Author Topic: General Falcon and Dragon discussion (Thread 13)  (Read 396604 times)

Offline Rebel44

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #340 on: 05/01/2016 12:25 am »
The 13.150kg number has been on the Falcon 9 page all day, but the Capabilities page has said 28,880kg the same time.

Perhaps 13,150kg is the RTLS number, or just didn't get updated.

They misplaced kg for lb.  It is 28,880lb not kg.
From all the previous discussion covering the v1.1 perfomance especially the available spaceX values from the performance Querry of the NASA NLS-II web site put s the v1.1 performance as 16,625 kg LEO and 5,725 kg GTO. So the FT values have to be larger. The performance improvement of FT over v1.1 is >30% from musk statements even before the flight of the first FT.

From all the math I believe the values as posted are the correct maximum (no margins) expendable performance. Now add margins for either stage return or engine out and the practical will be less.

Are you saying the Max LEO is 28,800kg?  A 30% increase in performance over 16,625 v1.1 would be about 21,000 kg.

The website specifically says 22800kg to LEO, not 28800kg.

number in pounds fits 28800kg - guess, we will have to wait a day or so for messed up numbers to be fixed.

Offline Craig_VG

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #341 on: 05/01/2016 12:26 am »

The website specifically says 22800kg to LEO, not 28800kg.

That's in the Falcon 9 section, we can assume that's for reuse. Check the capabilities and services page under About SpaceX for the full number, 28,800 kg.

Offline sewebster

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #342 on: 05/01/2016 12:27 am »
The website specifically says 22800kg to LEO, not 28800kg.

Not here... http://www.spacex.com/about/capabilities

Offline Lars-J

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #343 on: 05/01/2016 12:30 am »
Something doesn't add up - there must be a typo so where.

Offline Rebel44

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #344 on: 05/01/2016 12:30 am »

The website specifically says 22800kg to LEO, not 28800kg.

That's in the Falcon 9 section, we can assume that's for reuse. Check the capabilities and services page under About SpaceX for the full number, 28,800 kg.

And even F9 page has value in pounds that = 28800kg

Online oldAtlas_Eguy

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #345 on: 05/01/2016 12:32 am »
It looks like the 22,800 value is a typo since the value in lbs under it is 28,800 in kg.

Offline Rebel44

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #346 on: 05/01/2016 12:33 am »
Elons post, that there are no physical changes to engine, confirms earlier calculation, according to which Merlin now has around 199,5 trust-to-weight ratio

Offline Mader Levap

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #347 on: 05/01/2016 12:35 am »
Now webpage is fixed. 22,800 kg everywhere.

To be frank, SpaceX should be embarassed.
« Last Edit: 05/01/2016 12:48 am by Mader Levap »
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Offline Nomadd

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #348 on: 05/01/2016 12:40 am »
 How long ago was it that people were wondering if the F9 would ever make that early 12,500kg LEO figure?
Those who danced were thought to be quite insane by those who couldn't hear the music.

Offline OxCartMark

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #349 on: 05/01/2016 12:49 am »
It looks like the 22,800 value is a typo since the value in lbs under it is 28,800 in kg.
Inconsistencies in units and similar errors have a history of causing perfectly good landers to bonk into Mars.
Actulus Ferociter!

Online oldAtlas_Eguy

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #350 on: 05/01/2016 12:50 am »
Now webpage is fixed. 22,800 kg everywhere.

To be frank, SpaceX should be embarassed.

Thanks for update correcting the 40% and 30% RTLS and ASDS estimate cases for LEO
RTLS 13,680
ASDS 15,960

Offline joek

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #351 on: 05/01/2016 12:53 am »
Judging by Musk's latest tweets, it is NOT mistake.

So it seems... maybe... but still hard to believe.  At any rate they're going to need a new PAF, as the one in the last F9  Payload User's Guide is only good to 10,886kg.

Or maybe what we are seeing is the theoretical maximum, and does not account for other structural limits?  E.g., given the CG limits (see attached), is it feasible to launch a payload near 28000Kg?  Or maybe SpaceX has changed those limits?

Offline RyanC

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #352 on: 05/01/2016 01:03 am »
I don't know if this has been raised elsewhere, but what would happen if SpX converted Falcon 9 to methane for F9 v1.5 to complement a new Raptor Methane upper stage to maintain the "one set of fuels" commonality for lower costs?

Essentially, a minimum cost conversion for F9 and Merlin 1D to methane; accepting a lot of trade-offs in lower performance than you could get from the new propellant(s) in exchange for cheaper R&DT&E costs.

Offline GalacticIntruder

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #353 on: 05/01/2016 01:04 am »
Here are the official SpaceX numbers right now. All in kilograms. Earlier was a typo.

F9 LEO 22800 kg , GTO 8300kg.

FH LEO 54400kg, GTO 22200kg.

M1D+, SL 190,000lbf.
« Last Edit: 05/01/2016 01:04 am by GalacticIntruder »
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Online oldAtlas_Eguy

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #354 on: 05/01/2016 01:07 am »
Here are the official SpaceX numbers right now. All in kilograms. Earlier was a typo.

F9 LEO 22800 kg , GTO 8300kg.

FH LEO 54400kg, GTO 22200kg.

M1D+, SL 190,000lbf.
Thanks, that makes the F9 an equivalent LV to an Atlas V(551) in performance. That may not be something by chance but by design.

So payloads that needs a DIVH would need a FH.

Offline AncientU

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #355 on: 05/01/2016 01:18 am »
Now webpage is fixed. 22,800 kg everywhere.

To be frank, SpaceX should be embarassed.

Webpages have been known to be incorrect... now fixed.

As to embarrassed, this puts the F9 up as the most efficient rocket ever at a payload mass fraction of 4.15%.  (22,800kg payload/549,054kg liftoff mass=0.0415)

They should hang their collective head in shame!
« Last Edit: 05/01/2016 01:19 am by AncientU »
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Offline Lars-J

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #356 on: 05/01/2016 01:42 am »
Now webpage is fixed. 22,800 kg everywhere.

To be frank, SpaceX should be embarassed.

Webpages have been known to be incorrect... now fixed.

As to embarrassed, this puts the F9 up as the most efficient rocket ever at a payload mass fraction of 4.15%.  (22,800kg payload/549,054kg liftoff mass=0.0415)

They should hang their collective head in shame!

Indeed. Someone else should be embarrassed by seeing a web site typo as a major embarrassment for SpaceX. ::)

Offline The Amazing Catstronaut

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #357 on: 05/01/2016 02:23 am »

As to embarrassed, this puts the F9 up as the most efficient rocket ever at a payload mass fraction of 4.15%.  (22,800kg payload/549,054kg liftoff mass=0.0415)



"But the ISP!"    ;D
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Offline mlindner

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #358 on: 05/01/2016 02:58 am »

As to embarrassed, this puts the F9 up as the most efficient rocket ever at a payload mass fraction of 4.15%.  (22,800kg payload/549,054kg liftoff mass=0.0415)



"But the ISP!"    ;D

If your throw mass is greater than the market's payloads then your ISP doesn't matter. Better payload fraction means less rocket mass which means less assembly cost (assuming optimal assembly).
LEO is the ocean, not an island (let alone a continent). We create cruise liners to ride the oceans, not artificial islands in the middle of them. We need a physical place, which has physical resources, to make our future out there.

Offline mvpel

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #359 on: 05/01/2016 02:59 am »
"But the ISP!"    ;D

Risking mod wrath, but I can't resist.
"Ugly programs are like ugly suspension bridges: they're much more liable to collapse than pretty ones, because the way humans (especially engineer-humans) perceive beauty is intimately related to our ability to process and understand complexity. A language that makes it hard to write elegant code makes it hard to write good code." - Eric S. Raymond

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