What about Oxygen?
Methane as fuel is all well and good, but without oxidizer it doesn't get you very far... How abundant and available is oxygen on Mars?
Elon Musk has published his blueprint for “Making Humans a Multi-Planetary Species” by establishing a self-sufficient city on Mars. Elon Musk Elon Musk's Mars colonisation plan in a nutshell Musk reckons humanity needs to get off-planet before an extinction event comes along and that Mars is the best candidate for that …
But long-term, there's even more locked up in rocks and minerals, not to mention ice deposits..
You can tell it's hot today. I read thas as iccream, rather than ice deposits. Of course, if there's iccream on Mars, then we probably don't need to send pizza, as they're bound to already have it.
In space, noone can hear your ice cream...
"- Sufficient, even in the atmosphere, to get things going on Mars,"
There are only trace amounts in the atmosphere. ( it's about 0.1% of an atmosphere that is already very low pressure (~0.6% cf. earth )) It would need to be generated from water or some other source.
@Chemist - - sure - but there's an awful lot of a very thin atmosphere, and the production of fuel from simulant Martian atmosphere has already been tested, and it worked well - see Zubrin's 'Case for Mars' for the full story (I only linked to the article I did as it was the first hit I found and appeared to be correct). If there's one thing that IMHO there is little doubt of regarding Zubrin's plan, it's that in situ fuel production is entirely possible. Indeed, NASA's revision of Zubrin's plans for getting us to Mars also included in-situ fuel production.
Don't forget, people, that in order to get oxygen from the atmosphere it doesn't have to be either molecular oxygen or ozone - it can be chemically bound, and the Martian atmosphere is mainly carbon dioxide, so you take some hydrogen to Mars, use it to produce methane using the carbon in the carbon dioxide, and use the byproduct oxygen as the oxidiser.
So, as I said - in order to get exploration going, there's more than enough in the Martian atmosphere for that. Long-term, though, you'd be wanting to use non-atmospheric sources. Seiously, the numbers have been checked thoroughly by experts in the field, and the processes tested. It's one of the things about potential Martian missions that we can be very sure about.
"the production of fuel from simulant Martian atmosphere has already been tested"
I've no problem with the possibility of obtaining fuel ( from CO2) from the atmosphere it's the extraction of oxygen from a very dilute mix of other gases that I suggest will be a very energy intensive process. Probably better to produce hydrogen & oxygen from any available water even though that will also be very energy consuming esp. to produce/store liquid oxygen
It is a little more complex than that. Storing hydrogen for long periods(the estimate is that we will need 40,000 m² of solar panels to supply fuel for one ITS ever 26 months) is harder practical for Mars missions. We want to add a couple more steps, compressing atmospheric CO2 then using the Sabatier reaction to make methane from the H2 and CO2, so we can vastly simplify the fuel storage system.
Just like on Earth, until we find better materials for storing hydrogen, hydrogen storage simply costs to much to make it effective as anything other than an intermediate step in a larger production process.
@Chemist - I thoroughly reccomend that you read the the literature on the subject, it's extremely interesting. The people who've already looked into it are qualified scientists, not wide-eyed amateurs guestimating numbers (which is what I would be, if I tried). In 'The Case for Mars' Zubrin goes into this in detail, pointing out various options,and how the exothermic reactions can be used to help drive some of the endothermic ones. Indeed he looks at the range of gases and metals and plastics that might be produced in situ and how the various setups to produce them could/would need to interlink for best effect.
I've seen many critiques of Zubrins notions for how best to explore Mars, mainly to do with radiation throughout the trip and perchlorites in the dust once at Mars (and personally, I think he underestimated the amount of living room required to keep people sane for such an extended trip). I've yet to see anyone say that he got his chemistry wrong.
To quote from the NASA refernce design for a Mars mission:
"220.127.116.11 In Situ Resource Production
The highly automated production of propellant from martian resources is another defining attribute of the Reference Mission. The technology for producing methane and liquid oxygen from the martian atmosphere and some nominal hydrogen feedstock from Earth is an effective performance enhancement and appears to be technologically feasible within the next few years.
The split mission strategy allows the propellant production capability to be emplaced, checked out, and operated to produce the required propellant prior to launching the crew from Earth. In addition to spacecraft propulsion, the production capability on Mars can provide fuel for surface transportation, reactants for fuel cells, and backup caches of consumables (water, oxygen, nitrogen, and argon) for the life support system."
And that is the most critical assesment of the issue that I've come across - NASA saying that they think it'll possible in a few years, as against Zubrin saying that it's all known technology and could be made right now. If you feel like telling NASA that their chemists don't know what they're talking about, I'd be most interested in the response!
I'm not saying the chemistry is wrong it's not. I'm questioning the overall efficiency when the supply of energy is going to be limited. Given it will have to be solar or nuclear to run this lot I question how much kit they'll need. The Sabatier reaction, to produce the methane itself is exothermic once initiated but extracting or concentrating the necessary oxygen and then liquifying it will require a lot of energy.
For example to produce 1kg of hydrogen gas by electrolysis will require ~~ 60kW.hrs in the process producing 8kg of oxygen. To liquify the oxygen (for storage and engine use) needs ~~ 5kW.hrs for the 8kg.
I note some of the NASA papers don't actually mention the energy requirements
All of those are good replies... I was just a bit concerned, because rockets do use a ridiculous amount of fuel... I kinda remembered, that the Falcon 9 FT first stage has a LOX capacity of 287400kg.... But then again, the first stage has to punch through a whole lot more atmosphere than the actual lander thingy, so the number I had in my head was just way too large.
Fuel generation speculation is fun. Actually generating fuel on a small scale on Mars would be even more fun. Build a small prototype fuel plant, send it to the Red Planet, fill up from the local resources and fire off a rocket engine on live + delay television. C'mon, ESA, get it accomplished!
The fuel production procedure is to use water, compressed CO2, and electricity. First water is split through electrolysis. Then the hydrogen and CO2 are converted to methane using the Sabatier reaction. SpaceX is planning on running a fuel rich mixture. As such more oxygen is produced than needed. As we will already be compressing a lot of the oxygen freed by electrolysis it makes sense to make the O2 compression system large enough that it can capture all the oxygen.
Once a colony is established oxygen from fuel production becomes a minor contributor to the total oxygen supply rather quickly. Food crops will produce double what humans need to survive. Industrial processes, many using the perchlorates(I trust, as a chemist, that you would like to have a local source of chloride salts.) that some many are overly-concerned with gives us even more. The problem is what to do with all the oxygen we can create, not how to get it.
It is locked up in rocks, but it is easy enough to free using solar power.
I don't understand why Musk wants to set up a colony on Mars. The Moon is a much better location given how close it is, minimal communication delay, better efficiency for solar power, and less of a gravity well for return trips. Mars' atmosphere is so thin it does us no good, and terraforming is a ridiculous dream with our current or near future level of technology.
I get the desire to be the first man on Mars, but not the desire to set up a colony there in preference to one on the Moon.
When deciding on where to place the location there are two factors. How much Dv it will take to get there and what resources are available. The Moon's lack of atmosphere means that the total Dv to reach either destination isn't markedly different(Areocapture and areobraking really are that valuable). There are more identified resources on Mars than the Moon. If humans have problems with values of G between 0.16% and 0.99%we expect them to be worse at lower G levels(As we have no data this is just a guess).
Historically the number of colonists who have returned to their homelands is nearly 0%. Since, at current transportation costs, there will be very little in the way of physical goods returned, the added return costs are not a major consideration.
At the end of end of the day what matters is what resources we have available, how difficult it is to utilize those resources, and who will use those resources. On the first two points, based on everything we know, Mars wins. On the third point the Moon has a slight edge. Short travel times mean that we expect tourists in addition to the colonists. So far I've not been able to find production techniques that allow the expanded customer base to make up for the higher costs of local production. For long-term growth the target we want is Mars.
If you happen to have a business model for the Moon I have yet to consider, I could be convinced going to the Moon first is worth the effort. Please be aware the export cases commonly used, fuel depots and computer chip manufacturing to name a couple, require customers and a comparative advantage that overcomes the cost which do not exist unless we are undertaking a larger project, like colonizing Mars. For now the Moon is a path to nowhere economically.
We also have to consider that virtually all of the equipment for Mars and the Moon is similar, just more robust for the longer trips required to reach Mars. Design for Mars and we end up going to the Moon as well by default. Personally I'd prefer to target a more difficult destination(Both the Moon and Mars can be expected to be water importers) but few others are willing to consider targets like Ceres.
Some interesting discussions of the chemistry possibilies of Mars. But I think the big issue has been missed. Why?
"Because it's there" excites explorers. That got us to the Moon, but we didn't stay. And I'd say the same holds for Mars. Musk is fascinated by it and has the money to play with these ideas. But if you want a million colonists, you've got to attract them.
People upped sticks from Europe to the New World from the kind of poverty that even most of Africa is getting out of now. Or from political oppression / religious differences. But there are better places to go to if you've escaped your oppressive regime on Earth. If you want serious numbers of colonists, I don't believe that Mars has much to offer them in the way of hope for the future. People historically have been willing to put up with stuff getting worse, for the promise that their children will be in clover when they're dead - but I don't even see Mars holding out that promise.
Not unless we're talking of terraforming it. Now we don't have to have all the tech, and all the answers now. Just a general idea of what to do. I don't know how much atmosphere Mars can hold, but clearly it would be a lot more if we could greenhouse effect it, and give it some plants. Presumably algaes and mosses to help create topsoil and get nitrogen and carbon cycles going.
If that's not being talked of as a serious option, then I can't see Mars getting more than just thrill seekers.
The other driver of possible colonists is money. Filthy lucre attracts workers, and they need feeding, watering and people to marry (or at least have sex with). But Mars is at the bottom of a gravity well, and is unlikely to produce anything we can't do on Earth - or at least not well enough to negate the hideous shipping costs.
If you're not terraforming, then with the radiaton on Mars what it is, you're eventually going to be living underground. At which point why not the Moon? Which is easier to get off, and closer to Earth? Or even just a space station or an asteroid? We might not live on the Moon, so much as mine it to provide for orbital industries. Or get resources from asteroids, which we can obviously move (if we're feeling brave enough).
What are the sources of money in space? It seems to me there are only a few. Microgravity chemicals, pharmaceuticals and computer chips perhaps? But that's not going to happen unless we already have a presence in space that makes it economic to do the research into what we can actually make. So what can make money now is repairing/servicing/refueuling our existing and profitable satellite fleet - and tourism. All of that is in LEO/GEO, and the tourists might like to visit the Moon.
So it seems to me that mining the Moon for resources to feed industry in Earth orbit is economically feasible, and nothing else is. So nothing else but exploration will happen anywhere else. If we're talking real blue sky thinking, then why not the asteroids? Short of terraforming Mars, you're going to have a better and safer living space there than it's possible to ever get on Mars, and while you're hollowing one out you have space-based resources to sell to other people that need relatively little delta-v to get somewhere useful.
Selling a Mars colony as a backup pool of humans in case of catastrophe to Earth seems too esoteric to get a proper colony going.
Obviously we need fertilizer for our crops. Initially the rocket fuel plant will provide a large portion of our buffer gases(Nitrogen and argon being roughly 5% of the atmosphere). Trace elements such as phosphorus and sulfur are available in the Martian dust(Ideally we will find more concentrated sources but we have the elements we need). While I haven't fully examined everything need to make fertilizer all of the ingredients are available on Mars.
Yes, plants require oxygen. That doesn't really matter. Food crops will provide roughly twice the oxygen humans need. Crops grown for other purposes, fibers like cotton for textiles and cellulose for plastics production, further enhance the oversupply of oxygen. Inside we have far too much total oxygen. The little bit plants require is already available so there is no reason to be overly concerned.
Outside we already plenty of oxidizers available. What we really need on Mars is fuel.
I ain't Spartacus,
The answer is because we can. Once we get there we know we will learn valuable things but, because we don't yet know what those things are, we have no clue how to monetize them. At this point all that we can do is determine which short-term goals won't be able to turn a profit.
Excepting tourism all of the Lunar options you list require markets that don't yet exist. Our current satellite fleet was not designed to be repaired, serviced, or refueled. Much of the planned research into developing industrial processes got delayed when Shuttle cancellation was announced, and is still on hold. While you didn't mention it, I will add that He-3 mining requires fusion, which is still two decades away.
Honestly my preference is to go to as many places as we can. The problem is that there simply isn't enough money. Since we can afford to start one colony, assuming we don't use the traditional supply-side oriented funding techniques, the question is which target provides us with the best options for developing a local economy? Based on the information available, developing a local economy appears far easier on Mars. As ships that can travel from Earth to Mars will be able to easily do the Lunar trip(A Lunar specific lander is desirable though.) private enterprise can go to the Moon once there is demand for products they can make.
I just don't buy that Mars can become a self-sustaining colony. And nor, I stronly suspect, will any potential colonists. I think this is trying to run before we can walk, and what we can do now is simply baby steps.
To say we might find something useful when we know more is actually quite a huge assumption. There's a really important elephant in this room and that elephant is shipping costs. It's a very big elephant. Anything that can be traded in space is going to have to be low mass and very expensive, or it ain't going to be worth shipping. Or at least anything that requires boosting out of a gravity well. You might be able to chop an asteroid up for minerals and send it on a slow trip to your destination - where you then do something with it, but even that's probably 50 years in the future.
The only possible revenue streams from space in the next 20 years are tourism and satellite repair. There might be some early money with micro-gravity crystals maybe, but I suspect only if it can piggyback on otherwise profitable infrastructure.
Satellites are currently not designed for in-orbit servicing, but then neither was hubble. Even if it's just replacing thruster fuel and giving a bird an extra few years of life, that's probably worth tens of millions of dollars to do - and that's enough cash to tempt people.
Mining the moon would not be for HE3, but for oxygen bearing rock, water, topsoil maybe, perhaps even just rock to use as radiation shielding for a small space station. And that only if it can be got cheaper than popping up and down from Earth.
I don't think there's any point planning longer term than that. NASA should just explore, as now, with a possible trip to Mars if the politicians want to fund it for the wow factor. In the medium term we need resources in orbit before we can do anything else ambitious, and we have a funding source to pay for that (fixing satellites). Once that looks likely, satellites can then be designed to be even more expensive, so they're repairable - or even modular, so you can add to them as demand grows. That ought to be self-sustaining, or at least the numbers don't look ridiculous - given the billions we spend on satellites now.
The Moon is just the nearest source of resources that doesn't require expensive boosting from Earh. But if cost to orbit keeps falling, that may turn out to be irrelevant. Here's hoping Reaction Engines can strut their funky stuff.
Satellites use hypergolics. The most common fuel combination is monomethylhydrazine fuel and textroxide oxidizer. Lunar fuel plant designs are based around hydrolox. ISRU availability of nitrogen and carbon on the Moon is limited to trace amounts. Refueling satellites using Lunar fuel will require importing both nitrogen and carbon.
We want hydrogen, not oxygen, for spacecraft shielding. If we want to go the bulk mass route and use unprocessed rocks, grabbing an asteroid requires far less Dv. The trouble with the bulk mass route is we end up using a lot of fuel to get rock to the destination. That rock isn't useful for much else without processing. If we were building dozens of ships and stations it could make sense to build a rock processing center in space. We're not building dozens of ships and stations. At this stage is HSF it makes the most sense to send water to any stations/ships we build. At least there are multiple uses for the water.
The Moon simply is not a good source of resources. To change this we either need to import carbon and nitrogen(Assuming we don't discover extractable local sources in the quantities needed). Depending on the labor force needed to operate an industrial mass-production facility(Robots are great but, for the foreseeable future, we still need the guy with the spanner.) and the supply chain it is questionable whether we would have enough hydrogen for local uses. If we are going to the Moon using tax dollars it has to be because people actually want to live on the Moon. If casino owners want to set up Lunar Vegas on their own dime that is fine with me.
I am hoping the Sabre engine will fly. I don't see what exactly Skylon has to do with a discussion about the Moon versus Mars. Skylon is a space plane to LEO. When(think positive) it is operational it should lower the cost to Earth's surface to LEO. If anything it will make it more difficult for Lunar exports to compete.
Because I don't think I've covered it, which means it will probably come up, hydrolox(H2/O2) is not suitable for use as a satellite fuel. The current goal for "long-term" hydrogen storage on orbit is seven days(ACES developmental second stage).
If you read the "Ride Report" you will see one of the most thoughful processes at that time for planned exploration of the solar system. Sally Ride wrote it and it was very inspiring to a college kid like me at the time. I think Musk discounts the Moon in this plan because he knows we can bypass it if what we wan't to do is just get there. However you brought up points that make me think the Ride Report is still valid.
I propose that we mine He³ on the moon - it has the most dense source of this excellent fusion material that any other known source worth looking at. If we take advantage of the Moon's low gravity, we may be able to accelerate progress on accomplishing fission, and with that wonderful process you can make ANYTHING. The fusing of any atomic atoms, can result in anything you want from the periodic table, so you could throw moon dust in the process and make fuel, gold, whatever you want to enhance the next hop to Mars. Even if we establish this base and end up bypassing it, the lessons learned will go a long way toward building any base on Mars, and we would be much closer for any rescue missions that may come up.
And there again, many a rich folk might want bragging rights to being one of the first civilian moon walkers! Tourism might actually help pay for the next step.
First, Ask yourself this... Why do people climb Mount Everest? Because they can. That's why. No other reason. Second, To be the first to do it.. Period. Third, Because we are in dire need of another planet, similar in Size and Mass to our own, for it to be sustainable. We are ripping this planet to pieces, We are constantly under threat of extinction from something as simple as a rock the size of an 18 wheeler hitting our planet. We need to spread to other planets if we have any viable chance of survival in this universe. Yes we are in a pipe dream of being able to Terraform at our current technology level. But Necessity is the mother of all inventions. Once we get there, this will be a necessary tech to focus on, and it will be accelerated by the need to do so for survival reasons. Everything is accelerated by necessity.. didn't you know that?
When making methane using water, CO2, and electricity we end up with oxygen as a by-product. Roughly 90% gets compressed for LOX with the remaining 10% available for other uses.
Getting oxygen on Mars isn't the issue. In addition to the fuel plant, we get oxygen from our crops and other industrial processes. One of the issues currently being examined is what we will do with all the oxygen a Martian colony will have. We can't just let it build up in our habs because of the fire issues. Reducing the mass of our oxygen removal systems is a challenge ATM.
Personally I would just send an algae tank on the first mission. Vent the oxygen, save the biomass so it can be burned in-hab once colonists are growing food, and the problem is solved. The ashes should make a decent fertilizer as well.
How abundant and available is oxygen on Mars?
Mars' crust is mostly oxygen compounds: basalt, granite, etc. Roughly speaking, Mars' crust is 45-50% oxygen by mass, like Earth's.
There are a lot of industrial processes for separating the various elements in minerals from their oxygen jailers since most of the metals human love appear in Earth's crust as oxygen compounds. Therefore, the chemistry needed extract oxygen from rocks is pretty well established, it's just a matter of engineering details to focus on oxygen production over metal production. Iron ore refining, for example, tends to throw away oxygen in the form of carbon dioxide.
So, there's not a shortage of oxygen on Mars. However, there are easier options than trying to extract oxygen from basalt. Splitting water might be energy intensive, but the hardware is relatively simple.
: I can just see the Dominos app trying to keep up with your nearest branch ... "place order from
> London ... Reading ... Bristol ... ... ... New York ..."
No, no, no. If Musk can sent a pizza joint (mmm, two of my favourite things) to Mars, he can dam' well put them in LEO. Have a network, like with GPS satellites and you can literally "drop ship" the pizza. With some intelligent packaging it could (probably) land in your yard. And the heat of re-entry will keep it hot, too.
Talking of towers, I don't see the point of sending an empty ship back from Mars to Earth. They would be very useful as 'starter homes' on Mars, and/or would give the new residents a way to leave Mars if everything went tits-up there - after all the odds of an asteroid hitting our backup facility is just as great as it hitting our primary.
So I could order a lifetime's supply of pizza
The downside is that if you go to colonise Mars, a lifetime's supply of pizza could be one small pizza. In extreme circumstances, one slice.
I think I'd much prefer to live on a hollowed-out asteroid than on Mars.
Although, as I'm reading the Mote in God's Eye at the moment, I'd much rather live on the battlecruiser MacArthur. Well, perhaps maybe Lenin. The commander is rather less cheerful and it's a lot less exciting, but there's tea instead of (mostly bad) coffee and you can have too much excitement...
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