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.

Quote from: QuantumG on 12/18/2017 11:54 pmHe 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.

Quote from: meekGee on 12/19/2017 12:01 amQuote from: QuantumG on 12/18/2017 11:54 pmHe 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)

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.

Quote from: Robotbeat on 12/19/2017 05:14 am5 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.

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...

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

That can only apply in early stages...

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?

Quote from: john smith 19 on 12/19/2017 09:34 amStarlink 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 CH43443t LOXOnce 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/tso 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.

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).

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.

Quote from: Lar on 12/19/2017 12:16 amQuote from: meekGee on 12/19/2017 12:01 amQuote from: QuantumG on 12/18/2017 11:54 pmHe 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...

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.

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.