SpaceX Interplanetary Transport System (updates)


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DocM    16,962

BOTE, I'm guessing about 15 meters wide by 75-80 meters tall for the BFS lower stage. Betting BFS will be both the upper stage and the vehicle.  A 4:1 aspect ratio would make BFS about 60 meters long, which means a stack 135-140 meters tall.

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Unobscured Vision    2,692

Yep. 15 meter hull, likely vertical assembly. No way they'll be able to do an erector from horizontal with something this size, even dry mass.

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DocM    16,962

And no way is it a 10-13 meter hull. It'd take a stack 150 meters (~500 feet) tall to hold the propellants, and there's not enough base area to hold 20+ engines with 4.2 meter nozzles.

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DocM    16,962

Looking like a ~4 meter nozzle for the vacuum Raptor, and just under 2 meters for the sea level Raptor.

 

The combustion  chamber won't be much larger that a Merlin 1D's, more than 3x the pressure, but that dual multi-staged pumping system is going to be something to behold.

 

We ain't in Kansas anymore. 

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DocM    16,962

Looks like SpaceX updated the Raptor Wikipedia page - added proprietary info like mix ratio and more accurate thrust numbers.

 

Raptor 

 

Propellants: LOX/liquid methane
Mixture ratio: 3.8:1
Cycle: Full-Flow Staged Combustion
Pumps: 2× multi-stage
Chambers: 1
Chamber pressure: 30 MPa (4,400 psi)

 

Sea level performance


Thrust (S/L): 2.7 MN (610,000 lbf)
Isp (S/L): 321 seconds
Nozzle ratio: ?? (likely 50ish)
Nozzle diameter: ?? (likely <2 meters)

 

Vacuum performance


Thrust (vacuum): 3 MN (670,000 lbf)
Isp (vacuum): 362 seconds
Nozzle ratio: 150
Nozzle diameter: ~4 meters (13 ft)

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DocM    16,962

Typo correction

 

Isp (vacuum): 382 seconds

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Unobscured Vision    2,692

Yeah, we always lose about 10% at SL. That's the way of things ...

 

I stand by what I said though ... watching a night launch will be uncomfortable. Watching it in the daytime might be too. Two-dozen-plus Raptors going off at once is gonna be bright. :yes: 

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DocM    16,962

Musk corrected himself about the production Raptor area ratio.

 

@elonmusk

@rocketrepreneur Meant to say 200 AR for production vac engine. Dev will be up to 150. Beyond that, too much flow separation in Earth atmos.

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+John.    1,396

It's here! I've only been waiting since February!

7drHiqr.gif

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DocM    16,962

18:30 UTC. 
 

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Draggendrop    5,748

Ed the Sock.jpg

 

50 minutes to "showtime"....xmas in September....

 

 

 

 

 

 

 

 

 

 

:D

 

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anthdci    235

that video!

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anthdci    235

mind blown if they pull this off!

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FloatingFatMan    21,361

Hurry up! Stupid minutes and seconds ticking by so slowly!

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DocM    16,962

42 engines on BFR is about 28 million pounds of liftoff thrust.

 

Boosback

spacex-bfr-boostback.jpg

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anthdci    235

thats smaller than the 15m predicted... those engines must be packed pretty tight

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DocM    16,962

I figured 15m for 30 or less engines, but 12m for 42? 

 

Differential throttle steering?

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DocM    16,962

28 km/s , about a 25 day transit.
 

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Draggendrop    5,748

 

 

 

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