Author Topic: Elon Musk Reddit AMA on BFR  (Read 47808 times)

Online FutureSpaceTourist

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Re: Elon Musk Reddit AMA on BFR
« Reply #20 on: 10/14/2017 09:05 pm »
Bit of info on BFS development steps

Edit to add: more follow-up detail in 2nd attachment
« Last Edit: 10/14/2017 09:17 pm by FutureSpaceTourist »

Online nacnud

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Re: Elon Musk Reddit AMA on BFR
« Reply #21 on: 10/14/2017 09:08 pm »
*Speculation*

Perhaps this is the plan for Boca Chita now that flights from McGregor are a no no.

Offline Michael Baylor

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Re: Elon Musk Reddit AMA on BFR
« Reply #22 on: 10/14/2017 09:10 pm »
*Speculation*

Perhaps this is the plan for Boca Chita now that flights from McGregor are a no no.
Only other possibility is the Cape from a modified launch site. Doubtful that they could make that work though at a reasonable cost. This is going to need a serious flame trench, even though it will be possibly be less thrust.
« Last Edit: 10/14/2017 09:12 pm by Next Spaceflight »

Online vaporcobra

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Re: Elon Musk Reddit AMA on BFR
« Reply #23 on: 10/14/2017 09:14 pm »
*Speculation*

Perhaps this is the plan for Boca Chita now that flights from McGregor are a no no.
Only other possibility is the Cape from a modified launch site. Doubtful that they could make that work though at a reasonable cost. This is going to need a serious flame trench, even though it will be possibly be less thrust.

FWIW, LC-39A was overengineering for Nova from the start. It can handle BFR and even ITS-level thrust. The question is if SpaceX could realistically modify 39A to support Falcon and BFR while still satisfying their Commercial Crew obligations.

Offline calapine

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Re: Elon Musk Reddit AMA on BFR
« Reply #24 on: 10/14/2017 09:15 pm »

Offline Michael Baylor

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Re: Elon Musk Reddit AMA on BFR
« Reply #25 on: 10/14/2017 09:16 pm »
FWIW, LC-39A was overengineering for Nova from the start. It can handle BFR and even ITS-level thrust. The question is if SpaceX could realistically modify 39A to support Falcon and BFR while still satisfying their Commercial Crew obligations.
I am aware of that. I just logically ruled it out since the current timeline is before 2022. I suppose I maybe should not have ruled that out though. I just don't see them getting Pad 39A ready in time. It would take some serious modifications to an active launch site. But anything is possible!

Online nacnud

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Re: Elon Musk Reddit AMA on BFR
« Reply #26 on: 10/14/2017 09:25 pm »
The development plan for BFS seems like what the follow on to the DC-X should have been.

Offline calapine

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Re: Elon Musk Reddit AMA on BFR
« Reply #27 on: 10/14/2017 09:26 pm »
Next one...
Edit: fixed image
« Last Edit: 10/14/2017 09:28 pm by calapine »

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Re: Elon Musk Reddit AMA on BFR
« Reply #28 on: 10/14/2017 09:30 pm »
Tanker design
« Last Edit: 10/14/2017 09:31 pm by FutureSpaceTourist »

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Re: Elon Musk Reddit AMA on BFR
« Reply #29 on: 10/14/2017 09:33 pm »
BFS heat shield mounting

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Re: Elon Musk Reddit AMA on BFR
« Reply #30 on: 10/14/2017 09:40 pm »
BFS thrusters

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Re: Elon Musk Reddit AMA on BFR
« Reply #31 on: 10/14/2017 09:44 pm »
BFR heat exchangers

Offline calapine

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Re: Elon Musk Reddit AMA on BFR
« Reply #32 on: 10/14/2017 09:48 pm »
Raptor and 3D printing

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Re: Elon Musk Reddit AMA on BFR
« Reply #33 on: 10/14/2017 09:55 pm »
BFS wings

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Re: Elon Musk Reddit AMA on BFR
« Reply #34 on: 10/14/2017 09:57 pm »
BFS cylindrical shape

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Re: Elon Musk Reddit AMA on BFR
« Reply #35 on: 10/14/2017 10:01 pm »
Why no BFS tail

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Re: Elon Musk Reddit AMA on BFR
« Reply #36 on: 10/14/2017 10:04 pm »
Very interesting about the wings, if you watch the Mars descent video from the IAC presentation you can see the BFR entry is nothing like a shuttle or any other lifting body.

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Re: Elon Musk Reddit AMA on BFR
« Reply #37 on: 10/14/2017 10:10 pm »
4k rocket video (and with that Iím out of time, not sure how much more Elon is going to do)
« Last Edit: 10/14/2017 10:11 pm by FutureSpaceTourist »

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Re: Elon Musk Reddit AMA on BFR
« Reply #38 on: 10/14/2017 10:15 pm »
Why was the number of BFS landing legs increased from 3 to 4?

The BFS/2016 design used three landing legs, while the new BFS/2017 design uses four.
What is the motivation behind this change?

Elon Musk-Because 4

Elon Musk-Improves stability in rough terrain

Online nacnud

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Re: Elon Musk Reddit AMA on BFR
« Reply #39 on: 10/14/2017 10:17 pm »
This is an odd answer, three legs are more stable than four. I'll be back with links.

Edit: Can't find the link I was after (NASA study for lander legs, Mars Phoenix if I recall correctly) but basically three points define a plane so the lander won't rock. Where it is unlikely that four points on a rough surface form a plane, so it will wobble. Suspension can correct for this.
« Last Edit: 10/14/2017 10:24 pm by nacnud »

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