Mars is not a habitable planet for humans at present. It would be far far easier to live in Antarctica or on the summit of Mount Everest, or the heart of the Gobi desert. We don't have the technology yet to live in such places in a self sustaining way also making all our own machinery and needing to import nothing at all form the rest of the Earth. Too cold even for Eskimos to live there. And then on Mars you have to make all your own oxygen, grow your plants only in greenhouses, you can't go outside except in clumsy pressurized suits that are like mini spaceships currently cost about $2 million to make.
Some enthusiasts think that with a thousand year project we could make Mars more or less habitable for trees, and eventually even have an oxygen rich atmosphere.
But if that's possible it's a major mega engineering project, obviously longer term than any major technological project we have ever attempted before by an order of magnitude or more, more expensive every year than anything we have ever attempted, including the ISS, again by an order of magnitude or more, and I'm skeptical that it is possible at all.
If we moved Earth's entire ecosystem, atmosphere, etc to Mars, it wouldn't work. It wouldn't be warm enough. Even a pure CO2 atmosphere is too cold for Mars, not warm enough for trees to grow there. And CO2 is poisonous to humans above 1% concentration. Perhaps it had stronger greenhouse gases like methane to keep it warm enough to explain the clear evidence of ancient oceans and river beds.
At any rate the analogy of discovering a new continent on the Earth I think leads to the idea that Mars is far more habitable than it is. Even on Earth, discovering a new continent doesn't automatically mean we colonize it. When we discovered Antarctica, it attracted explorers and scientists, but nobody had any thought of trying to colonize it, as far as I know. Mars is like that.
It would be fine to let the Mars enthusiasts just try colonizing it, when everyone else thinks they will fail, let them try to prove us wrong. Take huge risks like base jumping. But there are a couple of problems with that.
First, the problem of contaminating Mars with Earth life. Though conditions there are so extreme now nevertheless, they aren't so extreme as to make life impossible. We even have quite a long list of Earth microbes that might be able to live on Mars. So we sterilize our robotic spacecraft for Mars to levels that would be impossible to achieve with a human mission. And in the worst case a human mission would have a percentage risk of a hard landing, I think everyone agrees. Could be 50%, could be 1%, there's bound to be some risk of a hard landing in a first ever human landing on Mars. Many of the robotic landings have failed and with Curiosity, they genuinely didn't know it would succeed. Even with Curiosity's successor - a successful landing doesn't guarantee that next time it will work for sure using the same system. It's a good chance it will succeed, but a proven system can still fail from time to time as we found with the Space Shuttle.
So, you could try to land a biohazard laboratory on Mars, inside out, with all the microbes associated with humans as the biohazard to keep away from Mars -some seem to think that much could be possible mainly because of the very harsh conditions over much of Mars so long as you keep humans away from areas where life on Mars is possible. It's a major challenge - especially because of the Martian dust storms and the atmosphere -so not like the Moon where contamination at one site would not risk contaminating the whole of the Moon - on Mars a microbe imbedded in a dust grain could be spread to anywhere on the planet in the dust storms, protected from UV light by the iron oxides in the grains of dust. But some seem to think that's possible.
But what if you have a hard landing? How could that, the human bodies and habitat contents strewn across Mars, and potentially anywhere on the planet, e.g. happened due to the insertion burn going wrong - how could that keep Mars protected from Earth Microbes?
If we land on Mars and find life there, only to discover life we brought there ourselves, it would be the worst possible anticlimax of all our searches for life there.
The far most interesting situation is one where Mars has its own native life of some form. And then we'd want to keep Earth life well away from it. At least to start with until we understand what is there and how it interacts with Earth life, both ways. And Mars is so large, so varied in landscape, it will probably take decades or longer to get a first idea of what is there.
Then the other problem is that this idea of Mars as a backup could, maybe already, is distracting away from the need to protect Earth. If people have in mind the idea that we could back up Earth to Mars maybe they might take risks, one in a billion type risks, with Earth, that they wouldn't otherwise.
But Mars is a great place to explore. If we treat it more like Antarctica, as an inhospitable but very interesting place, I think that is more realistic in the near future. As for more distant future, well if we do do space colonization, I think the Moon is the obvious starting point or habitats made using materials from the Moon or the asteroid built in free space perhaps in orbit around Earth. But I think they will depend on Earth to a large extent for the foreseeable near future, because it is so much easier to live on Earth. You can't beat an atmosphere you can breath, ground you can grow crops in without greenhouses that have to contain tons per square meter outwards pressure (in free space or on Mars), ability to work out of doors without a pressure suit, natural protection from cosmic radiation etc.
I think if some day we can build domed cities or Stanford Torus type habitats in space - and if those large habitats can be made either self maintaining or very easy to maintain -then internally they could be as easy to live in as on the Earth. But that is likely to be some way into the future. Right now they would be possible perhaps, though you need to find out for sure by building larger and larger closed system habitats and even the ISS is nowhere near closed system - but so expensive to build in the first place, and probably quite expensive to maintain - so I think likely to need support from Earth continuously - need to have some strong economic incentive for building them in space. If so, then surely compared to the population of Earth, only a small but maybe eventually significant number in space.
And I think that is just as well, because if some day we have millions, or even billions of people in space - that includes hundreds, thousands, maybe even millions who may be political extremists of one kind or another, or even just individuals with strange anti-social agendas, and give them space technology, spacecraft traveling at kilometers per second, and it could be quite dangerous. So I think that's a future not to rush into as fast as possible. Taking scientific exploration as a starting point seems a good idea to me. And for commercial exploitation, including space mining - it might well be of great future benefit to the Earth, but still, it could be destabilizing also. So I think it needs to be regulated like all the other forms of exploitation we have on Earth.
But in the case of Mars it is hard to see how it could be supported by any commercial exports from Mars to Earth in the near term future because it is deep within a gravity well, it could never compete in prices with, say, Near Earth Asteroid mining. It would be all one way, pouring billions of dollars into Mars, with no return except this idea of Mars as a "backup" and it seems at least possible it would actually be harmful to scientific exploration of Mars, and doesn't seem likely that it would lead to a self sustaining society in the near future to me.
With scientific exploration as your reason for being there, you could explore it from orbit, using virtual reality technology. From orbit, Deimos or Phobos. With care those might be places you can visit without risk of contaminating too much. Though even on a vacuum covered cratered landscape humans might be quite polluting. I think it is best to start on the Moon and see how easy it is to explore that with humans, and whether it's possible to do so in a way that doesn't mean the humans get in the way of he science, and see the effect of a long term base on the Moon first. And from that we can get an idea of how easy it is to explore with humans there directly.
A spacecraft in orbit around Mars seems the safest first step. Controlling robots on the surface via telepresence. Get it to Mars using a technology that doesn't risk impact into Mars of a human occupied spacecraft -there's a method called "Ballistic transfer" where you can get down to Mars orbit using only an ion thruster without need for a one off rapid burn which is risky for planetary protection in a human occupied ship.
I think that's the safest first human mission to Mars. It's a challenge, even that, but far safer than a surface mission. The saving of mass over a surface mission can be used to help protect from cosmic radiation and to provide backup spacecraft to make it all told far safer for humans than a surface mission. And avoids the "seven minutes of terror" landing. We could then take it from there, maybe go to Phobos or Deimos depending on both robotic discoveries on those planets and our experience of landing humans on the Moon. They both have many advantages over bases on the surface of Mars.
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
Trouble With Terraforming Mars
Why Nukes Can't Terraform Mars - Pack Less Punch Than A Comet Collision
Also my book: OK to Touch Mars? Europa? Enceladus? Or a Tale of Missteps?
About the Author
