"Cost per seat should be about the same as full fare economy in an aircraft. Forgot to mention that."
Extraordinary. Melbourne to London in an hour for the same cost as a flight in an ordinary jet? Once this technology is proven, who will want to fly on a conventional jet? When I talked about this in my previous post, the guess I had in my head was a ticket cost of $20,000, not something more like $1,000-$2,000. The SpaceX ship could probably seat 500, on maybe 8 levels with the pilots in the nose (though in fact automated). At this price, the cost of launch and landing (let's be conservative) will be $2,000*500 = $1 million. (Is this just fuel and maintenance or did Musk include depreciation in his calcs?)
When it comes to Mars, though, the big cost of a trip won't be fuel and maintenance, it will be depreciation, because of re-usability restrictions. Mars and Earth are only in alignment for a few months every two years, so each spaceship will only be used maybe 10 or so times one way, 20 times there and back over a 20 year life. Let's say the BFR costs $400 million (the cost of an Airbus A380). That means each trip to Mars will cost $20 million in depreciation. Cost of launch $1 mill. Food and such for 100 people: 6 months * $1000 per month* 100 = $600K. So total cost of each Mars trip $22 million plus contingencies and things I've missed $4 mill. However some of the cost will be borne by the cargo. So say $13 million for passengers--$130,000 per person. Except, initially anyway, SpaceX will be giving a free return ticket. But how many will actually make use of that ticket? I wonder. And how long will it continue to need to make that offer?
Can we doubt that Musk will get the cost of a journey to Mars below $100,000, given that this is still early days and that he is a genius at cutting costs? The BFR will get bigger, the engines more efficient, the journey faster. Once a regular biennial service begins, and competition gets started, costs will decline steadily.
Journeys to the moon, however, will be far cheaper than journeys to Mars, because the moon is less than a day away (384,000 kms from Earth at the speed of the Earth-to-Earth rocket of 27,000 kph = 14 hours, give or take curving path, acceleration, deceleration, etc.), so the BFR could in principle be in almost constant use. Unlike an Earth-to-Earth flight, the BFR would have to keep firing its rockets to accelerate from 27K kph to escape velocity (roughly 40K kph) and then decelerate to land on the Moon without the benefit of an atmosphere to slow it down. Which means that to get to the Moon and back, the BFR would have to refuel in orbit round Earth (it couldn't, initially anyway, refuel on the Moon). Musk didn't mention what payload the BFR could lift off the Moon, but he did say that the BFR's payload from Mars would be 20-50 tons (depending on the different phases of the Mars and Earth orbits, I guess). Gravity on the Moon is a bit less than half gravity on Mars, so, say 40-100 tons payload on the return journey from the Moon? So journeys to the Moon could cost perhaps 1.5 times the fuel with (say) 1/2 the total payload of a "flight" from Melbourne to London, or 3 times as much. The cost of a business class ticket. Did I screw up the calcs? Let's say 5, nay, 10 times as much. Still seriously, staggeringly cheap. Seriously. Stunning. Remarkable. World-changing. We've come a long way since Tintin and his friends journeyed to the Moon in 1954.
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| Hergé's vision of a moon trip in 1954. (Source) |
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| Musk's vision of a moon trip, 2017 |
(By the way, the ABC (Australian Broadcasting Corporation) has a nice piece on Musk's announcement to the IAC here, for those who don't like videos.)
[Update 22/08/19: Using stainless steel for construction will cut the cost perhaps 10-fold, not just because it's 50 times cheaper than carbon-fibre composite, but because construction is so rapid, as evidenced by two Mark 1 Starships under construction and close to completion right now]
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