. CASE FOR MOON FIRST - 08 Alternative positive vision for exploration of our solar system - main points
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ALTERNATIVE POSITIVE VISION FOR EXPLORATION OF OUR SOLAR SYSTEM - MAIN POINTS
With the Moon as our starting point, we can then explore Mars as well. I totally agree that Mars is a great place to explore and that we can learn much about exobiology from studying it. But I think this is best done with robots initially, with humans first controlling them from Earth, and then later on, from Mars orbit.
The Mars colonization advocates say that we need to send humans to the Mars surface to explore it. But I don't think this argument stacks up if you look at it in detail, as you will see. In this alternative vision, humans work together with robots to explore the entire solar system, not just Mars. It uses humans and robots each to their best advantage, where they are most needed.
I've added links to my other online articles in this section, which you can read to find out more details about some of the ideas outlined here. Some of them have book cover images - these are ones that have been made into kindle books. Click on the book covers to go through to kindle booklet. These have the same content as the articles with addition of a table of contents and a cover image, and of course, formatted for kindle.
So the main points are (with links to other articles and booklets to find out more)
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 . On Earth they can explore active volcanoes, the sea bed etc. In space they can explore places that are either too dangerous to go to, too remote, or places where we don't want to introduce Earth life quite yet.
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. These are exciting prospects for the future. For more on this :
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Why Mars Microbes Matter - Like Tigers - And More So? - Microbial ETs
One example of what we might find on Mars is some early form of life made extinct on Earth by DNA based life - I like this example because it makes it clear that what we search for on Mars can be vulnerable to Earth life. You often get the argument that anything we find there has to be better adapted to Mars, and Earth life can do it no harm - this just blows through that argument in one go.
This could for instance be RNA life using the small ribozymes (made up of many fragments of RNA) in place of the much larger ribosomes (which are a mix of RNA with proteins),
This early RNA based life could be similar in size to the contested microbe "fossils" in ALH 84001.
Indeed one suggestion for these "fossils" is that they could be the remains of early life from a time when cells were simpler and smaller than modern cells. Modern life with its two biopolymers RNA + DNA and huge ribosomes is far too complex to have arisen from pre-life organics in one go. RNA based cells with no DNA or proteins could fit the bill perfectly.
The idea that the structures in ALH84001 might be these RNA world cells was suggested originally by the fourth panel in a workshop convened soon after the news about ALH84001 see Size Limits of Very Small Microorganisms: Proceedings of a Workshop (1999). Now that scientists have found alternative ways the structures, magnetite, and organics could form without using life, based on unusual conditions on the Mars surface, this meteorite is no longer thought of as proving the existence of past life on Mars. But it hasn't disproved it either, and the idea that these may be RNA world cells is still discussed see Towards a Theory of Life, in Frontiers of Astrobiology (Page 37)
If life evolved independently on Mars, and if it went through similar stages to the ones hypothesized for Earth life, but with a different timeline, there is a chance that earlier forms of life may still be there.
Benner has also suggested that Earth life might have originated on Mars because deserts are much more promising for evolving RNA cells especially when rich in borate as it helps prevent the chemicals combining to form an "asphaltic mess" - see The case for a Martian origin for Earth life and for techy details see this paper - so in that case also, what if some species of this early form of life have still survived on Mars in some niche habitat there? Some biologists have suggested that RNA life may still survive on Earth, in a shadow biosphere, hard to detect because it doesn't contain ribosomes, but there isn't yet much support for this idea. If it hasn't survived on Earth, perhaps because of competition with modern life, what if it has survived on Mars?
If Earth shared microbes with Mars, Mars life could be vulnerable to microbes that didn't make the trip. As an analogy from Earth, some Arctic terns fly over both Europe and Australia on their yearly migrations from the Arctic to Antarctica and back again, but that doesn't make the European rabbits safe for the wildlife of Australia, because, of course, rabbits can't make the same trip.
We don't know if any life has been transferred to Mars, though it's possible in theory. There are formidable barriers in the way. These include the century long passage in the vacuum of space (that's the fastest transit from a giant asteroid impact on Earth), the cosmic radiation, and harsh conditions that only a few Earth species could survive.
They have to be anaerobes ( survive without oxygen), be able to grow in a place with a near vacuum for an atmospheric and tolerate high levels of UV light and cosmic radiation. They probably need to be tolerant of perchlorates (some microbes even use perchlorates as a food source), and probably salt loving, and also to be autotrophs capable of forming single species ecosystems, at least for the first ones to get there, amongst a few of the capabilities needed for a pioneer microbe from Earth to survive on Mars. There are microbes with all those qualities but did they got to Mars on meteorites? And did they find a habitat when they got there, given that the most hospitable places on Mars are also probably very rare? At present, nobody knows.
Perhaps one of the best candidates for a microbe to get from Earth to Mars might be Chroococcidiopsis, a photosynthesizing polyextremophile, one of the oldest microbes on Earth, able to handle almost anything you throw at it, and it can form a single species ecosystem. It doesn't eat other lifeforms (is a "primary producer autotroph"). If it did get to Mars, it might cause no problems, it might be useful food. This wouldn't mean that all Earth microbes are okay for Mars.
Does Earth Share Microbes With Mars Via Meteorites - Or Are They Interestingly Different For Life?
Could Microbes Transferred On Spacecraft Harm Mars Or Earth - Zubrin's Argument Revisited
No Simple Genetic Test To Separate Earth From Mars Life - Zubrin's Argument Examined
So we have to be careful when exploring Mars, also Europa and Enceladus, and anywhere likely to have an 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?
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 has been of places already occupied by humans, for thousands of years. We don't have any examples of large scale colonization of Earth deserts, or ice fields, or mountain tops or other uninhabited regions, not since neolithic times.
Overview of Pre-modern human migration - there is debate and controversy about the details, but generally agreed that humans were already present world-wide by the end of the neolithic period(which ends around 2,000 BC) or shortly after. Large scale colonization since then has always been of areas where humans can survive with stone age technology. More hostile places such as Antarctica, the highest mountain summits, and the sea floor, have not been colonized.
So the analogy of colonization on Earth is of limited relevance to space exploration. That doesn't mean it is impossible, but it's a new kind of thing that we have never done before, like colonizing the sea floor, and analogies with the past can't really tell us if it can be done or not, or how successful it is likely to be.
There have also been many failed colonizations such as the attempt of the Vikings to colonize America, and the attempt by the Scottish to colonize Panama, which was so disastrous it lead much of the lowland population of Scotland to bankruptcy, and resulted in an urgent need for unification with England to save them.
Flag of the Company of Scotland Trading to Africa and the Indies. Their "Darien Scheme" an attempt to colonize Panama, lead to the death of nearly all the colonists, and it also drained Scotland of an estimated a quarter of all its liquid assets. Scotland was saved from bankruptcy by England, in exchange for unification with England, higher taxes, and an agreement to service the English national debt.
If you focus just on the colonization attempts that succeed, you get only a partial picture, which may be over optimistic.
Mars is far more inhospitable than any of the places humans colonize on Earth, much more like the Moon than Earth in terms of habitability. It's more inhospitable than deserts and Antarctica and we don't colonize those places. Indeed even the top of Mount Everest (at 8.848 km above sea level) is far more hospitable than Mars. You need to go to an altitude of 30 kilometers on Earth, to have the same atmospheric pressure as the lowest points on the Mars surface, and the average temperatures on Mars in its equatorial regions are similar to Antarctica.
So, I think that space settlement in the early stages at least would be like an Antarctic base - where you are there because you are doing something of value. I suggest our focus should be on creating settlements that are of value for Earth rather than colonization for its own sake.
Yes we might get future tech that lets us build self sufficient habitats on Mars. But before then we'd be able to build self sufficient colonies in deserts, and do many other things. We don't have that technology yet. Perhaps we can consider colonizing places with a laboratory vacuum for an atmosphere, once we have learnt to make a self sufficient floating sea colony - that is to say one that only uses sea water and the atmosphere, and maybe a few rocks, and no other resources from Earth. That would be a far easier task to achieve.
Other places in space may be better for exploiting in situ resources than Mars. Using materials from the asteroids, and the moon has many advantages. You don't need to build a Mars surface rated human lander. Mars is the hardest place to land on in the inner solar system without crashing, with automatic systems needed to respond in 90 seconds to land safely, way beyond any possibility of human recovery in case of error. There would be no last minute Neil Armstrong type course corrections for a Mars landing.
".. with current EDL (Entry Descent Landing) capability, a large vehicle plunging through the tenuous Martian atmosphere has about 90 seconds to decelerate from Mach 5 to Mach 1, flip over from being a spacecraft to being a lander, open the chutes to decelerate some more, then fire those thrusters to navigate to the landing site before touching down". - page 137 of SpaceX's Dragon: America's Next Generation Spacecraft, by Eric Seedhouse
It may well be possible to solve this for humans. For instance SpaceX hope to use supersonic retropropulsion, which removes one of the stages, no need for the parachutes. But if you send humans to the Moon or asteroids, you don't have these problems in the first place. One less thing to deal with.
All the resources you can find on Mars are also available on the Moon or in asteroids. The Moon has a shortage of nitrogen, but is not as thoroughly explored as Mars in many ways, and may still have it, e.g. it does have some ammonia in the polar ices from the LCross results . Nitrates are rare on the Mars surface also.
Then, perhaps surprisingly, Venus cloud colonies have advantages over Mars too. This is the NASA scientist Geoffrey Landis' proposal, though first explored by the Russians in the 1970s. These "aerostats" have the lowest level of technology requirements of all the space habitats for their inhabitants. You could maintain them with almost a nineteenth century level of technology, especially if we can achieve closed system biological recycling. You might wonder how it is possible, on hostile Venus, but these are habitats that float just above the Venus cloud tops, where the temperature and atmospheric pressure is comfortably in the habitable range for humans.
There's the sulfuric acid in the Venus clouds to deal with of course. But there's no vacuum, and acid is far easier to deal with than a vacuum. To go outside your floating Venusian aerostat you would need an acid resistant suit and a closed system air breather like an aqualung. But you wouldn't need the millions of dollars spacesuit like a mini spaceship, which you need for any of the other suggested habitats in space.
The Earth's atmosphere of nitrogen and oxygen has a lifting capability about half that of helium in our atmosphere.
The first habitats there would be lightweight and inflatable, and would surely require less mass launched from Earth per person than anywhere else in the solar system outside Earth, and much more habitable volume per person. There are no detailed plans for these yet (at least I can't find one). But you can get some idea from airship designs on Earth.
An airship such as the Airlander 10, which has mass 20 tons and lifting capacity of 50 tons, if transferred to Mars with the helium replaced by breathable air, would have a lifting capacity of 15 tons in the Venus atmosphere. The ratio goes up with larger airships. A one kilometer diameter Buckminster fuller Cloud Nine type tensegrity sphere city in the Venus atmosphere could carry a weight of 700,000 tons. Since your lifting gas is breathable air, you can live inside the lifting envelope itself, so the interior is very spacious.
It's also safer than a Mars or Lunar colony in some ways, because the pressure is the same inside and out, like a hot air balloon or an airship. You can see this equalizing of pressure clearly with weather balloons destined for the stratosphere, which leave Earth's surface only partially inflated. So, if the aerostat outer cover has a hole in it, the air inside will escape only very slowly and the hole will be easy to patch. And the atmosphere would protect you from micrometeorites and even quite large meteorites as for Earth.
You also have shielding from cosmic radiation and solar storms by the atmosphere. The aerostat would float at a level with internal and external pressure equal to one bar, so you'd have around ten tons of carbon dioxide atmosphere above every square meter. And since it floats just above the cloud tops, it's in a clear atmosphere, with sunshine, and vast vistas over the cloud tops, like flying in a jet airliner on Earth.
Getting there is easier too. There is no hard surface to crash on, as your target altitude is many kilometers above the surface. Russia had ideas for sending humans to Venus in the 1970s, and NASA has considered sending robotic missions there first followed by humans exploring the atmosphere using airships in its HAVOC program. See project home page. This is an internal study, so it's at an early stage at present.
Returning to Earth of course is harder, the hardest return of any in the inner solar system apart from Earth. But it's possible - the NASA HAVOC proposal has the crew return to Earth of course.
Right now, I think this of most interest for outposts and temporary bases supported from Earth and eventually research stations rather than colonization. I think, though, that the comparison helps highlight how high tech and difficult Mars colonization would be and the level of support it would need from Earth with present day technology - rather than practicality of Venus colonization in the near future. Self sufficient floating sea cities on Earth using only sea water and the air from the atmosphere and a few rocks would be far easier to build than either of these, and we don't have them yet. This could change if there was an easy way to get to orbit from Venus - perhaps using orbital airships. For more on this, see Venus cloud colonies - a surprising low maintenance solution
Yes, we can build human settlements using resources from space. But the reasoning of the 1970s is still valid - that we don't need to look any further than materials from the asteroids and the Moon.
Some asteroids consist almost entirely of pure metals including iron, nickel, and heavier metals such as the industrially useful platinum, and gold (a small asteroid 452 by 1011 meters across, to take an example, was estimated to contain 90 million tons of platinum). These metals may also be capable of being extracted without physical mining using carbon monoxide at low temperatures of 50–60 °C to convert metals to gas (second half of the Mond process with no need to extract the pure metal first), and perhaps directly converted back to metal parts again from the extracted metal carbonyls in 3D printers operating at the higher temperatures of 220–250 °C. It works well for nickel carbonyl. The same process for iron though is much harder to do. Industrial production of iron pentacarbonyl Fe (CO)5 uses conditions such as 175 atm at 150 °C, and the reaction is also sluggish requiring use of iron sponge as a starting point, and it also reacts with sunlight to produce solid Fe2(CO)9, So that might not be so easy to scale up to asteroids. Nevertheless there are those who think it is a feasible way to mine iron rich asteroids, see for instance this paper by John Lewis.
Other asteroids have organics, volatiles, and everything that we need. The conclusions of the 1970s are still valid, that there is enough material in the asteroid belt to eventually build habitats with area the equivalent of a thousand times the surface area of the Earth or more. This is an observation that goes back to O'Neil in 1969 when he was teaching freshman physics, see Colonies in Space: chapter 2. So there's far more potential for settlement in the asteroid belt than there is on either Earth or Mars, measured according to the available land area. And what's more, you can choose whatever climate and even atmosphere, and gravity level that you like for the habitats.
Also, you can concentrate the sunlight using large mirrors with a fraction of the mass and technology needed for a space habitat. The space habitats could be moved inwards, for instance towards the Earth L5, but they could also migrate outwards. As the authors of the Stanford University 1975 publication "Space Settlements: a Design Study" wrote, "At all distances out to the orbit of Pluto and beyond, it is possible to obtain Earth-normal solar intensity with a concentrating mirror whose mass is small compared to that of the habitat.” So with habitats made from materials in the asteroid belt (or further afield) the entire solar system out to Pluto and beyond is open to us. We could also colonize the Oort cloud too but that would probably need some other form of power such as fusion power.
As T Heppenheimer put it in 1977 in his "Colonies in Space": "Mars, the focus of so many hopeful dreams, might be bypassed. It will see its research centers for geology and other studies, but it appears to have few resources which cannot be had elsewhere. Even if it did, its gravity would make it costly to lift them out. Its atmosphere is just thick enough to prevent the use of a mass-driver. Yet the atmosphere is too thin to screen the solar ultraviolet or permit the use of aircraft for transportation. Mars of the great volcanoes, Mars of the deserts, of the frosty nights and the whistling winds in the canyons—if it is to be colonized, it will be done as an afterthought in the history of the human reach into space. It may remain a vast dry land, far from the major centers of commerce or population, thinly populated and of interest mainly to the people that live there. Mars may be the Australia of future centuries."
Though of course I'm arguing here that Mars is better treated as an exoplanet in its own right to be kept free of humans altogether at least until we have some understanding of what effect we'd have on it, or rather the microbes that always accompany us.
(I find this is often the most telling point in the argument).
Asteroid Resources Could Create Space Habs For Trillions; Land Area Of A Thousand Earths
The Moon is far safer at this stage. We can send new supplies within days, and experts on Earth can trouble shoot problems with just a 2.6 second round trip delay. A base on the Moon could also have "lifeboats" for all the crew, similarly to the "lifeboat" spacecraft docked to the ISS, always ready to take them back to Earth within three days in the case of any emergency.
While a mission to Mars is like a long sea voyage without lifeboats. The only way back takes at least six months, and could be much longer. If there is some problem soon after you do the final burn to leave Earth, and you are already on your way to Mars, an Apollo 13 type rescue would involve trying to figure out how to survive for two years, to get back safely, not 87 hours.
This is something we can learn to on the Moon first, how to keep humans alive in space with minimal resupply from Earth, ideally for years on end. Until we can achieve that, I think it is just not safe to send humans to Mars.
Then trouble shooting at the distance of Mars with a 48 minutes maximum round trip time is bound to be harder than for the Moon. A situation like the Apollo 13 "Okay, Houston, we've had a problem here." if it developed as far away as Mars, would find the astronauts having to make many decisions on the spot, with Earth only able to advise them based on what they told Earth 48 minutes earlier. Take a look at the Apollo 13transcripts, and imagine how it would play out with a 48 minute delay.
Settlements on the Moon, or in space, using materials from asteroids, are likely to be easier to support economically - as it's much easier to export materials, to LEO, cislunar space or to Earth itself. It's not yet clear whether this can be done even for the Moon. But if this is possible, the launch costs from an asteroid or the Moon are far lower than from Mars. They could use ballutes, large parachutes, or similar, to land the materials on Earth. And if we can get Robert Hoyt's ingenious Cislunar tether transport system working, they could return material from the Moon to LEO with no fuel at all, just exploiting the higher position of the Moon in the Earth's gravitational gradient.
See also Would a space colony survive with only exports of intellectual property to pay for imports?
We don't yet know how well humans can cope with artificial gravity, or what level of gravity we need for health . The problem is that though we can simulate the physics easily, we can't simulate the human body. We can only find out human tolerances for spin rates, and the "gravity prescription" for health, with experiments in space. The best we can do at present is to simulate zero g using bed rest subjects on Earth with their heads lowered, then spin them to try to simulate artificial gravity in zero g. The only way to tell how well this simulates the health effects of artificial gravity is to get some ground truth from space.
There are many experiments we could do in space to resolve this. But until then, it's not really possible to say for sure whether humans will do best in lunar gravity, Mars gravity or spinning habitats in space, and which are easiest to build, and what spin rate is needed.
We don't know the optimal artificial gravity or real gravity level for health. Indeed the optimum could also be a mix of different levels during the day. It might even be that the optimal design for humans is a zero gravity module with a rotating sleep habitat at night as in the Nautilus X design - as this has never been tested. We know that humans are not healthy long term in zero g unless they do at least two hours of exercise a day and even that still keeps you less healthy than someone confined to a bed on Earth. We also know that a few days of lunar gravity can be tolerated with no apparent ill effects. Apart from that, we know almost nothing about the gravity prescription for human health.
I'd argue that it is far too soon to say what is the optimal type of habitat to build for humans in space, or where is the best place to build them, for human health.
Can Spinning Habitats Solve Zero g Problem? And Answer Low g Questions?
Can Astronauts Spend Years In Space - And How Quickly Can They Recover On Return To Earth?
We haven't yet attempted a self sufficient habitat in space. Several ground experiments suggest it may be possible, and that we could produce all our own food and oxygen from plants in a closed system with minimal supply of materials. The size of habitat you need, using hydroponics or aeroponics, is surprisingly small also, only 13 square meters of growing area per person to produce most of their food and all their oxygen, and 30 square meters to produce 95% of the food, water and oxygen. But though this works on the ground, this has not yet been tested in space.
The food by itself isn't such a big thing. Even the food for a multi-year mission, in dried form, is not so much by wy of mass. But growing food in space really comes into its own when you combine it with purging the CO2 and providing oxygen.
If the crew grow all plants equal in mass to the food they eat, they automatically also get all their CO2 purged and get all their oxygen from plants. It doesn't matter if they eat it or use supplied food. In more detail - if they eat half of the plant mass (if half the crop consists of inedible plant wastes, as is often the case) and the rest is stored or discarded, then they would need the other half supplemented as food. If they grow all their own food, then to complete the cycle any inedible plant wastes have to be oxidised back into CO2 for the plants to grow (e.g. burnt). See Design Rules for Life Support Systems, section SYSTEMS INTEGRATION AND RECYCLING)
So, the simplest idea here is to use algae for that, e.g. the spirulina algae – I think you can say that arguably that’s a more robust system than any complex mechanical way of doing it. Even if nearly all the algae die, through some problem of maintenance, you just need a few left, clean the container, and you are ready to go again. While if a mechanical CO2 scrubber or the equipment to make oxygen from water fails, you need mechanical part spares, and if you don’t have those, or can’t produce them, you are sunk. You can eat some of the algae as a supplement and just store or discard the rest. This is the method that was used for BIOS-1.
If instead as in BIOS-3, you grow most of your own food, you could have algae as a backup, for CO2 scrubbing and oxygen, plus extra dried food "emergency rations" in case of a disaster in the hydroponics. That wouldn't add much weight. But the BIOS-3 experiments managed fine for months without problems, and I think once we get over the early teething issues, the same will be true in space.
They would choose fast growing, easy to grow plants, and there would be no soil borne plant diseases or insect pests, and very controlled conditions with hydroponics or aeroponics. And especially so if we have artificial gravity, as a lot of the issues in the ISS and earlier experiments in MIR etc. were to do with growing the plants in zero g.
See Could Astronauts Get All Their Oxygen From Algae Or Plants? And Their Food Also?
Beautiful Edible Orange Zinnia - First Zinnia But Not First Flower In Space - And Astronaut Choices
So before developing grand visions of the future for humans in space, we need to look closely at those two points, artificial gravity and biological closed systems . And do them in a location where we can experiment safely. In my view, it's not yet the time to send humans on deep space missions until we know how to send them safely, say, as far as the Moon, and to live there for years on end. It's neither safe, because of the lifeboats issue, nor is it sensible.
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.
Human Spaceflight At "Coastline Hugging Phase" - Lunar Villages Not Interplanetary Voyages - Op. Ed.
Flags On The Moon - Like A Space Exploration Olympics - And Olympics Style World Flag
We are bound to have fewer people in space than on Earth in the near future. Just as Antarctic settlements are not self sufficient, but are supported by many people outside Antarctica - the same will be true for space settlements, in the near future at least. Whatever the ratio is - if you need a hundred people on Earth to support each space settler, for instance - 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. So, if you needed a hundred people on Earth for each settler, that would be a limit of 75 million people in space. Or 7.5 million if you have 1000 on Earth for each in space, or could be a higher ratio, as unless space settlers have some big hold over Earth dwellers, we might not get everyone on Earth just involved in supporting them. I think therefore in the near future that we will have possibly tens, even hundreds of thousands in space but not billions. This would change if we can make self sufficient colonies in space - but before that, we would have the technology for self sufficient sea colonies etc. on Earth.
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 remotely likely disaster could make Earth as uninhabitable as Mars, and some humans would survive anything that is likely to happen. That's because we live in a relatively quiet time in our solar system and a relatively quiet region of the galaxy.
For asteroids, then the large impacts in our solar system all date back to well over three billion years ago. There is no risk of an asteroid large enough to make such an adaptable species as tool using homo sapiens extinct. With just the most primitive of tools we can survive anywhere from the Kalahari to the Arctic. Turtles, crocodiles, alligators, flying dinosaurs (birds), dawn redwood, pine trees, they all survived the Chicxulub impact event. We would also. Even if we have to go back to beachcombing and surviving on shellfish, one way or another some humans would survive.
See Giant Asteroid Headed Your Way? - How We Can Detect And Deflect Them
And Mars is already far more inhospitable than Earth could possibly be even after the very worst asteroid impact - we'd have a nuclear winter - darkness - but still, air to breathe, cosmic radiation protection, water, seas, and surely a fair bit of food also available. Those left on Earth after such an event would be way ahead of the curve compared to anyone trying to survive on Mars.
And for the cosmological disasters like a gamma ray burst - why go to Mars? Here on Earth at least we are protected by the 10 tons per square meter Earth atmosphere. On Mars, you are only protected if you dig deep underground. This motive just doesn't add up in my view. And wherever you had your backup, Earth is the obvious planet to rebuild, no matter what happens, of the possible disasters. Indeed if you put it anywhere off planet, the Moon seems the obvious choice. See Backup on the Moon - seed banks, libraries, and a small colony
At the very least, anyone in a nuclear sub deep under the sea would survive nearly all those disasters. Most would be survived by anyone who happens to be on the other side of Earth at the time. So why go to Mars?
Why Elon Musk's Colony on Mars in 2020s is Unfeasible - What Could We Do - Really?
End Of All Life On Earth - A Billion Years From Now - Can It Be Avoided - And Who Will Be Here Then?
As for self created problems, again we can't escape from them in space. A future with many humans in space will have much communication back and forth, so we don't achieve a significant level of quarantine that way. And the high tech space colonies would be the most likely places to create and use the most advanced technology. So - 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.
For instance they would be amongst the most likely to try to make replicating machines or synthetic life, they might return extraterrestrial life from Mars to Earth, and with accelerated colonization with millions in space there’s also the possibility of wars between space colonies and Earth.
If you think Mars would be protected by a kind of six month quarantine because it takes so long to get there, remember that we have ideas for propulsion methods that could get us there in weeks possibly even days. Also we could set up a permanently quarantined colony on Earth easily enough for far less cost than a Mars colony.
A future with large numbers of humans in space with high technology is not necessarily the best thing to aim for. If you have millions of people in space, you will certainly have ISIS and North Korea in space also, and they will have technology greater than that of ICBMs at their disposal. Rushing into space could create the very problems we would want to run away from. You can't restrict it to just the "good guys" whoever you think they are, if you have millions in space. There is a chance we can achieve millions in space peacefully, but exactly how we do it surely matters.
Will Anyone Ever Own Their Own Land In Space - And May We Get Wars In Space In The Future?
Space settlement is neutral just like settlement anywhere - it could be good or bad. I don't think settlement and colonization is an "intrinsic good" in the sense of philosophy and ethics, but rather an extrinsic or instrumental good, good only because of its benefits (Intrinsic versus extrinsic good in Stanford online Encyclopedia of ethics).
As Kennedy said in his speech, talking about the US of course, but the same applies to all countries setting off into space:
"We set sail on this new sea because there is new knowledge to be gained, and new rights to be won, and they must be won and used for the progress of all people. For space science, like nuclear science and all technology, has no conscience of its own. Whether it will become a force for good or ill depends on man, and only if the United States occupies a position of pre-eminence can we help decide whether this new ocean will be a sea of peace or a new terrifying theater of war. I do not say that we should or will go unprotected against the hostile misuse of space any more than we go unprotected against the hostile use of land or sea, but I do say that space can be explored and mastered without feeding the fires of war, without repeating the mistakes that man has made in extending his writ around this globe of ours."
"There is no strife, no prejudice, no national conflict in outer space as yet. Its hazards are hostile to us all. Its conquest deserves the best of all mankind, and its opportunity for peaceful cooperation may never come again...."
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.
In my view, it seems likely to be more healthy if the main aim is to help and protect Earth or to expand our understanding. For instance, to go into space to explore and discover new things, as we do in Antarctica, or to build solar panels to supply electricity to Earth, or to mine resources from asteroids or the Moon, which can help move heavy industry into space, or for health benefits, if low g turns out to be beneficial to human health for some sick people e.g. with heart conditions, or for tourism, or adventure, or to discover asteroids and to protect against them. All of these could make space settlement positive in its effect, if done well, and with consideration of the effects on Earth.
It's not likely to be a "new form of society" in space in the near future. This is an argument given by some space colonization enthusiasts. The idea is that we can make a fresh start, perhaps a more anarchic (in the good sense), or more fluid society in space. But the space environment seems the least likely of all places to achieve this, in the near future at least. It would make more sense, I think, to try this on Earth. There are many remote uninhabited islands, where you could attempt to start up such a society.
The reason I think it's unlikely in space is because you have to be so extremely disciplined to survive there. Astronauts for the ISS are evaluated for their ability to fit into a team, and follow orders. They are relaxed and happy on the ISS because they are people that are content in such a situation. But if the commander says they have to evacuate to the Soyuz, for instance, that is what they have to do, following a detailed procedure that they have trained in numerous times, to be able to do without error and quickly.
It is like living in a nuclear submarine, you have to be able to follow orders and have someone in charge, for safety reasons, since life threatening situations can arise quickly. You also have to follow careful procedures to put on your spacesuit, which takes a long time, then during space walks each movement you make needs care and attention. For instance, you follow a careful procedure each time you move the tether that keeps you attached to the station, which you may do frequently. You have many check lists to follow through exactly. Then if mission control say you have to end the space walk early, there is no arguing, you just go back in right away. There is room for improvisation by individual astronauts, and finding new solutions and creative approaches, but for safety reasons this is done within the framework of a clear chain of command.
This may get easier as time goes on, but it would still be the most regulated modern society of any. It has to be, for safety reasons and because you are surrounded by high technology, dangerous if misused, and you are separated from the vacuum of space by a few cms of metal. The same is also true of other hazardous environments on Earth. In Antarctica, then inhabitants of the settlements have to be able to follow rules and guidelines carefully, especially in the Antarctic winter when it gets extremely cold outside the habitats and dangerous if you don't follow proper procedures. Space habitats are far more hazardous, so need even more care.
This may change in the future, but I suggest that currently this is the situation for space settlements or attempts at colonization.
As a young technological society, our priority should be to protect and sustain the Earth. Attempts at terraforming Mars, or any attempt for large scale human occupation would cost trillions of dollars. The resources used to construct the large space mirrors to warm the planet, or the hundreds of greenhouse gas manufacturing half gigawatt scale nuclear power plants on the surface could instead be used to provide solar power for Earth from space, to deflect asteroids and protect Earth from other hazards, and to move heavy industry into space. For deflecting asteroids see Giant Asteroid Headed Your Way? - How We Can Detect And Deflect Them
If we want to attempt creating Earth like habitats in space, then at our stage of development, I think we should try something rather smaller scale and more controllable like a Stanford Torus. Which we could complete in a couple of decades rather than the thousands of years of a terraformed planet (if it is possible at all), and at much lower cost.
The original Stanford Torus proposal has detailed costings at the end. They base this on a mass driver on the Moon supplying most of the mass (consists mainly of the shielding). and they estimate it as $190.8B in 1975 dollars. So that’s $851.99B in 2016 dollars. So if’ that’s right, it would cost less than a trillion dollars. Estimate here Building the Colony and Making It Prosper (converted to 2016 dollars using this online US Inflation Calculator). That’s about $100 million per person for the population of 10,000. If we can reduce launch costs of course it would go down further.
Sometimes the idea of creating colonies on other planets is motivated by the idea that it will make us a multi-planetary civilization, and that this will take us to type II in the Kardashev scale. But the scale is defined by the level of power we have available to us, not the amount of territory we “occupy”.
In the Kardashev scale, a Type I civilization is one that uses just about all the power available on its home planet.
Type I "with an energy capability equivalent to the solar insolation on Earth"
Putting a few bases on the Moon, or Mars or the asteroids will not take us to a type II civilization, or even the beginnings of one. Indeed if it has the effect of diverting resources away from Earth it could be a set back preventing us from getting to the type I civilization level.
(You can of course question the whole premise here - is a society with more consumption of energy necessarily better? But if you measure progress by the Kardashev scale, then going multi-planetary before you are ready for it is not necessarily a step forward in this scale and doesn't necessarily mean you are in a more robust position to deal with future crises).
Mars has turned out to be a much more likely habitat for present day indigenous life than previously thought, and the same also applies to some other places in the solar system, such as Enceladus and Europa.
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. There are seasonal changes when observed close up not caused by dust storms, winds, or by dry ice, that may be due to liquid water. And, since Phoenix in 2008, many independent lines of evidence suggest potential present day surface habitats on Mars. Liquid water has been confirmed indirectly by Curiosity, though most think that the particular liquid water layer is not habitable. Other liquid water layers on Mars may be habitable, and it is possible that life could even use the 100% night time humidity without any liquid. This is great news for exobiology, if it turns out that there is some form of life still existing on Mars. It will mean however that we need to take great care with human exploration because of the microbial hitchhikers that accompany us everywhere.
Our Spacecraft Could Look Straight At an Extraterrestrial Microbe - And Not See a Thing!
As Philae Awakes - Where Might Life Hide In Our Solar System?
NASA Says Mars Mystery Solved - What Is It? - Three Mysteries About Recursive Slope Lineae
Why Are Hydrated Salts A Slam Dunk Case For Flowing Water On Mars? And What Next?
It is tricky to explore habitable places without introducing Earth life. We are still figuring out how to explore the subglacial lakes in Antarctica without introducing surface life.
We shouldn't just assume we know how to do this on other planets, yet. Some places, like Europa's subsurface oceans may be currently impossible to explore with our technology, until we can manage 100% sterile robots. Perhaps the same might be true for liquid water habitats on Mars for similar reasons.
Lake Vostok is only 4 km below the surface, 0.5 km above sea level. Less than half the depth reached by the Trieste bathyscaphe, in 1960, yet the Russians wouldn't think of sending a bathyscaphe down there. They stopped drilling for several years, mainly to avoid contaminating the lake with drilling fluid. However another concern is not to contaminate it with surface life to avoid confusing the results.
The bathyscaphe Trieste reached a depth of over 10 km in the Challenger deep in the 1960s, with Jacques Piccard and Don Walsh on board. But we don't send even a robotic sub into Lake Vostok to avoid contaminating it with surface life.
The Russians drilled down nearly all the way to lake Vostok, but then stopped until they figured out how to do it safely, preserving the science value.
Scientists at the National Research Council have prepared guidelines to protect the lakes, similar to planetary protection guidelines. So, nobody would think of sending humans down there quite yet, as this is not possible within those guidelines.
It's not an exact analogy. In some ways Mars is less vulnerable than lake Vostok, because of the harsh conditions there. In other ways it is potentially more vulnerable because of the wider range of possibilities for what might be there, including some vulnerable form of early life, and because whatever is there has been isolated from Earth for a lot longer than lake Vostok.
However, the Vostok analogy shows that we can sometimes halt exploration because we don't yet have the technology to do it without impacting on science. Sometimes we need to wait until the technology is developed until we can continue further. It also shows that there are places we wouldn't send humans to, even on Earth, to protect them from introduced microbial life. So why not have the same situation in space?
100% sterile robots are possible in principle. You could for instance, build the robots without any organic parts, and then sterilize them of all organics, if we knew how to do that. But we don't yet have a 100% reliable way to do this. Heat sterilization to a high enough temperature works, but destroys the robot also. Ionizing radiation has similar issues, because electronic circuits are vulnerable to ionizing radiation. Supercritical CO2 snow is promising and being investigated by ESA. It's interesting as it not only sterilizes at low temperatures, and has no effect on electronics, but also removes the organics completely if the robot starts off reasonably clean. So if something along those lines could some day be made 100% effective, you not only get no life on the spacecraft, but no DNA fragments or GTAs or anything organic at all.
For the CO2 snow method, see See Deep cleaning with carbon dioxide. and Science Daily article about it.
CO2 a liquid at 100 atmospheres and 50 C.
And then on release of pressure turns to snow and takes the dirt, organics, everything away leaving the surface dry.
Mixed with Hydrogen peroxide and other chemical to increase effectiveness.
Can be used even with sensitive electronics. Was used to clean USB drives in testing and they functioned afterwards.
Surface is left with no trace of organics, not just with dead micro-organisms.
Another idea, this is an idea which I don't think anyone is working on as far as I know, but it seems to have potential. There are electronic circuits now designed to operate at up to 200°C . High-Temperature Electronics
There are other developments that should permit temperatures of 300°C . High-Temperature Electronics Operate at 300 degrees C | EE Times and Designing for extreme temperatures There’s an economic incentive for developing these electronics, as they are useful in oil wells and motor cars. It's back to the drawing board probably for a lot of the designs, to use chips and solders etc. that work up to high enough temperatures for 100% sterilization. But it seems like it may be possible! Thanks to Adeel Khan for the suggestion
Is this right? Is it possible to achieve 100% sterilization by heating electronics that’s capable of resisting temperatures of up to 300 C. I wonder if anyone working in the field of spacecraft sterilization has investigated this, either experimentally or in theory. Or is there some other way to achieve 100% sterile electronics.
If we could achieve that, we could send our probes right up to the liquid water, with no risk at all of contaminating the habitats with Earth life. Perhaps this might be easiest with tiny chipsats and such like, tiny rovers and landers that could be sterilized more easily in their entirety.
A human crash on Mars putting debris all over the planet would introduce Earth microbes and has to be avoided. A crash like this would surely mean an end to planetary protection of Mars. We don't yet have the technology to build 100% reliable spacecraft, and even a 1 in a 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 optimal way to do it for planetary protection is to send robots, either controlled from Earth or from Mars orbit.
"Ten Reasons Not To Live On Mars, Great Place To Explore" - On The Space Show
Space Habitats For Colonists - And Contamination Free Boots On Mars - With Telerobotic Avatars
Would Microbes From This Astronaut Make It Impossible For Anyone To Terraform Mars - Ever?
Telerobotic Avatars On Mars With Super-Powers ("Teleporting" from orbit) - Search For Life - And Long Term Exploitation
Myth of automatic terraforming - many people seem to think that terraforming is easy - just introduce life to Mars and give it enough time and it will turn into a second version of Earth. I think the background to this is a kind of mythological version of the Gaia hypothesis - the idea that if you introduce life to any planet that has a capability for sustaining life, that it will automatically turn into a second Earth, almost like Earth. But a bit of reflection will show that this can’t be the case. Earth itself is going to become uninhabitable half a billion years from now, when it becomes too hot for anything except the most heat tolerant thermophiles
Grand Prismatic Spring, Yellowstone National Park, home to heat tolerant thermophiles. Eventually as the sun gets hotter, only heat tolerant thermophiles will survive on Earth - though that’s half a billion years into the future, long enough for humans to evolve a second time from the simplest of multicellular microscopic lifeforms.
Say we find some exoplanet that hot, then adding life to it will not turn it into a second Earth. It may have life already, but though habitable, it’s not very habitable. It’s even possible that Venus has life in its upper atmosphere. If so, this life has just lingered as the planet got hotter, and has not kept it habitable for less acid and heat tolerant lifeforms.
Just possibly there might be some biological way to do something about this to cool down that future Earth or exoplanet using microbes - but why would just adding a lot of microbes from present day Earth cool it down automatically? If it could sort itself out, it would have done it already. Mars may well have life already, and if so, it has not terraformed it, and why then would life from Earth terraform it if its own native life has not?
In the case of Mars, it probably started off nearly as habitable as Earth, but lost much of its atmosphere, and also got colder. Being further from the Sun, it never was warm enough for trees to grow, unless it had powerful greenhouse gases such as methane making up much of its atmosphere.
So, it may have habitats for cold tolerant microbes. They’d also be salt tolerant, able to withstand high levels of perchlorates and use them as food. But that doesn’t mean that if we seed it with extremophile photosynthetic life like Chroococcidiopsis that it will become habitable to Earth life. The first effect would be to cool it down even further as the microbes convert CO2 into oxygen so removing what little warming effect its atmosphere has. But probably there isn’t enough liquid water for enough of this microbe to grow to have a significant effect on its atmosphere. It may be there already indeed, as it is one of the few microbes that might possibly both survive a trip to Mars on a meteorite lasting for a century or more and to find a habitat it can survive in once it is there.
If you could magically transfer Earth’s atmosphere and ecosystems to Mars, they wouldn’t survive long as it would be far too cold, with not even much by way of CO2 to warm up the planet. Longer term there’s no continental drift. The volcanoes are still active on geological timescales (we know this from new features in the caldera of the volcanoes formed in geologically recent time). However, there is so little activity there we haven’t yet spotted any volcanoes or heat spots on the entire planet, a planet with the same land area as Earth. This means that long term it will lose carbon into carbonate rocks, Perhaps this has happened already. There’s very little by way of CO2 in the form of dry ice on Mars. There may be enough to double its atmospheric pressure, it's not sure that there is enough to get to ten times its current pressure to start a runaway greenhouse effect.
And then CO2 is poisonous to humans. You couldn’t even survive in a CO2 atmosphere at Earth pressure with an oxygen supply, but would need a full closed system with both oxygen and nitrogen supplied to you, or you’d die of CO2 poisoning. Then you need nitrogen too. And if you sort all that out, you still have the temperature issue. Even with an Earth pressure atmosphere of CO2, Mars would be too cold for trees. Converting all that CO2 to organics (covering Mars with a thick layer of the organics taken out of the atmosphere) might take as long as 100,000 years by natural photosynthesis, and it would cool the atmosphere down even further.
Your microbes introduced by mistake could cause unintended effects. A secondary consumer introduced by mistake eats your algae. Methanogens produce methane you don't want, or methanotrophs eat it when you want it as a greenhouse gas. Maybe you want to increase oxygen levels but you introduced aerobes that eat the oxygen? Maybe you want to increase methane levels but you accidentally introduced methanotropes that eat it? Maybe you introduced secondary consumers that eat the algae that you want to use to introduce oxygen. Many things could go wrong as a result of microbes you introduced by mistake.
Or a simpler example from Cassie Conley, planetary protection officer for the USA, some microbes create calcite when exposed to water. After an accidental introduction you might find that all the underwater aquifers have got converted to cement.
Also, whatever you introduce is also going to evolve in the dramatically different environment of Mars and evolution of microbes can be rapid. So who knows what you might end up with? Maybe microbes that are a nuisance in the habitats or for humans in some way, after all they would be microbes that started off in human habitats and spread across Mars - extremophiles often retain capabilities to live in more hospitable surroundings so they would still probably have the capability to live in the human occupied habitats.
The strong Gaia hypothesis, has evolved and developed into a compelling myth, in science fiction at least. The idea is that if you just add a few microbes, transformation of the planet will just happen by itself with a bit of a helping hand from humans and that what you get will be a planet that is pleasant for humans to live in. But even for Earth, probably there was a large element of luck as well.The weak Gaia hypothesis is generally accepted that there are many cycles that help keep the Earth’s climate more or less in balance at present. But what about the evolution of photosynthetic life at just the right time to remove CO2 from the atmosphere when the Sun was warming up, to cool down Earth enough to compensate? How can that be due to Gaia? Surely it is just coincidence that this happened at just the right time, and if it happened later, the Earth would get far too hot, and if sooner, it would have got too cold for a while in the past. Either way, the Earth might easily have been uninhabitable for anything except microbial life for billions of years, and we would probably not have evolved.
But instead, we were lucky, it continued at more or less the right temperature, with a few hiccups, for billions of years. David Waltham in his “Lucky Planet” argues that this is to a large part coincidence, and I think there’s something in that myself.
The Gaia hypothesis explains many things but I don’t think it explains why oxygen producing CO2 removing life evolved at just the right time to cool down the Earth.
Adding life to a planet could push it in many different ways and there is no way of knowing if it would make it better or worse. The one thing it definitely does do though is to close off future options. After you've done that, you can never roll back, if you later find that one of the lifeforms you introduced is a major problem on the planet. Not with microbes. It is hard enough to roll back higher lifeforms like rabbits, cane toads, rats, Kudzu or Japanese knotweed. Even camels are a problem in Australia since the continent is so huge. How could you roll back a problem microbe from a planet as large as the land area of Earth?
What will you do if you have introduced some problem microbe? Maybe you want to increase oxygen levels but you introduced aerobes that eat the oxygen? Maybe you want to increase methane levels but you accidentally introduced methanotrophs that eat it? Maybe you introduced secondary consumers that eat the algae that you want to use to introduce oxygen. Many things could go wrong as a result of microbes you introduced by mistake.
As one simple example of how microbes introduced by mistake could mess things up quickly, some bacteria convert water to calcite, and if you introduce them by mistake, you might find that these microbes have converted all the underwater aquifers to cement. That's an example from Cassie Conley, current planetary protection officer for the USA - she is a microbiologist / astrobiologist.
I think this is based originally on Lovelock’s Gaia hypothesis in its strong form, the idea that life makes planets more habitable for itself. The weak Gaia hypothesis that the Earth has many systems that work together to help keep it in a habitable state, mediated by life, is widely accepted. But the idea that such a system arises automatically on all terrestrial planets with life is not at all universally accepted. That’s the “strong Gaia hypothesis”. Some things about our own planet are puzzling, for instance, why did photosynthetic life evolve at just the right time to turn a CO2 into oxygen, to cool our planet to keep it habitable, instead of arising too soon, to make it too cold, or too late, leaving it too hot? Then in science fiction the strong Gaia hypothesis has been exaggerated to mythology, the idea that introducing life to a planet not only helps keep it habitable for that life, but that it also automatically makes it habitable for humans too. Why?
Most habitable Gaia for Mars would have a methane atmosphere or some stronger greenhouse gas
The way to make Mars the most habitable it could be for life would be for methanogens to evolve to convert all the atmosphere to methane, which is a strong greenhouse gas. That would make Mars nearly as warm as it could be, using natural methods, though if the strong Gaia hypothesis was true, then surely also the life would evolve to generate stronger and stronger greenhouse gases on Mars to keep it warm. That would make it more habitable, but not an environment humans could live in.
I think few would subscribe to such a strong version of the Gaia hypothesis. But the idea that life would automatically make Mars Earth-like is even more absurd than that one, I think. Microbes and "Gaia" know nothing about humans, it's not teleological. Why would all planets evolve to an oxygen atmosphere, even at the distance of Mars where oxygen makes the planet colder?
With this background, then Earth life to Mars would probably do nothing to make it more habitable, not without some long term plan, mega engineering, and careful selection of which lifeforms to introduce when. You can't just leave it "up to Gaia" to do it for you. And it would probably need artificial greenhouse gases or large planet scale mirrors or both to remain warm enough long term. In a thousands of years project that then goes on and on, trillions of dollars a year keeping it habitable.
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 long megatechnology project. Suppose it is possible, how sure can we be that we will continue such a project, when it is likely to cost billions, or even trillions of dollars a year and need support from Earth for thousands of years?
The Mars trilogy is science fiction, with the calculations fudged using poetic license, for the sake of a good story, to make the events happen within a few generations. The optimistic real world estimate from the Mars Society takes a thousand years to a stage where trees can grow but with no animals or birds yet, and humans need aqualung like closed system breathing kits to get around. Even that optimistic scenario is based on assumptions about the amount of dry ice on Mars which are not yet confirmed, and doubts have been cast about how much dry ice still remains there.
Then, as well as that, do we have the scientific understanding needed for it? We have never terraformed a planet, and with all our technology on Earth, we find it hard to just keep the CO2 levels on Earth from rising by tens of parts per million. Our attempt at making a much smaller ecological closed system of many species with Biosphere II failed, due to interactions with the concrete. What interactions with the surface of Mars might cause surprises in a terraforming project there? Would Mars unterraform as easily as it terraformed or go to some undesirable end state. Is terraforming Mars possible at all?
What about accidental planet transformations, for instance lifeforms that remove oxygen when we meant to encourage the ones that create it, produce methane or carbon dioxide instead. Or vice versa, organisms that remove greenhouse gases like methane or carbon dioxide when we meant to increase them? They may change the climate and in unexpected ways. And Mars gets much less light than Earth, so an Earth atmosphere would not be warm enough for without planet scale thin film space mirrors to double the amount of light reaching Mars, or industrial levels of production of artificial greenhouse gases, with many nuclear power stations to supply power, and cubic kilometers of fluorite ore mined per century to make the gases.
Then, whether it is practical or not, it's a project we are doing not for ourselves but for our descendants at least a thousand years from now. Will they be pleased that we started the project so soon and made Mars just as they wanted it, or will they be frustrated by our failed projects, and lament the pristine Mars they would wish to be able to study and possibly transform for themselves in a different direction?
At our stage, as a young technological civilization, I think the priority is to look at the situation with open eyes, before we close off possible futures that we maybe don't understand the potential of yet. Attempting to terraform a planet is bound to close off futures, taking the planet into new states that may be impossible to reverse from, especially if those new states include introducing new life forms or new lifeforms evolving there.
While creating new space habitats and exploring biologically closed systems in those is opening futures rather than closing them. So I think that's the better way to go. In terms or habitable area, space habitats have got more potential actually, as we saw, asteroid resources could create a habitable area a thousand times the land area of Earth. Then, you can complete a Stanford torus on a timescale of decades, not thousands or hundreds of thousands of years. It's rather like terraforming, but on a very small scale, an experiment that's within our capabilities and on a timescale that we can manage.
The things we learn by doing that could help us to avoid some of the pitfalls, if we ever decide the time has come to do a much larger planet transforming project. If a Stanford Torus atmosphere goes bad, or some nasty lifeform takes it over, becomes a pest and you can't do anything, or some microbe becomes a nuisance, or if things get out of balance - you can at the worst vent the atmosphere, sterilize the soil, and start again. So it is biologically reversible. Biological mistakes can be solved. Or if there's an excess of methane, or hydrogen sulfide or some other gas in the atmosphere, well the entire atmosphere of the habitat is small enough so you can scrub the problem gas out of it.
Or if there is something fundamentally wrong with the whole design and approach, you can try a new approach with a different space habitat with a different design. If for instance some of the materials that make up your habitat react with the atmosphere in adverse ways (like the concrete in the Biosphere 2 reacting in a way that indirectly removed oxygen from the habitat), you can even build a habitat mark II using different materials. All these are things that would be very hard to impossible to fix for a planet. So it makes sense at our stage to start with the smaller biospheres of a space habitat in free space, or a city dome on the Moon, or a biosphere in lunar caves.
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Paraterraforming - covering the planet and developing a habitable environment within that covering - a simple way to do this is to cover the planet, or parts of it, with greenhouses, probably using hydroponics or aeroponics. This is much faster than terraforming. You could complete a large habitat on the scale of a domed city in a time period of years or decades perhaps, and it surely doesn't need the thousands of years timescale for terraforming.
There are two ways of doing hydroponics, with or without microbes. If you supply the nutrients chemically, and introduce higher organisms only, then it might not be an issue for planetary protection. But if you introduce micro-organisms - then though you may only intend to paraterraform, it might be impossible to do that without introducing life to the planet as well, unless you can be very sure that the microbes you introduce can't possibly survive outside the habitats.
With sterile hydroponics, controlled from orbit, it's potentially biologically safe for Mars, if done with great care. But there's still a question of whether that's the best way ahead. Once it becomes large scale, it's transforming Mars, warming up the surface, releasing carbon dioxide, melting water. Since we know so little about Mars, and about how planets can change, I think it could well be questionable, in the sense there could be unexpected consequences of doing it, if done too soon. But it would avoid contaminating Mars irreversibly with Earth life.
My main question here would be, why do it on Mars? Especially, why start on Mars? Paraterraforming also works on the Moon, at least up to whatever number of people can be supported by the water ice there. Which if Paul Spudis is right, amounts to resources enough for many millions of people. And it's closer to Earth and an easier place to start. Also, I think the logical limit of paraterraforming is to go to the asteroids and use the same techniques to turn asteroid material into habitats, because there's much more space there than on planetary surfaces. Of course not living on the asteroids, and I think hollowing out asteroids is an unlikely way ahead myself too, rather, using the materials to make Stanford Torus etc. type habitats with artificial gravity.
If you are not terraforming a planet, but rather, creating enclosed biologically closed systems, then doing it in space gives you much more flexibility. You can move to wherever the level of sunlight is optimal, or wherever it is best to build a base for technological or scientific reasons, and establish whatever gravity level is optimal inside the habitat.
On the other hand, a habitat made of asteroid material or made on the Moon would need an input of volatiles to compensate for losses of water and air into space. Venus habitats floating in the upper atmosphere could extract water and nitrogen and other materials from the atmosphere. On Mars, you could use its thin atmosphere as a source for water vapour too, and nitrogen, and also use its ice deposits.
However, if we get to a future with a million people on the Moon, surely it would be vitally important to reduce losses of water. A 1 kg loss per person per day would be a thousand tons lost per day. That could be reduced to almost zero by living in the lunar caves, and using ionic fluids based liquid airlocks, or other techniques to make sure that almost no water or air is lost when you go in and out, and much improved recycling. I expect similar methods would be used on Stanford Torus type habitats as well. Then, in that future with millions in space, there would be the technology to supply water ice from the asteroids.
I think we can meet this issue when we come to it. At early stages, of Antarctic base type settlements of a few hundred people, it's not going to be an issue. Even at a loss of one kilogram per person per day, then the 600 million tons would last a thousand people for 1.64 million years. It would last a million people for 1.64 thousand years. And by the time we have an easy way to get a million people on the Moon, we have probably found easy ways to send large quantities of water from Earth into space too, reached the point where it is as easy to get into space as it is to travel to another continent in an airplane today.
Paraterraforming is certainly a much faster and easier way ahead than terraforming. I think it's well worth looking into, but I think that the Moon has many advantages as a place to get started with the approach, and can't really see any reason to rush to try it on Mars at an early stage. Maybe later on, depending on discoveries and technology changes.
Introducing life to Mars as a result of a human crash or landing is likely to be biologically irreversible. As a result, the situation is asymmetrical.
If you hold off from landing humans on Mars to protect it from our microbial hitchhikers while you study it carefully for science and to learn about exobiology and the origins of life, you still have the option to introduce Earth life in the future at any time.
But if you introduce Earth life to Mars right away in a biologically irreversible fashion, then for all future time, you never have any chance of studying Mars without Earth life on it. For the scientists, it might then become a race to try to find and study habitats on Mars before Earth life got to them through spores transported via the dust storms. 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.
If there is no life there. Mars is still of interest as a planet without life. Indeed it would be of a fair bit of interest to study what happens on a planet like Earth without life, especially if it has complex organics, and habitats for life but with no life in them - what happens in those situations, and why didn't life evolve there? We might learn a lot about exoplanets and the origins of life.
It's the same also with terraforming. Life introduced to Mars by mistake could send it on unexpected paths and interfere with your intended end state. E.g. methanogens producing methane which you might not want, or it might be you want the methane but methanotrophs eat it, or aerobes consuming the oxygen, or primary consumers eating algae that you are trying to use to transform the planet etc. etc.
So again 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.
It seems a situation where we need to think about future consequences quite carefully before we act. Otherwise we may find we close off valuable potential futures before we know that they are possible.
Perhaps we can send humans to Mars in a biologically reversible way - but if so - with this vision - we need to be really sure that it is reversible
The only way I can see to do this in the near future, that could be given some reasonable guarantee of planetary protection, would be to use a metal sphere - that enters the Mars atmosphere at a shallow angle, so slows down to terminal velocity before hitting, with a human being inside. Then even if all systems fail, it would hit the surface at at most a few hundred miles per hour - in that case the human would not survive, but perhaps a sphere could be guaranteed to remain intact, or at least, not breached, after a crash on the surface?
Hollow spheres (rocket parts) that re-enter the much thicker Earth atmosphere survive intact to the surface. This hydrazine propellant tank from a rocket:
survives to the surface looking like this
If all goes well, the human would land on Mars and then could be lifted off again - but of course can never leave the sphere or even look outside directly (as it is opaque), so I'm not sure if this would be thought worth doing.
Another suggestion is to send humans to Olympus Mons.
Olympus Mons Caldera Region This might be the area on Mars most biologically isolated from the rest of Mars of anywhere, due to the thin air, high altitude, and the caldera walls. But it is a difficult place to land technically, and also - would even this be a biologically reversible place for a human base on Mars? The idea is that it is so high above the surface that the air is very thin and there is almost no dust. This was suggested as a planetary protection measure in an article in The Space Review. It's a major challenge to do this with present day technology though, see Rob Manning's talk on the Space Show. In the space settlement article, they are suggesting a future with new technology with human bases already on Deimos. Some of the technologies Rob Manning mentions could be relevant such as deployable extending heat shields, or using larger parachutes than any of the ones tested supersonically to date.
In any case, there's the same problem as with other human landings - we are unlikely to have 100% reliable landing systems. Even with your target the caldera at the summit of Olympus Mons, a failure during approach to Mars, entry, descent or landing could easily land you somewhere else. And would a human party - say inside the Olympus Mons caldera - really be biologically insulated from the rest of Mars? Also after a crash there? And would such a landing be biologically reversible in the future, if we need to remove the spores from Mars?
Yes, if there is anywhere on Mars, where humans can land in a biologically reversible way - or at least in a way that keeps the landing site separate from the rest of Mars, with only one area is contaminated - then this might be it.
I think though, it would take a lot of research to be sure of this. If not biologically reversible, you have the possibility of an "oops" moment where you realize you have introduced Earth life to Mars, can't remove it, and have found a lifeform there you want to preserve or a biology such as ancient RNA based life, and can't do anything to prevent its eventual extinction.
We can do a lot more in situ exploration of Mars from Earth with more bandwidth. The main bottleneck at present is not the light speed time delay, but the bandwidth. If we could communicate back and forth every 40 minutes, decreasing sometimes to 8 minutes, we could do a lot more, much more quickly than in the present situation where we communicate back and forth every day. We could probably complete Opportunity's ten year mission in a matter of months. Perhaps even faster with rovers with more autonomy and use of artificial real time (a technique from computer gaming that builds up a model of the landscape on Earth, and then you drive around and explore the virtual model at the same time the rover explores it on Mars, with warning colours to indicate regions that are imperfectly modeled).
The search for life on Mars is best done in situ, at present, and a sample return probably won't help. It is more practical, and you can study many different regions at different depths anywhere in the rover's exploration region, which could span many kilometers, 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. NASA's cache of samples from its 2020 Curiosity C mission, if we manage to return them to Earth, is likely to be no more informative for the detection of present day or past life on Mars than the Mars meteorites we already have (though it would surely help with the other goals of the mission). I know that's a controversial thing to say, but let's look at the reasoning behind it:
Mars has organics from meteorites which are easily confused with life unless we have in situ life detection. The organics that Curiosity found so far are thought to be from meteorites. As a result, early sample returns are unlikely to contain present day life unless it is already identified as life in situ, or unless life is very abundant on Mars.
The situation is similar for past life because of the difficulty of preservation in Mars conditions, with surface radiation which removes organics completely over a billions of years timescale. There is an excellent possibility of interesting fossil organics from early Mars in ideal conditions in which the material is rich in life based organics originally, is buried quickly to depths of ten meters or more, is preserved from leaching by flooding, and is returned to the surface rapidly soon before discovery (or recovered by drilling). But it seems likely that it will take in situ life detection searches to find these organics, and to distinguish them from the meteorite organics.
As eight exobiologists wrote in in a white paper submitted to the 2012 decadal survey,
"In the worst scenario, we would mortgage the exploration program to return an arbitrary sample that proves to be as ambiguous with respect to the search for life as ALH84001."
Colonization enthusiasts often cite the "Safe on Mars" report as a reason to get a sample from Mars as soon as possible, to prove that any life there is safe for humans. But actually, if you re-read it carefully, "Safe on Mars" recommends in situ exploration as the best way to find out about Mars and prove that it is safe for humans. It only recommends a sample return because it concluded that the technology of the day was not good enough for an in situ search.
"As stated above, there are currently no measurement techniques or capabilities available for such in situ testing. 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)
More than ten years later, we can now miniaturize many of the machines that required entire labs back then to small chips and machines that require minimal power and weigh hardly anything. These include DNA sequencers, electron microscopes, ultra sensitive biosignature detectors able to detect a single amino acid in a sample, and updated versions of the Viking Labeled release using chirality to eliminate false positives. Our instruments also include the exquisitely sensitive electrophoresis "lab on a chip" methods mentioned by Bada et al. Another new idea is the Solid3 approach of using polyclonal antibodies - which can detect, not just the organics you find in Earth life, but a wide range of organics, again with exquisite sensitivity. This also is a "lab on a chip".
Mars has also turned out to be much more complex on its surface than was realized ten years ago, with many seasonal and daily surface processes, with some of them now confirmed to involve salty but potentially habitable liquid water. So the situation has changed hugely since "Safe on Mars" was published in 2002. With our current understanding, a sample return can at best just prove that there are some rocks on Mars that are safe for humans. I think the authors of "Safe on Mars" would surely recommend in situ searches, if it was written again from scratch today.
Returning exobiology in a sample return is one of the few things we could do that could potentially make us extinct or severely reduce future human life prospects on Earth. It has similar risks to creating artificial lifeforms in a laboratory. It is also potentially tremendously positive, especially if we do find some other form of life on Mars or in the Europa oceans etc., but we do have to take care. This is not something we"know how to do" as we have never had to return biology from another planet before.
It seems easy when you first think about it, but when you look at it in more detail there is much more involved than you might think, and the expert studies of this topic by the ESF and NRC conclude that methods used to contain DNA based life in biohazard level 4 laboratories can't be guaranteed to work for all possible forms of non terrestrial biology. For instance, they concluded that cells based on another biology may be smaller even than ultramicrobacteria, impossible to see except with an electron microscope, only 50 nanometers across or less. You also have the unusual requirement to exclude all Earth biology and organics from the sample requiring a double wall technology never used before.
The main problem here is the need to contain any conceivable exobiology when we have no empirical data to work on except Earth biology. It would be much easier to contain a known exobiology once we have a chance to study it for a while. For instance, if Mars only had early life, made extinct on Earth by DNA, then after some careful study, we might decide there is no way it could survive on Earth and it might not need any special precautions at all to return it.
Other forms of exobiology might need elaborate precautions, or we might decide it is simpler to just return the Mars samples to telerobotic facilities above GEO. Bear in mind, that by the time we can do a sample return, it is probably going to be easy to send hundreds of tons to above GEO, also that our telerobotic capabilities which are already impressive will be advanced much further by then, that one of the ways to return it to Earth involves a rendezvous spacecraft anyway, that we can return sterilized material right away from GEO if we do it this way, and that if we become totally sure it is safe to return unsterilized samples, we can still do so after examining it in orbit first telerobotically.
The key, I think, is to study it in situ on Mars first. Which is also what some exobiologists recommend as the best and fastest way to discover either past or present life on Mars and find out the most we can about it most quickly in the initial stages of the direct search for exobiology on Mars. Then if necessary we can return it to above GEO, and then study it more closely, while returning sterilized parts of it to Earth right away - and then finally if all is well, return it to Earth.
See my
Broadband communication would need to be set up to send humans to Mars. Why not prioritize this, and use it for our robots first, and see what we can do with robots with broadband to Mars?
Humans don't have special advantages for Mars surface missions. A robot can sit in one place for years if needed, with only a trickle of sunlight. Robots can explore caves and cliffs far too dangerous for humans. Small robots can be made light enough to fly in the near vacuum atmosphere of Mars. Humans in spacesuits are clumsy, and it takes a long time to put them on, and humans are much more vulnerable to danger in a spacesuit.
Sometimes you get the argument that humans are needed to drill, which is especially important for the search for past life, as well as any present day life that may live deep underground in geological hot spots, or kilometers below the surface, or beneath ice sheets. However, in Mars conditions, robots can drill as easily as humans in spacesuits, and probably more so. During the Apollo missions the astronauts had a lot of trouble drilling by hand for just two meters, sometimes falling over. So humans have problems too. The Insight lander will drill to five meters using a self hammering robotic drill. Most of the drilling is into regolith for the first few meters. The regolith thickness varies, here is an estimate for the site of the Insight lander - they estimate that ~90% of the Insight landing region is covered by a regolith that is at least ~2 to 3 m thick. ... and that the regolith is 5 to 6 m thick over ~50% of the region. Honeybee robotic are working on a drill that will be able to drill through gypsum and hard ice to a depth of hundreds of meters. I'm sure they'll progress to harder rocks later on. The drills have to be reliable as of course they can't be repaired if they fail. That's true also if you send humans there.
Humans have great advantages for on the spot decision making, fine control and creative approaches to problems - but this can be done from orbit, more safely.
Soaring, Buzzing, Floating, Hopping, Crawling And Inflatable Mars Rovers - Suggestions For UAE Mars Lander
Methods designed for human missions to the surface can be used for our robots also, so that they can travel faster, and explore more in each day. We can generate fuel in situ using hydrogen feedstock from Earth just as for human mission proposals. Or we can use solar power and batteries, adapting the Mars One idea to spread a large area of thin film solar photovoltaics over the Mars surface for power. The Apollo lunar roving vehicle had a rated top speed of 8 km / hour (though it could go faster), weighed 210 kg, for the entire vehicle, and had a range of 92 km, nearly twice the total distance Opportunity covered in ten years. So it's not lack of power that limits our rovers - they could go much faster, and further, if there was the need to design them to do so.
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 that you can experience the surface with bright colours as if lit by a midday sun on Earth, even colour corrected to a blue sky if you like.
Exploring Mars By Telepresence From Orbit Or Phobos And Deimos
Further into the future, what about habitable planets around other stars? There are no habitable planets in our solar system outside of Earth and I think it is not at all clear that Mars can be terraformed for humans, as I said, and anyway is that the best thing to do with the only Mars like planet in our solar system? But there may be easily habitable planets around other stars, and some very closely resembling Earth. So - what about that future? If we find planets like that, could we colonize them? And if so, should we, and is it wise to do so?
I'll look into this for the next few sections, but these are issues we are not likely to encounter for decades. It's a look at our long term future perspectives. If you want to skip this discussion for now, go ahead to 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.
This is amongst the most earthlike planets found around other stars to date. Though there are surely many more to discover and we know very little about the ones we found so far. As he said in that video, there may be 60 near Earth twins orbiting the 600 stars within 30 light years of Earth. But at the moment they are hard to spot and it’s even harder to tell how closely they resemble Earth.
Here are some of our best candidates to date:
See also: The 'Most Earthlike' Planets We've Found So Far Are Not Very Earthlike
What happens though if some day we get the ability to colonize some of these places - perhaps these, or other very habitable planets - should we?
First, if it has indigenous life, then this is not Star Trek :). It's very unlikely we can eat it, it's not likely to be biologically compatible as food and may well be poisonous too, except for some simple ingredients like water, some alcohols, some salts, and some sugars, see my
So should we destroy the indigenous life on an exoplanet, in order to set up home there and to be able to grow crops? That's got obvious ethical and practical issues.
But apart from those sorts of considerations, for instance, if it is a lifeless planet, but easily terraformed, in a long term stable way, or that for some reason Earth crops can be grown there without problems, should we set up home around another star then? You might well think the answer is an obvious Yes, but in a moment we'll see why it's not quite as simple as that.
Or colonize our entire solar system In the near future, not quite now, we may also find the ability to create habitats really easily in space. Let's try to look ahead a few decades.
Right now, it might cost up to a trillion dollars to make our first Stanford Torus (as we saw in: As a young technological society, our priority should be to protect and sustain the Earth ). This might be worthwhile if it’s useful for asteroid mining, or solar power, or some such, and is easy to maintain. Then, if the company or country that built the habitat was able to earn, say, a trillion dollars every decade or two in profit, then every few decades they could build a new one. That’s the idea behind the original Stanford Torus proposal. Perhaps each of those habitats then builds a new one every few decades. Perhaps also we find ways to automate the process using 3D printers, and more and more of the materials sourced in space, and the prices go way down, and the habitats get built more quickly? It could take off in a big way very quickly if that happened.
Soon also, we may have easy fusion power, even perhaps small scale plants like the Polywell, which would be about three meters across if it works well, the same size as one of these jet engines
- and producing about the same amount of power but using hardly any fuel.
There are many other ideas for small scale nuclear power plants. Whether any of them works, who knows, but some time or another we are likely to get nuclear power, even if it is only a big skyscraper like plant like the ITER. With those, we’d have almost limitless power available anywhere where there is fuel, which might be as simple as just hydrogen or water.
With power sources like that, and with large space habitats much easier to build than they are now, we could set up home anywhere in the solar system relatively easily, and there might be no obstacles to colonizing our solar system right out to the very distant Oort cloud that extends most of the way to the nearest stars. Eventually the entire Oort cloud might fill with colonists. Indeed if it was an exponential process, this might happen as soon as a few centuries into the future, that the entire Oort cloud fills with habitats.
This shows the Oort cloud. If we have easy nuclear fusion power in the future, we could set up home on any of the objects in this cloud which is thought to extend much of the way to the nearest stars and partly mingle with other stars' Oort clouds.
Once we do that, then there is not much to stop the expanding population of humans from filling the entire galaxy by stepping from one Oort cloud to another, from one star system to another. We wouldn’t even need to do decades long interstellar journeys but just hop from one icy body to another setting up habitats in space, throughout the galaxy.
They could then fill our galaxy in the not so distant future. A long time perhaps in human lifetimes, but compared to geological time, just a blink of time. Probably in less than a million years.
Crossing over to other galaxies is quite a challenge - but the space between galaxies is not devoid of material. There are stars in between and gas clouds also, and with the technology we’d have by then we’d probably be able to move planets with fusion suns, at close to the speed of light, a bit like the Puppeteers in the Larry Niven novels. There are parts of the universe disappearing beyond the speed of light horizon under its expansion, so without warp drive it would be limited, but we could spread to millions of light years, eventually billions of light years in every direction. If we set it off here, without foresight and planning, that’s surely the inevitable outcome.
Is this a rosy future? It may seem a rosy outlook at first, for those who are keen to colonize space. It looks as if there will be nothing to stop us starting a process that will end up by filling the entire galaxy with our species, and even much of the local area of our universe, as soon as we manage to achieve a few technological breakthroughs. We might be able to start on this within a century - and indeed do it in such a way that the result is irreversible. Short of warp drive technology, it's hard to see how anyone could stop it once you have colonies light years away skipping from one Oort cloud to another through the galaxy.
But I think we need to do something about our destructive ways, whatever future we go into. The ability to colonize an entire solar system right out to its Oort clouds, or even a galaxy won't miraculously turn us into a peaceful species. Indeed, our destructive tendencies will be magnified in their effect, written large across an entire galaxy.
You need to think about not just our “good guys” colonizing space, whoever you think those are - maybe Star Trek heroes for instance (though the Russians might have other ideas and the Chinese other ideas again) - but instead of any of those, think about the North Koreans, or the likes of our worst terrorists. ISIS for instance. They also surely will get into space in that future, or whatever the future equivalent of them is will arise in space. So you need to start with our worst terrorists and regimes of the present day, then imagine them with almost unlimited power, and future technology such as the ability to make self replicating machines, cyborgs, “uplifted” creatures of any sort with human intelligence, etc. This is surely what we would get if we just rush into space as we are now, with no political and human developments towards some more peaceful future.
If we expand into our galaxy with those capabilities, with no planning or foresight, it would actually favour the most aggressive of our descendants or perhaps their even more aggressive evolving intelligent creations. The most aggressive and risk taking ones would fill more star systems more quickly, and would surely have a good chance to win in an exponential growth through the galaxy. They might not be so good at creating long term stable societies, but with the sort of technology we are imaging here, they don't need to.
Also it will favour those able to replicate quickly. The “winners” of this race of a highly technological species into an uncolonized galaxy might reach maturity within a decade, or even less, just a few years between generations. The ones that become mature sooner can increase their population more rapidly and so fill more star systems more quickly too. Those would surely be the ones that win the race to fill the galaxy, and then they would come back at some point to take over Earth too, chances are.
That’s not such a rosy future. So, I think any far sighted civilization would look at that, and decide that we need foresight and planning. Maybe it would happen like that, maybe it wouldn't, but it doesn't seem wise to just "roll the dice" as it were to see what happens. We are not slaves to evolution. We are intelligent beings and we often look at the consequences of our actions in ways that animals can’t do. And we make many decisions based on that foresight.
Setting up new colonies “beyond the horizon” of your civilization without foresight about the possible effects would be seen like letting off a nuclear bomb in the middle of your home city. Something that no sane person, or being, would do.
I don't know what those decisions will be of course. But I think it's a reasonable guess that robotic exploration of the galaxy will play a large part, in the early stages at least.
Why robots are far safer for the first stages of galactic exploration. Yes, as many have said, robots that are self replicating and evolve are a major issue. We have to be careful if we fill it with them too, but as we've just seen, it's also an issue whether the self replicators are robots, or humans, cyborgs, uplifted animals, artificial lifeforms, or extra terrestrials.
I think that at least some of the "great filters" of the Fermi paradox are ahead of us - but that they are not necessarily self destruction though. Rather, I think that when the time comes, unless we are very reckless, we will decide of our own volition not to colonize the entire galaxy right away - or at least, not to do it in an uncontrolled evolving exponential expansion kind of a way. I think also that any sensible ET would do the same.
The reason would be the same as their reason for not filling the galaxy with self replicating evolving robots, which I think just about everyone who has thought about this would say is a bad idea. With evolving robots the issue is that since you don't know what they would evolve into. they could come back and destroy you, or they could just turn the entire galaxy into paperclips, depending how narrowly the original evolving robot was programmed.
That's the whimsical paperclip maximizer or we could call it the "paperclip event horizon" :). It goes back to a paper by Nick Bostrom where he imagines those robots as super intelligent, with all their intelligence narrowly focused on the task set for them by their creators of optimizing the number of paperclips they can make or find. But it could also happen even if they don't develop any intelligence, but are just evolving to become supremely good at making everything into paperclips. The problem with that is that with their narrow focus, they would turn our spaceships, planets, even ourselves into paperclips too. Not out of any malice, but just because they were built to maximize the number of paperclips and are remaining faithful to their original design.
Well if we fill the galaxy with humans, they could do the same thing, either a misguided paperclip manufacturer a thousand light years away sets loose self replicating robots that turn the galaxy into paperclips - or they themselves evolve into creatures that have strange philosophies, war like perhaps, fast reproduction rate, descendants of humans themselves that have evolved to be as bad as the worst of the robotic beserkers of science fiction. If robots can evolve into beserkers like that, why not humans also?
I think that in an uncontrolled expansion into the galaxy, it's not the "good guys" that would win but the most rapidly reproducing, most aggressive guys, because they would conquer the most solar systems and expand most rapidly. That doesn't seem like a good future scenario to aim for.
Paradoxically perhaps, I think self replicating robots are far safer for us and the galaxy than humans, because they can be controlled and made safe in ways that are impossible for humans.
This is for much the same reason as sending microbes to uninhabited planets. It's an irreversible thing. As soon as the first space colonies get set up beyond the light speed horizons, out of communication with Earth, then there is no way of reversing this. We'd better be very sure that this is the way we want to go before doing that.
So the robots, paradoxically, are safer for the galaxy, just because we can, ethically, make them completely safe by design. They can be mass produced with identical copies sent to many destinations which can't replicate. Alternatively, we can make self replicating machines, designed with many replication safety restrictions so that they can't be a nuisance to the galaxy (e.g. telomere style maximum number of generations, and a "keep alive" signal from Earth so that they stop functioning and self destruct if they no longer get it).
If there are any wise ETIs, they must find some solution that doesn't involve them or their robots trashing the galaxy. And we must do that too. So whatever filters are behind us, this is a clear filter in front of us, seems to me. The careful robots approach is one way they and we might do it. This is surely one of the safest ways to start galactic exploration, and may explain why we don't find our solar system and the rest of the galaxy already filled to the brim with ETs. They may make similar decisions for the same reasons.
Will our civilization become an ineradicable dangerous weed or a beautiful flower in the galaxy?
The anthropologist Mary Dora Russell says:
'Anthropologists used to say that Homo sapiens was a unique and special species because we were the only ones who used tools, or who were self-aware, or had language, or passed culture to our offspring… Then we started finding out that chimps and dolphins and crows and African grey parrots and snow monkeys were making a mockery of our pretensions to uniqueness, so we’ve kind of shut up about all that in recent years.
If you want a nice reductive definition of our species, I could defend this: “Human beings are bipedal tailless primates who tell stories.”
That’s probably just as stupid as earlier definitions, but it’s catchier than my other version, which is
“Human beings are a dangerous, invasive weed species that has invented central heating, air conditioning, and food that can be stored for up to ten years, so not even a direct hit by an asteroid would likely make us extinct.”'
When nothing else matters, by Mary Dora Russell
I think that’s rather how I see the future of us in the galaxy if we just expand into it without foresight. But far worse than a weed on Earth. We’ve unnaturally made ourselves almost impossible to go extinct already by our technology and if we expand through the universe without evolving social breakthroughs of some sort, to catch up with our technology breakthroughs, I think we’ll become the ineradicable weed of the galaxy. But harmful to ourselves as much as to everyone else, and able to create even more dangerous replicators through our technology.
It's not just us. Our galaxy may well contain many non technological species, for instance intelligent fish-like or octopus-like creatures, living in the oceans of icy moons, or ocean planets, where they have no chance to develop control of fire. Or creatures that are just not very strong, and don't have good "hands" like us for manipulation, like parrots or crows. Even an elephant would have a lot of trouble building a fire and smelting metal. Ancient civilizations, perhaps advanced in mathematics, art, poetry, music, perhaps socially very advanced, yet without technology they would be especially vulnerable to a new technological species spreading out of control like an ineradicable weed through the galaxy. Out of all the intelligent creatures on Earth, I think only humans also had a decent chance of developing technology based on fire, even with intelligence. So if that's a good basis for generalizing, then the non technological civilizations universe wide may well outnumber the technological ones many to one. So, even a billions of years old civilization could still be highly vulnerable to a few centuries old civilization of technological ETs such as ourselves, could be.
I think any sensible ET will look at that possible future for themselves and the galaxy, and find a way to become a flower of the galaxy instead of a weed that will eventually choke all the species in the galaxy, including themselves. If they can’t see a way to a future like that, then if they have any sense, they just stay at home until they can. And if they haven’t the sense to do that, I think, perhaps, that they either make themselves extinct, or they keep destroying their own spaceflight capabilities, and get nowhere, until they develop some sense.
We don't need to be a civilization of puffy clouds and rainbows :).
Circumhorizontal arc, in cirrus behind cumulus, photographed in Idaho, June 3, 2006, by Gavin Anderson
Surely amongst the many ETIs (if we do have neighbours) there will be those that are competitive, as with the Olympic games, innovative, eccentric, genius. But we need to find a way to embrace the good sides of those qualities, that which also works in the universe we live in without being a nuisance to ourselves and the other species we share our galaxy and universe with.
Let’s be one of the civilizations in our galaxy and universe that flowers like a beautiful flower.
Or a field of flowers
Or we might even give rise to many flowering human originated civilizations each unique in its way, and all sufficiently in harmony with our galaxy or universe not to be a nuisance to each other or other ancient civilizations in our galaxy.
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. The universe is not set up in such a way as to make it impossible for us to make mistakes. So we need to think things through in space, and consider the long term future consequences of our actions.
There may be many other solutions apart from the safe robots approach. For instance very long lived ETIs could simply explore the galaxy in person, crisscrossing it many times in an individual lifetime. Or perhaps they find a way to colonize the galaxy, but in small numbers, only a few of the many stars, and never more than a few ETIs to a solar system, or a few thousand, or a few million. Or maybe they find some solution we can't imagine yet.
If typically beings had lifetimes, say, of a billion years, you could easily go from one side to the other of the galaxy a thousand times at a tenth of the speed of light. If you suppose also an ultra stable society - somehow they have dealt with all the issues we have - then - I could imagine it being possible that they become a galaxy spanning or even universe spanning stable civilization. There might not be many beings in the galaxy in this civilization. The galaxy has a hundred billion stars, very approximately, more than ten times the number of humans on the Earth.
With billion year lives, our future descendants might be altogether happy with a few hundred billion humans in total in the entire galaxy - especially if we find it has other inhabitants in it also. Say average of one or two humans per star, but of course concentrated in some places, or maybe traveling or exploring the galaxy? If so that might be why we haven't seen ETs yet, because though they are there and are maybe quite widespread through the galaxy, we are due a visit some time in the next million years or so, which to them seems a short time, just a thousandth of their lifespan perhaps, and nearest ones, maybe a small settlement a few tens of light years away. I think that's one possible scenario.
What I am pretty sure of is that any sensible ETI with foresight would not choose to fill the galaxy with unrestricted, evolving self replicating copies of themselves, disappearing beyond the light speed horizon to evolve or to create self replicating machines or modified lifeforms that could turn into almost anything imaginable or unimaginable. Before they do that, if they have any sense, they think through the long term consequences of their actions first, and find a way to do it safely for themselves and for the galaxy.
I think also that the best way to get to a galaxy spanning civilization in the Kardashev scale if we decide we want to, is to go through the earlier stages first. That you can't suddenly jump to a galaxy spanning civilization simply by scattershot sending colonies throughout the galaxy, self replicating robots, cyborgs, uplifted species etc. It might eventually use much of the energy available in the galaxy - but it wouldn't be a galactic civilization; it would just be galactic chaos. I wouldn't call that anything like Kardashev level 3. You probably need something like the Star Trek warp drive, or immensely long lives at the least, or some other galactic unifying element, to have a galaxy spanning civilization.
So, first, before we even become solar system spanning in a true way, we need to be established in our own home planet, as the most hospitable place for humans. If we can do that, then we are established here for at least hundreds of millions of years into the future. If we can't, especially if we destroy our home world in some way or make it uninhabitable, I don't think we have a chance of getting any further, myself.
Then if we have the capability to make efficient use of our sun, that's stage 2 of the Kardashev scale, At that point you are not likely to disappear even when the sun goes red giant and then collapses to a white dwarf - if worst happens you just migrate to a nearby star with that level of technology.
Perhaps it's only when you are at that level and also developed either immensely long lives or warp drive or something of that order, that you are at the point where there is some possibility of going galaxy wide in a way that is safe for yourself and other beings in our galaxy.
There's no hurry here though. Perhaps at least for billions of years the most important thing is just to make sure Earth is safe. We can explore the galaxy with robots. Even without going as far as stage I of theKardashev scale, with millions of years of future technology development, we'd be able to do almost anything if we wanted to. You don't have to use all the energy from the sun even that arrives on Earth just because you are capable of doing so.
I think there may well be ETs who have the capability even to go right up to the galaxy wide stage 3 civilization using most of the energy from all the suns in an entire galaxy if they so wish, but just choose not to, for various reasons, and stay at an earlier stage, and they might be the wisest and most farseeing of all the ETs. They might be galactic explorers - but see no reason to remodel the galaxy just because it is something they know how to do. And even with a population of many trillions, they could still have minimal impact on the vast galaxy. That might well be through choice, not because they are unable to do it.
An exponential growth anyway can’t keep going indefinitely. It will hit a crunch at some point, indeed very quickly. Even just doubling every century, if we did that for ten thousand years we’d need to create a sun’s mass of humans every century to keep going with the exponential growth. At some point we have to stop exponential growth. Luckily we reached "Peak child" in 2005. The number of children in the world has remained steady for over a decade now. Our population will continue to increase rapidly for a while, because people world wide are living longer (on average). It seems at least possible that our population will level off naturally. Even the “middle of the road”projections now show the population leveling off by the end of the century.
Our galaxy could be home for trillions of ETs, and if they have found a solution to exponential growth, the nearest may be hundreds of light years away.
So we may encounter ETIs, but if so rather than living around every star they probably are quite small in number compared to the galaxy as a whole. There is plenty of room for trillions upon trillions of extra terrestrials in our galaxy and yet none within hundreds of light years, if they don’t engage in unrestricted exponential growth but somehow limit their growth - which they have to anyway to avoid what would surely be appalling suffering to have the alternative of constant exponential growth followed by population collapses within an entire galaxy.
We can be one of the wise ETs. I think, there is evidence that we may be wiser than the most reckless ETs possible, which might destroy themselves in space wars pretty much as soon as they begin on spaceflight. Carl Sagan refers to this as "the intrinsic instability of societies devoted to an aggressive galactic imperialism".
Though we have stumbled a lot, we have made many good decisions, such as dealing with the problems of DDT and CFCs, human rights (a lot of progress though much still to do), preventing chemical and biological warfare (even in the almost all out conflicts of WWII neither side used the chemical weapons of WWI, I know there have been exceptions but most wars don’t use them).
We've developed nuclear weapons, and yet, for decades we haven't used them. Indeed Carl Sagan suggests that maybe weapons of mass destruction are the deciding factor here. After talking about our own efforts to deal with nuclear bombs he then goes on:
"If every civilization that invents weapons of mass destruction must deal with comparable problems, then we have an additional principle of universal applicability. Weapons of mass destruction force upon every emerging society a behavioural discontinuity: if they are not aggressive they probably would not have developed such weapons; if they do not quickly learn how to control that aggression they rapidly self destruct. Those civilizations devoted to territoriality and aggression and violent settlement of disputes do not long survive after the development of apocalyptic weapons. Long before they are able to make any significant colonization of the Milky Way, they are gone from the galactic stage. Civilizations that do not self-destruct are pre-adapted to live with other groups in mutual respect."
He goes on to say that because we have only just reached this stage then this future scenario of mutual respect may seem unlikely because of our short term perspective. He suggests that the required changes may take a thousand years or more, for us to reach maturity as a species. From Carl Sagan's "The Solipsist approach to Extraterrestrial Intelligence",
We’ve prevented starvation with the often forgotten Green Revolution between the 1930s and the 1960s, stopped nearly all whale hunting, done lots of work to preserve species and environments etc. If you compare our present world with what it could have been without all those initiatives - I think it gives room for optimism for the future too. And I think we’ve made an excellent start on peaceful use of space with the Outer Space Treaty.
Although it’s frustrating that we don’t have warp drives or even the Star Trek “Impulse drive”, and easy ways to build habitats in space, I actually think it helps, that space is so hostile. Hopefully by the time we figure out how to live sustainably in space habitats, we also have figured out how to do it peacefully, or reasonably so. With competition of course, but more like the Olympic Games than WWIII. Hopefully we can become more forward looking as we continue to colonize space. Perhaps the increased resources from space can help us to become more peaceful if we can handle it right.
If so we might well eventually have a chance to explore even our entire galaxy peacefully, and without harmful consequences to ourselves and other intelligent species that may exist in our galaxy. And if we meet ETs, the ones that still retain space technology, then they also I think would be ones that have figured out how to explore the galaxy in a similarly peaceful way.
I’m pretty sure there can’t be any aggressive exponentially expanding ET out there (such as we could become potentially) except by some amazing coincidence. That’s because unless they started on their expansion less than a million years ago, a tiny slice of the age of the galaxy, they would have occupied Earth and our solar system already, long before we evolved indeed, probably.
Any ET that managed to expand to a few star systems or to the Oort clouds, also I think can never stop expanding, short of warp drives. That's because if there are any of their species left anywhere in the galaxy that are expansionist, they will start up again, and take over from all the others that give up. How can that ever stop? Even if they started billions of years ago, they would still be at it, I think, even if most of them retreat into Dyson spheres or whatever it is they do, the few who don't would continue to expand through the galaxy.
So any "great filters" have to operate before any ETs out there start on any major push of galactic imperialism.
It's obviously not happened to our galaxy yet, as our solar system is pristine, with no extra terrestrial colonies or robot miners. We don't even have any tracks on Mars or the Moon, so they can't have been visited for millions of years (or the ETIs are very careful about clearing up their tracks when they leave).
I think the most likely reason is either
We are the first, so then it's our responsibility to make sure we take good care of our galaxy, leave it in a decent state for future generations and civilizations just as we would want earlier civilizations to leave it for us.
If so, we must be exceptionally far sighted and careful as our decisions can reshape the entire galaxy for ourselves and other intelligent creatures in the galaxy for all future time. If we get this wrong, we can turn it into a never ending chaos that no-one will ever be able to calm down.
Or if there are other technologically advanced ETs, they have all found some way to explore the galaxy without major impacts on it, and without doing this uncontrolled galaxy cramming exponential expansion, or else they just “stay at home”. And the reason for that would be because the far sighted ones show restraint, eventually, maybe only after centuries or millennia of social development, or maybe quite quickly. And the ones who can't do that simply never get that far.
Grand plans such as terraforming ideas, and ideas for ways that humans might be able to survive on Mars etc. are well worth studying. I'm not at all suggesting that we should stop studying such ideas. As we study how to terraform Mars, for instance, maybe we find a way to terraform the planet easily, and gradually gather the technology and knowledge to do it safely in a way that will keep it terraformed for billions of years into the future. Or maybe we don't. But either way, we find out more about how planets work, learn about other potential futures for Mars, may learn things that help with studies of exoplanets, get a better understanding how Earth works, and it may have many other benefits.
And whether or not they are eventually used for humans on Mars, all these studies could have many other spin off benefits. Studies for in situ resource utilization on Mars for humans could be directly useful for robotic exploration, e.g. to help robots to travel faster, return materials to orbit and so on. Studies for ways to grow plants on Mars could be used for sterile hydroponics, which might even in the future be useful for astronauts in orbit around the planet - plants can be grown safely on Mars in principle without any planetary protection issues as seeds can be sterilized. And many of those ideas can be applied directly to other places, with no planetary protection issues, such as the Moon, asteroid belt, or even Jupiter's outer moon Callisto orbiting outside its harmful radiation zone (which is currently thought to not need planetary protection, as though it has a deep subsurface ocean, there is thought to be no communication with the surface).
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".
And they should be reversible until we know better. We should avoid actions that could transform planets, or even the whole galaxy, in an irreversible way, until we have had a chance to do that long term thinking. And when we don't know, in something potentially as large in its implications as this, I think it would be irresponsible to just "throw the dice" and see what happens.
If we show that it can be done on the Moon, this will actually help human exploration of the rest of the solar system, not hinder it. The amount we spend on human spaceflight is actually tiny when you work it out per person. The ISS cost a little over $8 per year per person for the US, and the ESA estimates its contribution as one euro for the entire project - less than the price of a single cup of coffee per person.
For more on this see Is the International Space Station the Most Expensive Single Item Ever Built? (I argue that it probably is, but that's because it is built by a larger population. Per capita it is comparable to earlier mega projects).
Saying that we have to choose between sending humans to the Moon, or to Mars or Jupiter or Venus or Mercury or the asteroid belt is a bit like saying we have to choose between sending satellites to LEO or GEO. It's a false dilemma. We send satellites to both, and can do so because everyone can see the value of both to Earth. Once people see the value of human exploration, the finance will be easy to find. It will be easier and safer to demonstrate the value of humans in space on the Moon and in the Earth Moon system first.
In this vision we continue with robotic exploration of the solar system, and send humans to other places once it is safe and worthwhile to do so.
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.
In the process we can discover what role humans have in space alongside the robots that are already exploring the solar system as our remote sense organs in space. We can also get some ground truth about how much contamination human missions cause in a pristine extraterrestrial environment where it doesn't matter so much, as there are hardly any global processes to move the materials around the surface (justelectrostatic dust levitation).
The few square kilometers around our first base on the Moon might get so contaminated with Earth organics that it is hard to study the faint traces of lunar organics in the regolith. That seems likely from the experience of the lunar sample studies (as we saw above with the analysis of the Apollo samples). Well it doesn't matter on the Moon, as there's always another cleaner square kilometer further away. There's no risk at all that our microbes could grow exponentially and colonize some habitat or other on the Moon, as far as we know. They would just lie where they fell, except maybe for the levitating dust.
We can also develop the technologies needed to permit safe deep space missions and appropriate and safe space settlement in the solar system. These settlements would surely continue to be more like an Antarctic base than a pioneer's log cabin in the near future.
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