Author Topic: SpaceX Q&A  (Read 123854 times)

Offline Astrosurf

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Re: SpaceX Q&A
« Reply #100 on: 05/08/2014 04:00 pm »
i get that they probably are going to need more nitrogen thats easy to get, I dont know about ablitive, the legs may or may not need ablative they seem to hold up fine, where would ablative go on the first stage? i thought  first stage didnt go through atmospheric reentry, since its not going fast enough

All launch vehicles have to deal with non-trivial aeroheating on ascent, and the use of an ablative TPS is a common way of handling that. Engineered cork materials are one of the preferred options. The nosecones of the Shuttle SRBs were covered in the stuff. Any recoverable first stage will indeed have to deal with aeroheating from reentry, it's just not as extreme as what a vehicle coming in from orbit has to put up with.
I get what you mean  wsomething going over mach 1 is gonna get a little heat, Is the heat similar to that of a household oven ?
 Ive seen High power model rocket launches and whenever they recover the ones that go really fast and high, they show signs of heat shock and allot of the paint is gone I know the heat actually got hot enough in this one launch where it actually melted the go pro casing mid flight

Offline mgfitter

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Re: SpaceX Q&A
« Reply #101 on: 06/02/2014 10:20 pm »
How is the TEA-TEB mixture delivered to each of the Merlin-1D's?

Does each engine have its own reservoir or is it piped-in from a central tank located somewhere else?

If the former, then at what point do they fill each engine's storage container? Before rollout or on the pad?

-MG.

Offline terryy

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Re: SpaceX Q&A
« Reply #102 on: 06/07/2014 07:42 am »
How is the TEA-TEB mixture delivered to each of the Merlin-1D's?

Does each engine have its own reservoir or is it piped-in from a central tank located somewhere else?

If the former, then at what point do they fill each engine's storage container? Before rollout or on the pad?

-MG.

If you're talking about the first stage Merlin-1D's then the TEA-TEB is delivered via the pad and is not part of the first stage.

Offline guckyfan

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Re: SpaceX Q&A
« Reply #103 on: 06/07/2014 08:54 am »
How is the TEA-TEB mixture delivered to each of the Merlin-1D's?

Does each engine have its own reservoir or is it piped-in from a central tank located somewhere else?

If the former, then at what point do they fill each engine's storage container? Before rollout or on the pad?

-MG.

If you're talking about the first stage Merlin-1D's then the TEA-TEB is delivered via the pad and is not part of the first stage.

But for Return to the landing site they now have been given air restart capability. So TEA-TEB for restart is stored onboard. I don't know how it is done. However considered that TEA-TEB is provided externally for launch there is probably piping to distribute it from one input. So my best guess is they have one storage container and any engine can be restarted by openinig its input valve. Seems easier to me than having separate tanks for each restartable engine.


Offline pagheca

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Re: SpaceX Q&A
« Reply #104 on: 06/07/2014 02:36 pm »
Who builds SpaceX's CBMs?

what CBM means please, Common Berthing Mechanism?
« Last Edit: 06/07/2014 02:38 pm by pagheca »

Offline Wetmelon

Re: SpaceX Q&A
« Reply #105 on: 08/12/2014 03:45 am »
If you're talking about the first stage Merlin-1D's then the TEA-TEB is delivered via the pad and is not part of the first stage.

Maybe for the first ignition, but if the first stage were devoid of plumbing how would they relight engines for boostback and landing?

Offline penguin44

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Re: SpaceX Q&A
« Reply #106 on: 01/12/2015 06:24 pm »
Why does SpaceX keep attempting controlled landing of first stage as opposed to a parachute like shuttle boosters?

Offline pericynthion

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Re: SpaceX Q&A
« Reply #107 on: 01/12/2015 06:28 pm »
Salt water, impact damage.  The goal is "gas and go" reusability rather than Shuttle-style refurbishment.

Offline rpapo

Re: SpaceX Q&A
« Reply #108 on: 01/12/2015 06:29 pm »
Why does SpaceX keep attempting controlled landing of first stage as opposed to a parachute like shuttle boosters?
Because they tried parachutes, and they didn't work for them.
« Last Edit: 01/12/2015 08:07 pm by rpapo »
Following the space program since before Apollo 8.

Offline OSE

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Re: SpaceX Q&A
« Reply #109 on: 01/12/2015 07:06 pm »
i get that they probably are going to need more nitrogen thats easy to get, I dont know about ablitive, the legs may or may not need ablative they seem to hold up fine, where would ablative go on the first stage? i thought  first stage didnt go through atmospheric reentry, since its not going fast enough

All launch vehicles have to deal with non-trivial aeroheating on ascent, and the use of an ablative TPS is a common way of handling that. Engineered cork materials are one of the preferred options. The nosecones of the Shuttle SRBs were covered in the stuff. Any recoverable first stage will indeed have to deal with aeroheating from reentry, it's just not as extreme as what a vehicle coming in from orbit has to put up with.
I get what you mean  wsomething going over mach 1 is gonna get a little heat, Is the heat similar to that of a household oven ?
 Ive seen High power model rocket launches and whenever they recover the ones that go really fast and high, they show signs of heat shock and allot of the paint is gone I know the heat actually got hot enough in this one launch where it actually melted the go pro casing mid flight


I've attached a figure from Modern Compressible Flows by John Anderson that shows temperature behind a normal shock at 52 km altitude for various velocities. The most accurate line is the ``Equilibrium chemically reacting gas''. The IRBM reference point is probably most similar to the F9 stage 1 so I'd guess that surface temperature is less than 6000 K.

EDIT:

Mach 5 (complete guess, if someone has a better number let me know) at this altitude is about 1.6 km/s which would put the surface temperature at about 1500 K.
« Last Edit: 01/12/2015 07:11 pm by OSE »

Offline ClaytonBirchenough

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Re: SpaceX Q&A
« Reply #110 on: 01/16/2015 12:57 pm »
Has SpaceX ever shown interest in solid rockets?
Clayton Birchenough

Offline Proponent

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Re: SpaceX Q&A
« Reply #111 on: 01/18/2015 04:55 pm »
No.  (I mean, I can't categorically state that no one at SpaceX has ever brought up the idea, but I've certainly never heard about it.)

Offline ClaytonBirchenough

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Re: SpaceX Q&A
« Reply #112 on: 01/18/2015 06:19 pm »
No.  (I mean, I can't categorically state that no one at SpaceX has ever brought up the idea, but I've certainly never heard about it.)

What I thought... thanks!

I guess solids and reusability don't mix well.
Clayton Birchenough

Offline DecoLV

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Re: SpaceX Q&A
« Reply #113 on: 02/21/2015 05:42 pm »
 I imagine whatever ground support communications exist at pad 39A are hard-wired to NASA's LCC building, which SpaceX isn't going to use. If SpaceX is presumably going to control pad 39A from its center in Port Canaveral, how is that going to happen?

Offline Jim

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Re: SpaceX Q&A
« Reply #114 on: 02/21/2015 06:36 pm »
I imagine whatever ground support communications exist at pad 39A are hard-wired to NASA's LCC building, which SpaceX isn't going to use. If SpaceX is presumably going to control pad 39A from its center in Port Canaveral, how is that going to happen?

Just like any rewiring, cut, break, disconnect and add as needed.
« Last Edit: 02/21/2015 06:37 pm by Jim »

Offline DecoLV

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Re: SpaceX Q&A
« Reply #115 on: 02/21/2015 10:02 pm »
I imagine whatever ground support communications exist at pad 39A are hard-wired to NASA's LCC building, which SpaceX isn't going to use. If SpaceX is presumably going to control pad 39A from its center in Port Canaveral, how is that going to happen?

Just like any rewiring, cut, break, disconnect and add as needed.

That's a whole lotta wire! I thought they might be doing wireless RF some way. In any case, they're going to need IP routers, repeaters...maybe new conduit. Sounds like a potential mess.

Offline Jim

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Re: SpaceX Q&A
« Reply #116 on: 02/21/2015 11:30 pm »
Why would it be a mess?. The shuttle use old technology, none of the stuff you mentioned.  Laying new conduit is a common occurrence at the space center.

It wouldn't be a lot of wire, much less than the shuttle.  And fiber would be used for cross country
« Last Edit: 02/21/2015 11:34 pm by Jim »

Offline Proponent

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Re: SpaceX Q&A
« Reply #117 on: 02/24/2015 12:59 am »
Will SpaceX be using any of the original RP-1 infrastructure at LC-39A, or will it all be new?

Offline ClaytonBirchenough

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Re: SpaceX Q&A
« Reply #118 on: 07/18/2015 05:53 pm »
Has SpaceX ever shown interest in solid rockets?

(In response to my own question)

I'm actually reading "Here Be Dragons" by Stewart Money, it actually says on page 114, "At first, engineers considered a number of approaches to achieve the greater liftoff thrust, including adding either liquid or solid strap-on boosters, or significantly upgrading the Merlin main engine while maintaining the 5 engine arrangement."

So SpaceX did, at one point, consider solid rocket strap-on boosters! Food for thought...
Clayton Birchenough

Offline Space Invaders

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Re: SpaceX Q&A
« Reply #119 on: 12/16/2015 09:48 am »
An unsourced statement on Wikipedia says:

Historically, the Falcon 1 was originally planned to launch about 600 kilograms (1,300 lb) to low-Earth orbit for US$6,000,000 but later declined to approximately 420 kilograms (930 lb) as the price increased to approximately US$9,000,000.

Is that correct? Did the Falcon 1 really go from a projected 10,000 $/kg to an actual 21,428 $/kg?
« Last Edit: 12/16/2015 09:51 am by Space Invaders »

 

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