Well the Moon is also interesting. It's of special interest to us because it is so close to Earth and because a collision of a Mars sized body with proto Earth is thought to have formed both Earth and the Moon. And we still don't know that much about it considering how close it is to Earth. The astronaut missions were not especially focused on science, the science was more of an add on. They returned many rocks, but only in the last mission were the rocks selected by a geologist on site.
And just explored a tiny area of the Moon - which also has caves, probably ice at its poles, many things of interest. It must also have meteorites from early Earth - the problem will be finding them - but - they may tell us a lot to help fill in gaps in our understanding of evolution of life on Earth.
Mars is of special interest because it was similar to Earth in the early solar system - with an ocean and a thick atmosphere. Life might have evolved independently on Mars. If so - it might have a completely different biochemical basis from Earth life. We could learn so much from that.
It might also have life there still. Very hard place to find life - you can't spot it from orbit. Ancient life would get destroyed by the cosmic radiation which is amazingly damaging long term. A million tons of amino acids would get reduced to just atoms over a period of three billion years (a trillion fold reduction for every extra billion years).
So it's going to be hard to find traces of ancient life on Mars. And also hard to find traces of present day life - but there may well be present day life there also - increasing evidence of possibility of liquid water even on the surface.
It's not much use for colonization though. Not really. Because it's got almost no atmosphere left, no seas, lakes or rivers, no trees, no plants, no animals or fish, no oxygen, lighter gravity, no magnetic field, no continental drift. And not just no water - it's also dry, in the equatorial regions - like the Sahara desert (despite recent reports that there is water trapped in the sand - the amount of water though surprising for Mars is about the same as the amount of water in the sands of the Sahara desert by percentage). And dried out far below the surface in the warmer equatorial regions.
Very cold - no warming atmosphere, and half the sunlight of Earth because it is further away. Cold enough for dry ice to form naturally. Humans couldn't survive the temperatures there at night without heating.
But the atmosphere is an almost vacuum also - pressure is a tenth of the Armstrong limit - the point at which your saliva and other bodily fluids exposed to the atmosphere would boil. Absolutely you'd die very quickly if exposed to the Mars atmosphere. On Earth it would count as a reasonably good laboratory vacuum.
That also means - that if you build there - you need to build to hold in the atmosphere - about as hard as building to contain a vacuum on the Earth. It has to withstand ten tons per square meter of outward force. Okay for very small things - but for the likes of greenhouses etc - no way you can set up a polytunnel or similar on Mars using the technology you can use on the Earth. You need some very strong, thick clear plastic - some plastic able to withstand tonnes of pressure per square meter - and all structures spherical or tubes with rounded ends - like the ISS.
And - make all your own oxygen, get the water from ice, need several meters of regolith covering your habitats to keep out the cosmic radiation - limit exposure to the surface (including in rovers or spacesuits) unless you want to increase your lifetime risk of cancer.
It's just not an ideal place to colonize. Where I live in the West coast in Scotland we have many uninhabitated islands - which are uninhabited mainly because they are inaccessible. I.e. because you need to go on a boat trip and hire a boat to get out there, or own a boat, and a trip of maybe a few hours to get there, and another few hours to get back.
With Mars - it's a six month journey to get there, which you can only do every two years. To a place with almost no atmosphere, and basically totally unlivable in except with high technology. These islands - they are absolute paradises by comparison. Some of them had people living in them until recently when they gave up because it was easier to live on the mainland or the larger islands with roads, a daily postal service, regular ferries, buses etc.
I can't see Mars colonization working myself, and don't see the point in it. Exploring the ideas fine, and who knows, maybe things will change in the future, but right now, I very much hope that they don't try.
Because it would lead to a lot of people dying, loss of hope, disillusionment with technology and space, probably means no true settlements either, calls to stop these dangerous space activities most likely.
The deaths here would be because it would be so easy to lose your life when surrounded by vacuum when just a fall and tear of your spacesuit or damaged faceplate would kill you, and because the landing on Mars with its thin atmosphere - not enough for a parachute, too much for a controlled descent like the Moon - is probably most hazardous in our solar system - and because of the supply issue that it can take over two years to get resupply of a vital component if something goes wrong, and communications issue of up to 40 minutes delay for each question when you try to communicate with experts on the Earth in an emergency.
But the worst thing about colonization is that it would introduce Earth life to Mars. Which you might think is great if you want to terraform Mras. But remember - it might very well have life there already. And Earth has gone through phases when it was a snowball Earth - it recovered because of the continental drift returning limestone to the atmosphere as CO2, the greenhouse gas, life by itself probably would not have been enough to let it recover. Mars as it is now, lost nearly all its early atmosphere and nearly all its early water - quite possibly shows us the end result of what happens if you seed Mars with life.
So just introducing life to Mars - not likely to make it habitable. Indeed - ideas for terraforming Mars - they take about 1000 years of high technology - greenhouse gas factories, mirrors in space to increase amount of sunlight etc - and that's to get to the point where you can grow trees, and your saliva etc won't boil so you don't need spacesuits any more - but people still have to use oxygen breathers, for many more millennia after that.
And that's the optimistic projection. The timescale in the Mars trilogy is massively speeded up, nobody suggests that as a possibility in real life. And there's a lot to go wrong.
So - I know that there is a strong message you read in the States - that we need to colonize Mars to save the Earth. But the reality, is really not like that at all. Hopefully people will see sense.
I can see a lot of value in space settlement. I.e. you are in space - not to colonize -but rather for similar reasons to Antarctica - because you have some other reason for being there. Could be scientific research, could be mining, could be tourists. But some good reason for being there.
But nobody would colonize a place like Mars on the Earth. We have many places far more hospitable that we don't colonize. Indeed very hard to find anywhere on the Earth that is as inhospitable as Mars. Though much of the surface of Earth and pretty much entire sea bed (shallow parts at least also far more hospitable than Mars) is uninhabited.
Mars though is a fascinating place to explore - it's got such varied geology - and possibility of finding past and present day life there also. And - ET microbes - you might not think they are that interesting - but try to imagine what it would be like to find - even microbes, or lichens - that are based on a different biochemistry from Earth.
True ETs, not evolved on the Earth? Not based on DNA. Or maybe they do share a history with Earth life - but - say - do photosynthesis differently - not using the green chorophyll and not in the same way as the red pigmented halobacteria, which is the only other way of doing photosynthesis we know of on Earth - what if they have some other method? Or some other way of generating energy that no microbe on Earth has yet explored?
The last thing we want to do is to go to Mars and discover life - but the life we discover is life that we brought there ourselves. So we have to be careful, shouldn't go all out and try to send humans to the surface.
We can send humans to the Moon. To asteroids. To comets even, to Mercury, many places in the solar system. Even to Titan potentially - it is far too cold for Earth life to survive.
But we shouldn't send humans to:
until we know for sure what is there - and whether or not we can send humans to these places without first contaminating them with Earth life - and then just discovering the life we brought to them.
We can however, with enough care, study them using sterilized rovers from the Earth - also robots controlled by telepresence from orbit, even from the Mars moons - so long as great care is taken to make sure that the humans can't crash land on the surface and so contaminate it.
That's my view anyway!
And - many don't know - but actually we have an international treaty, the Outer Space Treaty that protects these places from Earth life - and a body of scientists called COSPAR that meets every two years to work out the details of how to protect them, and the planetary protection office also in US, counterpart also in Europe - and any mission with robots to these places is sterilized to prevent it contaminating Mars.
Mars, Europa and Encladus are the three places in our solar system that these scientists identify as most in need of protection from Earth life.
They have identified a few other destinations as possibly needing protection, depending on research, for instance, is there any possibility for life on Ceres? Most think it unlikely but it hasn't yet been ruled out, some way that ice could melt perhaps and life form there on the surface or near it? We've had enough surprises so that we can't rule that out yet but most think it is ulikely.
Nobody knows what the situation will be for humans on Mars. The workshops so far all agree that it has to be protected, the question is, can humans land on the surface of Mars consistent with protecting it from Earth life? All the workshops so far concluded with the message that more information is needed.
The planetary protection office has said they think it will be possible. But they don't make the decisions here, they just implement the decisions made at a higher level.
I can't see them approving a human mission to the surface of Mars in the near future at least - because - how can it be safe for purposes of planetary protection, especially in case of a hard landing?
Unless you proved that the surface of Mars is totally sterile, that no Earth life can grow there. But we are far from being able to show that. Indeed there is evidence that there may be habitats on the surface of Mars, just top few cms, in places. At any rate will need to know a lot more about Mars before we can know either way, if there are potential habitats for Earth life there that could be contaminated by an expedition by humans from Earth.
The problem is that humans can't be sterilized. Plants can be, if we were like plants, growing from a seed, not needing anything else except nutrients - if you could grow humans in sterile hydroponics and have a sterile life support system - it would be no problem to land sterilized humans on Mars right away. But sadly, we can't be sterilized, we'd die if you tried.
You can find out more in my other answers here. And also - it's not going to help in event of natural disasters destroying parts of the Earth - because you'll always have survivors on Earth for any credible disaster. Even a giant asteroid - it would have some human survivors - at the very least - in submarines.
Tsunamis and firestorms are a surface phenomenon - and no giant meteorite since the first few hundred million years of the solar system, in the geological record, is anything like big enough to make entire surface of the Earth molten and boil the seas. Largest crater was made by a meterorite of up to 10 km in diameter - several orders of magnitude too small to make humans extinct. On an image of the entire Earth - even if blown up quite large - would be hard to spot something as small as 10 km across.
Same for the other possible threats. We don't need to escape Earth to avoid them. About the only thing that could make us extinct - would be something that is the result of our technology. But a space colony would be by far the most dependent on technology of any colony that has ever been in the history. Sort of like living permanently in a submarine, but far harder than that. If technology is the problem, then any issue would probably start in the space colonies as like as not.
So - I see Mars as a fascinating place to explore, can see space settlements eventually maybe throughout our solar system - but don't see space colonization in near future as at all likely. Rather the settlements if they are doing the likes of mining etc - would be doing it to help supply the Earth which is by far the easuest place to colonize in our entire solar system - by comparison nowhere else is even worth considering for a colony if you've got an option to build it on Earth - and can't see that changing any time soon.
See also, many other answers here - I'm in process of organizing them in lists to be easier to find:
Mars and Space by Robert Walker on Lists of My Answers
Also
And just explored a tiny area of the Moon - which also has caves, probably ice at its poles, many things of interest. It must also have meteorites from early Earth - the problem will be finding them - but - they may tell us a lot to help fill in gaps in our understanding of evolution of life on Earth.
Mars is of special interest because it was similar to Earth in the early solar system - with an ocean and a thick atmosphere. Life might have evolved independently on Mars. If so - it might have a completely different biochemical basis from Earth life. We could learn so much from that.
It might also have life there still. Very hard place to find life - you can't spot it from orbit. Ancient life would get destroyed by the cosmic radiation which is amazingly damaging long term. A million tons of amino acids would get reduced to just atoms over a period of three billion years (a trillion fold reduction for every extra billion years).
So it's going to be hard to find traces of ancient life on Mars. And also hard to find traces of present day life - but there may well be present day life there also - increasing evidence of possibility of liquid water even on the surface.
It's not much use for colonization though. Not really. Because it's got almost no atmosphere left, no seas, lakes or rivers, no trees, no plants, no animals or fish, no oxygen, lighter gravity, no magnetic field, no continental drift. And not just no water - it's also dry, in the equatorial regions - like the Sahara desert (despite recent reports that there is water trapped in the sand - the amount of water though surprising for Mars is about the same as the amount of water in the sands of the Sahara desert by percentage). And dried out far below the surface in the warmer equatorial regions.
Very cold - no warming atmosphere, and half the sunlight of Earth because it is further away. Cold enough for dry ice to form naturally. Humans couldn't survive the temperatures there at night without heating.
But the atmosphere is an almost vacuum also - pressure is a tenth of the Armstrong limit - the point at which your saliva and other bodily fluids exposed to the atmosphere would boil. Absolutely you'd die very quickly if exposed to the Mars atmosphere. On Earth it would count as a reasonably good laboratory vacuum.
That also means - that if you build there - you need to build to hold in the atmosphere - about as hard as building to contain a vacuum on the Earth. It has to withstand ten tons per square meter of outward force. Okay for very small things - but for the likes of greenhouses etc - no way you can set up a polytunnel or similar on Mars using the technology you can use on the Earth. You need some very strong, thick clear plastic - some plastic able to withstand tonnes of pressure per square meter - and all structures spherical or tubes with rounded ends - like the ISS.
And - make all your own oxygen, get the water from ice, need several meters of regolith covering your habitats to keep out the cosmic radiation - limit exposure to the surface (including in rovers or spacesuits) unless you want to increase your lifetime risk of cancer.
It's just not an ideal place to colonize. Where I live in the West coast in Scotland we have many uninhabitated islands - which are uninhabited mainly because they are inaccessible. I.e. because you need to go on a boat trip and hire a boat to get out there, or own a boat, and a trip of maybe a few hours to get there, and another few hours to get back.
With Mars - it's a six month journey to get there, which you can only do every two years. To a place with almost no atmosphere, and basically totally unlivable in except with high technology. These islands - they are absolute paradises by comparison. Some of them had people living in them until recently when they gave up because it was easier to live on the mainland or the larger islands with roads, a daily postal service, regular ferries, buses etc.
I can't see Mars colonization working myself, and don't see the point in it. Exploring the ideas fine, and who knows, maybe things will change in the future, but right now, I very much hope that they don't try.
Because it would lead to a lot of people dying, loss of hope, disillusionment with technology and space, probably means no true settlements either, calls to stop these dangerous space activities most likely.
The deaths here would be because it would be so easy to lose your life when surrounded by vacuum when just a fall and tear of your spacesuit or damaged faceplate would kill you, and because the landing on Mars with its thin atmosphere - not enough for a parachute, too much for a controlled descent like the Moon - is probably most hazardous in our solar system - and because of the supply issue that it can take over two years to get resupply of a vital component if something goes wrong, and communications issue of up to 40 minutes delay for each question when you try to communicate with experts on the Earth in an emergency.
But the worst thing about colonization is that it would introduce Earth life to Mars. Which you might think is great if you want to terraform Mras. But remember - it might very well have life there already. And Earth has gone through phases when it was a snowball Earth - it recovered because of the continental drift returning limestone to the atmosphere as CO2, the greenhouse gas, life by itself probably would not have been enough to let it recover. Mars as it is now, lost nearly all its early atmosphere and nearly all its early water - quite possibly shows us the end result of what happens if you seed Mars with life.
So just introducing life to Mars - not likely to make it habitable. Indeed - ideas for terraforming Mars - they take about 1000 years of high technology - greenhouse gas factories, mirrors in space to increase amount of sunlight etc - and that's to get to the point where you can grow trees, and your saliva etc won't boil so you don't need spacesuits any more - but people still have to use oxygen breathers, for many more millennia after that.
And that's the optimistic projection. The timescale in the Mars trilogy is massively speeded up, nobody suggests that as a possibility in real life. And there's a lot to go wrong.
So - I know that there is a strong message you read in the States - that we need to colonize Mars to save the Earth. But the reality, is really not like that at all. Hopefully people will see sense.
I can see a lot of value in space settlement. I.e. you are in space - not to colonize -but rather for similar reasons to Antarctica - because you have some other reason for being there. Could be scientific research, could be mining, could be tourists. But some good reason for being there.
But nobody would colonize a place like Mars on the Earth. We have many places far more hospitable that we don't colonize. Indeed very hard to find anywhere on the Earth that is as inhospitable as Mars. Though much of the surface of Earth and pretty much entire sea bed (shallow parts at least also far more hospitable than Mars) is uninhabited.
Mars though is a fascinating place to explore - it's got such varied geology - and possibility of finding past and present day life there also. And - ET microbes - you might not think they are that interesting - but try to imagine what it would be like to find - even microbes, or lichens - that are based on a different biochemistry from Earth.
True ETs, not evolved on the Earth? Not based on DNA. Or maybe they do share a history with Earth life - but - say - do photosynthesis differently - not using the green chorophyll and not in the same way as the red pigmented halobacteria, which is the only other way of doing photosynthesis we know of on Earth - what if they have some other method? Or some other way of generating energy that no microbe on Earth has yet explored?
The last thing we want to do is to go to Mars and discover life - but the life we discover is life that we brought there ourselves. So we have to be careful, shouldn't go all out and try to send humans to the surface.
We can send humans to the Moon. To asteroids. To comets even, to Mercury, many places in the solar system. Even to Titan potentially - it is far too cold for Earth life to survive.
But we shouldn't send humans to:
- Mars
- Europa
- Encladus
until we know for sure what is there - and whether or not we can send humans to these places without first contaminating them with Earth life - and then just discovering the life we brought to them.
We can however, with enough care, study them using sterilized rovers from the Earth - also robots controlled by telepresence from orbit, even from the Mars moons - so long as great care is taken to make sure that the humans can't crash land on the surface and so contaminate it.
That's my view anyway!
And - many don't know - but actually we have an international treaty, the Outer Space Treaty that protects these places from Earth life - and a body of scientists called COSPAR that meets every two years to work out the details of how to protect them, and the planetary protection office also in US, counterpart also in Europe - and any mission with robots to these places is sterilized to prevent it contaminating Mars.
Mars, Europa and Encladus are the three places in our solar system that these scientists identify as most in need of protection from Earth life.
They have identified a few other destinations as possibly needing protection, depending on research, for instance, is there any possibility for life on Ceres? Most think it unlikely but it hasn't yet been ruled out, some way that ice could melt perhaps and life form there on the surface or near it? We've had enough surprises so that we can't rule that out yet but most think it is ulikely.
Nobody knows what the situation will be for humans on Mars. The workshops so far all agree that it has to be protected, the question is, can humans land on the surface of Mars consistent with protecting it from Earth life? All the workshops so far concluded with the message that more information is needed.
The planetary protection office has said they think it will be possible. But they don't make the decisions here, they just implement the decisions made at a higher level.
I can't see them approving a human mission to the surface of Mars in the near future at least - because - how can it be safe for purposes of planetary protection, especially in case of a hard landing?
Unless you proved that the surface of Mars is totally sterile, that no Earth life can grow there. But we are far from being able to show that. Indeed there is evidence that there may be habitats on the surface of Mars, just top few cms, in places. At any rate will need to know a lot more about Mars before we can know either way, if there are potential habitats for Earth life there that could be contaminated by an expedition by humans from Earth.
The problem is that humans can't be sterilized. Plants can be, if we were like plants, growing from a seed, not needing anything else except nutrients - if you could grow humans in sterile hydroponics and have a sterile life support system - it would be no problem to land sterilized humans on Mars right away. But sadly, we can't be sterilized, we'd die if you tried.
You can find out more in my other answers here. And also - it's not going to help in event of natural disasters destroying parts of the Earth - because you'll always have survivors on Earth for any credible disaster. Even a giant asteroid - it would have some human survivors - at the very least - in submarines.
Tsunamis and firestorms are a surface phenomenon - and no giant meteorite since the first few hundred million years of the solar system, in the geological record, is anything like big enough to make entire surface of the Earth molten and boil the seas. Largest crater was made by a meterorite of up to 10 km in diameter - several orders of magnitude too small to make humans extinct. On an image of the entire Earth - even if blown up quite large - would be hard to spot something as small as 10 km across.
Same for the other possible threats. We don't need to escape Earth to avoid them. About the only thing that could make us extinct - would be something that is the result of our technology. But a space colony would be by far the most dependent on technology of any colony that has ever been in the history. Sort of like living permanently in a submarine, but far harder than that. If technology is the problem, then any issue would probably start in the space colonies as like as not.
So - I see Mars as a fascinating place to explore, can see space settlements eventually maybe throughout our solar system - but don't see space colonization in near future as at all likely. Rather the settlements if they are doing the likes of mining etc - would be doing it to help supply the Earth which is by far the easuest place to colonize in our entire solar system - by comparison nowhere else is even worth considering for a colony if you've got an option to build it on Earth - and can't see that changing any time soon.
See also, many other answers here - I'm in process of organizing them in lists to be easier to find:
Mars and Space by Robert Walker on Lists of My Answers
Also
- Why We Can't "Backup Earth" On Mars, The Moon, Or Anywhere Else In Our Solar System
- Ten Reasons NOT To Live On Mars - Great Place To Explore
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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