Monday 19 February 2018

Colonising Mars

SpaceX are almost certain to be successful in their aim with the BFR to make travel to Mars at a cost that some people will be interested in taking up, albeit the target timeline looks optimistic, visit SpaceX - Mars for more information on their plans.  Around $200,000 seems to be the eventual target being talked about.  Surviving on Mars however is difficult and most people say it would be way to expensive and risky to do so anytime soon.  Personally I disagree with the pessimism and have included the way I think we can do it in this post.

To colonise Mars we are going to have to be extremely efficient so don’t be assuming we would do everything as we would on Earth at present.  Food brought from Earth for example will be dried, given about 2000 calories per day you are probably looking at around 500g or 183kg per year.  We will be aiming to grow food on Mars but whilst plants are an hell of a lot more efficient then animals they aren’t the most efficient way, single cell organisms are likely to be a lot more efficient as a source of food with the advantage that they could also be used as a source for manufacturing, oil for bioplastics for example as well as medicines.  There is a TED talk for using single celled organisms for food at A forgotten Space Age technology could change how we grow food we will probably grow vegetables as well, probably hydroponically, another TED talk at This computer will grow your food in the future shows the type of technology we may use and allows for much denser growth that conventional farming, growing on the surface under cover is likely to be used primarily for trees.

With regard to were we will live, probably the best place initially is underground, a primary reason I believe Musk probably started the Boring company and wants to make smaller tunnels which may allow for smaller machines that could fit in the BFR, a 6m diameter for example should allow for decent sized rooms, 4m would probably be tolerable to the type of people that would initially go to Mars especially since length could be as long as you wanted.  Reinforcement will probably be using regolith mixed with a polymer, probably made using oils from single cell organisms eventually although a polymer from Earth may be brought to Mars initially, a small manufacturing plant would probably build these for the boring machine to install.  Living space could be made on the surface as well using a similar regolith/polymer mix but tunnels are likely to be easier, surface building will probably need to have pretty thick walls or extra shielding added, TED has an interesting talk on building potential homes at Adventures of an interplanetary architect

Few people will be interested in spending most of their life underground so there will probably be structures on the surface pretty quickly, using clear glass or plastics  to provide a view since there would be little benefit to structures aimed at human use above ground with no view or sunlight than there would be from the tunnels, this is likely to be more a recreational area with trees, probably a pool and sports facilities.

Most spare parts will probably be 3d printed on Mars itself, complex stuff that is small such as processors etc will be brought from Earth, it’s also likely that some modern stuff that is too complex to be made on Mars and too bulky to be worth sending from Earth will instead be replaced with modified versions of older technology that can be built on Mars, whilst not as powerful as what we would use on Earth the ability to be able to make it on Mars will make it a better option than trying to import from Earth.

Solar power is unlikely to be reliable enough on Mars to be the primary power source, as such it is pretty likely that something else will provide at least the minimum amount needed to sustain the colony.  It is highly unlikely that hydrocarbons exist in any significant quantity, small amounts of methane have been detected so technically there are hydrocarbons.  The atmospheric pressure is insufficient for windpower to be viable which leaves nuclear and geothermal as the only realistic options.

A small nuclear reactor or possibly RTG from Earth will probably be the primary source initially, see Nuclear power in space for some things we might look at providing but we will want to use Mars resources as much as possible for future power.  Drilling kms into the ground for geothermal energy is unlikely to be a viable option early on given the restrictions on cargo size that can be flown so base power is probably likely to be some of the simpler modern nuclear designs although if a geothermal source can be found close to the surface that may be viable.  Based on what I've read on energy production a molten salt reactor seems to provide the easiest nuclear design using technology we know will work.  There are some organisations working on small fission such as Lockheed Martin Compact Fusion Reactor and General Fusion but I've not read anything to suggest they are likely to be a viable source any time soon, fission always seems to be a decade or two away, it seems more theoretical at present that eventual designs will work efficiently.

Another point I've seen mentioned is that Mars won't be able to pay for any resources it needs to import from Earth and therefore won't be viable without massive subsidies that Earth is unlikely to give.  With regard to that point I would mention the following.  

There will be people that produce intellectual property that can be sent to Earth wirelessly such as scientists doing research, software developers developing software, Artists producing Music, films etc etc which could provide a Mars export that doesn't require finding physical stuff to export to Earth that is likely to be needed on Mars anyway.  There are likely to be people going to Mars that have businesses on Earth that could fund them, if Musk moves to Mars for example then his businesses will still be running on Earth, producing money he can use to purchase resources to send to Mars.  Most people going to Mars permanently are likely to sell up everything they have on Earth and use the money to invest in Mars so there will be companies based on Mars that produce stuff on Mars and that never has to leave Mars.  They can sell those products to people moving to Mars from Earth and use the Earth based income to purchase any resources they need from Earth needed to produce those items.  Basically no physical products necessarily have to be created on Mars and exported to Earth for a colony to be potentially viable although if it does turn out there is something on Mars that Earth would like to have and Mars either doesn't or has a surplus of then that would certainly be beneficial in helping Mars to increase its imports.

Basically Adam sells everything he has for say $500k, he buys a ticket from SpaceX for $200k, maybe purchases a property on Mars from MartianHomes.com for $200k and leave $100k in his Earth based bank account or exchanges it for Martian currency from InterstellerCurrency.com.  MartianHomes.com needs some Machinery from Earth, costing say $1m so uses the income from selling 6 homes to purchase it and send it to Mars.  There are no cows on Mars and MartianPizza.com needs cheese, he only has martian dollars however so he exchanges then for Earth dollars at InterstellarCurrency.com so he can purchase cheese from Earth and have it flown to Mars.  InterstellarCurrency.com needs martian currency to sell to Earthling emigrating to Mars so is quite willing to sell Earth Dollars in exchange for Martian dollars.

Another point I’ve seen mentioned is gravity, the likelihood is that we can survive on 37% gravity, yes we will probably lose bone and muscle mass due to the lower gravity, primarily because the body doesn’t need it and so recycles it. The same thing happens if you just lie in bed permanently, you build muscle mass if you excercise and lose it if you stop, various excercise regimes in space help to combat it to some degree so it would seem less likely to be something intrinsic to lack of gravity rather than the body recycling mass it doesn’t need in an attempt to be more efficient. Certainly there is some degree of risk but anyone wishing to go to Mars is going to be accepting of that anyway.

The longest consecutive spaceflight was done by Valeri Polyakov, who spent nearly 438 days on the former Russian Mir space station. And Gennady Padalka, who recentlystayed on the ISS with Kelly, has spent a combined 878 days in space. (Taken from google search, initial source theverge.com)

The risk of a 2 year stay on Mars being fatal to those coming back to Earth is almost certainly negligible, there is probably more chance of them dying by being hit by a meteorite. As such we should be able to safely get information on how gravity on Mars will affect humans, if it looks like staying another two years would be risky then the option is there to abort. Almost certainly though any loss will stabilise and could probably be made to stabilse at a better value by say wearing clothing that has weight distributed around it, put enough weight in and you might actually gain mass, especially that that you lost during the zero g journey to Mars. It would probably make sense for at least the first few people to use extra weight to ensure that the loss does stabilise, if it doesn’t then it will be important to abort, if it does stabilise then the weight can gradually be reduced to see what the effect is. Certainly for the first few ships of colonists there will need to be enough ships left on Mars in order to be able to return all colonists if something unexpected happens but I would almost certainly expect much smaller numbers initially going to Mars, it seems Musk wants to allow 100+ to be in each ship, I suspect the first transport will probably only have around 20, the next round will probably only be half full.

Yes the above on the effects of gravity is speculative, we can't know for sure until we have been but it seems reasonable to me based on everything I've read and I've certainly not read anything to remotely suggest a 2 year stay on Mars is remotely likely to be fatal.

Long term Mars will need to be terraformed if we want it too have millions rather than thousands of people, from what I've read it seems feasible, especially once we have a decent sized colony on Mars that could do most of the manufacturing needed, I'll probably do a detailed post on terraforming Mars at some point but reading Terraforming of Mars might give some idea of what is likely to be involved.

As a final note, I would like to point out that anyone that seriously wants to colonise Mars considers it a backup for Earth if something catastrophic happens such as an asteroid strike, and most would certainly encourage the fight against global warming, the only people who argue that we want to colonise Mars is because we think humanity is going to screw up Earth itself are presumably scientifically illiterate or deliberately misleading, presumably because they think the money involved would be better spent on Earth although the technology required to transport humans to Earth will make it far more likely we could protect Earth from an asteroid than what we currently have.  Humanity could burn every fossil fuel on Earth (co2 has been over 10 times higher in the past so a runaway on the level of Venus seems incredibly unlikely), detonate every nuclear weapon we have and Earth will still be easier to survive on and fix than Mars.  Sure it will devastate Earth, probably killing 99% of multicellular species if we did it quick enough, will probably only support maybe a million humans in underground bunkers using similar survival technology to what Mars will require but it would still be easier to fix than starting out on Mars will be, it is likely to take hundreds of years, quite possibly thousands to be able to terraform Mars to the point we can survive outdoors with just an oxygen mask and warm clothing and probably an extra thousand to have enough oxygen to drop the oxygen mask although hopefully improvements in our knowledge will speed that up.

This is an initial version of the post, I'll probably look for some better links to add and probably incorporate any useful information that any commentators might provide.

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