I'll be on David Livingston's the Space Show this Friday, 27th May, to talk about my new "Case for Moon". It's main themes are: first, the Moon as our natural first destination in the solar system. Then, planetary protection and biologically reversible human exploration as core principles for human space exploration. Then, the Moon as a gateway for human exploration of the entire solar system, not just Mars. Finally, that it's most realistic to approach space in an open ended way, with the aim to find new knowledge, to protect Earth, to move industry into space, for solar power, and so on. In this vision, any settlement arises naturally out of those explorations, rather than as your main aim.

Executive summary for "Case for Moon"

I've added an executive summary to highlight the main points so if you want a quick overview, that's a good starting point. This is me reading out the executive summary:

And here is its text:
(most of the links in this executive summary take you to the online book to find out more)

The Moon is our nearest unexplored territory outside Earth. To ignore it is like ignoring Antarctica after the first few landings in the nineteenth century. Why rush humans as quickly as possible to distant Mars, the one place in the inner solar system most vulnerable to Earth microbes?

  • The Moon is resource rich, with volatiles at the poles, possibly hundreds of millions or a billion tons of them, with water, ammonia and carbon dioxide. It has many metals and nanophase pure iron in the regolith, also easily made into glass. It has a high grade vacuum for chip manufacture.
  • It has many advantages for a human base, including the peaks of eternal light, and possibly enormous lunar caves.
  • It is of great interest for science, with many new discoveries to be made.
  • It is far safer than Mars as a first destination for humans.
  • There are many places other than Mars to settle and perhaps colonize.
  • We don't know which gravity levels humans need for health, or what spin rates we can tolerate. You can’t draw a straight line between the effects of zero g and full g based on two data points.
  • Everything humans need in space is available in the asteroid belt, sufficient to build full g spinning habitats with a thousand times the land area of Earth.
  • Terraforming Mars is a far off dream. We are not yet mature enough as a civilization to see this thousands of years long megatechnology project through to completion. Failed attempts would introduce new lifeforms to Mars which may get in the way of future goals.
  • Earth is the best place for a backup and to rebuild civilization. We live in a quiet galactic region, at a quiet time in our solar system. None of the proposed disasters could make Earth as uninhabitable as Mars, leaving Earth as the best place to rebuild. While if our technology is the problem, surely the solution can't be to set up one of the most highly technological societies ever, in space.
  • As a young technological civilization, we should have protection and sustenance of our home planet as first priority, A trillions of dollars megatechnology “backup” attempt could distract from this. We can use our space technology to protect Earth against asteroids, to move damaging mining operations into space, for solar power, and for scientific discovery.
  • Mars has much more potential for surface and near surface habitats for indigenous life than realized before. These habitats could host lifeforms that are vulnerable, for instance early life based on RNA and ribozymes instead of ribosomes, out evolved on Earth by DNA based life.
  • We have protection guidelines on Earth to stop microbial contamination of vulnerable habitats such as lake Vostok (an isolated lake below 3.5 kilometers of ice in Antarctica). Humans would not be permitted to descend into this lake at present.
  • Mars can be explored from orbit more effectively than from the surface, using telerobotics.
  • Humans in clumsy spacesuits don't have special advantages over telerobots on the Mars surface
  • From orbit, you can “teleport” via telepresence to anywhere on Mars with immersive virtual reality experience of the surface.
  • We have miniaturized life detection instruments on a chip, that just a decade ago filled an entire laboratory
    "If such capabilities were to become available, one advantage is that the experiment would not be limited by the small amount of material that a Mars sample return mission would provide. What is more, with the use of rovers, an in situ experiment could be conducted over a wide range of locations." (Page 41 of Safe on Mars)
    These are now the most effective way to search for Mars life, past and present (as eight exobiologists said in a white paper for the decadal review). With our recent complex understanding of Mars processes, a sample return will not prove that Mars is safe for humans, or that humans are safe for Mars. Find out more
  • We should return samples from Mars either sterilized or to above GEO, or both, at least for preliminary investigation. It is far easier, both physically and legally, to return them to Earth after we know what is in them. Otherwise we are left with the daunting task to design for safe handling of any conceivable Mars exobiology, based only on knowledge of DNA based life.
  • If we show that human exploration of the Moon is of value to Earth, this will help human exploration of the rest of the solar system, not hinder it.
  • The same open ended principle should be used for all our explorations in space . Rather than grand overarching plans - we need an open step by step approach. At each stage we learn from what we have found so far, and can adapt and change our goals rapidly.
  • Until we know a lot more than we do now, we should not close off future possibilities for ourselves, our descendants and all future civilizations on Earth, but should keep all options open.
  • In this approach, planetary protection and biological reversibility are core principles.

The Moon in this vision is a gateway to the solar system, a place to develop new techniques and explore a celestial body that is proving much more interesting than expected. Along the way, we are bound to get human outposts in space, and colonization may happen also.

However, settlement in space doesn't need to be the driving force, any more than it is the driving force behind the study and exploration of Antarctica. If we try to turn Mars and other places in space into the closest possible imitations of Earth as quickly as possible, this may close off other futures, like the discovery of vulnerable early life on Mars, or better future ways to transform Mars.

Once we develop the ability to live in space for years at a time, the whole solar system will open out to us. While keeping future options open on Mars we can explore Venus, Mercury, asteroids, Jupiter's Callisto and further afield, and Mars itself via telepresence. We also have many experiments in human settlement to try closer to hand on the Moon. This can be an exciting future, with humans working together with robots for remote exploration, as our mobile sense organs and hands in the solar system and galaxy.



One of the things I've discovered as a result of writing this book, is that the Moon is not only much closer, and a safer place to send humans - it's probably also in many ways more suitable for human habitats than Mars! That will probably surprise you if you come to it after reading Robert Zubrin's "Case for Mars". Probably you will say something like this:

"It's got no 24 hour day, no CO2 atmosphere - it seems dull as concrete - and some of the ideas for colonizing Mars will work on the Moon, but others will not. You can't make methane from a hydrogen feedstock on the Moon without a CO2 atmosphere for instance. So how can the Moon possibly be an easier place for humans to live than Mars, when only some of Robert Zubrin's ideas will work there?"

But if you look at it on its own merits, then things suddenly turn around, like those images of a young girl and an old lady

One of the early versions of the Young Girl Old Lady Illusion.

The 24 hour day of Mars actually leads to huge differences of temperature between day and night in Mars' very thin atmosphere. At night in the Martian "tropics" the air gets so cold that carbon dioxide freezes out as dry ice, carrying water with it to form the Martian frosts photographed by Viking. While in the day time the temperatures can get well above zero at times.

You might think the Moon is even worse with its long night, as long as fourteen Earth days. But there's one other big difference between the Moon and Earth, that turns out to be very important. Unlike Earth and Mars, which have an axial tilt of over twenty degrees, the Moon has a tilt of only a bit over 1 degree. So it has no seasons.

That's why you get those peaks of almost constant sunlight, and just next to them, permanently shaded craters. A habitat, such as the proposed "ESA village", sited at those "peaks of eternal light" will have a constant external temperature of about -50 degrees centigrade, year in, year out. You'd see the sun slowly skim around the horizon, completing its circle every 28 days. And you'd be in almost constant sunlight there. It would be easy to keep your habitats warm just with solar collectors.

Then the carbon dioxide atmosphere of Mars is so thin it counts as a laboratory vacuum. You would die quickly without a pressurized spacesuit, as the water lining your lungs would boil into the vacuum. But it's not thin enough to be a very useful vacuum. While on the Moon you have an ultra high grade vacuum, so good that you could build particle accelerators on the Moon with no need for an evacuated tube to fire the particles through. It's actually a far better vacuum than is used for chip manufacture on Earth. You can make a solar panel on the Moon by vacuum deposition of silicon on glass, a process that only works with very high grade vacuum conditions on Earth, which are expensive to achieve.

So the Moon scores here too, with a much more useful vacuum than Mars!

Then, the Mars CO2 is not really that much of an advantage. You need much less rocket fuel to land and take off from the Moon - look at how small the rocket engines were for the lunar module. So the Sabatier reaction to create methane on Mars solves a problem that you don't have on the Moon. And the Moon has lots of sunlight anyway for power, and you can use it to split water to make hydrogen fuel cells.

Also, you don't need CO2 for plants. It's often a waste gas to get rid of in space habitats. If you can manage a biologically closed system, you don't need much input at all indeed. You exhale about one kilogram of carbon dioxide a day, which is almost exactly what the plants need to grow your food for a day, and the plants in turn, if you grow all your own food, are then guaranteed to make enough oxygen for you to breathe. That's just the way the equations add up. So in a biologically closed system then you don't need a constant input of carbon dioxide, or water, or oxygen, or nitrogen or much of anything. You just need a bit of input from time to time to deal with any materials that get lost due to imperfect recycling. As recycling gets better, you need less and less. And then, it turns out that, though we can't know this yet for sure, the Moon quite possibly has millions of tons of carbon dioxide from comets at the poles anyway in the form of dry ice.

In the same way, through one comparison after another, the Moon often turns out to be better than Mars. I was quite surprised as I hadn't realized until I wrote Case for Moon quite how many advantages the Moon has. This depends on whether it has large amounts of volatiles at the poles, but there seems at least a decent chance that it has enough to be usable for human habitats, and possibly enough to fuel rockets back and forth to LEO as well, even to export fuel and water to LEO.

The only one case where Mars might be better than the Moon is for gravity, and there, we can't say much. We only know about full g and zero g (there is not enough health data from the lunar astronauts to conclude much), and you can't just draw a straight line between two data points. We also don't know how much any health issues can be ameliorated with artificial gravity on the Moon or Mars, and so far,we don't even know for sure that the Moon is worse for human health than full g. It might even be more healthy for some people. There's only one way to find out for sure, to send humans there long term, or at least, to test humans in lunar levels of artificial gravity long term in LEO.

I also found it a bit surprising how little we understand the Moon, how many geological questions and mysteries there still are about it. I think it may have many other surprises in store for us once we send landers and rovers back there, and eventually astronauts too.

Though the "Mars firsters" seem to be the ones that get most news and attention, especially in the US, there's a lot of quiet support for "Moon first". Including ESA, Russia, China, and many astronauts and scientists, and the US used to support a Moon first plan as well. So this much of the book has wide support.


Another central theme of the book is that we should make planetary protection and biologically reversible exploration core principles of our human spaceflight programs. The idea is that the last thing we should do, right now, is to send humans as quickly as possible to the Mars surface (Mars orbit is fine). It's the one place in the inner solar system most vulnerable to the trillions of Earth microbes that hitchhike a lift with us wherever we go.

This is widely supported for robotic spacecraft, but when it comes to humans, then it seems as if many think that microbes on human spaceships should get a "free pass" to Mars. But if we need those planetary protection measures for robots, why should we drop them for human occupied spacecraft?

Perhaps once we realize that the Moon is just as useful for human habitats as Mars, and perhaps, even more useful, then we can find a way forward here? That's the hope anyway. Then later on, if we can use materials from the asteroid belt to make habitats, there is enough there to make Stanford Torus type space habitats with a thousand times the land area of Earth. So there is no shortage of space to settle humans. We can have a thousand copies of Mars, the Earth, even other exoplanets, as space habitats. But we have only one Mars in our solar system, and the nearest place to look for anything else like that is orbiting another star, light years away. So if there is anything unique in our solar system on Mars (by way of an example, early RNA based life, made extinct on Earth by DNA life), and we destroy it by introducing our Earth microbes, we may never be able to find anything like it again, for all future time, at least into the near term foreseeable future. So there is no rush to go to Mars right now.


Another theme is that the Moon is our gateway to the solar system, and that by going there first, we can open out the entire solar system to human exploration, not just Mars.


Even with all those advantages of the Moon, I don't think that our main aim should be colonize the Moon at this stage. We are like the first explorers to get to Antarctica. If they had had that as their main objective, to "live off the land" they might well have succeeded for a while, killing seals and penguins for food and using their fat for fuel to keep warm, a bit like high tech inuit. After all Shackleton's party did survive an Antarctic winter while he and a couple of companions set off to find rescue for them in a small open boat. But I can't see a colony on Antarctica with early twentieth century technology surviving for long. However enthusiastic the first settlers were; soon their children would decide they'd had enough, and want to come home, and not continue with the harsh difficult way of life their parents had chosen.

Instead of attempting this, the early Antarctic explorers did their exploring, and scientific study, and then came back to their warm comfortable homes at the end of each expedition. And then for year after year they continued to explore, built temporary bases, then more comfortable ones, then now we have many bases in Antarctica that are occupied all the year round (though with fewer people there in the Antarctic winter). There is no sign at all that we have come to an end of the science we can do in Antarctica, or that people will lose interest in going there as tourists, or going on adventures there. Yet, we are nowhere near to starting up a true colony there, and nobody has that as an objective at present.

So, I think it's the same with space. That if we go into space to try to colonize right now, we will never succeed. It is just too hard. Would you colonize a mountain plateau 30 kilometers into the atmosphere, more than three times the height of Mount Everest? At that height you'd have the same atmospheric pressure as Mars, but it would be much more hospitable in other ways. Perhaps it could be done, but why live in a place where everything is so difficult to do? Unless you have some very strong reason for living there, people just wouldn't set up home in a place like that, Not once the novelty wore off.

But you'd go there for adventures, you'd have scientists studying, and so on.

Maybe eventually we will find a way to live in such harsh conditions as the Moon easily. Maybe we can do this with 3D printers, and biologically closed systems. Maybe this will lead us to find a way towards a more sustainable future here on Earth as well.

But even so, if we achieve the ability to do this easily, the technology would still work much better on Earth than in space. You can use much the same design for your colony - except that you can drop all the cosmic radiation shielding, forget about airlocks and spacesuits, and just have windows and doors, instead, which you can walk out of, into a breathable atmosphere. And then put that habitat almost anywhere on Earth, in a desert, or floating on the sea - and that would be a far easier place to live than any space habitat. So if those types of habitats became possible in the future, even as a spinoff from space habitat research, I think most of them would be built on Earth rather than in space, at least to start with.

So, in this vision of the future, we have humans in space, but they aren't there to colonize. They are there rather to explore and study, and for adventure and so on, for many of the same reasons we have people in Antarctica. In the near future anyway. I think this is just being realistic; choosing a future that is within our reach rather than a rather beguiling far future science fiction fantasy that is probably centuries or even thousands of years out of reach, such as a terraformed Mars.

In this way, without that imperative that we have to colonize as quickly as possible, and turn everything into the nearest to a pale imitation of Earth as we can manage - then we can have a more open ended future. It gives us space to consider other possibilities; or at least, to look at them. For instance, in one possible future we could introduce Earth life to Mars, accidentally and irreversibly, perhaps from a crashed human occupied spaceship, creating a new geological era on Mars. But we don't have to do that. There is no need quite yet to make such an irrevocable decision for ourselves and all future civilizations on Earth.

Let's study Mars carefully from orbit first. There is no hurry, and this would be a fascinating exploration using telepresence, once we can get humans there. Maybe we will know enough in the future to make such far reaching decisions, but meanwhile, let's keep our options open for the future.

12th April 2011: International Space Station astronaut Cady Coleman takes pictures of the Earth from inside the cupola viewing window.- I've "photoshopped" in Hubble's photograph of Mars from 2003 to give an impression of the view of an astronaut exploring Mars from orbit.

This next video is not telepresence as such; rather, it's a new way to explore the Mars landscape to help with controlling the rovers from Earth. However, I think it gives as good idea of what telepresence might be like for those operating rovers on Mars in real time from orbit, some time in the future with this vision.


See Scientists Can Virtually Wander Around Mars for Miles with HoloLens

Meanwhile the Moon is turning out to be a fascinating place to explore, and by sending humans there we can develop capabilities that will mean we are not limited to the Moon and Mars, but can also send humans to Mercury, Venus, Jupiter's Callisto, and further afield in the solar system. But first I think we need to go back to the Moon, and find out there what it is humans can do, how well we can work with robots, and the advantages and disadvantages of each.


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 not to 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 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!

(This article consists mainly of extracts from Case for Moon)

Where to find "Case for Moon"

The kindle book may be useful if you want it formatted as a book, which you can read on your kindle, and also on most major smartphones, tablets and computers, using the free kindle reading app.

Note: I have the old version of the entire book here on the Science20 as well, but it's getting rather long now (well over 100 pages), and for techy reasons it's hard to keep them all synchronized, also the Science20 version doesn't have a table of contents, so I've stopped maintaining that and it is out of date.


I'm David Livingston's on the SpaceShow this Friday, May 27, 2016,

9:30-11AM PDT, 12:30-2 PM EDT, 11:30 AM-1 PM CDT, 17:30 BST

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And I have many other booklets on my kindle bookshelf

My kindle books author's page on amazon


When I founded this group, 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. You can join in here: Case for Moon for Humans - Open Ended with Planetary Protection at its Core