What does it take to get to a million people on Mars?

[DanielW]

Churches? Surely if you're going to start populating a new planet it would be the perfect opportunity to finally get rid of religion? Do we really want it ruining another planet?

That is merely a list of some of the stereotypical ways that people get to know one another prior to committing to procreation. The fact that some people might not like some items on the list is immaterial. Other people will and they will find a way to bring those things of their own accord.

[john smith 19]

Churches? Surely if you're going to start populating a new planet it would be the perfect opportunity to finally get rid of religion? Do we really want it ruining another planet?

That is merely a list of some of the stereotypical ways that people get to know one another prior to committing to procreation. The fact that some people might not like some items on the list is immaterial. Other people will and they will find a way to bring those things of their own accord.

I think you're underestimating the scale of population growth needed and the consistency of it over time. 

[Ludus]

If we want to answer the "what it takes" of mass colonization, we must first reasonably quantify costs and benefits. Unfortunately, we cannot yet reasonably do so with much rigour due to the large number of unknowns in play. How easy will living on Mars be or become? We really have no idea what 1/3g does to a human being, and especially what it might do over a lifetime or a pregnancy. 1/3g might have health benefits, it might be damaging, it might result in birth defects, effects might only become clear after decades and decades. What about radiation? We don't know the effects of chronic radiation flux, as virtually all medical research on radiation sickness thus far has been on short-term exposures. What sorts of mineral resources does Mars exactly have? Are there relatively cheap ways in which we could take small terraforming steps on Mars that could support mass colonization (a la a simple Martian L1 radiation shield), or is terraforming so neccesarily expensive that it could only be justified once there are already millions of colonists?

Something that is more problematic for this topic, however, is that the fact that this sort of discussion is usually focused on comparing the merits of transportation technologies, while the human dimension of the problem is ignored and social factors are assumed. In other words, human societies are often treated as if they were machines, and not filled with subjective, self-interested individuals and social constructs that change over time.

Why should human societies send large numbers of people to Mars in the first place? Unlike an Apollo-esque flags-and-footprints mission or a McMurdo-esque research base, a million-strong colony would require orders-or-magnitude larger investments representing a sizable portion of global GDP and for those investments to be sustained over decades. Thus, while the former could be paid for out of a single goverment's pocket change on a whim, the latter cannot be (sustainably or substantially) bankrolled through platitudes about "human destiny" or other intangible justifications. Colonization will need to provide clear, concrete, and competitive value to some combination of public or private investors, or it simply will not happen.

Since a million-strong colony would require decades of immense investments by terrestrial societies and would be becoming a society in-and-of-itself, both costs and benefits are largely dependent on entirely subjective social developments. The answer therefore depends on not just presently unknown scientific factors, but also inherently unpredictable social ones. Because of this, "what does it take to get a million people on Mars" is a question that we cannot begin (with any semblance of accuracy or rigour) to provide specific answers to today.

Take, for instance, the question of manpower. A million-strong Mars colony would require an unprecendented recruiting effort that is for a number of reasons totally incomparable with humanity's experience with space thusfar or the colonization of the Americas. One might argue that is this is a non-issue, that plenty of people will want go to Mars. After all, a cursory glance around this forum (or almost anywhere across the internet) and you can see a huge percentage of people who claim that they would sign up to be a Mars colonist without hesitation and in spite of any danger.

But how willing will people really be to go to Mars, While many people may claim they want to go to Mars, claims made on the internet are very different from actually going. Currently, Mars colonization is a futuristic fantasy; what happens to peoples perceptions of colonization if it starts to become historical reality? What happens when it is no longer where no man has gone before, when you would no longer have the chance to make history by going in the first waves? What happens when the fantasy starts to lose its luster, and Mars begins to be just another job? What happens if the fantasy turns sour? Living on Mars would probably mean chronically high risk of sudden death, high probability of getting cancer, having to live underground in dark, cramped conditions, rarely being able to go outside, leaving behind everything you've ever known and loved, and doing all of the above for the rest of your life.

In short, how eager will people be to sign up for your Martian colony if it eventually becomes known as the perfect stewing pot for mental breakdown, depression, and suicide? Furthermore, rather than looking at space enthusiast forums, how eager will the extremely-skilled elite individuals such a colony requires be? It won't be the downtrodden or refugees who would colonize Mars- it would be (post-)graduates from elite universities who could make at least seven figures doing anything they wanted back on Earth. Is it really such a given that these people would pay hundreds of thousands of dollars en masse for the privilege of dying young on Mars, as Elon Musk suggests? What if your mass-colonization effort instead has to cut expensive paychecks, guarantee eventual returns for colonists, or recruit less qualified individuals?

My point in all of this is that we should not put the cart before the horse when it comes to Mars. Our focus should be on providing value to humanity, not simply doing whatever is technically possible with our present-day or near-future technologies. The fact of the matter is is that, as of now or the foreseeable future, Mars (and all of space outside LEO) is a worthless rock and mass colonization cannot begin to provide any practical return for humanity. Importantly, it will not necessarily always be so, and quantifying unknowns in a cost-effective manner (robotic exploration, medical research on ISS), developing technological capabilities (space nuclear, high-power ion propulsion, ISRU), and expanding the existing space economy (COTS, in-space manufacturing) are rational investments that can create and strengthen business cases for deep-space activities.

It is these sorts of invesments that actually expand our space capabilities in a sustainable manner, unlike the neo-Apollonian proposals of Mars Direct or Spacex's proposed Mars colony. Like the Apollo program, they would be very good ways of wasting a lot of money over a short period of time, drawing it away from better intermediary investments, provide a poor return because they "skip steps", and you ultimately lose the capabilites you did develop because you can't sustain the investment. We'll have a million-strong Mars colony when we can establish that it is a good idea, and ought to do so no sooner.

This POV assumes there is such a thing as sustained governmental or society wide interest in becoming space faring. The evidence doesn’t really support this. After the space race that ended in the early 1970’s, only the US spent significant money on space and most of that wasn’t really on space but local political pork barrel projects.

In the modern setting NASA’s budget is greater than the rest of the world combined by a large margin. Most of that NASA budget isn’t for anything advancing humanity becoming spacefaring. Pretty much only SpaceX and Blue Origin sustain any slender thread of hope that humanity will break out and establish a sustainable presence off the earth before events close the window of opportunity.

The idea of slow sustained “rational” progress involves sustaining high levels of public spending on things without any rational economic motivation, decade after decade, likely for centuries. It’s a very improbable alternative.

Alternatively, rather than a government program recruiting people, market based alternatives have demonstrated that people will accept a lot of hardship and risk in exchange for high earnings that can benefit their families. The world in 2017 has endless examples.

Humans will live off the earth at the scale of a million people when individual incentives to do so are present.

[Ludus]

5 engines per BFS. They currently can make like 200 engines per year, let's say they up that to 400. That's enough, over a 30-32 year BFS lifespan, to keep over 1000 BFSes in circulation. Up to 200 people per BFS (stretched a bit, passengers only, 5 people per cabin), that means they can move 200,000 people per synod. Only takes ~10 years to move a million people. Longer if you assume only 2-3 people per cabin.

It's not actually absurd to talk about moving a million people with BFR/BFS.

Elon also said, that he expects that for every passenger flight there will be 10 cargo flights.

That can only apply in early stages...

Not sure. It might apply for a long time, as long as Mars is rapidly growing. No idea what the mass or volume ratio is now on earth of freight vs. human transport but it seems reasonable it’s 10:1 as an order of magnitude. It seems very possible Mars transport will stay 10:1 indefinitely. It’s reasonable to assume most ships to Mars will only carry cargo. Most BFS built will be cargo variants. Most spaceships in a spacefaring future will be automated cargo transports.

[john smith 19]

Not sure. It might apply for a long time, as long as Mars is rapidly growing. No idea what the mass or volume ratio is now on earth of freight vs. human transport but it seems reasonable it’s 10:1 as an order of magnitude. It seems very possible Mars transport will stay 10:1 indefinitely. It’s reasonable to assume most ships to Mars will only carry cargo. Most BFS built will be cargo variants. Most spaceships in a spacefaring future will be automated cargo transports.

This is one of the things V2.0 of the game will address.

So far it's looking tricky. The proportion of ongoing BFS's that are cargo has serious implications for settlement growth rates, as (it turns out, although perhaps it should have been obvious from the start) does the life expectancy of the ships.

Logically what the settlement would need to identify what are the big volume items. Things that tie up a disproportionately large chunk of fleet capacity continuously with every trip from Earth.   

I'm not sure what these would be.

It's obvious pre assembled prefabricated buildings should be avoided, they don't provide much radiation protection without a lot of work, so why not do something more productive with that work, but what else?

Moving to a local food production ASAP should radically reduce MRE consumption and CO2 scrubber cartridges (bio regeneration), but again that should self evident. Clothes? I'm not sure if the ISS has yet been equipped with a washer. , which on Mars (half a million x further away) would be just stupid, once adequate water and power supplies become available (yet another use for the "waste heat" from that Kilopower reactor  ).

So maybe soap powder is the next target item to move to local mfg?

[philw1776]

Washing clothes?  In-situ CO2.

https://www.trendhunter.com/trends/supercritical-washing-machine

http://e3tnw.org/ItemDetail.aspx?id=512

[launchwatcher]

I'm not sure if the ISS has yet been equipped with a washer.

All sources I've seen say that it hasn't, yet. 

which on Mars (half a million x further away) would be just stupid, once adequate water and power supplies become available

plus, on the surface of Mars (vs ISS), it should be much easier to (a) adapt a washer design built for 1g to 1/3g than 0g, and (b) deal with vibrations from the spin cycle...

[john smith 19]

I'm not sure if the ISS has yet been equipped with a washer.

All sources I've seen say that it hasn't, yet. 

which on Mars (half a million x further away) would be just stupid, once adequate water and power supplies become available

This is another one of those "Turning a base into a settlement" things. It sounds trivial, but I don't think any of the major Arctic bases ship their laundry back to their home country to do it. Same for most large foreign military bases (AFAIK).

plus, on the surface of Mars (vs ISS), it should be much easier to (a) adapt a washer design built for 1g to 1/3g than 0g, and (b) deal with vibrations from the spin cycle...

True. You've got a whole planet to bolt it to.    The water from a washer seems exactly the sort of "Grey water" that all that ISS work has been focusing on reclaiming.

It's one of those "I never really thought about it, but the mass does seem to mount up" things. Choose a set of daywear (including footwear) and weigh it. How many days would you be willing to wear that before wanting to change? My instinct is that for quite some time hauling washers to Mars is (at $130/Kg) for private use is going to be too expensive and the Martian laundromat will be a thing.

That said washers are an example of a product with both a mature market and mature mfg chains adapted to Earth economics.  A washer designed and built on Mars, for Mars use might be quite different to an Earth model, due to the very different manufacturing and end user priorities but that's OT for this thread.

[john smith 19]

Not sure. It might apply for a long time, as long as Mars is rapidly growing. No idea what the mass or volume ratio is now on earth of freight vs. human transport but it seems reasonable it’s 10:1 as an order of magnitude. It seems very possible Mars transport will stay 10:1 indefinitely. It’s reasonable to assume most ships to Mars will only carry cargo. Most BFS built will be cargo variants. Most spaceships in a spacefaring future will be automated cargo transports.

This is one of the things V2.0 of the game will address.

And by way of a late Xmas present here it is.

[EDIT Following comments from various posters it has a good few more fields to vary.

Major changes are

2nd sheet breaking out the propellant cost calculations and what a BFS tanker variants structure would have to weigh in order to accommodate the full propellant load in 6, not 7 launches. I think we can assume the tanker won't have the 40 passenger cabins fitted, and if each one weighs as little as  875Kg that will lower the weight enough to accommodate the extra payload needed.

BFS now has a finite operating life. This has the very interesting effect that once you reach it the fleet size no longer grows, as the same number are added as are retired. Obvious in hindsight but I didn't see it coming.  Wanting a bigger fleet means building more ships after a certain age or extending their operating lives.
This also (at present) puts a floor on cost curve calculations and hence on the minimum number of flights (either cargo or passenger) before the build cost is recovered. IRL the total number of ships keeps rising and the cost curve should keep falling. It's on the todo list for V3.0.

Varying the proportion of the fleet that carries cargo also has a substantial effect on settlement growth rate.

You can set the the proportion of flights that are treated as cargo only (Initially 150 tonnes at $130/Kg, but both can be varied).
The key question here is wheather the reduction in support per person exceeds the number of people being brought by fleet growth? 
If it does settlement growth can accelerate until a higher equilibrium is reached. If it does not the proportion of fleet allocated to cargo rises and the growth rate due to new settlers falls, again to a new equilibrium. Bottom line. Working out what are the biggest imports in terms of physical volume and mass, and planning to phase them out ASAP, is a really good idea if you want to speed up settlement growth. IRL this is likely to be much easier said than done.

Different people will have different ideas what that initial cargo BFS fraction will be, and how low it can go and how quickly it will go. Keep in mind Musk reckons it's going to stay about 90% cargo. OTOH watching the 2017 IAC presentation again he mentioned he thinks the 40 cabins could be good up to 5 passengers each IE the basic BFS design could go to 200 passengers without needing a "BFS 2.0" version.

The interactions  are the key. 

One interesting question. Retire the BFS's on Earth (for reprocessing to new BFS's) or Mars? They will be the biggest propellant storage tanks and/or controlled, pressurized volume (known leak free) on Mars. Maybe return the engines for the next generation BFS's? ]