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SpaceX Vehicles and Missions => SpaceX Starship Program => Topic started by: john smith 19 on 12/18/2017 11:19 pm

Title: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/18/2017 11:19 pm
Elon Musk has said he wants to build a city on Mars to have a million people in it.

The BFS is designed to be the biggest spaceship that has ever left Earth's orbit but how many of them would be needed to do this in a reasonable amount of time?

To get some idea of the options to this, and the time scales they would give, I have built a little simulation game in Excel.  It's split into 2 windows, so you can change the parameters and see the growth patterns of various parameters. As usual cells with Blue borders are for user entry. All others are generated from them.

The game lets you change assumptions on the fleet of BFS's going to Mars and the passengers it will carry. The  fleet calculation supports a "learning" curve factor that can lower the cost of BFS's as the size of the fleet expands.

Population growth is much more tricky to describe over time  as AID and IVF radically open up the options for childbirth. The game uses a simple idea that people on each new arriving fleet pair up and have a certain average number of children shortly after arrival. 10 launch windows (that's hard wired in, despite it being possible to shorten the gaps between launch windows) later these children then have an average number of children also.

The game runs up to 52 launch windows, or 104 years from the landing of the first ships crewed ships. 
The sheet shows wheather the assumptions result in the settlement exceeding a million people and if so what year that happens. An interesting range to aim for would be around launch window 24 or 48 years. Assuming the first landing is 2022 that would be when Musk is 99 years old.

I'll let people download it and play with it first before commenting on some of the results.
Title: Re: What does it take to get to a million people on Mars?
Post by: QuantumG on 12/18/2017 11:54 pm
He also said the later ships would make the ITS (the bigger design before the BFS) look small. So it's not really sensible to talk about doing it with BFS.

Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/19/2017 12:00 am
He also said the later ships would make the ITS (the bigger design before the BFS) look small. So it's not really sensible to talk about doing it with BFS.
The number of ships built before each launch window, and the number of passengers they carry, can both be varied. To a first approximation any potential "BFS 2.0" can be treated as an increase on the average number of passengers and a reduction in the number of vehicles built (along with an increase in the first cost of the ships, which can also be changed).

But I'll keep that in mind if there's enough interest in doing an upgrade for the game.
Title: Re: What does it take to get to a million people on Mars?
Post by: meekGee on 12/19/2017 12:01 am
He also said the later ships would make the ITS (the bigger design before the BFS) look small. So it's not really sensible to talk about doing it with BFS.

Also, population growth.  Considering a 50 yr timeline, people will do what people do.
Title: Re: What does it take to get to a million people on Mars?
Post by: Lar on 12/19/2017 12:16 am
He also said the later ships would make the ITS (the bigger design before the BFS) look small. So it's not really sensible to talk about doing it with BFS.

Also, population growth.  Considering a 50 yr timeline, people will do what people do.

He said you can tweak the average number of children per pair (But not how long it takes to get them)
Title: Re: What does it take to get to a million people on Mars?
Post by: meekGee on 12/19/2017 12:27 am
He also said the later ships would make the ITS (the bigger design before the BFS) look small. So it's not really sensible to talk about doing it with BFS.

Also, population growth.  Considering a 50 yr timeline, people will do what people do.

He said you can tweak the average number of children per pair (But not how long it takes to get them)
Yup.

For a colony, it will be a cultural thing...  Assume n>>2...  Look at any frontier society.  N=6?

A generation is ~25 years.

So over 50-100 years, self-growth will be a big factor even if there's no influx.

Which is good, since it's hard to move 1000000 people when you can only go every 2 years...

Title: Re: What does it take to get to a million people on Mars?
Post by: Robotbeat on 12/19/2017 05:14 am
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.
Title: Re: What does it take to get to a million people on Mars?
Post by: jpo234 on 12/19/2017 08:21 am
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.
Title: Re: What does it take to get to a million people on Mars?
Post by: meekGee on 12/19/2017 09:24 am
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...
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/19/2017 09:34 am
He also said the later ships would make the ITS (the bigger design before the BFS) look small. So it's not really sensible to talk about doing it with BFS.

Also, population growth.  Considering a 50 yr timeline, people will do what people do.

He said you can tweak the average number of children per pair (But not how long it takes to get them)
Shortening the pregnancy cycle for women is a whole other thing. 

My instinct is that somehow ways will be found to shorten the gap between launch windows. America was settled with 8-12 week voyages but with (in principal) daily departures in both directions. Sets of BFS's on cycler orbits (1 fast out, multiple slow "outs" to give the equivalent fast returns later on)?, ion thrusters after initial boost? (Dare I suggest it?) Nuclear thermal? Within the SoA but ruinously expensive to design and test 9and unlike Kilopower I don't think NASA has any actual hardware in test. Yet)

I know it will take a lot of delta V to do this but let's remember compared to nearly everything else in spaceflight propellant (anything, including LH2, except NTO/Hydrazines) is cheap.
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.
No one said it wasn't. It just needs enough of them.
Prior to each launch window you are planning to add another 80 BFS's to the fleet and they will carry 200, not 100 passengers. Being a bit crude this also assumes the first 2 will seat 200 as well, but it gives you the idea.

And you could send more than a million people to Mars in 24 years, which is well below "retirement age" for BFS (good point. I'll have to add an "age out" entry to the set up). That excludes any children to increase the total. An average of one child per couple would top a million in less than 20 years.

The cost to build that fleet would be $93294m IE about $93.3Bn. 

Starlink will have to sell a really large amount of bandwidth to build that fleet, although 200 passengers at $500K is $100m. Now will that offset only the propellant or some of the build cost as well?

But at 6 children per couple (Meekgee's preferred level) that's only 14 years and $71.5Bn in build costs.
Yup.

For a colony, it will be a cultural thing...  Assume n>>2...  Look at any frontier society.  N=6?

A generation is ~25 years.
The number in the game is an average. Keep in mind if someone had only a couple of children that would mean another couple would have 4 more, or 2 couples would have another 2 each, or 4 couples would have another 1.

I'd suggest there is a certain amount of cultural variation on what constitutes a generation.
Quote from: meekGee
So over 50-100 years, self-growth will be a big factor even if there's no influx.
Provided there are no major issues with gestation and child birth in 1/3 g. You might like to look up the evidence for that.
Quote from: meekGee
Which is good, since it's hard to move 1000000 people when you can only go every 2 years...
Hard, but not impossible. Just very expensive.
Elon also said, that he expects that for every passenger flight there will be 10 cargo flights.
Good point. Another one for the to-do list.
"Percentage of flights that will be cargo only"

Looks like there will be a V 2.0 after all.
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/19/2017 09:43 am
That can only apply in early stages...
Should only apply in early stages.

But it depends.

As you move to locally made products the range of goods you need to buy in narrows, but the number of people who need those bought in goods has grown.  If the former exceeds the latter then then the overall proportion of cargo flights falls. If not it stays the same, despite the settlements greater self sufficiency.
Title: Re: What does it take to get to a million people on Mars?
Post by: launchwatcher on 12/19/2017 10:55 am
Starlink will have to sell a really large amount of bandwidth to build that fleet, although 200 passengers at $500K is $100m. Now will that offset only the propellant or some of the build cost as well?
Raptor propellant is cheap.

IAC2017 slides say total BFR takeoff mass is 4400T.

Assume it's all propellant (we're just going for a ballpark estimate here..)

Assume a mass ratio of 1kg CH4 to 3.6kg LOX; 4400/4.6 = 957 so:

957t CH4
3443t LOX

Once source I found said NASA paid $0.16/kg for LOX.   That's $160/t.   

Natural gas is mostly methane, and the price of natural gas is dynamic.   Let's pick one of the higher prices (~$10 per thousand cubic feet) which is ~$450/t

so one BFR-load is 957*450+3443*160 ~= $980,000.   

So each pair of $500k tickets buys the raw fuel for one BFR launch.   If it takes 6 BFR launches to get one BFS to Mars, you need to sell 12 $500k tickets (or 24 $250k tickets)  to pay for the fuel.



Title: Re: What does it take to get to a million people on Mars?
Post by: Hotblack Desiato on 12/19/2017 11:46 am
In theory, they should be able to ramp up the production rate of BFS aswell. Means, from these initial 8 BFS to something more reasonable, like 20 or even more per launch window, and from there to 100, etc... (essentially exponential growth of production and launch capacity).

And for financing BFS, we should factor in a Moon Colony and LEO-stations. BFS can earn additional money by doing these short trips over there. If a BFS lasts 25 years and/or 100 launch-reentry cycles, that would waste 76 cycles because it just can't do more than 12 flights to Mars and back (especially since landing on Moon doesn't count as atmospheric reentry).

Another intersting point will be the price tag on the ticket. $ 500k is a nice value, but Musk already indicated that it might be much lower, in the ballpark 200k or even 100k. For Mars, it seems to be 6 launches to get a full set of 100 passengers to Mars, while Moon requires just 2 launches and LEO even one launch (maybe Moon and LEO can be done with more than 100 passengers, just because its a much shorter time period for the flight (3-5 days vs 120 days - less consumables, less internal volume requirements, etc). Means a Moon ticket could be at $20-100k and a LEO ticket at below 10-20k. And all that helps keeping the price low for a ticket to Mars.

I think, we won't see that 1 million number within the first 25-30 years (first flights will just have a very limited number of passengers) but once the regular BFS flights with >100 passengers start happening, we will see numbers rising pretty quickly. Once that million is reached, it won't stop. For example, in your file, with your standard-settings, we have the million people at window 50. but already at window 61, it's 1.5 million and at 70 it's 2 million.  ;)
(and at this point, we will exceed 10 million on the Moon, just as a sideproduct of the Martian Colonization effort)

Will be very interesting to see the future.
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/19/2017 12:05 pm
Starlink will have to sell a really large amount of bandwidth to build that fleet, although 200 passengers at $500K is $100m. Now will that offset only the propellant or some of the build cost as well?
Raptor propellant is cheap.

IAC2017 slides say total BFR takeoff mass is 4400T.

Assume it's all propellant (we're just going for a ballpark estimate here..)

Assume a mass ratio of 1kg CH4 to 3.6kg LOX; 4400/4.6 = 957 so:

957t CH4
3443t LOX

Once source I found said NASA paid $0.16/kg for LOX.   That's $160/t.   

Natural gas is mostly methane, and the price of natural gas is dynamic.   Let's pick one of the higher prices (~$10 per thousand cubic feet) which is ~$450/t

so one BFR-load is 957*450+3443*160 ~= $980,000.   

So each pair of $500k tickets buys the raw fuel for one BFR launch.   If it takes 6 BFR launches to get one BFS to Mars, you need to sell 12 $500k tickets (or 24 $250k tickets)  to pay for the fuel.
Thanks for that. I couldn't find my download of Musks 2017 IAC presentation.  That also implies there would be money left over to offset BFS construction costs. I went with an initial cost of $400m but the sheet includes a learning curve to lower costs as production experience grows, although how much by is debatable.
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/19/2017 12:28 pm
In theory, they should be able to ramp up the production rate of BFS aswell. Means, from these initial 8 BFS to something more reasonable, like 20 or even more per launch window, and from there to 100, etc... (essentially exponential growth of production and launch capacity).
True, if the existing facilities can accommodate the ramp up, otherwise you're looking at serious upgrade costs.
Quote from: Hotblack Desiato
Another intersting point will be the price tag on the ticket. $ 500k is a nice value, but Musk already indicated that it might be much lower, in the ballpark 200k or even 100k. For Mars, it seems to be 6 launches to get a full set of 100 passengers to Mars, while Moon requires just 2 launches and LEO even one launch (maybe Moon and LEO can be done with more than 100 passengers, just because its a much shorter time period for the flight (3-5 days vs 120 days - less consumables, less internal volume requirements, etc). Means a Moon ticket could be at $20-100k and a LEO ticket at below 10-20k. And all that helps keeping the price low for a ticket to Mars.
In the 2016 presentation Musk said he expected a Mars ticket would cost the equivalent of "The mediun price of a house in the United States." Today that is about $189 000.
Quote from: Hotblack Desiato
I think, we won't see that 1 million number within the first 25-30 years (first flights will just have a very limited number of passengers) but once the regular BFS flights with >100 passengers start happening, we will see numbers rising pretty quickly.
Actually it is possible. The whole point of the game is to see what you have to do if you want it to happen.

For example with an average 100 passengers a ship (to overcome the early flights which were not full up) you could do it with a fairly modest 2 children per couple  in 24 years if you're ready to build 80 new BFS's per launch window. 

My instinct for BFS is that as SX gain experience and become comfortable with ECLSS margins they will carry more people. I think they will build more BFS's to add to the fleet with every launch window, but more like 8 than 80 at a go. Time will tell who's right.

 IIRC the pads in Florida were designed to support up to 14 million lbs of thrust. The hard limit is set by this.  Beyond that SX will be plowing up cubic miles of concrete to go bigger.

So the first upgrades will be whatever the BFS ECLSS can actually carry (20more? 30more?)  and "BFS 2" will be up to the full T/O thrust limit of the pads, about another 14% bigger (5500 tonnes of thrust is already about 12.1 million lbs).

My bet is on SX (somehow) spending more propellant to widen the launch window. If SX have taught one lesson it is propellant is (relatively) cheap but time is expensive. Even cutting the time between launch windows a few months makes a huge difference in the long term. [EDIT. For example the launching of the fleet can be broken up into smaller units (call it a "squadron" for example), so less of a "surge" and more of an even work flow as each group departs. This also offers the chance for any last minute orders for parts or equipment to be loaded onto the last group to leave. ]
Title: Re: What does it take to get to a million people on Mars?
Post by: JamesH65 on 12/19/2017 02:13 pm
I don't think the limit is how fast you can get them there, but how fast you can build somewhere for them to live.

How many cities on Earth, built from scratch, had 1M inhabitants in less than 50 years, less than 100 years etc in STABLE accommodation (i.e. not shanty towns). Not many, if at all.
Title: Re: What does it take to get to a million people on Mars?
Post by: RonM on 12/19/2017 03:01 pm
BFS is a good architecture to get Mars settlement started, but not practical for large scale.

Once there is enough infrastructure on Mars to allow for rapid settlement expansion, a larger scale system can be deployed. Big spacecraft to transfer settlers by the thousands will travel back and forth between Earth and Mars. These spacecraft will be refueled in Earth orbit using propellant created from resources mined from the Moon and NEAs. Once they arrive in Mars orbit, they can be refueled from Mars, Phobos, Deimos, or asteroid mined resources.

Passengers will be transported to and from orbit by smaller vehicles, such as BFS.

Blue Origin, ULA, and others can develop cislunar space to proved the Earth end of this infrastructure for SpaceX to buy propellent.
Title: Re: What does it take to get to a million people on Mars?
Post by: LM13 on 12/19/2017 03:13 pm
He also said the later ships would make the ITS (the bigger design before the BFS) look small. So it's not really sensible to talk about doing it with BFS.

Also, population growth.  Considering a 50 yr timeline, people will do what people do.

He said you can tweak the average number of children per pair (But not how long it takes to get them)
Yup.

For a colony, it will be a cultural thing...  Assume n>>2...  Look at any frontier society.  N=6?

A generation is ~25 years.

So over 50-100 years, self-growth will be a big factor even if there's no influx.

Which is good, since it's hard to move 1000000 people when you can only go every 2 years...

I wouldn't be so sure about N=6.  I'd expect N=3 for a while to be the high end, with most couples closer to just 2.  The reason is that education tends to correlate with reduced birth rates (something Musk himself has complained about, remarking in the Vance biography that not enough intelligent women are having enough children).  The kind of people most likely to go to Mars for a while will generally be more educated, which also makes them older when they get started on the trip, and thus less fertile (30 y.o. people vs. 20 y.o. people).  The likely absence of specialized medical care for special-needs children (more likely for older parents) will also likely prompt caution in procreation for these older citizens. 

Unless, of course, we propose the existence of specialized schools that optimize their graduates for life on Mars by the age of 18, and either a "Mars Loan" program to be repaid over time, or a scholarship/trust fund. 
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/19/2017 03:21 pm
Once there is enough infrastructure on Mars to allow for rapid settlement expansion, a larger scale system can be deployed. Big spacecraft to transfer settlers by the thousands will travel back and forth between Earth and Mars. These spacecraft will be refueled in Earth orbit using propellant created from resources mined from the Moon and NEAs. Once they arrive in Mars orbit, they can be refueled from Mars, Phobos, Deimos, or asteroid mined resources.

Passengers will be transported to and from orbit by smaller vehicles, such as BFS.
That would certainly save the wear and tear on the vehicles that have the fewest opportunities to amortize their costs (IE the inter orbit transports).

Obviously getting to a stage where the budgets for such an optimized vehicle is justified (and you can bet that won't be cheap) is going to take some time.
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/19/2017 03:26 pm
I don't think the limit is how fast you can get them there, but how fast you can build somewhere for them to live.

How many cities on Earth, built from scratch, had 1M inhabitants in less than 50 years, less than 100 years etc in STABLE accommodation (i.e. not shanty towns). Not many, if at all.
A fair point but keep in mind the next population burst is very predictable (barring really massive breakthroughs in propulsion), so the settlement has 2 years to get the last batch "settled" before the next batch arrive.

Of course the population growth model does assume half of these people will be getting pregnant so thre will be a lot of construction going on to build out the settlement.
Title: Re: What does it take to get to a million people on Mars?
Post by: meekGee on 12/19/2017 03:39 pm
A Mars colony would be very unlike an earth city, where higher education correlates with an easy, "everything handed to you" society.

This will be a frontier society, where survival and growth are explicitly on the forefront of everyone's thoughts.

Having kids will be almost a requirement...

This is the difference between a colony and a base...
Title: Re: What does it take to get to a million people on Mars?
Post by: philw1776 on 12/19/2017 04:08 pm
I see a delay for several synods before families emigrate.  Wait to check out environmental affects on humans. 
Then the next gating factor would be the ability to construct large living spaces that would make families beyond the first few thousand really want to go.  Elon said it would be fun.  Need to make it so.  Just takes a few more synods.

Like the fact the BFS passenger quantity can be increased in the spreadsheet.  I don't think that a BFR/BFS architecture and design implemented in the teens will survive deep into the 2040s when really mass emigration of families beyond initial base(s) construction.  SpaceX is the last company that would stop innovating.  A 2 decade return on the base BFS design plus enhancements F9 to Block 5 style would be a nice return on the teens design.  Maybe "Block 5" BFSs would be used late 40s and beyond as shuttle vehicles Mars surface to orbit unloading really massive MCTs Mars Colonial Transports carrying 500-1,000 colonists.  These MCTs would never touch a planetary surface. 
Title: Re: What does it take to get to a million people on Mars?
Post by: speedevil on 12/19/2017 04:29 pm
So each pair of $500k tickets buys the raw fuel for one BFR launch.   If it takes 6 BFR launches to get one BFS to Mars, you need to sell 12 $500k tickets (or 24 $250k tickets)  to pay for the fuel.

Propellant is completely in the noise, compared to BFS cost to Mars.
If we assume that BFR cost is $100M, then just to keep pace with interest at 5% is $6M or so.
If you start actually trying to pay off the investment in 10 years, it's more like $25M than the $6M of fuel.

The numbers change if you can use P2P transports that have 'aged out' and hit cycle limit counts at say 1000 on earth, and are already paid off.
Title: Re: What does it take to get to a million people on Mars?
Post by: launchwatcher on 12/19/2017 05:48 pm
I don't think the limit is how fast you can get them there, but how fast you can build somewhere for them to live.

How many cities on Earth, built from scratch, had 1M inhabitants in less than 50 years, less than 100 years etc in STABLE accommodation (i.e. not shanty towns). Not many, if at all.
See the post-WWII building boom in the US.   Santa Clara County, California  went from a population of 26,000 in 1870 to just over 1 million in 1970 (and 1.78 million by 2010).

At its peak, the builders of Levittown (a post-WWII planned suburban community) were finishing 30 two-bedroom homes a day.   (The houses included an unfinished attic for expansion space which was commonly finished when needed for kids bedrooms).

1M in 50 years is 20,000/year, or 54 people/day.

Title: Re: What does it take to get to a million people on Mars?
Post by: launchwatcher on 12/19/2017 05:51 pm
So each pair of $500k tickets buys the raw fuel for one BFR launch.   If it takes 6 BFR launches to get one BFS to Mars, you need to sell 12 $500k tickets (or 24 $250k tickets)  to pay for the fuel.

Propellant is completely in the noise, compared to BFS cost to Mars.
Yes, that was exactly my point.
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/19/2017 07:15 pm
I see a delay for several synods before families emigrate.  Wait to check out environmental affects on humans. 
Then the next gating factor would be the ability to construct large living spaces that would make families beyond the first few thousand really want to go.  Elon said it would be fun.  Need to make it so.  Just takes a few more synods.
Quite possibly.  Having a mix of people, some of whom can and can't bear children on the BFS complicated population modelling even further.

Quote from: philw1776
Like the fact the BFS passenger quantity can be increased in the spreadsheet.  I don't think that a BFR/BFS architecture and design implemented in the teens will survive deep into the 2040s when really mass emigration of families beyond initial base(s) construction.  SpaceX is the last company that would stop innovating.  A 2 decade return on the base BFS design plus enhancements F9 to Block 5 style would be a nice return on the teens design.  Maybe "Block 5" BFSs would be used late 40s and beyond as shuttle vehicles Mars surface to orbit unloading really massive MCTs Mars Colonial Transports carrying 500-1,000 colonists.  These MCTs would never touch a planetary surface.
Although it's labelled "BFS" and the defaults are geared to it (in cost terms and size) I've tried to make everything that could (even remotely) be altered be alterable.
However a "Next Generation" BFS also means a development budget to go with it.
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/19/2017 07:22 pm
Propellant is completely in the noise, compared to BFS cost to Mars.
If we assume that BFR cost is $100M, then just to keep pace with interest at 5% is $6M or so.
If you start actually trying to pay off the investment in 10 years, it's more like $25M than the $6M of fuel.
Since this is not a government sponsored project I fully expect SX to try to recover as much of the costs of building every BFR/BFS they build in fares.

Assuming a $100m build cost and $6m propellant then it will be paid off after the 3rd flight.
Title: Re: What does it take to get to a million people on Mars?
Post by: RoboGoofers on 12/20/2017 01:30 am
It's interesting to consider that Alaska has a population of only 742k.

The point being that even with a gold Rush and a payment to residents for oil drilling, "modern" man hasn't populated a easy real estate* with more than 3/4 million people in 150 years.
 
It might be good to consider a lower bounds to keep the discussion grounded; Historically there have been 0 people on Mars.

*(Easy compared to Mars)
Title: Re: What does it take to get to a million people on Mars?
Post by: wes_wilson on 12/20/2017 01:54 am
I may be doing it wrong?  But the formula for children feels weird to me; if I put 4 in cell D9 it looks like each couple has that many kids per window.  So 4 in that cell means each woman is having a kid every 6 months window after window?

Again, likely me doing it wrong, but I'm having fun playing with it.  Thanks for putting it together! 
Title: Re: What does it take to get to a million people on Mars?
Post by: Ludus on 12/20/2017 05:45 am
I don't think the limit is how fast you can get them there, but how fast you can build somewhere for them to live.

How many cities on Earth, built from scratch, had 1M inhabitants in less than 50 years, less than 100 years etc in STABLE accommodation (i.e. not shanty towns). Not many, if at all.

https://en.m.wikipedia.org/wiki/Demographic_history_of_Detroit (https://en.m.wikipedia.org/wiki/Demographic_history_of_Detroit)
Detroit went from 285k in 1900 to over 1.5M in 1930 with stable accommodations. There are likely many others, I just had a notion that it applied to Detroit and confirmed it. Of course Detroit wasn’t built from scratch, just scaled by over a million in 30 years.

https://en.m.wikipedia.org/wiki/Demographics_of_Chicago (https://en.m.wikipedia.org/wiki/Demographics_of_Chicago)
Chicago is a good fit going from almost nothing in 1840 to over 1 million in 1890. Whether it meets the stable criterion, not sure.
Title: Re: What does it take to get to a million people on Mars?
Post by: jebbo on 12/20/2017 06:50 am
How many cities on Earth, built from scratch, had 1M inhabitants in less than 50 years, less than 100 years etc in STABLE accommodation (i.e. not shanty towns). Not many, if at all.

More recently than the Detroit example, Shenzhen (I was there last week).  It was essentially a small market town (~30K people) until 1980 and now has >11 million residents ...

I suspect there are other examples in China.

--- Tony
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/20/2017 08:38 am
I may be doing it wrong?  But the formula for children feels weird to me; if I put 4 in cell D9 it looks like each couple has that many kids per window.  So 4 in that cell means each woman is having a kid every 6 months window after window?

Again, likely me doing it wrong, but I'm having fun playing with it.  Thanks for putting it together!
You're welcome. Seeing what happens when you "twiddle the knobs" was exactly the point of doing it.

 You're not doing it wrong, but the interpretation is a bit tricky.

It's labelled as "Launch windows" but "Arrival window" might be more accurate.
Selecting a high number of children means that Mothers will continue to have children overlapping the arrival of the next passenger group 24 months later, and further. 9 children implies they will be using settlement medical resources into the following 3 landings as well, as will the Mothers of those landings.

So it looks odd but captures the growth correctly. IRL it means medical personnel would continue to be doing births at a time when the next passenger group has started getting pregnant.

This is one of the simplifying assumptions to work out when the the children born just after arrival can start having children of their own.
Another is they have as many children as their parents and only one generation is tracked. It does not track births from the next generation after that, and minimum time before first generation born on Mars can have kids is hard coded in terms of the number launch windows (rather than absolute time) since their birth, despite the possibility of changing this (since long term I believe people will find ways to shorten that gap down from 2 years)

Let me repeat that IRL the only studies on conception and child birth in partial gravity are (AFAIK) the partial g studies on the ISS for rats.

Large families also suggest that some kind of communal childcare becomes a necessity, unless women commit to be stay at home moms. In the 3rd decade of the 21st century will women actually revert to the social norms of the mid 20th?

Historically large families have been driven by
a)A complete lack of any social safety net
b)High infant mortality rate
c)The lack of any accumulated wealth to fall back on.
Average family sizes have fallen in the developed world as measures of all of these 3 things have improved.
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/20/2017 08:55 am
It's interesting to consider that Alaska has a population of only 742k.

The point being that even with a gold Rush and a payment to residents for oil drilling, "modern" man hasn't populated a easy real estate* with more than 3/4 million people in 150 years.
 
It might be good to consider a lower bounds to keep the discussion grounded; Historically there have been 0 people on Mars.

*(Easy compared to Mars)
You're right, with housing built to relevant modern standards and suitable clothing Alaska is easy to live on compared to Mars.

It is astonishing.  Given the size of the state it's average population density is almost zero.

http://www.citymayors.com/gratis/uscities_100.html

Lists 9 US cities with populations > 1 million (in 2012) and a further 8 (Charlotte, NC being the smallest) with populations greater than the whole state of Alaska (in 2012).

Indeed, despite state support, no immigration barriers (AFAIK) stopping anyone from the other 49 going there and spectacular scenery, low crime (?) and (presumably) a strong sense of community (given the sizes of most places)  people don't actually want to go there.  :(

Is it really that much colder than Chicago or Minnesota? Are the wolves and bears that terrifying?
Title: Re: What does it take to get to a million people on Mars?
Post by: JamesH65 on 12/20/2017 09:41 am
I don't think the limit is how fast you can get them there, but how fast you can build somewhere for them to live.

How many cities on Earth, built from scratch, had 1M inhabitants in less than 50 years, less than 100 years etc in STABLE accommodation (i.e. not shanty towns). Not many, if at all.

https://en.m.wikipedia.org/wiki/Demographic_history_of_Detroit (https://en.m.wikipedia.org/wiki/Demographic_history_of_Detroit)
Detroit went from 285k in 1900 to over 1.5M in 1930 with stable accommodations. There are likely many others, I just had a notion that it applied to Detroit and confirmed it. Of course Detroit wasn’t built from scratch, just scaled by over a million in 30 years.

https://en.m.wikipedia.org/wiki/Demographics_of_Chicago (https://en.m.wikipedia.org/wiki/Demographics_of_Chicago)
Chicago is a good fit going from almost nothing in 1840 to over 1 million in 1890. Whether it meets the stable criterion, not sure.

Which sort of proves my point. There are some examples of cities on Earth that gained a million inhabitants in 50 years,perhaps slightly less. But not a huge number, and they already have air and power....

Now think of Mars. You have to build accommodation for 50 people per day, you need to have the machines to do it, the raw materials, the power to run machines, to have life support. Compared to this, getting them there is the easy part.
Title: Re: What does it take to get to a million people on Mars?
Post by: Lar on 12/20/2017 10:36 am
We have not yet seen a high tech colonization/expansion into previously unoccupied land, so I suspect the historical birthrate findings might not apply. I predict high family sizes and some people going into daycare as their full time job. Also I expect mothers to work from home (teleoperating things? crafting things like pump fittings or whatever? Growing specialty crops?) a lot...
Title: Re: What does it take to get to a million people on Mars?
Post by: STS-200 on 12/20/2017 11:39 am
Looking at the topic slightly differently:

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

-A reason for them to be there.

I'm not intending to be negative with that statement, I want to go to Mars "because its there",  and I'd like to see a million living there.
I believe would be a "good thing to do", but I have never really heard a solid argument for doing it right now.
The best I have heard is that we should start as soon as possible, because if we want to survive we will need to become a spacefaring species. Instead of reacting to external pressures, we can make a choice in advance.

However, that still doesn't answer the question "Why do the first million go?". What is in it for them?
I can't see that any of the traditional reasons apply strongly enough - jobs, land, resources or "freedom" (in all its meanings) are going to be easier to obtain on Earth for the foreseeable future.
I would argue that the growth debates in several posts above might only apply to the "second million" - i.e. once there is a functioning society/industry/trade system, there is the reason and means for growth. Before that, you might be looking for a very odd group - people wanting high-tech subsistence lives, and who are willing to pay up-front for the privilege.

I'll stop there, as I'm in danger of thinking too negatively, but however fascinating the engineering of getting a million to Mars is, they still need a reason to go.
Title: Re: What does it take to get to a million people on Mars?
Post by: allhumanbeings07 on 12/20/2017 01:22 pm
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.
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/20/2017 05:59 pm
Looking at the topic slightly differently:

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

-A reason for them to be there.
True.

Unfortunately this is completely OT for this thread, which is more focused on the logistics and parenting involved behind making that happen. It is assumed that the settlers have reasons already.

It has been discussed at length. Use the sites search for "Martian homesteading" for more details.
Title: Re: What does it take to get to a million people on Mars?
Post by: DanielW on 12/20/2017 07:44 pm
Since reproduction will have to play a critical role in reaching 1 million people; requirements will be theaters, mini-golf courses, brew-pubs, lawns serviceable for picnics, candles, champagne, churches, and plenty of personal space.
Title: Re: What does it take to get to a million people on Mars?
Post by: Welsh Dragon on 12/20/2017 08:45 pm
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?
Title: Re: What does it take to get to a million people on Mars?
Post by: DanielW on 12/20/2017 09:21 pm
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.
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/20/2017 10:37 pm
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.  :(
Title: Re: What does it take to get to a million people on Mars?
Post by: Ludus on 12/23/2017 07:13 pm
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.
Title: Re: What does it take to get to a million people on Mars?
Post by: Ludus on 12/23/2017 07:33 pm
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.
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/23/2017 08:03 pm
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?
Title: Re: What does it take to get to a million people on Mars?
Post by: philw1776 on 12/23/2017 09:16 pm
Washing clothes?  In-situ CO2.

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

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


Title: Re: What does it take to get to a million people on Mars?
Post by: launchwatcher on 12/24/2017 02:12 am
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. 
Quote
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...

Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/24/2017 06:54 am
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. 
Quote
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).
Quote from: launchwatcher
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.
Title: Re: What does it take to get to a million people on Mars?
Post by: john smith 19 on 12/26/2017 09:08 pm
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? ]