or whatever you think is especially valuable that you could find on Mars). For gold, perhaps the geological processes on Mars involving water in its past have concentrated deposits of precious metals just as they do on Earth? It's also surely had many iron / nickel asteroids hit the planet so may have deposits of platinum, gold etc. for similar reasoning to Dennis Wingo's reasoning for the Moon. Indeed more so, because it is closer to the asteroid belt so gets hit by them more often.

• Robert Zubrin's list here includes silver, germanium, hafnium, lanthanum, cerium, rhenium, samarium, gallium, gadolinium, gold, palladium, iridium, rubidium, platinum, rhodium, europium, etc.

Remember, that

• You have to do all the work to actually run the gold mine on Mars, and then send the gold into orbit.

• The price of gold is going to go down as it becomes available from space - or else the amount you can sell to Earth gets regulated to keep prices artificially high.

• If it is viable from Mars, it’s likely to be viable from other places too, particularly, robotic mining of asteroids may undercut you, and then you’d get less for the price of your gold than you spent on mining it, if robot mining of asteroids costs less.

• There may be much easier of access sources of platinum, gold etc. from the Moon if Dennis Wingo is right. If you can get the transport costs from the Moon down to almost zero by using Hoyt's cislunar transport system or similar (see Exporting materials from the Moon), it would be very hard to compete with that from Mars.

• If the mines are operated by humans on Mars, you have to pay for all the supplies to the miners on Mars which could amount to trillions of dollars a year, before you can turn a profit. For telerobotic or robotic mining you have to pay for the telerobot replacement, maintenance and repair and you also have to pay for all the equipment needed, drilling machinery etc. Will humans be able to compete with telerobots or robots operated from Earth with maybe just a small number of humans in situ?

So, in short, it has to be competitive with platinum, gold etc. mined elsewhere in the solar system, and you have to bear in mind that the prices you can get from Earth will surely go down, or else your exports are limited to keep the prices artificially high. On the other hand if the material you are mining is very valuable, and launch costs are low, perhaps the margin due to cost of export from Mars doesn't make such a big difference. E.g. suppose the launch costs a few hundred million dollars but you are returning tons of material, worth billions of dollars, perhaps it doesn't matter so much that a few percent of your product's price is due to transport. Maybe other elements of the price such as mining are somewhat less expensive than they are for asteroids?

However for this to work, there has to be a reason why other elements of the cost of mining are low. Asteroids and the Moon have the advantages of:

• Iron rich asteroids consist of pure metal, not oxidized.

• There may be easy robotic ways to extract it e.g. using gas carbonyls, no need for drilling as this turns the metal directly into gas

• Much lower delta v requirements than Mars for some of the NEOs, and in case of the Moon could even be zero delta v with Hoyt's cislunar tether transport system.

It seems unlikely that the thin Mars atmosphere would help much with mining operations. Would the Mars gravity help, or be a hindrance? And the large temperature swings from day to night, could they help in any way to make it easier to mine materials?

• Getting colonists to pay using their fee for the passage out to Mars, and pay some more on Mars from proceeds of the sale of their home on Earth - and to subsidize exports by using the nearly empty vessels for the journey back.

Elon Musk says that prospective colonists with half million dollar homes will sell their homes to go to Mars and he says this is how the colony will sustain itself to start with through the sale of the homes of its prospective colonists. Here is his interview where he says so (on the SpaceX channel):

What is the Business Model for Mars?

If you get colonists who pay in advance for their flight out to Mars - and they use the Mars Colonial Transporter - a 100 people at a time, if SpaceX succeed in producing that spaceship - then the spacecraft has to come back to Earth after every run to transport colonists to Mars, and would be able to take exports with it, which is essentially free transport. So there would be a multiplier effect there of the original passage fee.

However unless the products are already worth returning for one of the other reasons, then at most they could get back their original passage fee by selling the material. Otherwise you'd have a case for sending empty colonial transporter ships to Mars just to return the products.

So, you'd get exports, yes, for as long as the colony continues to expand rapidly. However, that's not a business case in the long term, as it's not going to be sustainable, as a way of supporting a colony there. Even if they can get their money for the flight back from the goods returned from Mars, they then have to support themselves on Mars indefinitely, not just pay for the flight out.

And with increasing numbers of colonists on Mars, each new colonist adds to the numbers of colonists that have to go out there every year to support them with the passage fees. Suppose for instance that 1 colonist needs one extra colonist a year to bring enough into the economy of Mars to support them. So you start with 1 colonist. Next year you have 2, and next year 4, next year 8 and so on. It is similar for any other ratio of numbers of colonists needing to arrive each year to support each colonist there. You are talking about an exponential progression, and that gets large very rapidly.

If you get increasing numbers of spaceships sent there to send them their supplies, again you need to pay for that somehow.

So, I don't think relying on the nearly empty transporter as it returns to Earth as a way to support the colony is likely to work long term. It works only as long as you have exponentially increasing numbers of colonists going to Mars and nobody coming back or few people coming back.

At most it's a doubler effect. And it is hard actually to see how the colonists could pay even to get established on Mars with a habitat and a spacesuit, surely the minimum you need.

After all, even spacesuits currently cost two million dollars each and are good for a couple of dozen or so space walks from the ISS (much less wear and tear than you get for a Mars suit) and need constant servicing. Even if they are reduced in cost ten fold, it's $200,000 each, and they will need to be repaired - and will need to be replaced from time to time. Then what about the cost of your habitat on Mars? It will probably cost hundreds of millions of dollars. And it will have a finite life - if it is like the ISS it will last a few decades before most of it has to be replaced.

You have got to Mars, but you are planning to live there for the rest of your life and raise a family there too, presumably, or it is not really a colony. Your half million dollars won’t last long. Some is gone on the ticket out there - Elon Musk says the ticket price is $200,000. So after buying your spacesuit as well, now you have a $100,000 deposit on your (much smaller) habitat on Mars and that’s your half million dollars already gone before you have done anything on Mars. Suppose you can earn $200,000 by returning materials you found on Mars to Earth in the empty return flight you get for free with your ticket price (assuming they do it that way). So now your deposit on your habitat is $300,000. There is still no way you are going to make any more payments on your mortgage for your habitat. Never mind sustain yourself on Mars. And Mars as a whole has made a loss on you, you have got there and you start with a debt and you have a very expensive mortGage to pay off now. With no way to earn anything to pay for it.

What next?

I don't really see how that's going to work. It is only possible if there is some other way to pay for it on top of the passage fee and the money they pay for a spacesuit and deposit on the habitat.

• Paid for by retirees to Mars. This is another idea sometimes mentioned online - could a small colony be paid for by retirees? Perhaps some people might be willing to pay large amounts to “retire to Mars” and older people nearing the end of their lives are more likely to be able to afford such a trip using their life’s savings.

After the initial romance of being “the first settlers on Mars” is over, would there be such huge demand to retire to Mars with not so much by way of home comforts as Earth and far away from their friends, relatives and children? Many older people take a lot of interest in their younger relatives and might not want to retire to Mars on their own and leave them behind on Earth.

Also, presumably the idea is that they can pay for the colony because they won't live long when they get there. But it doesn't work like that. If you have survived, say, to 65, your total life expectancy is much higher than for someone who has only survived to 20, because everyone who died before 65 are removed from the population at that point. Quote from here:

• "A man reaching age 65 today can expect to live, on average, until age 84.3.

• "A woman turning age 65 today can expect to live, on average, until age 86.6."

That's an average, so many of the population will live more than 20 years after they reach their 65th birthday.

It continues like that. The life expectancy of an 85 year old woman isn't 1.6 years, it's 7 years. The life expectancy of a 90 year old woman, if they live that long, is still 5 years. Then on top of that, they have to be healthy enough to get to Mars, so it would be biased towards healthier old people. Those figures are from the US social services life expectancy calculator.

Even if you only accept 90 year olds, you'll want super fit 90 year olds which mean they will probably live for more than five years, maybe a decade or more, especially with improvements in medicine.

So, we have to expect retired people to live for decades after they retire. They need more hospital care, and nursing than the general population. They may also get Alzheimer's, and are less strong, on average (some may be super fit of course, for their age, but still they are not quite as strong as a 20 year old, athletes "retire" at a young age). How could that work?

I can’t see the retirees migrating from Earth paying for their own requirements for the rest of their life. And if it is a mix of older and younger people, even more so, I can't see the retirees paying for the requirements of all the younger people for the rest of their life.

This again becomes a case where you would need exponentially increasing numbers of immigrants needed to pay for the colony, and exponential growth can’t continue for long. Of course retirees would have a place to play in a colony that can support itself financially, as in any society. Just saying that the one off sum of money that retirees pay to go to a space colony can't be used as an income to support it. It's just the same as for younger folk, they need some way to continue to support themselves once there. So we need to keep looking.

• Export of deuterium from Mars. In “Case for Mars” page 239 and following Robert Zubrin suggests deuterium as an export.

This is one of the main points in the International Commerce section in Case for Mars, and is also often mentioned in discussions, so I should go into it in some detail.

So first, let's look at the data on deuterium abundances in our solar system. Curiosity measured a deuterium to hydrogen ratio five times greater on Mars than in the Earth oceans, probably due to the loss of hydrogen from the upper atmosphere of Mars over billions of years. See Heavy hydrogen excess hints at Martian vapour loss. This is for near surface ice. The Mars meteorite studies also suggest another reservoir of water below the surface with a lower ratio of two to three times that for Earth’s oceans which probably comes from an earlier phase of Mars history. Meteoritic evidence for a previously unrecognized hydrogen reservoir on Mars.

Deuterium occurs naturally on Earth in water as 1 in 6,400 hydrogen atoms or 1 part in 3,200 by weight. On Mars it is one deuterium for every 1,284 hydrogen's. Though Mars has a higher deuterium to hydrogen ratio than Earth, it’s not the most abundant source of it in the solar system. Rather, Earth’s abundance is if anything rather low, compared with many sources although high compared to the concentrations in the Sun and Jupiter and hydrogen from the solar wind. The solar wind hydrogen trapped in the lunar regolith also has a very low deuterium concentration.

Venus has the highest deuterium / hydrogen ratio recorded in our solar system of 120 times Earth’s and so 24 times that on Mars in its atmosphere. Implications of the high DH ratio for the sources of water in Venus' atmosphere.

Most meteorites that hit Earth have close to terrestrial abundances of deuterium but some have very high levels. This meteorite has 13 times the abundance of Earth’s oceans, so more than twice the abundance for Mars (many types of rock contain hydrogen and so you can measure their deuterium concentrations, this is a chondrite meteorite ).

Antarctic Meteorite Lab Photo of Sample WSG 95300 - details about it here - the deuterium measurements for this meteorite are here: Deuterium enrichments in chondritic macromolecular material—Implications for the origin and evolution of organics, water and asteroids

(see table 2, the δD there is measured in parts per thousand relative to terrestrial abundances, so for instance δD +1000 for double terrestrial values)

Jupiter family comets have higher deuterium abundances than Earth, perhaps around three times terrestrial abundances as for Comet 67p from the Rosetta mission, though there is some question here about whether comet outgassing may somehow concentrate the deuterium and lead to over estimates of the abundances.

So is Mars the best extraterrestrial source for deuterium? And is it worth importing from space at all?

Currently the main use of deuterium is as a moderator in a nuclear reactor. You have the choice of enriching the uranium, and using ordinary water, which is the method used currently in many reactors, or of using ordinary unenriched uranium and heavy water, as is used in heavy water reactors such as the ones developed by India. That works because heavy water slows down neutrons without capturing them so permitting a chain reaction with a lower concentration of radioactive Uranium than light water which captures many of the neutrons.

However his quoted price of $10,000 per kilogram for deuterium seems a bit high. You can get 99.96% pure deuterium oxide for $1,000 per kg from Cambridge Isotopes. (Deuterium Oxide 100%) You can get 99% pure deuterium oxide for $721 per kg (Deuterium oxide 99%) Unless he’s referring to the price for pure deuterium separated from the oxygen?

99% pure deuterium oxide is sufficiently pure for the production of plutonium from uranium. Because of this application, the technology to produce heavy water is tightly regulated and the deuterium produced in a plant is tracked carefully. (For an example of how this is done, see "Selection of a safeguards approach for the Arroyito heavy water production plant" )

He says that the price of deuterium would go up if we develop deuterium / tritium fusion. I don’t really see that, since the main cost comes from extraction and there is no shortage of water to extract it from. Would a higher demand not just lead to us building more deuterium extraction plants, and a search for methods to reduce the costs using larger scale production facilities, for economies of scale, and other methods of generating it, which would reduce the price rather than increase it?

And what if some other form of fusion power turns out to be more efficient or have advantages over deuterium / tritium fusion? It’s a bit tricky arguing based on a technology we don’t have yet, and there are many possible ways of generating fusion power being explored at present.

He says deuterium would be a natural byproduct of electrolysis of water sourced on Mars, which would produce around one kilogram of deuterium for every six tonnes of water electrolyzed on Mars. However to do this then you have to add a deuterium / hydrogen separation stage to the hydrogen production plant. How easy is that? He doesn’t go into details of how it would work.

That 5 times enhancement over the deuterium in Earth’s oceans is still a long way from 100% concentration. It’s normally extracted by using many stages, and each time the amount of deuterium is increased. With only one atom in 1,284, or 0.078% consisting of deuterium you would still need to concentrate it many times over to reach 99% concentrations. For instance water electrolysis, one of the most effective methods of concentrating it, would increase the deuterium concentration 5 to 10 times each time it is used. The 5 times higher concentration on Mars would just save one stage of water electrolysis of many that would be needed. Though in practice electrolysis has such high energy costs it is best used only once for a final stage, for water that is already 50% D2O. The Argentinian plant uses methane as a feedstock because the hydrogen can be dissociated thermally from methane, much more easily than from water. Similarly for other techniques. There are many methods used to extract deuterium. Each of them requires many stages of concentration and I don’t see how an enhancement of 5 times in the feedstock would make a significant difference here.

So that then leads to the practicality of building and operating an extraction plant on Mars and providing the high power levels needed to extract the deuterium (the main reason for its high cost). If it needs vast amounts of electricity to do the separation, it’s not going to be worth doing I think. Also heavy water plants on Earth are large scale and massive structures. This is the heavy water plant in Argentina:

Heavy water plant near Arroyito, photograph by Frandres This plant produces most of the world’s deuterium, at a rate of 200 tons per year, and is powered by a nearby hydroelectric power station at Arroyito dam with a power output of 128 MW. (I'm not sure how much of that power output is used for the plant, do say if any of you know).

The equipment for extracting deuterium weighs 27,000 tons including the support structures and includes 250 heat exchangers, 240 pressure vessels, 90 gas compressors 13 reactors and 30 distillation columns. (Statistics from Arroyito Heavy Water Production Plant, Argentina)

Would the five times higher concentration of deuterium lead to more than a minor saving in the costs of the plant? And how would that offset all the difficulties of setting up and operating the plant with near vacuum conditions outside it, as well as transport costs for equipment that can’t be built on Mars?

Of course Mars is different in many ways and though most of them seem to be disadvantages for operating such a planet, could any of them be advantages, such major advantages that it makes it worthwhile to build and operate it on Mars? For instance, could the near vacuum of its atmosphere be made an advantage somehow? (E.g. for distillation).

On the face of it, there doesn’t seem to be a compelling commercial case for this. If there is, it needs to be spelt out in more detail.

Details here come from Heavy Water: A Manufacturers’ Guide for the Hydrogen Century and Future Trends in Heavy Water Production (1983) - has details of the Argentina plant. and heavy water.

• Export of fuel to Mars orbit and further afield

Some of the internet discussions talk about this as a business case. The main issue I see with supplying fuel from the Mars surface is, would it compete with fuel generated on Deimos or indeed on the Moon for astronauts in orbit around Mars? Also, is methane valuable enough as a fuel in space, to make it worthwhile to export hydrogen to the Mars surface to convert into methane and return to orbit, or to split the hydrogen from water on Mars and use it to make methane?

That leads to the next idea:

• Export of water from Deimos for use as fuel in LEO (if there is water ice on Deimos).

This is the premise of the Deimos Water Company outlined by David Kuck. The delta v back to Earth is much less than from the Mars surface, and you can produce your own fuel for the journey. It would have to compete with volatiles on the Moon if those exist and are easy to mine. I think it's hard to judge this at present as we don't know what the volatiles are like on the Moon. We know they exist but don't know how abundant they are locally, or how easy or hard they are to extract. And so far we don't yet know for sure if there are any volatiles on Deimos, although spectroscopically it resembles a type of asteroid that often has them.

Supposing Deimos and the Moon have volatiles equally easy to extract, then the Deimos volatiles would still be favourable for use on Deimos and Phobos and for export to the Mars surface. They would also be favourable for delivery to Mars orbits such as Mars capture orbit at a delta v of 0.57 km / sec from Deimos. So, it would make a lot of sense for a base on Deimos to supply fuel to the Mars system. But that's not a commercial case for colonization. As Zubrin says - you need something over and above ISRU for a commercial case for exports you sell to pay for the things you can't produce there.

So we need to look into whether this can be competitive with the Moon for supply to the Earth Moon system. For the Moon to LEO the delta v is 5.7 km / second, and a bit more if supplied from polar regions - while it's 4.87 km / sec for Deimos to LEO which would seem to favour Deimos. However that does not take account of Hoyt's cislunar tether transport which could make the delta v for supply from the Moon to LEO almost zero.

So, in summary, there do seem to be a number of potential exports from Mars even at quite an early stage, although this is mainly based on internet discussions with not much actually published on the topic in peer reviewed journals. But they all depend on future discoveries so we won't know if this is possible until we know more about Mars. A few of the potential exports, involving exobiology, might require us to keep Earth microbes out of Mars.

There may also be exports from Deimos, but that depends on how easy it is to extract the volatiles, and if the lunar volatiles are as easy to extract as the ones from Deimos, then it might be hard to put a business case for export from Deimos to the Earth / Moon system, though it may be very useful for volatiles for spacecraft in orbit around Mars, on its moons or on its surface. As for exports to the asteroid belt, the chances are that they will find a way to mine their own volatiles out there, so it seems an unlikely case to me for the special case of volatiles.

Here I'm using the delta v figures from Hop David's cartoon delta v map.

Here are some of the online discussions I looked at. Of course they are not always 100% accurate. This is just enthusiasts discussing the topic, some more knowledgeable than others, and it may also contain a fair bit of nonsense in some of the discussions, so you have to filter and look up details to see if what they say is correct. Anyway if you are interested in doing that, see for instance:

• Is Mars worth mining for Earth purposes? answers on Quora

• Exporting goods from Mars discussion on Nasaspaceflight.com

• Exports discussions on the New Mars Forums under Martian Politics and Economy, for instance: here, here and here.

• What about bringing back valuable resources from Mars to finance one way trips for humans? (Reddit)

• Elon Musk quotes on Reddit with discussion

• Discussion of Zubrin's paper on Reddit

Wikipedia also has a page on Space Trade, though there isn't much in it yet. Then there's Robert Zubrin's paper, already mentioned, and the Interplanetary Commerce section of Case for Mars.

That's about it, do let me know if you have more sources!

IDEA THAT MARS WILL HAVE ITS OWN INTERNAL ECONOMY LIKE EARTH - WHICH DOESN’T NEED EXPORTS

This is a nice idea in principle, to set up its economy - like another planet. Earth doesn’t need exports so why would Mars?

However the difference is that conditions are so hostile on Mars. Remember if you could do anything there, you could do it far easier in a desert on Earth. We have not yet got to the point where someone could do that.

Even if you had e.g. a spacesuit making factory in the middle of the Gobi desert then it would need imports, and the people in the factory would need to be fed, and their clothes imported and generally it would have loads of imports which it would pay for by selling its spacesuits to the rest of the world.

But you can't do that on Mars. Not until you have all that stuff already there.

I don't know if eventually you could, if you had big city domes and inside can do Earth industry with an ultra low maintenance outer skin to the dome - or if you paraterraformed it and covered it with a low maintenance reliable meteorite proof transparent roof over the Valles Marineres or something. Maybe then you have areas where humans can work on Mars as easily as on Earth and produce things at low cost locally. It might then have an economy that can work on its own without imports or exports to other planets.

But if so, there is a long way from here to there. Right now, there's no way that it would work unless you have exports to Earth from Mars to pay for your spacesuits and other high tech imports - or you have people on Earth with big pockets willing to pay out trillions to get a Mars colony underway.

WOULD A SPACE COLONY SURVIVE WITH ONLY EXPORTS OF INTELLECTUAL PROPERTY TO PAY FOR IMPORTS?

As we saw, Elon Musk and Robert Zubrin both are skeptical about any possibility of material exports from Mars, at least in the early stages (though Zubrin thinks there might be a case for deuterium exports), and both think that a space colony could pay for imports solely through licensing of intellectual property to Earth. Robert Zubrin draws the analogy with the "Yankee Ingenuity's flood of inventions" which he says was due to a situation of acute labour shortage in the US in a technological culture, which would be paralleled on Mars. But how would that work in practice?

First, for US readers, I'd like to point out that this whole idea is based on a US perspective on inventions. I'm from the UK and we also talk about our country as the source of a flood of inventions, frequently. Here is an example.

"We're a nation of inventors, from the worldwide web to the electric vacuum cleaner - here's a rundown of our most influential innovations", intro to a list of the 50 greatest British Inventions from the UK in the Radio Times.

And putting aside national pride, which all countries have, surely for such a small country, we have indeed made many inventions here. We don't have the same narrative that it was due to a labour shortage, nor do we think of the US that way either. I'm not talking about historians here, but ordinary folk. Robert Zubrin's quote was the first I heard of this idea, which I assume from the way he put it, must be quite commonly accepted in the US. We just think that we are a nation of inventors, and leave it at that. We don't try to explain why.

At any rate if it's true of the US, surely it can't explain why we have so many inventions from the UK as we've never had a significant labour shortage. Indeed the opposite, here technology put many skilled people out of work leading to uprisings by working people during the industrial revolution followed by military repression

The leader of the Luddites - self employed weavers who feared getting put out of work by the newly introduced weaving technology of the late eighteenth and early nineteenth century, and replaced by less skilled workers. They destroyed industrial equipment in protest. Later on agricultural workers joined in, destroying threshing machines. The UK government responded by military action against them, executions, deportation, and they made destroying industrial machinery a capital offence. The US narrative that invention was the result of a labour shortage just doesn’t work when applied to UK inventions. It was almost the opposite, inventions caused a labour shortage here, at least of skilled workers

Let’s look at some of the metrics that measure the talent and creativity of a country. The rankings vary from year to year, but in 2015,

• For R&D investment, Israel is top, (4.4 percent) followed by Finland (3.84 percent), South Korea (3.74 percent), Sweden (3.38 percent), and Japan (3.26 percent).

• For patents, South Korea is top ( 3,606 patent applications per million people) followed by Japan (2,691), Singapore (1,878), Hong Kong (1,797) and the United States (1,644).

• For the percentage in the creative class (workers in science and technology and engineering; arts, culture, entertainment, and the media; business and management; and education, healthcare, and law), Luxembourg takes top spot with more than half (54 percent), and United States is a fair way down the list at (33 percent) rank.

• For education, South Korea takes the top spot with a 100 percent in universities, colleges etc (tertiary education), and the United States is second (94 percent) with Finland just behind in third (94 percent). When you add in tolerance (which makes your country more open to creative people from other countries and to the ideas of creative minorities in your own country) then Canada is top followed by Iceland, New Zealand, Australia, and the United Kingdom. The US is eleventh.

When you combine all these measures, the US comes second with only Australia ranked higher. So it doesn’t seem that being inventive is the most important attribute when it comes to becoming a leading technological nation. It is one of several factors. Availability of education, tolerance and openness to ideas also has a lot to do with it as well as the numbers of people in the creative classes in society. See list of the most creative countries and then for the detailed stats, Global Creativity Index.

Perhaps there is some correlation with labour shortage, for instance, Japan, second in the list of inventiveness by patent applications, is top in the list of countries facing acute skill shortages - but which way does it go? Does innovation lead to skills shortages or vice versa? The whole question is a complex one. Here is a survey of the literature from 2005 from the Department of Trade and Industry in the UK which looks at some of the drivers of innovation. The focus is more on trying to find ways to fill the gaps in skill shortages, and ways to encourage workers to get involved in innovation since innovation often comes from the less skilled workers - it also looks at different styles of innovation - the radical creativity that we may be most familiar with and incremental accumulation with a slow and steady pace of innovation.

I think it is hard to say for sure whether space colonies would be more innovative than countries on Earth on the basis of this information.

Also, the space colonists would be using many inventions from Earth, so surely they would have to pay many royalties in the other direction back to Earth? How could it be possible to set up a system where the Earth has to pay royalties to Mars and not vice versa?

And then - how also could it work, even if a space colonists did turn out to be much more inventive than Earth? The only people who would be able to earn foreign currency for imports to Mars would be the ones who make these inventions. But it's not enough to be inventors. They have to make their inventions into paying inventions also. And highly profitable inventions too, to pay for such items as spacesuits.

It’s best to think of spacesuits as more like mini spaceships than the suits of science fiction stories and movies, which are depicted as not much more complicated than wetsuits with aqualungs. They have to be pressurized to hold in atmosphere at a pressure of tons per square meter when surrounded by a vacuum, yet also flexible too with many joints, also able to withstand minute micrometeorites hitting at kilometers per second, and to keep the astronaut cool because the vacuum of space is a good insulator, like a vacuum flask. This makes them far more complex than any diving equipment.

A typical NASA spacesuit would probably cost about $2 million dollars to build from scratch - that’s as a recurring item, not including the initial design costs. It requires about 5,000 hours of work and would take someone who had all the necessary skills about two and a half years to build, given supply of all the parts and materials needed. I get those details from Space suit evolution (NASA). It’s possible that this could change with future designs. But that’s the current situation, and for the foreseeable near future.

I'm an inventor, and I have invented dozens of things (mainly games and software ideas) but I only earn dollars per day from them, and many have never been published in any form (attempted to publish some of them with no success).

Similarly I've written many original articles, but again, though I earn a bit from the kindle booklets, it's only a dollar or two a day, at present anyway. And that's not at all unusual. For instance I have many composer friends, but it is rare for them to earn a living entirely from composing.

As for composers, artists, writers, or other creative people, earning amounts that would let them buy multimillion dollar spacesuits for all their friends, and ship them to a space colony - well forget about it, unless the next Harry Potter is written on Mars. Even then, J. K. Rowling’s estimated wealth is 1 billion - enough to buy spacesuits for 500 people. She earns 23 million a year, enough to pay for 11.5 spacesuits a year. You’d need a lot of J. K. Rowling’s to support a large Mars colony.

Amongst all my friends and relatives here in UK, another country with a high proportion of inventors, then yes many of them are indeed innovative and creative and inventors in spirit. But I can't think of many that make a living from their inventions, especially just as intellectual property rights. It's the same also for software programmers - most independent shareware developers that I know, often authors of very inventive software, do it part time, and couldn't earn enough from it to support themselves or their families.

Only a few of all the people who invent things go on to make millions of dollars from their inventions, enough to pay for spacesuits and the like for all their friends and colleagues if they so wished. Even Elon Musk came close to bankruptcy once, in his worst year.

"We were running on fumes at that point," Musk says. "We had virtually no money... a fourth failure would have been absolutely game over. Done." Elon Musk in an interview with Scott Pelley, March 30 2014.

So there is a measure of luck there as well. SpaceX would not be here today if his fourth test flight had gone wrong.

So, if you had a million colonists, I don't think we can expect to have a million Elon Musk's. You might be lucky to have one. I think it is fair to say he is at least a one in a million success story. And however brilliant he is, would he earn enough just through intellectual property rights on Earth, managed remotely from, say, Mars, to pay for all the imports needed for a colony of a million people? Even a billion dollars a year of earnings is only $1000 per person which wouldn't get you far importing expensive components from Earth to Mars.

There's also the question of how that would work in practice. Is it going to be a communal system or even communist (in the good sense) where the inventor's earnings are used equally to support everyone? If so, where is the incentive for the inventor to not just invent, but to go to all the work to get their invention into production, or for entrepreneurs to join in with them? Or is it the case that the inventors who are successful are the only ones who earn anything in Earth currencies, and so are the only ones who can afford to import goods, and they then sell them on to the other colonists at any price they care to set in the local Mars currency? And what’s to stop them from emigrating to Earth once they become financially successful, especially since most of their earnings would accrue on Earth and the on the spot business decisions would be made on Earth, and the meetings with investors and manufacturers etc. would also be done there?

I'm not expert in politics or economics. I may well be missing something here. But it seems on the face of it to be quite a problematical way to support a colony. I'm interested in any thoughts on this - do say in comments on the Science20 articles or the kindle booklets pages or here.

On the face of it, at least, this seems a major advantage of the Moon, that you'd have many different revenue streams to pay for imports, at least potentially.

• Intellectual property rights and royalties of course, for any inventions and intellectual creations, the same as for Mars. If Robert Zubrin is right, you have the same labour shortage in a highly technological society, which he thinks should lead to creation of lots of valuable intellectual property in space.

• Exports of the volatiles - initially supply of volatiles to cislunar space - depending on how easy they are to extract

• Exports of precious metals - with the much lower delta v, then these just possibly might be commercially viable. Dennis Wingo thinks that the Moon may have valuable resources of platinum, gold etc. as a result of impacts of iron rich meteorites as well as the core of the giant impactor that created the south pole Aitken basin

• Manufacture of computer chips that need high grade vacuum, readily available on the Moon, higher grade than anything easily achieved on Earth.

• Export of solar power - solar panels should be easy to make on the lunar surface using in situ resources and the high vacuum - and some think there may be an economic case for exporting this solar power to Earth.

• A place to build large particle accelerators - with no need for cooling or evacuation of the chambers.

• Scientific research stations which would be funded from earth - hard to set up at the distance of Mars (though we may get them there eventually).

• Astronomer's radio telescopes on the far side and passively cooled infrared telescopes and liquid mirror telescopes in craters - paid for by Earth - they may be built from Earth but probably need at least some human presence on the Moon.

• Tourists as well. It's reasonably possible that you'll get wealthy tourists going for holidays on the Moon in the not so distant future. But who would go on a holiday to Mars, whether to the surface or to orbit or its moons, if it means you have to take two years or more out of your life to go there and back? Venus also seems too far away to have much tourist traffic in the near future. The Moon seems likely to get the lion's share of any space tourist industry beyond LEO in the near future, unless transport is speeded up hugely, and especially also given the much higher costs of a long mission to Mars or elsewhere in the solar system.

I haven't listed exports of Helium 3 for fusion here. Although it gets a lot of publicity, it's based on technology we don't have, and some experts think we will never have. Also, Crawford calculates (page 25)"* that manufacturing a square meter of solar panels on the lunar surface - which you can do by melting the indigenous silicon and using the high grade lunar vacuum to form panels in situ - would create as much power through solar power in seven years as you'd get from mining the same region for Helium 3 to a depth of three meters.

So, if mining for helium 3 is viable, this suggests that beaming solar power from the Moon back to Earth or to spacecraft in LEO would also be viable and a better business case than Helium 3. It may however be a useful byproduct of other mining operations on the Moon, for cryogenics, neutron detection, and MRI scanners, and possibly for fusion in the future. For details, see Helium 3 .

Of those, only the first, intellectual property, applies to Mars, at least in the early stages.

That is of course, apart from the ideas mentioned in the previous section, but they are none of them things we can count on right away, and some may depend on keeping Earth microbes out of Mars.

Also, if Mars geology could lead to unique gems such as the possible Mars opals of the previous section, then what about the Moon? Might it also have unique exports that can only form in the lunar conditions? For instance, could there be lunar gems?

Surprising discovery in 2008 - the near side of the Moon has large deposits of relatively pure chromite spinel, which is a gemstone on Earth. This was discovered from orbit. The moon rocks have small amounts of spinel mixed up in them, but this was a much stronger signal. Could the Moon have spinel gemstones? As with the Mars gems, if they exist, they probably wouldn't be worth the cost of returning to Earth unless they have something distinctive about them due to formation in lunar conditions.

Or might there be anything else unique to lunar geology that we might prize back on Earth?

MAINTENANCE COSTS

For a profitable colony, I think the main thing in the very long term is how easy it is to maintain habitats and equipment in the years and decades into the future. If habitats have to be replaced every few decades (as for the ISS), and spacesuits similarly, the long term costs are going to be very high even if the startup costs are reduced.

As an example, the ISS cost €100 billion so over $110 billion, see How much does it cost? with a design life of about three decades (though it may be extended), and normal maximum number of inhabitants six. That makes the cost about 600 million a year or so per inhabitant with most of that due to the limited design life of the ISS.

The projected cost for the Stanford Torus was over $200 billion in 1975 US dollars for ten thousand inhabitants. That’s around a trillion dollars in 2016 dollars (Inflation Calculator), or a hundred million dollars per inhabitant.

If we can find a way to pay for a habitat as a one off cost, for instance through government funding, private funding, or it pays for itself commercially (the Stanford Torus was going to be paid for by exports of solar power from space to Earth), then the main issue after that is how to maintain it.

If the habitats costs a few hundred thousand dollars a year per inhabitant, then still, only the very rich could live there even after the build costs are paid off, and no matter how much the initial build costs are reduced, unless its exports are very valuable.

Then, if you can build the same habitats on Earth, for instance in a desert or floating on the sea, with no cost for its breathable atmosphere or cosmic radiation, solar flare and micrometeorite shielding, the exports from space have to be very valuable to make the space colonies competitive.

If you can reduce the maintenance cost to say hundreds of dollars per year per person then space does have some advantages over Earth, with no storms or earthquakes (depending where you build), no weathering from rain, wind, etc. Then a “home in space” might become a viable long term prospect.

On the downside you have micrometeorites, cosmic radiation, need for spacesuits etc. Can the cost of those really be reduced so much, or the exports from space be so valuable, that they compete with costs of maintenance due to weathering of buildings on Earth?

In this way, an easy to maintain colony will need exports mainly to pay for luxuries, while a hard to maintain colony will need many high value exports just to survive.

REDUCING MAINTENANCE COSTS FOR SPACE HABITATS

The three things here of most importance I think are:

1. An envelope that is low maintenance to preserve the habitat - to keep in air, and protect against any external hazards such as cosmic radiation, solar flares and micrometeorites.

2. A closed system biosphere inside - we need this for any long term space habitat as the logistic requirements and expenses are just too high otherwise. The variation in maintenance costs here would be mainly due to variations in how you supply light and heat to the habitat, and whether you get leaks of gases, water, and other materials that need to be replenished from time to time.

3. Maintenance and resupply of equipment for essential needs, for instance space suits, environment control, solar cells

For 2, I know a lot is made of the CO₂ atmosphere for Mars but you don’t actually need much by way of in situ resource utilization. For instance if it is a reasonably closed system, you don’t need constant supply of water, CO₂, or nitrogen. You just need to be able to top up any losses that there may be in the system. Plants don’t need a constant supply of CO₂ to grow, they get the CO₂ from the exhaled air of the astronauts. The astronauts in turn get their food and oxygen from the plants. In a biologically closed system those numbers all add up. If you produce enough food from plants, you automatically produce enough oxygen too and the astronauts eating that food produces enough CO₂ for the plants to use in their next growth cycle, as the Russians proved in practice with their BIOS-3 experiments.

MAINTENANCE FOR HABITATS IN FREE SPACE AND CITY DOMES

The costs can be reduced if you have a single envelope enclosing a large area, for instance a domed city or a cave or a Stanford Torus or O’Neil Colony style spinning space habitat. That’s because it requires less mass per volume to enclose a larger volume (area of envelope goes up as the square of the radius and the volume enclosed as the cube). So the launch mass and cost per inhabitant of maintenance for the envelope will be much lower for a larger colony.

The Stanford Torus design has 20 tons per colonist, or five colonists for every hundred tons of structural mass, excluding the radiation shielding. The ISS weighs 400 tons for up to 6 astronauts typically. As a Stanford Torus habitat, that much mass could support 20 colonists,s, and later designs are more efficient per colonist, for instance flattened torus or multiple levels inside the torus.

Apart from the radiation shielding, there isn't much difference between the Stanford Torus and other habitats on the surface of a moon or planet. The radiation shielding for the Stanford Torus would be supplied by mass drivers fed by bulldozers on the Moon, so doesn't need to be launched from Earth.

See also Using the Moon to build habitats in free space

MAINTENANCE FOR LUNAR CAVES

The Moon scores over just about anywhere else for the early stages, because of the lunar caves - at least, if they are as large as the Grail data suggests. See Lunar caves. They may be up to kilometers in diameter and over 100 km long. That’s as much internal area as an O’Neil colony.

Somewhat smaller ones, of up to a few hundred meters across would be preferable because the mass of the atmosphere becomes significant for larger ones. If it is easy to convert them into a low maintenance envelope for the habitat, turning interior walls to glass perhaps, the maintenance costs might go right down. They would protect from cosmic radiation, solar flares, micrometeorites and hold in the atmosphere against the vacuum of space.

You might wonder about power requirements to produce food on the Moon with the 14 day lunar night. Robert Zubrin uses figures of 4 MW per acre for artificial sunlight in his Case for Mars (page 237) or about a kilowatt per square meter.

However the power requirements per habitant are far less than you might think as with efficient hydroponics, you only need 30 square meters per person, to provide 95% of their food and oxygen, from the BIOS-3 experiments. Also those figures for the power requirements to illuminate the crops must be for the older halogen lights. Modern LEDs are far more efficient and can be optimized to emit only the frequencies of light that are most useful for plant growth. The result is that you only need 100 watts per square meter or about a tenth of the figures in Case for Mars.

When you combine those lower power requirements per square meter with the small growing area needed per inhabitant from the BIOS-3 experiments, that makes it only 3 kilowatts per inhabitant, which you’d need for 12 hours a day. On the Moon you’d only need it during the lunar night (in the caves, you can use solar collectors on the surface and light pipes during the lunar day). That's 12 hours a day for the lunar night of 14 earth days, so 504 kWh in total. That’s a power level that could be supplied using solar cells during the lunar day then power storage such as fuel cells or batteries for the lunar night.

Alternatively you can lower the temperatures of the crops during the lunar night from 24 °C to 2.5-3 °C (which helps maintain plant vitality during darkness) and leave them in darkness, which results in edible crop yields reduced by 30 - 50%. So that would require up to double the growing area, or around 60 square meters per astronaut, and no need to supply extra illumination during the lunar night.

For more on this see:

• Sending humans to Mars for flyby or orbital missions - comparison of biologically closed systems with ISS type mechanical recycling (also relevant to long duration lunar missions)

• Fertility of lunar and Mars soil

• Earth length day on Mars versus advantages of close to 24/7 solar power at the lunar poles

For need for artificial gravity in the lunar caves, see:

• What about gravity - isn't that a big advantage for Mars over the Moon?

• Artificial gravity on the moon to augment lunar gravity

VENUS CLOUD COLONIES - A SURPRISING LOW MAINTENANCE SOLUTION

However if you want to reduce maintenance to an absolute minimum in space habitats, well there is one other place that has far lower maintenance costs even than a lunar cave. It also has greatly reduced initial costs for the habitats as they are very low mass. It’s a surprising one to most of you perhaps. That’s Venus cloud colonies. So I’ll briefly mention those too.

Venus, just above the cloud top level, is in some ways the most habitable region in our solar system outside of Earth. The temperature and pressure there is the same as for Earth. There’s abundant sunlight, and clear skies. The atmosphere above you provides the mass equivalent of ten meters of water, shielding you from cosmic radiation and solar flares, also from micrometeorites - they are not an issue at all. Solar flares will cause large scale magnetic effects because Venus has no magnetic field to shield from them - but this is only an issue if you have kilometers long conductive cables - which are not likely to be needed.

Earth’s atmosphere is a lifting gas in the dense CO₂ of Venus’ atmosphere. And just as with a weather balloon or airship - the pressure is the same inside and outside the envelope. So an airship could be filled with Earth pressure atmosphere with just a thin envelope to hold it in. Even if it is damaged, the air would leak out only slowly and the Venus acid filled atmosphere would also percolate in slowly too. Unlike any other space habitat, it would not be an emergency that you have to respond to in seconds, but something you could repair over a timescale of minutes or hours or even longer.

Russian idea for a cloud colony in the upper atmosphere of Venus, proposed in 1970s. This illustration is from Aerostatical Manned Platforms in the Venus atmosphere - Technica Molodezhi TM - 9 1971

This makes the Venus atmosphere the place offworld with the lowest maintenance costs of anywhere, I think. Also its atmosphere has all the main chemicals for life. It has carbon, oxygen, hydrogen, nitrogen and sulfur in abundance. The concentrated sulfuric acid is a source of water (it dissociates naturally into water and SO2 in the Venus sulfuric acid cycle). You can make plastics, and you can grow trees and other plants. You could even build new habitats using mainly wood and plastics and some thin layer to protect against sulfuric acid and UV light. To protect suits, airships, cloud colonies etc. from the acid involves covering them with an acid resistant coating, such as teflon (suggested here on the basis of tests simulating Venus atmosphere conditions).

Instead of $2 million spacesuits, you have acid resistant suits, which eventually you’d make locally, and aqualung style air breathers. This is a major saving since spacesuits are so complicated, and components for them when they fail would be a large budget item in any space colony I think.

Venus also has gravity levels identical to Earth, so if full Earth gravity turns out to be best for human health, this is easily achieved in the Venus cloud colonies.

Its long day may seem a disadvantage, as its solar day is a very long 116.75 Earth days. However the upper atmosphere super rotates once every four Earth days in a steady jet-stream like flow which gives the cloud colonies a two Earth day “night” and a two day “day” which is much more acceptable.

The cloud colonies also score at an early stage because you can launch a much larger habitat to the cloud colonies for far less mass per inhabitant. Or much more living space for the same mass sent to Venus. This would be an inflatable habitat like the Bigelow Aerospace idea - but one that is as lightweight as an airship.

Much of this will seem unfamiliar and unlikely to many of my readers. The thing is that ideas for Mars have been worked out in considerable detail, by the Mars colonization enthusiasts and the Mars Society etc. We don’t have any similar advocacy group for Venus or even the Moon. So there’s a tendency to look at everything with “Mars spectacles” and see how the Mars solutions would work on Venus or the Moon. And not surprisingly you find out that the solutions devised for Mars work better on Mars than anywhere else. But once you start looking at these other places in their own right, then a different picture may emerge.

If you are interested in this idea and want to follow it up further, see my Will We Build Colonies That Float Over Venus Like Buckminster Fuller's "Cloud Nine"?

So I think at least potentially Venus cloud colonies have the lowest maintenance requirements of all and might well hit that $100s per colonist per year figure at an early stage.

Still you need to pay back the initial build costs. The Stanford Torus was projected to take 22 years to build for 10,000 colonists at a cost of around a trillion in 2016 US dollars (see Building the Colony and Making It Prosper). A Venus colony wouldn't need anything like as much mass, for instance no regolith shielding is needed, you only need thin envelopes and there is no need to contain the pressure of an Earth atmosphere against a vacuum. The engineering is simpler as well. You could probably launch it all from Earth for a similar number of colonists over a similar timescale at a much lower cost than the Stanford Torus

But you still need some motivation for doing it. Even if it costs much less, and is easier to maintain once built, how can you do it if there are no profitable exports and they can't pay back the build costs? So let’s just look briefly at its commercial value for exports.

ORBITAL AIRSHIPS FOR VENUS AND MARS

This depends a lot on how easy it is to export from Venus. That’s why I don’t see this happening in the very near future, for as long as you need massive rockets to launch from the colonies to orbit similarly to the ones needed for Earth. However JP Aerospace are working slowly and steadily on their idea for orbital airships. Even in the near vacuum of the Earth’s upper atmosphere, hydrogen and helium float in the near vacuum of oxygen and nitrogen. And that’s even more so with the denser Venus CO₂ atmosphere. They accelerate using ion thrusters, slowly over several days, and meanwhile also rise higher and higher in the atmosphere. Eventually they break the speed of sound barrier - but by then they are so high it is an almost vacuum and it is not a problem.

Artist’s impression of orbital airship from JP Aerospace’s Airship to Orbit handout - this would be a very lightweight 6,000 foot airship which slowly accelerates to orbit from the upper atmospheric station using hybrid chemical and electrical propulsion over a period of several days

You need a staging post at a high level in the atmosphere for Venus or Earth where passengers and goods are transferred to a high altitude orbital airship which is much larger and lighter, designed for upper atmosphere operations. See my Projects To Get To Space As Easily As We Cross Oceans for an overview, also see their book: The Airship to Orbit Program

Note that this also applies to Mars too. Their orbital airships would be able to accelerate to orbit from the Mars surface with no need for an upper atmosphere staging post. If this is possible, then you could have both Venus and Mars as “garden planets” and Venus would score over Mars in that respect because the greenhouses would be far less substantial for a larger living area and much lower maintenance.

But the Moon also would have low cost exports because of its low delta v and because of Hoyt’s cislunar transport system which could reduce costs to almost zero (see my Exporting materials from the Moon)

Apart from this idea of a garden planet, it needs to be some product of the Venus atmosphere. Sulfuric acid is the obvious one, but not especially valuable. Might there be some really high value product? One possibility might be deuterium. As I mentioned in the discussion of Mars exports, Venus has a deuterium / hydrogen ratio 120 times Earth’s (and 24 times that of Mars) Implications of the high DH ratio for the sources of water in Venus' atmosphere. Instead of six tons of water electrolysis yielding one kilogram of deuterium, as is the case for Mars water, this would yield 24 kilograms of deuterium, or four kilograms per ton. However as for Mars, can we count on deuterium to be a valuable commodity in the future? And would the higher deuterium levels lead to more than a modest saving in the costs of extracting deuterium? Even with one atom in 54 consisting of deuterium, that’s still far from pure and would require many stages of whatever process is used. On the other hand unlike Mars, Venus does have abundant solar power, even more so than Earth, which may help. Still, as for Mars, this seems a bit of a stretch to me, unless some method is developed for making it much easier to extract deuterium quickly with minimal power requirements - but in that case costs would also be reduced hugely on Earth as well.

As for Mars, another possibility is products of indigenous life, as there is a small chance of life in the Venus clouds. There is indirect evidence in the form of asymmetrical microbe sized particles in the atmosphere and carbonyl sulfide, a clear sign of life here on Earth (though it could be created inorganically on Venus). See my: If there is Life in Venus Cloud Tops - Do we Need to Protect Earth - or Venus.

Again, as for Mars there’s the possibility of growing plants if conditions in the Venus clouds let you produce unusual food or decorative plants more easily, for instance, rare flowers on Mars that are very expensive to grow elsewhere, or similarly unusual and tasty rare new food stuffs that grow best on in the Venus clouds for some reason, perhaps genetically designed for those conditions, since the environment of the Venus clouds would be hard to replicate on Earth.

As for Mars, we have to explore Venus first.

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VAMP/LEAF

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A New Class of Vehicle for Exploration

01:47

https://www.youtube.com/watch?v=0EjgoEFiKko&feature=youtu.be

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Concept for a robotic airship called VAMP to explore Venus. It weighs only 450 kg, although its wingspan of 46 meters dwarfs the space shuttle . It would inflate while still in orbit around Venus attached to its mother ship, and then spiral down to the cloud tops in a slow motion re-entry that needs only minimal thermal protection. Incredible Technology: Inflatable Aircraft Could Cruise Venus Skies, details hereVenus Atmospheric Maneuverable Platform It could explore the Venus atmosphere for years at the cloud tops, the same level that’s suggested for the Venus cloud colonies. Video discussion here.

At a later stage, we could send astronauts to explore the atmosphere using airships, then return to Earth as explored in NASA’s HAVOC concept study. See project home page. The return to orbit would be accomplished using something like the Pegasus air launched rocket. This is an internal study, so it's at an early stage at present.

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A way to explore Venus

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NASA Langley researchers want to get a better idea about conditions on our nearest planetary neighbor, Venus, so they have come up with HAVOC or a High Altitude Venus Operational Concept – a lighter-than-air rocket ship that would help send two astronauts on a 30-day mission to explore the planet’s atmosphere. Exploration of Venus is a challenge not only because its smog-like sulfuric acid-laced atmosphere, but also its extremely hot surface temperature and extremely high air pressure on the surface.

03:34

https://www.youtube.com/watch?v=0az7DEwG68A&feature=youtu.be

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NASA Study Proposes Airships, Cloud Cities for Venus Exploration. Technical details here.

Perhaps it’s possible that we might discover something of high value as we explore and study the Venus clouds. However, we can’t count on it at present.

MARS AS AN ASTEROID MINING HUB FOR THE DISTANT FUTURE - OR SHOULD IT BE VENUS?

I mentioned earlier that Robert Zubrin talked about the Mars system as a base to support asteroid miners in the more distant future. He thinks that Deimos and Phobos might be especially useful here. So, let’s just look at this for the more distant future. Intuitively, Mars is closer to the asteroid belt so you’d think, surely it’s the best place to support asteroid miners? However, the situation is not as clear as you might think.

First, asteroid mining is likely to start with NEOs - we get many asteroids that do close flybys of Earth, Venus or Mars, some with orbital periods close to the Earth or Venus year. The ones that do low delta v flybys of Earth seem the most likely ones for early mining operations after the Moon. We have dozens of large NEOs to mine first, kilometers in diameter. It’s not likely we’ll exhaust those any time soon, and this also has the extra benefit that we are removing asteroids that have the potential to hit Earth at some point in the maybe distant future. For NEOs ranked in various ways including commercial value, see astrorank.

We can also mine the Moon for asteroid resources - the Moon has been hit by many asteroids in the past, so whatever materials you have in asteroids are probably also on the Moon or in it. It's mainly a question of how accessible those materials are. There's some evidence suggesting that the Moon may have rich surface deposits of platinum (and so also of other metals) from the metallic core of the 100 km asteroid that created the Aitken basin as well as other iron rich asteroids and other asteroids of other compositions in the past (see Metals). The Apollo missions only explored a small part of the Moon and a few spots within that region and didn't travel far from their landing sites. Also they did nowhere near to a thorough survey of the places they did visit. They just didn't have the time for that, and only had a geologist there for the last mission. As for later investigations, you can only do so much with the few orbital missions we've had since then.

Then, when we do have humans in the asteroid belt, it's a lot of delta v to go from one asteroid to another and going via Mars doesn't help except on rare occasions. Most of the time, it will take much more delta v to get to an asteroid via Mars than a direct route, and the same is true for travel to / from Earth. Mars is only useful when you have an energy efficient trajectory that takes you from Mars to the asteroid, for instance via Hohmann transfer.

However, Geoffrey Landis has made a rather surprising observation here in his Colonization of Venus. See Accessibility of Asteroids from Venus in this paper. Even though Venus is closer to the Sun than Earth, because of Venus's faster orbit, the flight time to Ceres or Vesta is actually less from Venus than from Earth or Mars via Hohmann transfer. So Venus actually has advantages as a main asteroid belt mining hub over Mars, a bit counterintuitively. The transfer time is less and you have more opportunities also to get there because of Venus’s shorter year of 225 days instead of Mars’s 687 days, which is three times longer. So you’d get several opportunities to visit an asteroid from Venus for every single opportunity to visit it from Mars, though of course the delta v required is greater.

Hop David suggested the idea of Asteroid Cyclers to work in the same way as a Mars cycler, to cycle materials between Earth orbit and "railroad towns" colonies in the asteroid belt where the mining goes on. The same idea could be used to cycle materials between Venus and the asteroid belt.

Hop David has also suggested that Venus, and Mars would be good places to park large asteroids for mining operations - if it's too hazardous to risk parking them in Earth orbits. The Case For Asteroids. Of course this is for asteroids that already do close flybys of those planets.

Venus cyclers, like the more famous Mars "Aldrin cyclers", can get passengers from Earth to Venus by shuttling them to large spacecraft in permanent orbits that takes them back and forth between Earth and Venus over and over. The result is a somewhat shorter journey time than for Mars cyclers, and you can travel to Venus frequently, every 1..6 years instead of more than 2 years between visits. See his Case for Venus. If this happened, the cloud colonies could be useful for supplies to the asteroid miners, in return for supply of metals and other asteroid derived resources to the colonies.

So - though Mars might well be a useful staging post later on if we have a lot of people in the asteroid belt - the case is not as clear cut as you might think, and Venus might be as useful as Mars, even for supplies to the asteroid belt, depending on your priorities and the exact future situation. In the shorter term it might well be useful for mining asteroids that do close flybys of Venus, captured into Venus orbit temporarily for the purposes of mining.

CONCLUSIONS - IMPLICATIONS FOR INTERPLANETARY COMMERCE

So in short my conclusion is that the Moon is far superior over Mars in this respect and I am skeptical of the idea that a Mars colony could pay for itself via intellectual property. I just don’t see why the flow of intellectual property of commercial value has to be from Mars to Earth rather than vice versa or most likely both ways and I don’t find Robert Zubrin’s labour shortage argument in favour of that at all compelling.

Also it depends on not just inventing things but having the commercial talent to spot how to make the invention financially viable and the persistence and luck to take an invention all the way through to success. Why should Mars colonists be much better at this than anyone else? I don’t get it.

By contrast, I think a Lunar base could potentially be of commercial value, mainly because it has a low escape velocity and is so close to Earth and always at the same distance - especially so if something like Hoyt’s cislunar tether transport system is in place reducing transport costs almost to zero. It is also close enough for tourism to be a major industry eventually.

Mars I think will be the province of government sponsored or philanthropic explorations for some time - like Antarctica, where the return is not financial but scientific knowledge or just interest / excitement. I think that the initial stages of lunar exploration are also likely to be supported in a similar way - but that there is some possibility there of commercial value entering into the mix as well.

And I think we should explore Mars from orbit until we have a good understanding of surface conditions and especially not introduce Earth life to the planet. We could exploit it commercially from orbit through telerobotics, but that would depend on finding something there of commercial value to export. And I think conceivably there might be commercial exports from Mars in the future. Especially if the Mars biology produces some unique valuable biological product that can’t be made anywhere else - that might be worth exporting. But there’s currently nothing we know of that could be worth the cost of export from Mars, and whether there will be in the future, only the future can tell.

Longer term, Venus cloud colonies also seem of special interest. I suggest they are the least maintenance of all offworld habitats outside of Earth, so would need less income per habitant than any other space colony, but even so, it isn’t so easy to find a commercial case for more than an Antarctic style habitat maintained because of its science value and perhaps some tourism, because of the high costs of exports to orbit. Long term, if the orbital airships work out and reduce export costs to orbit almost to zero, perhaps Venus could be a place to grow food for export with the lowest mass and least maintenance greenhouses anywhere in the solar system outside of Earth. Orbital airships would also make Mars more commercially viable too. However, orbital airships would make it easier for Earth to export to space as well so both would have to compete with Earth, and of course the Moon.

In the more distant future both Mars and Venus could become a mining hubs for the asteroids, perhaps with asteroids parked in orbit around the planets for mining. In such a future, Venus, perhaps surprisingly, has some advantages over Mars for ease of access to the asteroid belt in terms of faster journey times and more frequent opportunities for travel.

ADVANTAGES OF THE MOON OVER MARS - SHORT SUMMARY

The idea is to go to the Moon first before we decide whether to go to Mars, but while researching this book I've found many advantages of the Moon suggesting it's a far better place for humans anyway.

• Potential commercial value - potentially, lunar colonies could be supported by export of water and other materials from the Moon. Hoyt's cislunar tether system could give us a way to export materials from the Moon's surface to LEO with no fuel at all. Or we could mine water and use that as fuel for our spacecrafts to use to send other exports to Earth. It's harder to make a case for near term commercial value for exports from the Mars surface to Earth. The only near future commercial value I've seen is mining ice from it's outermost moon, Deimos if it has ice. See also Commercial value for Mars and Would a space colony survive with only intellectual property to pay for imports? above.

• The commercial value of the Moon seems similar to the asteroids, with addition of some materials not available in near earth asteroids - such as titanium, aluminium, and especially the water ice in such pure form if it's available.

• Stays at the same distance from Earth, easy to get to and from at any time - this could give the Moon an advantage over asteroid mining, since typically Near Earth Asteroids can send their exports on minimal delta v transfer orbits only every decade or so.

• Lifeboats to get back to Earth within three days, from anywhere on the Moon

• Ideal for tourism - for both those reasons and more. Once we have regular transport to the Moon, you'd be able to go there and back within a week, or for a longer visit, in a fortnight. And you'd be safer than anywhere further afield because of the lifeboats. And the light gravity, including sports like human flight, and possibilities of lunar railways, no dust storms or other weather issues at all, possibility of vast underground caves, has many advantages for tourism, but most of all,it's proximity to Earth. Yet, it's a landscape you can actually stand on. And on the near side you'd see Earth in the sky. You could experience lunar eclipses when the entire landscape goes red. On the far side, experience an unfamiliar world, walking on land you can't see from Earth, and with Earth not even in sight anywhere.

• Very little lunar ascent fuel needed to get back to Earth - no need for a "Moon One" like "Mars one", if you can get to the Moon, it's not that hard to get back again.

• If the volatiles are easy to extract and exist in the quantities the preliminary results suggest, then water, nitrogen, carbon dioxide may be as accessible as on Mars, with perhaps enough to support millions of space settlers eventually.

• Some unique advantages that Mars doesn't have such as the regolith, easy to turn into glass using microwaves, high grade vacuum for chip and solar panel manufacture.

• Dust is probably less hazardous than for Mars, and is a known hazard, and with no dust storms or winds. It can be turned to glass and a region around a base or landing strip kept dust free, which is impossible on Mars

• Much of the research done for humans on Mars can be applied directly to the Moon.

• Scientifically interesting in many ways. Including biological interest for organics in the ice at the poles and search for meteorites from early Earth, Mars and perhaps even Venus

• Near constant sunlight at the peaks of (almost) eternal light for solar power and a steady temperature for all except a few days in mid winter

• Potential for huge caves, if we are lucky, these could be as large as a few kilometers in diameter and over 100 km long, similar in habitat area to an O'Neil cylinder.

• No concerns about introducing Earth life, with classification of category II, and plenty of space to explore to see effects of other forms of contamination by humans around the habitats

• What we learn there will help us as we do longer duration missions further afield

• Expect the unexpected.

The main advantage of Mars, as far as a colony of hundreds of thousands or a million, is the somewhat higher gravity. But we don't know if Mars gravity is okay for human health, or indeed maybe lunar gravity is just fine. Or in both cases we may need to augment the local gravity. I cover this in What about gravity - isn't that a big advantage for Mars over the Moon? and Artificial gravity on the moon to augment lunar gravity.

The Mars surface also has some natural protection from solar storms due to its atmosphere, also Phobos's Stickney crater has advantages there too, however there's more risk for radiation on the journey to Mars or in orbit. In both cases it's possible to take precautions to prevent the worst effects. See Solar storms and radiation shielding - Moon and Mars

BACKUP ON THE MOON - SEED BANKS, LIBRARIES AND A SMALL COLONY

This is an idea from this book by William Burroughs, which had a lot of mentions for a year or two then seems to have been forgotten.

I find this suggestion much more plausible than Elon Musk's ideas of a backup on Mars. The idea is not to try to set up a colony that would survive the implausible complete destruction of Earth to the point that Mars is more habitable than Earth. Rather, it's more like a seed bank, like the Norwegian seed bank, but one on the Moon, combined with a library of human knowledge, and a small group of people who could sustain themselves there for a century or two if necessary until the time comes to return to Earth. And they could even restore humanity to Earth if they became extinct here (though this seems very implausible to me for the reason mentioned above that humans with stone age technology can survive almost anywhere on Earth from the cold of the Arctic to the hottest deserts, so we are amongst the least likely species to go extinct).

So anyway - this is an idea that's much more within our reach in the near future, to set up a colony on the Moon with sufficient supplies of the things they can't make on the Moon to last them for a century or two. Together with enough "lifeboat" spaceships to return to Earth easily, spacesuits to last them out / repairs for them etc. We don't need to make it totally self sustaining, just self sustaining enough for a small community of, say a dozen or a couple of dozen people to last for a few centuries.

And - I don't actually think we will lose all our technology on Earth, I think looking at past history that even when civilizations end, the technology doesn't vanish completely. Since the iron age, the world never lost the ability to smelt iron even though many small tribes can't do it. It never lost writing after it was invented. It never lost simple maths ideas like how to count, addition etc.

As it is now, I think we will never lose the place notation, fractions (quite a late development in maths), zero, and very very unlikely to lose algebra or calculus. Only a certain percentage can differentiate or integrate, but you don't need everyone to be able to do it to have a few teachers to pass it on to the next generation.

In medicine, we won't forget anesthetic, the microbe theory of diseases, the need for surgeons to wash their hands before surgery and nurses to keep clean, or vaccination,

I don't think we'll lose the ability to build airplanes either. Or bicycles. Both are really easy to do with a small amount of technology and mainly based on knowing it is possible and if we have engineering - even if we forgot most of it, we can reinvent it quickly.

The only remaining photograph of the original Colditz Glider made by British prisoners of war using bits of wood and wiring, including bed slats and floor boards. They designed it using details from a 1939 book Aircraft Design which they found in the prison library of Colditz.

And here is a video of the flight of its modern replica (no people on board, remote controlled for safety).

(click to watch on Youtube)

YOUTUBE VIDEO

Colditz Glider Flight

43,271 views

•Mar 17, 2012

1136SHARESAVE

Alex W.

9 subscribers

SUBSCRIBE

Escape from the Castle

00:23

https://www.youtube.com/watch?v=nSHugyLm8u4&feature=youtu.be

==

So, future humans could build a glider like this just based on a single book surviving from our era on the topic plus ingenuity and understanding of technology. You don't need very advanced tools to build a successful glider.

Probably similarly, our descendants in some such post disaster Earth won't forget the principle of the jet engine, or the rocket, even though they were innovative ideas at the time. Probably they would remember what a transistor is and the idea of an integrated chip even if we lose ability to make computers. They are not likely to forget how internal combustion works, or indeed steam engines. They would surely retain the knowledge of telephones, and of radio transmission. Once you know how to do it, it's easy to generate and receive radio waves, or to build a simple electric motor or generator.

Here for instance is how to build a simple "foxhole radio". You can alternatively use a crystal such as galena in place of the pencil and razor blade, and make one of the early crystal radios. You can use anything that rectifies the alternating current from the radio waves.

(click to watch on Youtube)

YOUTUBE VIDEO

How to Make a Foxhole Radio

1,352,624 views

•Sep 14, 2007

6.2K224SHARESAVE

Make:

1.68M subscribers

SUBSCRIBE

During World War II, GIs in the field built really amazing simple radios to listen too. These were made with materials that they could get their hands on and were small enough to carry around in a big pocket. You can modify this design if you want to set it up so that it's tuneable too! To see all the plans, go to makezine dot com slash podcast! Learn more here: http://makezine.com/video/how-to-make...

03:49

https://www.youtube.com/watch?v=skKmwT0EccE&feature=youtu.be

==

This is so simple, that it's surely unlikely that we'll lose the capability to listen to radio in some crude way or another so long as there are people around who understand some of the basic concepts of how radio works and are reasonably good with their hands, and we have access to wire and other basic components.

So long as some "higher education" continues, each generation teaching ideas to the next, or some library of books remains somewhere on Earth to explain these concepts to us, these ideas will surely not be forgotten. But we could lose the organization of society. Again I think we are probably in many ways much more robust than previous societies but looking forward, what if there was some "perfect storm" of nuclear war say, followed by a super volcano eruption, then maybe a giant impact just as we are recovering?

Possible "one-two punch" for dinosaur extinction. The Chicxulub impact surely was a significant factor in the extinction of the dinosaurs. Probably the earlier supervolcanoes of the Deccan Traps helped push the dinosaurs into a situation which made them more vulnerable - this artist's impression shows the Deccan Traps. That double whammy was separated by 100,000 years.

However a recent idea is that the asteroid impact itself could have triggered volcanic eruptions from the Deccan traps.

(click to watch on Youtube)

Could some closely spaced double whammy cause problems for Earth civilization? (Credit: Zina Deretsky for the National Space Foundation)

Even then I find it implausible that there wouldn't be some pocket of technology left. For instance after a global nuclear war, if we ever came to it, then the nuclear free zones such as Australia, New Zealand etc. would surely be spared and they have the entire Pacific ocean around them.

In this diagram, blue stands for nuclear weapon free zones. In these zones, even if the territories are owned by nuclear weapon states they have agreed not to station weapons there. This makes them very unlikely to be targets in a nuclear war. As you see, apart from a few islands, pretty much the entire southern hemisphere is free of weapons. Red stands for nuclear weapons states,, orange for territories where US nuclear weapons are stationed under a sharing agreement, and yellow for none of the above, but still subject to the non proliferation treaty. After a global nuclear war, should it ever come to that most of the Southern hemisphere would probably be unscathed and retain its technology.

This for instance is the South Pacific nuclear free zone, established by the treaty of Rotaronga. No testing, stationing or use of nuclear weapons permitted anywhere in this zone.

And with technology, even with a nuclear winter, or an asteroid impact winter, surely many would survive and carry through our knowledge and libraries into the future. After all we are not like the dinosaurs. With the most primitive of tools and our intelligence we can survive many things that would kill us easily without technology. It's only because of our technology of course, but that makes a huge difference. You don't get many great apes living in the Arctic or the Sahara desert.

But still, you could imagine that if we are unlucky and encounter turbulent political and environmental conditions, that we might lose some of our most important libraries, seed collections etc. If the billions of dollars semiconductor fabrication plants stop making computer chips, many of our modern machines depend on their output and could no longer be built. We could also lose the ability to send rockets into space, maybe even lose ability to make jet engines for a while. In that future, without computers and the internet, after living in a world increasingly dependent on it, perhaps we would indeed forget some of the vast store of our present day knowledge, even if we surely wouldn't lose it all.

All that knowledge could be preserved on the Moon so then later when we restore the ability to get into space we go up there and find it. Or else, if there's a small colony there, they can educate us via radio and come back to Earth when conditions are suitable here.

With present day technology, if we lose the capability to launch rockets into space, anyone living in a lunar colony could still return to Earth. That would be easy, using its "lifeboat" spacecraft which could be permanently kept next to the colony. But this would be a one way trip as there would be no way to return to the Moon without new large booster rockets to get them back into space again, along with a dedicated space launch pad and the staff and equipment to man it.

This may well change with future developments, if so, perhaps members of a lunar colony could return to Earth, refuel, pick up supplies, do what they can to help residents here, and go back to the Moon using just their own spacecraft without dependence on Earth. But until then, they would be dependent on supplies sent to the Moon in advance, to last them as long as needed for anything they can't make in situ on the Moon.

We don't actually need a permanent presence of humans on the Moon to preserve DNA and knowledge there. Some of the lunar caves probably have an internal steady temperature of around -20 °C (see page 5 of this paper). This is similar to the −18 °C for the Svalbard Global Seed Vault and should be perfect for an off world seed bank.

Entrance to the Norwegian Svalbard seed vault, photo by Bjoertvedt. The seeds need to be kept refrigerated, which is done using locally mined coal. A similar seed vault in a lunar cave would keep the seeds at the right temperatures by passive cooling.

As for preserving our knowledge, well we could leave physical written texts on the Moon, or we could leave engraved glass or diamond, or DNA, or radiation resistant glass DVDs amongst the various suggestions.

There is a Bible on the Moon already, perhaps it would be readable in the distant future?

“A Moment of Reflection” painting by Ed Hengeveld depicts Apollo 15 Commander Dave Scott placing a red leather Bible on the console of the lunar rover before departing the moon.

There's a company wants to send a Torah to the Moon as a hand written scroll preserved in an airtight compartment. They asked SpaceIL to take it to the Moon but were refused, but eventually surely texts like this will be taken to the Moon. The idea is to preserve some of our most ancient texts as a project for preservation of culture. If they succeed, they would send other ancient texts later on such as the Hindu Vedas and the I Ching

Lunar Mission One have as their goal to send a spacecraft to the lunar poles to drill into the ice - and when the mission is over, to bury a capsule with both DNA from human hairs, personal messages, and a digital archive of Earth's knowledge.

Lunar mission one, artist's impression. The aim is to drill and obtain an ice core to return to Earth. But before it returns to Earth, it will put a digital archive in the hold buried deep below the surface at the lunar poles. See "A time capsule on the Moon".

The Part time scientists, one of the teams left in the Lunar X Prize challenge, as a partner with, are planning to take a disk with part of Wikipedia on it to the moon as Wikipedia to the Moon.

Back in 2004, Transorbital, a California based company was first to get permission from the US government to launch to the Moon, planned to use a decommissioned Russian ICBM for the task. They also had the idea toset up a server on the Moon for digital backup services for companies worried about security of data on the Earth after September 11. These plans don't seem to have come to anything though they did send a small satellite into orbit around Earth.

KEO is a more ambitious plan to send data into orbit in glass radiation resistant DVDs into an orbit that will decay and return the satellite to Earth 50,000 years later as a kind of a space time capsule. The idea is that everyone on Earth can store a four page message for the future. The DVD could be played on a DVD player - but of course in the future they wouldn't have our players so it includes information on how to build the player.

The KEO glass DVD is a bit like the idea of the Voyager golden record though in their case the record is in audio format like one of the old analogue records but more durable. We could send a copy of both to the Moon.

A copy of the Voyager record on display at the Udvar-Hazy Center in Washington Dulles International Airport

Photographs of the cover and contents, of the actual record sent on Voyager

See Contents of the Voyager Golden Record to find out what is on it.

As it gets easier to send missions to the Moon, I think it is certain that we will leave various physical and digital data repositories on the Moon. The idea of the lunar backup is a more extensive version of the same. We could build a seed vault / library / small human colony with supplies sufficient for at least a century or two on the Moon with no imports from Earth.

Examples of what it could preserve digitally include:

• all the books in our libraries - at least the ones out of copyright or if the authors gave permission, including of course the entire Gutenberg collection of 50,000 free ebooks. And I wonder if a special case could be made for Google Books to be released unrestricted in its entirety with the understanding that it can't be accessed until after the copyright period is over? I can't imagine that any authors would complain about that. Maybe indeed publishers also would be willing to donate digital copies of their books on this understanding?

• all the academic journals (public access ones, and others as well if they had permission),

• huge archives of astronomical images etc. - our larger archives are copied using DVDs anyway, faster than sending them over the internet, so it would just be a case of sending a copy to the Moon.

• visual records of our art, sculptures, etc.

• audio recordings of music, sound, speeches

• video recordings of films, movies, TV shows

• The whole of Youtube - no reason why not in some near future with lots of storage available on the Moon. Or any other such repository.

• the Internet Archive, which has amongst its objectives, to keep a historical record of the internet for future generations.

Physically it could preserve

• seeds and DNA samples in perfect conditions for preservation long term, and any other small valuable physical objects that we can send to the Moon.

And it could have human caretakers

• with a small population of caretakers, with plenty of supplies, it could also act as a "backup" which could help and educate people on Earth remotely via radio in the case of some future chaos which leads us to losing some of our capabilities and libraries on Earth. The caretakers would consult their many archives up there for information needed, a bit like the librarians in Asimov's Foundation series.

It does have advantages over repositories on Earth, as the lunar caves provide perfect conditions for passive preservation of seeds and anything else that is best preserved in cold conditions in a geologically stable environment. The best analogue we have here might be in Antarctica, if we could arrange some backup in a cave excavated into the cold and stable conditions of some of the Antarctic mountains. Temperatures at the surface on the high Antarctic plateau seldom rise above 20 C, though they can dip down to below 60 C. So there may be places there also where you could build a passively cooled seed vault, which would cost far less than a lunar seed vault and be easier to supply. But you couldn't duplicate the lunar vacuum and very long term stability even over geological time scales. Also you would have to cope with the six months long Antarctic "night" for anything that requires solar power, while on the Moon it's a maximum of only 14 days of darkness, and less if close to the poles.

Of course, eventually, you would duplicate your lunar repositories. Especially you would have more than one copy of the most important information and materials on the Moon. You would need that as precautions in the remote chance that it gets a direct hit from an asteroid hitting the Moon. That's about the only thing that could happen there, and would be exceedingly rare, especially if it is located in a cave protected beneath the surface from most asteroids.

Future Humanity Archives on the Moon - Artist's impression, illustration by Madhu Thangavelu and Paul DiMare © from The Moon: Resources, Future Development and Settlement

Artist's impression of a vault on the Moon.

It's also scaleable. You can start off by just sending archives to the Moon which can't be read from Earth, but are there for future lunar visitors to discover. The next stage would be archives that you can read remotely from Earth, like the lunar server backup idea. And later, you could have a telerobotic facility on the Moon which can be controlled remotely from Earth, getting the telerobots to look up things that are stored there, even recover seeds and "post" them back to Earth. And then finally, presence of a small group of human "caretakers" normally rotating in and out every few years if they want to - but with sufficient supplies to last them out for centuries on the Moon if needed, with closed system recycling.

I'm not sure if this is really needed for a backup. Can we not do the same on Earth, as we are doing already with the likes of the Svalbard seed vault? Even set up an identical self sufficient small colony underground in Antarctica?

But it's going to happen anyway, at least in a limited way, and the passive cooling is a great advantage for seeds, which are also light things to send into space. It would also provide perfect conditions for long term preservation, for billions of years into the future, even for future civilizations on Earth. And, in my view, it seems a lot more practical than ideas of a "backup on Mars", because it is so much closer to Earth, more accessible if we ever need it, far easier for its human inhabitants to get back to Earth, and easier to communicate with via radio.

SO MANY EXCITING NEW THINGS TO DO IN SPACE WITH THIS VISION

We have so many other things humans can do in our solar system, apart from the usual objective of colonization and boots on Mars. Including exploring the Moon, asteroids, Venus, Mercury, Jupiter's Callisto, Mars from orbit and its two moons, maybe even further afield. Plenty to sustain interest.

If the aim is just to "land boots on Mars / Moon / Venus / Mercury / Callisto" I think our space explorations to all these places will be short lived, just as they were for the Moon. And I happen to think that attempts at colonization would be short lived also, as they run out of funds, and can no longer get people from Earth to support their expensive attempts to live in places with a near vacuum, where they have to create all their own oxygen to breathe, etc. etc., and many of their needs, can only be met by supplies sent to them on rockets.

While settlement in space supported because of their benefits to Earth, with humans accompanied by robotic explorers finding out new things about our solar system, would grow and grow. Look at how much interest there is in Curiosity, the Dawn mission, Philae the comet lander, and the New Horizons mission to Pluto? And there's no sign that any country wants to pull out of scientific exploration of Antarctica.

We need some longer term positive vision, and what I outlined here is a suggestion for first steps towards an alternative to the usual colonization motivation for sending humans into space.

GOING INTO THIS WITH OPEN EYES

The main message is that whatever we do, with Mars, we should do it as a choice, not as an accident. We shouldn't just have a human occupied ship crash on Mars, and then say "Oops, we have now introduced Earth life to the planet". The main thing is that we shouldn't just jump off a cliff into the sea with our eyes shut and hope for the best. We need to understand what we are doing and to go in with open eyes.

So, then if we hold back from sending humans to Mars, this leaves all our options open. We can always send them next year, or ten years later, or fifty years or a century later. Mars will still be there. But if we send microbes to Mars in an irreversible way, this closes off many futures. For instance, maybe we want to introduce particular microbes to Mars only, maybe only methanogens, or methanotrophs, or photosynthetic life. Maybe we want to keep the predatory secondary consumers away from Mars until much later.

Or maybe we have an opportunity to set aside Mars for the Martians. There's plenty of material in the asteroid belt for human habitats. But perhaps on Mars we have the opportunity to restore an early Mars like early Earth, with pre-DNA life on it. Imagine how wonderful that would be. Or some alternative biology not based on DNA at all. Maybe that is one of the futures we would be closing off - to have an exoplanet in our own solar system, which has ETs on it, even if they are just microbial or lichen like ETs, with a totally different biology from Earth life.

When we have a choice that closes off futures for an entire planet, or for some vulnerable habitat, or unique form of life, I think we need to look long and hard at that choice. And whatever we do, we shouldn't do it just through carelessness, by accident, or without thinking through the consequences.

While when our choices are open ended, and open out to more and more future possibilities, as exploring the Moon seems to do, then that's a way forward that we should encourage and walk into with open eyes. We can follow a path like that with a sense of wonder indeed!

QUESTIONS ABOUT THE VISION IN "CASE FOR MOON" ON THE SPACESHOW

I was on David Livingston's "the Space Show" on 27th October 2016. It was a one hour and 27 minutes program, with many interesting questions sent in by email from listeners to the show.

You can listen to it here:

• Broadcast 2710 Robert Walkerfrom the UK

IS THIS A POSITIVE VISION?

This is work in progress, and I'm interested to hear whether you think it is a positive vision for the future. Or is there anything else that could make it more positive? It might well be missing something that I just haven't seen yet.

Also do share your own visions for the future too.

And - what do you think about "boots on Mars"? Do you think there's a chance we will find a way to land humans on Mars compatible with planetary protection and preserving its interest for science? Or is this likely to be impossible? What about a crash on Mars, how does the potential for that change the situation?

Should we explore Mars in a biologically reversible way until we understand it better? If so, can you think of any way that could be done with humans on the surface, or should they remain in orbit?

Some think we should just land humans on Mars anyway. That we should do our best we can to study it scientifically first, and then, whatever the state of science, once the technology is there to land humans, forget about planetary protection and just land humans, taking the best precautions we can in the circumstances.

Is that your view? If so do say so. Don't be shy. I'm interested to hear all views on the topic.

AIM TO STIMULATE DEBATE

The main reason for writing this is to stimulate debate on these topics, and to help make sure the debate is done with an informed background.

What do you think about these ideas? Do say in the comments on the online article - or you can start a discussion on the kindle booklet page. Or comment in the Case for Moon for Humans - Open Ended with Planetary Protection at its Core facebook group. Or just send me an email to support@robertinventor.online.

Also if you see any errors at all, whether typos, or more fundamental errors, please don't hesitate to let me know or say so in the comments. Thanks!

SEE ALSO

• TheSpaceShow Broadcast 2663 Dr. Catharine (Cassie) Conley: Topics: Planetary protection

• TheSpaceShow Broadcast 2660 Robert Walker: Topics: Planetary protection and human spaceflight to Mars

• TheSpaceShow Broadcast 2710 Robert Walkerfrom the UK: Humans to Mars, Mars contamination, Planetary Protection, much more - about the "Case for Moon"

• Why We Can't "Backup Earth" On Mars, The Moon, Or Anywhere Else In Our Solar System

• Will We Meet ET Microbes On Mars? Why We Should Care Deeply About Them - Like Tigers

• No Simple Genetic Test To Separate Earth From Mars Life - Zubrin's Argument Examined

• Can You Suggest A Second Earth Apart From Mars?

• Does Earth Share Microbes With Mars Via Meteorites - Or Are They Interestingly Different For Life?

• Are There Habitats For Life On Mars? - Salty Seeps, Clear Ice Greenhouses, Ice Fumaroles, Dune Bioreactors,...

• Could Microbes Transferred On Spacecraft Harm Mars Or Earth - Zubrin's Argument Revisited

• Asteroid Resources Could Create Space Habs For Trillions; Land Area Of A Thousand Earths

• To Explore Mars With Likes Of Occulus Rift&Virtuix Omni - From Mars Capture Orbit, Phobos Or Deimos

• "Super Positive" Outcomes For Search For Life In Hidden Extra Terrestrial Oceans Of Europa And Enceladus

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KINDLE BOOKSHELF ON MY AUTHOR'S PAGE

And I have many other booklets on my kindle bookshelf

My kindle books author's page on amazon

CASE FOR MOON - FACEBOOK GROUP

I've made a new facebook group which you can join to discuss this and other visions for human exploration with the Moon first, and with planetary protection and biological reversibility as core principles.

When I founded it, to discuss the approaches outlined in Case for Moon, I was so surprised that I couldn't find any other group on facebook for discussing Moon first approaches to humans in space, although it's easy to find groups for discussing colonizing Mars.

So, as the group description says, it's for anyone interested in a Moon first approach. With the vision in Case for Moon as one of many.

Case for Moon for Humans - Open Ended with Planetary Protection at its Core

You may also be interested in this group to discuss my newer book:

• OK to Touch Mars? Europa? Enceladus? Or a Tale of Missteps?

You can get notifications of new posts on my Science 2.0 blog by 'liking' my page:

• Robert Walker

- Science20 Blog Alerts

OTHER RESOURCES

You may also be interested in Moonwards, Kim Holder's Virtual Moon Colony project, to explore a vision of what a focused drive to settle the Moon could create. Listen to her talk about it on the Space Show.

If you know of any other good groups or websites focused on Moon first ideas, or on exploration of our solar system with planetary protection as one of the core values behind the exploration, do say and I'll add them in.

CITATIONS - TEST

This is a test of a possible way of adding citations to my books. Amazon requires that you have a hyperlink in both ways to take you back to the text after you read the footnote.

The only solution I can think of is this one, which is just a test to see how it works - to cite the same paper multiple times, to use the same symbol for all the citations in both directions so an * to get to the footnote and a ^ to get back (for instance) - and since there are no natural page divisions in the web page version of the article - to put them all at the end of the chapter, or more easily at the end of the book like this: Maybe I can find a way to automate it e.g. using <ref> </ref> tags as for Wikipedia and a pre-processor to auto generate the links both ways. For now doing it by hand.

It would need to be autogenerated in some way to have numbers for the footnotes, so that the numbers still work when I add new cites or new material.

^"Lunar Resources: A Review", Ian Crawford,, Progress in Physical Geography, vol. 39, pp. 137-167, 2015

^"Lunar Resources: A Review", Ian Crawford,, Progress in Physical Geography, vol. 39, pp. 137-167, 2015

^"Lunar Resources: A Review", Ian Crawford,, Progress in Physical Geography, vol. 39, pp. 137-167, 2015

^"Lunar Resources: A Review", Ian Crawford,, Progress in Physical Geography, vol. 39, pp. 137-167, 2015

^"Lunar Resources: A Review", Ian Crawford,, Progress in Physical Geography, vol. 39, pp. 137-167, 2015

^"Lunar Resources: A Review", Ian Crawford,, Progress in Physical Geography, vol. 39, pp. 137-167, 2015

^"Microwave sintering of lunar soil: properties, theory, and practice", LA Taylor, TT Meek - Journal of Aerospace Engineering, 2005

^"Lunar Resources: A Review", Ian Crawford,, Progress in Physical Geography, vol. 39, pp. 137-167, 2015

^"Lunar Resources: A Review", Ian Crawford,, Progress in Physical Geography, vol. 39, pp. 137-167, 2015

^"Lunar Resources: A Review", Ian Crawford,, Progress in Physical Geography, vol. 39, pp. 137-167, 2015

^"Lunar Resources: A Review", Ian Crawford,, Progress in Physical Geography, vol. 39, pp. 137-167, 2015

CHANGE LOG

16th May

• Added new section WHERE TO BUILD OUR FIRST LUNAR BASE FOR HUMANS. covering bases in the lunar caves and the poles.

• Added image of the ESA lunar village in the POSITIVE VISION FOR HUMANS IN SPACE section.

• Added launching pad robot idea to the Lunar Glass section.

• Added mention of Buzz Aldrin's 2009 Mars first views, and the views of the Space foundation and ROSCOSMOS to THE MOON IS TURNING OUT TO BE MUCH MORE INTERESTING THAN EXPECTED section.

• Added information about the LEND results and caution about the indirect detection for the 600 million metric tons figure to the section VOLATILE RESOURCES

17th May

• Added Buzz Aldrin quote from Mission to Mars. I'm not sure though what to make of this article about his latest "No dream is too high"? I've ordered the book and will update the article if he has changed his views again. If anyone knows for sure do say!

18th May

• Added link to Ice may lurk in shadows beyond Moon's poles (Nature, 2012) about the possibility of regions of permanent shade with ice below the surface down to 58 degrees from the poles to the sectionVOLATILE RESOURCES. Replaces statement suggesting ice may be possible in caves at lower latitudes. I think that was just a mistake - as the temperatures inside the caves seem to be far too high for ice - unless perhaps below those permanently shaded regions? Also added link to the article peaks of (almost) eternal light in the online NASA astrobiology magazine. for information about the temperatures of these peaks, to Earth length day on Mars versus advantages of close to 24/7 solar power at the lunar poles

19th May

• Added executive summary

• General copy editing.

• Changed some section titles

• Added sections on Thorium, The romance of space, Robots and humans together, Meanwhile in LEO - sustained research into human factors

20th May

• More copy editing

• Added video with 600 meter tether for lunar gravity to Meanwhile in LEO - sustained research into human factors

• Added two new sections: International co-operation and role for China - USA policy and ESA, Russia and China

21st May

• More copy editing

• New quote for the section International co-operation and role for China - USA policy

• New sections Space assets and strategic, economic and military significance of space and This booklet outlines one particular vision of many

22nd May

• More copy editing

• New section Earth best for a "backup"

23rd May

• More copy editing, with some more cites and a bit of new material also

• Added a new section Solar cells from lunar materials, Possibility of using lunar solar power for Earth, and Other Moon - Mars comparison

24th May

• More copy editing

• Added Geologically active moon, Using the Moon to build habitats in free space, Expect the unexpected, Mars or Moon spectacles and the old woman young woman illusion, Going into this with open eyes, and We are like the early Antarctic explorers.

25th May

• New section Coping with the dust

• New quotes from Buzz Aldrin from "No dream is too high" in Moon firsters - ESA, Russia, Many astronauts, former US Vision for Space Exploration etc

• Added the oriental fruitfly as example in Why do microbes on human occupied spacecraft get a "special pass" for Mars? (Got the idea of using it as an example from Buzz Aldrin's "No dream is too high" page 139 - he uses it when talking about their quarantine on return to Earth).

• Added material about whether it would be economically worthwhile to return platinum to the Metals section, mentioning Dennis Wingo's fuel cells idea.

• Added new section on Stanford Toruses as a way to experiment with terraforming ideas in a small scale way to It is not at all clear that we can terraform Mars

26th May

• Added Exporting materials from the Moon, Comparison of exports from the Moon with asteroid mining and supply from Earth and Searching for a non confrontational way ahead subdivided into How many years to do a biological search of Mars, Clash and confrontation?, Compromise attempts, Moving your house to avoid a pond for great crested newts, What if there seems to be no alternative? We must have Mars!, Ponds and flightless parrots again - back to the Moon

27th May

• Separated out Buzz Aldrin's remark to a new section: Buzz Aldrin's "been there and done that" - not meant to be taken seriously

• More copy editing

2nd June

More new sections:

• Planetary protection about forward and backward contamination in the sense of the OST - the rest of the book could be a bit puzzling at times without that background.

• Robotic missions to the Moon already planned or likely to happen

• Sending humans to Mars for flyby or orbital missions - comparison of biologically closed systems with ISS type mechanical recycling,

• Conclusions and implications of these calculations - an ISS system style mission to Mars seems possible,

• Hybrid system - adding algae to an ISS type system,

• Implications for mass requirements for humans to Mars (flyby or orbit),

• Questions about the vision in "Case for Moon" on the spaceshow,

• What about all the people who research space exploration because they are excited by the prospect of Mars exploration?,

• Two futures - humans landing on Mars or habitable surface with humans in orbit only,

• Advantages of the Moon over Mars - short summary

• What about gravity - isn't that a big advantage for Mars over the Moon?

Minor changes:

• After Meanwhile in LEO - time to rediscover the adventure in human spaceflight - some copy editing (including change of that section title), divided into sub sections: Robotic scouting phase - need to go back and find out what's there first and How our ideas might change as a result of a longer period of robotic exploration

• Added more about the lunar village to the section now titled: Who this is for - and more about the ESA lunar village

• New title for the "meanwhile in LEO section: Meanwhile in LEO - time to rediscover the adventure in human spaceflight - artificial gravity and biological closed systems research

• Replaced "peaks of eternal light" by "peaks of (almost) eternal light" throughout.

3rd June

New sections:

• Paraterraforming - covering the planet and developing a habitable environment within that covering

• Dealing with periods of darkness at the lunar poles

• Heat rejection

• Power during the night

Minor changes:

• Some extra work on the text for Planetary protection including a short paragraph on issues of returning extra terrestrial life from Mars to Earth.

• Added the bullet points in the section Alternative positive vision for exploration of our solar system - main points to the contents to make it easier to skip to the individual points.

5th June

• Added link to Design Rules for Life Support Systems, section SYSTEMS INTEGRATION AND RECYCLING to We haven't yet attempted a self sufficient habitat in space

• Added new example with horizon data to Dealing with periods of darkness at the lunar poles from this paper

• Added extra part about shakedown cruise (after the dash) to this section title: Mass requirements for humans to Mars (flyby or orbit) - and shakedown cruise suggestion and a bit more work on the section.

• Highlighted some especially interesting entries in bold, in the longer sections of the contents, e.g. in "The Moon is resource rich", to help your eye find its place.

14th June

• Added quote from Kennedy's speech to Space settlement is neutral just like settlement anywhere - it could be good or bad

• Added Extraction of meteoritic metals from lunar regolith, experiment with actual extraction of the iron, to Metals

• Started new section Basalt (like glass fiber) (more to be added to it)

15th June

• Added material on Team Hakuto's lunar X mission to explore the Lacus Mortis pit with a tethered rover lowered into the pit in 2017 to Robotic missions to the Moon already planned, or near future, from 2017 onwards (section also renamed)

• Added information about the Lacus Mortis half collapsed skylight and possible volcanic cinder cones, and the remarkable King-y natural bridge as a new section. Example lunar cave skylights - Lacus Mortis, Marius pit and the King-y natural bridge.

• New subsections - just subdivided the existing material: Record keeper of inner solar system (including astrobiology and early life on Earth) and Ideal for radio and infrared observation of space

19th June

• Why quarantine won't work - protecting Earth, and humans sent to Mars, from Mars life (if it exists)

• Spell check of the new material, and some copyediting.

• Added link to the article: China has signed an agreement with the UN to open up the Chinese space station to spacecraft, science experiments and astronauts from around the world. to the section on International co-operation and role for China - USA policy

• Added section about KREEP and link to Emily Lakdawalla's article to Thorium and KREEP (Potassium, phosphorus and rare earth elements) (title changed, old title just said Thorium)

• Changed title to "Case for Moon First" subtitle "Gateway to Entire Solar System - Open Ended Exploration, Planetary Protection at its Heart". Previous title was "Case for Moon", subtitle "Humanity's Gateway to the Solar System - Open Ended Exploration with Planetary Protection at its Heart"

22nd June

• Water lock

• New material in Compromise attempts with quotes from Carl Sagan and link to research on survivability of microbes and spores in Mars dust storms (I can't find much research on this so far).

• New material in Who this is for - and more about the ESA lunar village - added link to Jan Worner's video talk and q/a about his village idea.

23rd June

• How an international lunar village saves money, is safer and better, through use of communal resources

• Long shadows at the lunar poles and early and late in the lunar day elsewhere

• Commercial value for mars

25th June

• 3D printing on the Moon

• Cubesat explorers and rep rap printing

• 3D printed food in space

• Lunar swirls

• Found a paper by Robert Zubrin which goes into Mars exports in more detail, to discuss in Commercial value for Mars. Also added discussion of whether Mars or Phobos / Deimos could export fuel to outside the system to this section.

27th June

• New sections made by dividing up Why quarantine won't work - protecting Earth, and humans sent to Mars, from Mars life (if it exists) into three sections: Current requirements for samples returned to Earth and legal situation and Suggestion to return samples to above GEO instead and some copy editing of those sections.

• Added some more details about robotic drilling to Humans don't have special advantages for Mars surface missions

• To the section How many years are needed to do a biological survey of Mars? added: Speeding the search up with miniature robots - what could we do if we had funding for a preliminary exobiological survey of the whole of Mars from Earth? and So a rapid survey of Mars does seem possible - however none yet planned to guide our decisions by the 2020s

• Need for new comparison studies of the various ways of exploring Mars

• Lunar railways

• Moon quakes - can they damage lunar habitats, railways etc?

• Micrometeorite damage

2nd July

• Artificial gravity on the moon to augment lunar gravity

• Small centrifuge based artificial gravity experiments in LEO

• Renamed section: Meanwhile time to rediscover the adventure in human spaceflight in LEO and divided it into: Biological closed systems research in LEO, Joe Carroll's tether experiments in artificial gravity - which we could do right now, and After lunar mapping is over

• Lunox - how we would have done it in the 1990s

• Added image of greenhouse inside hab to Greenhouse construction - comparison of the Moon and Mars plus information about solar collectors.

3rd July

(some of this also later in the day on 2nd)

• More work on Small centrifuge based artificial gravity experiments in LEO with images of the Bigelow modules.

• Added 2010 farm module proposal and figure to Biological closed systems research in LEO

• Rewrote As for exploring a galaxy, robots are far safer and Generally, sending humans into space is something new, that humans have never done before - including adding new material on the Kardashev scale there

• Only one Mars - no warp drive yet

• Micrometeorites - comparison of the Moon and Mars

• Terraforming the Moon

• Paraterraforming the Moon

4th July

• Mini moons and asteroid redirect missions

6th July

• Backup on the Moon - seed banks, libraries, and a small colony

• Added more details to 100% sterile robots are possible in principle

• Added Preface

7th July

• Some copy editing of the new sections from yesterday. Added new content to the Backup on the Moon including mention of the Voyager golden disk.

• Added costings for Stanford Torus to As a young technological society, our priority should be to protect and sustain the Earth

8th July

• Would a space colony survive with only exports of intellectual property to pay for imports?

• Some more copy editing of the preface

• Gradually going through the book reading it out loud for a final check through for errors you can miss with a spell checker, and to see if there are any gaps to be filled. Already found one place where the text just broke off mid sentence, now fixed, and done a fair bit of copy editing improving the presentation.

10th July

• Solar storms and radiation shielding - Moon and Mars

• Further into the future, what about habitable planets around other stars?

• Or colonize our entire solar system

• Is this a rosy future?

• Why robots are far safer for the first stages of galactic exploration (relabeled and some editing)

• Added information about the Chinese agreement to let astronauts, science experiments, etc. on their space station to ESA, Russia and China

• More copy editing

• A bit more in Earth best for a "backup"

12th July

• More copy editing of sections Further into the future, what about habitable planets around other stars? and following.

22nd July

Have added several of Madhu Thangavelu and Paul DiMare's wonderful illustrations from The Moon: Resources, Future Development and Settlement with permission from Madhu Thangavelu :).

• Added flying on the Moon illustration, to What about gravity - isn't that a big advantage for Mars over the Moon?

• Added Humanity Archives illustration, to Backup on the Moon - seed banks, libraries, and a small colony

• Added a couple of railway illustrations, to Lunar railways

• Or return samples to the Moon - new section with illustration of hazardous biology facility on the Moon, also idea to return to a lunar cave. Plus added a short final para about debris from defunct satellites in the graveyard orbit above GEO for the Suggestion to return samples to above GEO instead

• Will our civilization become an ineradicable dangerous weed or a beautiful flower in the galaxy?

• Added a bit more about galaxy or universe spanning civilizations by ETIs, or our descendants, with very long lifespans to Generally, sending humans into space is something new, that humans have never done before.

• Added medical use of titanium to Metals

• Added tourism to Advantages of the Moon over Mars - short summary

• Added costs of spacesuits to Would a space colony survive with only exports of intellectual property to pay for imports?

21st September 2016

New sections:

• Maintenance costs

• Reducing maintenance costs for space habitats

• Venus cloud colonies - a surprising low maintenance solution

• Orbital airships for Venus and Mars

• Conclusions - implications for interplanetary commerce

Added Buzz Aldrin quote about the ants to Why quarantine won't work - protecting Earth, and humans sent to Mars, from Mars life (if it exists)

Added calculation about rate of loss of water exposed to a vacuum to the section Liquid airlock

Added Uranium to: Thorium and KREEP (Potassium, phosphorus and rare earth elements), and some uranium

Added discussion of Deuterium to Commercial value for Mars

Added discussion of Luddites to Would a space colony survive with only exports of intellectual property to pay for imports?

Added mention of Gerald Kulcinski's helium 3 reactor to the Helium 3 section.

24th September 2016

Added an image and a video to Orbital airships for Venus and Mars, also mentions VAMP - an interesting proposal for a robotic airship mission to Venus upper atmosphere, and HAVOC (again) I thought a good way to end it.

Also a small amount of extra work, formatting and discussion of what drives innovation to Would a space colony survive with only exports of intellectual property to pay for imports?

Added (See chapter II, Experiment M131. Human Vestibular Function in Biomedical results from skylab) as a citation for the mention of otoliths in Small centrifuge based artificial gravity experiments in LEO - about the hypothesis that the reason you don't get sick or dizzy in zero g when you spin like Tim Peake is because the otoliths which sense gravity along the spin axis on Earth are not stimulated in space when there is zero g along the spin axis.

Later in the day:

• New section: Fertility of lunar and Mars soil

• Added COSPAR guidelines for category 5 (sample return) missions to Or return samples to the Moon: "(The Moon must be protected from back contamination to retain freedom from planetary protection requirements on Earth-Moon travel)".

• Added introductory descriptions of BIOS-3 and MELiSSA to Sending humans to Mars for flyby or orbital missions - comparison of biologically closed systems with ISS type mechanical recycling (also relevant to long duration lunar missions)

• Added mention of Spirulina to Hybrid system - adding algae to an ISS type system

• Added mention of BIOS-3 experiment with reducing the temperature of the plants from 24 °C to 2.5-3 °C so that they can cope with the darkness of the lunar night to Earth length day on Mars versus advantages of close to 24/7 solar power at the lunar poles

26th September

Some more work on the interplanetary commerce sections.

• Added Mars as an asteroid mining hub in the distant future - or should it be Venus?

8th October

New sections:

• But wouldn't it be the most wonderful thing to introduce Earth life to Mars?

• What if The Moon had blue skies? One small change to Apollo photos

• Nitrogen

• Scouting out caves with robots

• Can we fill lunar caves with air?

Moved the list of processes that can concentrate ores to the head of the Metals section, and added meteorite impacts to the list.

Expanded Using the Moon to build habitats in free space with discussion of the mass per colonist.

Added calculation about RTGs to Power during the night and discussion of power storage for LED night time illumination of plants.

Divided the section Earth length day on Mars versus advantages of close to 24/7 solar power at the lunar poles up with two new sections Lower power LEDs for plant growth through the lunar night and Plants capable of good yields when kept in darkness for the lunar night

For Greenhouse construction - comparison of the Moon and Mars - added extra info to the image: this was for the Lunar Oasis proposal for a ten year program to establish a self sufficient science outpost on the Moon to act as a test bed for space settlements. A bit more work on Power during the night mainly presentation but also included a couple of new paragraphs on molten salt thermal storage and superconducting magnetic storage.

Added photograph of Joshua Lederberg to the Planetary protection section.

Added example of cocoa plants which produce theobromine which kills dogs if they eat too much chocolate, to Why quarantine won't work - protecting Earth, and humans sent to Mars, from Mars life (if it exists)

Added more Joshua Lederberg cites and a quote to Why quarantine won't work - protecting Earth, and humans sent to Mars, from Mars life (if it exists)

Bit more work on intro to We are like the early Antarctic explorers with photos of Shackleton's expedition and Everest.

Expanded the section on paying for space settlements through retirees in Commercial value for Mars, explains about life expectancy, how anyone who lives to 65 still has a life expectancy of about 20 more years in the US, and a 90 year old still has a five year life expectancy, so they still have to support themselves once there, can't just be a one off cost.

---

Added links to David Schrunk et al's "The Moon: Resources, Future Development and Settlement" to The Moon is resource rich.

Have done some copy editing of the sections of Case for Moon First used in my new article An Astronaut Gardener On The Moon - Summits Of Sunlight And Vast Lunar Caves In Low Gravity, including the sectionsLong shadows on the Moon, especially at the poles, added a photo of a marigold flower to Fertility of lunar and Mars soil

10th October

Work on the preface and new cover picture based on the famous Apollo 8 Earthrise photograph.

11th October

Added estimates of the total land area needed to feed the world by the various systems to the Fertility of lunar and Mars soil section. Added information about the mass of a typical heavy goods train and calculation of percentage of population that could be fed using BIOS-3 system using indigenous resources from the Moon to Can we fill lunar caves with air?

New section: Ballutes - return of high value resources such as platinum to Earth and copy editing of Exporting materials from the Moon

14th October

New subsection headers and some copy editing for:

• Maintenance for habitats in free space and city domes

• Maintenance for lunar caves

Also added new material to this section with title changed

• Solar cells from lunar materials - solar panel paving robot

Also new cover image.

16th October

Added images to the preface, with captions, for the ESA village and for Shackleton's Endurance caught in the Antarctic ice.

17th October

Added some more on biological closed systems to CO₂ on the Moon . Added a shorter versions of the contents list to the title page.

24th October

Typos, copy editing, and sizing of pictures. Also expanded a bit on Ideal location for radio and infrared telescopes to observe space and organized in bullet points. Added link to experiment on the Wake Shield Facility on the Space Shuttle to Solar cells from lunar materials - solar panel paving robot

Added Bigelow aerospace to Moon firsters - ESA, Russia, Many astronauts, Bigelow aerospace, former US Vision for Space Exploration etc

31st October

Added Myth of automatic terraforming

Added details about the 18.6 year axial precession of the Moon and it's value for liquid mirror telescopes to Ideal location for radio and infrared telescopes to observe space

1st November

Added Most habitable Gaia for Mars would have a methane atmosphere or some stronger greenhouse gas

6th November

Expanded the section on Ideal location for many types of radio and infrared telescopes and other observatories (now renamed)

23rd March 2017

Added Trash, rocket exhausts and microbes on the Moon - testing ground for planetary protection measures for a human base

copy editing and minor fixes

New section Solar power at the lunar poles with new material on TransFormers

Origami rover

Two dimensional planetary surface landers

Added link to See Toxicity of lunar dust to Lunar dust inhalation compared to Mars dust

Added lunar vacuum cleaner idea to Coping with the dust

Added NASA's lunar resource prospector to Robots first

Added Could some co-operation be possible between the US and an ESA village that incorporates China?

24th April

Added new interpretation of Ina depression to Geologically active moon

Updated Robotic missions to the Moon, already planned, or near future, from 2017 onwards to say that astrobiotic have pulled out of the competition in 2017 (but still plan to go there in 2018)

Corrected figures for Hybrid system - adding algae to an ISS type system. I said 17 kg per person but it was 18 kg per person on checking the cite.

Expanded Small centrifuge based artificial gravity experiments in LEO

18th February 2018

Added Protection of the historical Apollo landing sites

Minor rewrite and subdivision into two sections of

• Space assets and strategic, economic and military significance of space

  • Idea that we should all share in the space mining boom, and of a sovereign wealth fund from space industry

  • Tapered tax recognizing risks

New sections

• Possibility of extracting metals from lunar regolith.

  • How much is there in the regolith?

  • Many questions about platinum in lunar regolith

  • How many craters on the Moon are formed by impacts of platinum rich iron meteorites?

  • How to separate out the platinum group metals - and the iron and nickel - Mond process

  • Could we extract it?

7th October 2018

Solar cells from lunar materials - solar panel paving robot - added layer by layer details of the composition of the solar cells proposed.

Power during the night - fixed mistake here - I'd misread Wh as kWh in one of the cites about Nickel Hydride batteries (oops) - fixed it. Also mention that keeping liquid hydrogen cool would be much easier at the lunar poles and also be a natural power storage system if you are already splitting the ice for export of fuel to LEO. Also tried the calculation for equivalent power per colonist of the ISS on top of the lunar agriculture.

Commercial value for Mars - added a bit more about Elon Musk and the video on the SpaceX channel of an interview "Business Model for Mars"

Liquid airlock - expanded with new sections:

• Diving through the waterlock - is that possible in a spacesuit??

• Need for very low vapour pressure liquid - water would lose around 60 meters depth of per day at 0 °C

• Idea to use low viscosity room temperature ionic fluids

• Vacuum stable light oils

• Funicular type railways driving though a sump and out onto the surface

• The high column and low density of water as an asset

• What if the water freezes?

• What about leaks?

• Protection from lunar dust

More detail to Hoyt's cislunar tether transport system (new section)

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and for more information please view the following web pages

( please using the right click of your mouse, and Open Link in Next Private Window, )

https://robertinventor.online/booklets/Online-Case-for-Moon.htm

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