Author Topic: How many BFR Boosters will SpaceX need to build?  (Read 4200 times)

Online Lars-J

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Re: How many BFR Boosters will SpaceX need to build?
« Reply #20 on: 10/05/2017 09:03 PM »
They will likely manufacture in blocks. My guess would be 4 in Block I. Performance, tweeks, and emerging customer demand will determine advancements incorporated in and numbers produced in successive blocks.

4? I think you underestimate the cost of BFR booster. They will be valuable hardware costing many times more than expendable rockets. They'll want to make sure and perfect the design before they build any more than they have to. Two at most for "Block I" is all I see, although as with F9 the block divisions will hazy at best. But they certainly don't want to build too many in case a critical design flaw is discovered.

Online TomH

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Re: How many BFR Boosters will SpaceX need to build?
« Reply #21 on: 10/05/2017 11:11 PM »
They will likely manufacture in blocks. My guess would be 4 in Block I. Performance, tweeks, and emerging customer demand will determine advancements incorporated in and numbers produced in successive blocks.

4? I think you underestimate the cost of BFR booster. They will be valuable hardware costing many times more than expendable rockets. They'll want to make sure and perfect the design before they build any more than they have to. Two at most for "Block I" is all I see, although as with F9 the block divisions will hazy at best. But they certainly don't want to build too many in case a critical design flaw is discovered.

They may well do one single prototype as Block 0 (like STS Enterprise), then go to Block I. I'm still guessing 4 for Block I. And of course, that is a very wild @$$ guess. And I'm looking at the word block as meaning a production run. I would not be surprised to see that spread over several years with minor changes to each booster, just as was the case with STS. But we shall see. I have to say, this discussion of what lies ahead is much more optimistically enjoyable than the one we all had re. a different monster rocket over the last 8 or so years.

Online Zed_Noir

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Re: How many BFR Boosters will SpaceX need to build?
« Reply #22 on: 10/06/2017 03:04 AM »
Think there will be an initial build of 3 boosters with 2 additional projected builds when BFR ASDS become available to established initial Intercontinental P2P service and polar orbit capability.

#1.  trials & spare unit (inactive)

#2. LC-39A resident unit

#3. Boca Chica resident unit

#4. New England offshore resident unit (projected)

#5. California offshore resident unit (projected)

With one new booster as each additional offshore pad come online. Plus a spare boosters for every 8note 1 active boosters.


note 1 - Or what ever number that SX decide is appropriate

Online Robotbeat

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Re: How many BFR Boosters will SpaceX need to build?
« Reply #23 on: 10/06/2017 03:14 AM »
If ships get 100 reuses and boosters get 1000, then to get 1000 flights per year on average (and both numbers include hull losses), they need 1 BFB per year and 10 BFSes per year. 111 Raptors per year.

Pretty easy math.

I suspect early numbers will be a factor of 10 worse, so again like 1 BFB per year (3 a year at first to fill out launch sites and provide spares) and 10 BFSes, for a total of 100 flights per year, which is about what they need if the constellation works out well.

It's possible they'll need more launches if they make the constellation satellites much bigger.

So SpaceX might keep a similar production rate as they have now.
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Offline RocketmanUS

Re: How many BFR Boosters will SpaceX need to build?
« Reply #24 on: 10/06/2017 06:44 AM »
What is the turn around time for the booster for relaunch once landed back on the launch pad?
After how many flights will it have to stand down for refurb?
How many launches will there be per year?

That is part of what is needed to know for how many boosters will be needed.
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Offline RonM

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Re: How many BFR Boosters will SpaceX need to build?
« Reply #25 on: 10/06/2017 05:57 PM »
What is the turn around time for the booster for relaunch once landed back on the launch pad?
After how many flights will it have to stand down for refurb?
How many launches will there be per year?

That is part of what is needed to know for how many boosters will be needed.

SpaceX will have estimates, but no one will really know the answers to those questions until production boosters are flying. For example, the Shuttle never got anywhere near the predicted flight rate. We'll have to wait and see if SpaceX is being overly optimistic or if they can successfully do rapid turnaround.

Offline AC in NC

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Re: How many BFR Boosters will SpaceX need to build?
« Reply #26 on: 10/07/2017 02:53 AM »
Duh!  42.

Offline tdperk

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Re: How many BFR Boosters will SpaceX need to build?
« Reply #27 on: 10/08/2017 03:40 PM »
This just a silly thread.  Nobody knows the answer.  Not even SpaceX.

Saying SpaceX doesn't know is silly. Did NASA roll dice to determine how many Shuttles to build? Of course not. They had a plan and so does SpaceX.

"Jim" is an instantiation of a vague grumble.

Online oldAtlas_Eguy

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Re: How many BFR Boosters will SpaceX need to build?
« Reply #28 on: 10/08/2017 09:27 PM »
Some boundings to the problem.

1- Initially the life (number of launches) capable by the two elements will be close to the same.

2- Quickly the booster will extend its life first past 5 then past 20. This will be done in only a few design iterations.

3- But the spacecraft or US however one wants to refer to it will take awhile and quite a few launches and design iterations to get the life beyond 20 or even just 5.

4- This difference in the rate of the life expansion would be represented by the differences in the build rates between the booster and SC elements. With the booster possibly even decreaseing in rate with the SC rapidly increasing in rate. A booster with life of 100 gas-n-go matched with a SC life of 20 gas-n-go would need 5 SC built for every 1 booster something similar to what SpaceX faces now with F9.

5- The general rule would be that the factor difference between will grow rapidly to a significant number before the SC maturity catches up to the almost design frozen booster.

With all of this the numbers built [my WAG]:

in the first 2 years would be: 3 boosters and 5 SC [launch/yr rate at end of period = 15]

in the first 5 years would be: 6 boosters and 20 SC ->Flying 4 boosters Life (50), 15 SC Life (10) [launch/yr rate at end of period = 50]

in the first 10 years would be: 11 boosters and 70 SC->Flying 5 boosters Life (250), 50 SC Life (25) [launch/yr rate at end of period = 200]

after that the dichotomy of build rates would start to close back


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