How Much Will BFR Cost?

Sam Dinkin runs the numbers. Looks about right to me. People really don’t appreciate how little of the cost of a launch is propellant, and once we fix that, how much we can reduce it.

21 comments on this post.
  1. Calvin Dodge:

    Long ago in an article on SSTOs, Jerry Pournelle said “structure is expensive, fuel is cheap” (in that case, emphasizing that landing vertically on rocket thrust was a better idea than using wings and landing gear). It’s nice to see that others have recognized this.

  2. ken anthony:

    So if we have 100 colonists the ticket would be…

    $620k + markup (call that one million) for 4.5 tons (2 tons consumed enroute.)

    That’s 5 times less cost and 2.5 times more mass per ticket than my plan proposes to pay as initial price.

    If every colonist has one ton of personal property they arrive with over $200k in assets to start there new life. (Things they would otherwise have to pay transportation costs to have delivered from earth.)

    The main bug in the ointment being the cost of a mars suit which should be included in the ticket price.

  3. Ray:

    Somewhere I ran across a blogger that had a (quite clever I thought) plan to fund Mars colonization. I think it was something like making a market in Martian land (and products/shares? Can’t remember), and giving a portion to settlers, and the speculation in the market would provide the funding for the project.

    Was this you? If not, do you perhaps know who it was?

  4. Edward M. Grant:

    The problem is, land will be cheap once we get established off this planet. Just take an asteroid apart and build the world of your dreams.

  5. ken anthony:

    Land will always vary in value depending on local conditions. Land is always going to be worth more when you have neighbors doing their own independent development.

    Cheap land isn’t always worth the cost.

  6. ken anthony:

    Ray, if I can ever finish it, I’m working on a book that has the central concept of using a bank founded on developing mars with mars assets (which today would be worth trillions if people just accepted the idea which is losing to the competing communistic concept that space belongs to the bureaucrats: “all mankind”)

    This concept is often confused with fraud where some with no historically valid claim try to enrich themselves..

    My plan was to fix flaws in the space settlement initiative. Which SpaceX is now making viable.

    Somehow the road to serfdom is winning because of those that benefits.

  7. ken anthony:

    This Wired article refers to Rand’s article on the subject.

  8. wodun:

    Does the passenger ship also allow for 50t down for cargo?

  9. wodun:

    A million dollars a seat plus the cost of the assets needed once on Mars puts moving out of range of most people but for less than the price of sending a couple of astronauts to the ISS on a Soyuz, our government could send 100 people to Mars.

    The various cargo required to support those people could be rather expensive, especially if paid for the old way, but the launch costs wouldn’t. It might not be a crazy assumption that for what NASA spends on SLS/Orion every year, they could support a Martian outpost, assuming that the design/construction of one was done ala COTS.

  10. ken anthony:

    Or instead of corrupt politicians trying to carve up any value for themselves… you let the free market (anybody) bid for plots and that money only used for mars development.

    14.4 trillion hectares sold at auction would finance development of the entire planet in just a few decades. If the colonists get free tickets (by lottery) their personal property (one ton included in their ticket) gives every single colonist the resources (a minimum of hundreds of thousands of dollars) to develop the colony in ways we could never do otherwise.

  11. McG:

    You know, I had a tongue-in-cheek idea of what BFR stood for until I was finally moved to run it down despite not finding it spelled out in the article linked here.

    Wikipedia finally sort-of-confirmed my fifth-grader guess, and it doesn’t help that the G-Rated version reminds me of all those times Dr. McCoy snapped, “Are you out of your Vulcan mind!?”

  12. M Puckett:

    β€œAre you out of your Vulcan mind!?”

    That would be an appropriate question for ULA.

  13. Calvin Dodge:

    Given its shrinkage, I now refer to it as the NSBFR.

  14. Ray:

    Biggish Falcon Rocket?

  15. Dave Salt:

    Big ‘Friendly’ Rocket, surely… with apologies to Roald Dahl πŸ™‚

  16. MfK:

    I first heard of the BFR in 2005, and the F stood for what it actually stands for (the sanitized version is “Falcon”}. Elon has never changed that, at least among his friends.

    Sam’s analysis is pretty good. The first place I always go is propellant cost. That is the floor cost. It also shows why solid propellant rockets will never, ever be economical ($25/lb cast and cured as opposed to $0.28 per pound for fewer pounds).

  17. Rand Simberg:

    Yes, I was surprised to hear all the surprise in the media at Gwynne’s use of Big Falcon Rocket. I’ve also heard that for over a decade now.

  18. wodun:

    The BFR architecture anticipates five booster trips instead of six for the ship and the tankers, but there will be ten booster trips if we consider the companion cargo version of the ship.

    So each cargo/passenger ship requires 4 refueling tanker launches? hmm

  19. ken anthony:

    A ship in orbit could buy fuel from anyone creating a market. Let the creative competition begin.

  20. Paul D.:

    It’s interesting that propellant is still ~1% of the total cost there.

    I have been wondering… what drives the cost of propellant here? LOX and methane are cheap, but just how cheap depends on the details, specifically on how pure they have to be.

    LOX comes contaminated with heavier gases (nitrogen, argon) and traces of hydrocarbons. I have wondered if any of the latter affects subcooling. You don’t want solid hydrocarbon phases to freeze out as the LOX is cooled below its normal boiling point, as this would present an explosion hazard.

    Methane comes with other hydrocarbons mixed in. Getting to pure methane is probably unnecessary, but how precise does the mixture have to be? And removing sulfur compounds (to < 1 ppm) is highly desirable to prevent corrosion of the engine.

  21. Rand Simberg:

    I wonder if they plan to subcool for the BFR?

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