SpaceX: General Falcon and Dragon discussion (Thread 5)

[docmordrid]

http://www.wacotrib.com/wacotoday/135938808.html

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“We are, in fact, looking at digging a very deep flame trench so that instead of firing Falcon Heavy engines on elevated test stands, they fire into the ground, reducing noise levels,” said Kirstin Brost Grantham, SpaceX spokeswoman.
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[Jim]

Does SpaceX's decision to do the underground test stand have more to do with:

A) The neighbors      (Is this a really big deal?)

B) Economics           (Which would be more expensive?)

C) Secrecy               (Merlin 2 or strange fuel types with obvious hue)?

D) Engineering Risk   (No need to lift the engines onto a massive 500 foot tall stand, etc.)

E) Testing Convenience    (No need to climb a ladder for 15 minutes if a wire comes loose, etc.)

F) Other Factors     

Huh?

A deep flame trench does not mean underground test stand.

and he says the reason, noise. 

The rest are meaningless.  You don't build a new stand to save money.  There is no added secrecy.   A lift is a lift.  20 or 500 feet, it is the same risk.

You are looking for things that are not there.

[Antares]

I think underground is a mischaracterization.  Think of the stands at AFRL and Santa Su built into the sides of landforms.  In flat East Texas, they're having to build their own landform.

[hyper_snyper]

LOL 'underground test'.  They're not building nuclear bombs.

[Kabloona]

Does SpaceX's decision to do the underground test stand have more to do with:

A) The neighbors      (Is this a really big deal?)

B) Economics           (Which would be more expensive?)

C) Secrecy               (Merlin 2 or strange fuel types with obvious hue)?

D) Engineering Risk   (No need to lift the engines onto a massive 500 foot tall stand, etc.)

E) Testing Convenience    (No need to climb a ladder for 15 minutes if a wire comes loose, etc.)

F) Other Factors     

Sometimes the truth is exactly what the PR person says it is...according to the Waco Trib article, engine tests are "window rattlingly loud" in town, and if I recall, the first Merlin engine test down there startled a lot of residents who didn't know what the he77 was happening.

With SpaceX planning to ramp up production, engine tests should become more frequent. Sounds like Elon wants to be a good neighbor and stay on the right side of the locals. Plus he seems genuinely to like the Texas attitude and outlook. Trying to minimize the annoyance factor in an area where SpaceX plans to be a long-term player makes sense.

Plus, Elon is looking ahead to the Merlin 1D, which will be more powerful, and presumably even louder.

[go4mars]

"To fire all 27 engines at the same time, which is required to lift the massive rocket, a test stand will be built deep into the earth."

But I'll take your word for it until we see otherwise (as in an actually underground facility). 

[Chris Bergin]

Go for Mars..... about five posts up:

http://www.wacotrib.com/wacotoday/135938808.html

>
“We are, in fact, looking at digging a very deep flame trench so that instead of firing Falcon Heavy engines on elevated test stands, they fire into the ground, reducing noise levels,” said Kirstin Brost Grantham, SpaceX spokeswoman.
>

[Kabloona]

"To fire all 27 engines at the same time, which is required to lift the massive rocket, a test stand will be built deep into the earth."

Sometimes reporters who aren't rocket scientists have difficulty explaining exactly what it is that the rocket scientists are planning to build 

[go4mars]

1)You don't build a new stand to save money. 

2) There is no added secrecy. 

1) I'm not suggesting that they are building a new stand to save money.  I'm wondering which would be less expensive, a test stand as they propose it, or a big tall one like a scaled-up version of the old beal one.  Educated guesses are welcome. 

2) If there is a switch from RP-1 to a different fuel, the hue of the plume could be analyzed if it is visible to all of the neighbours.  If it isn't visible to all of the neighbours, then it can't be.  Also, it is might be obvious if all of the smoke and noise is coming from 27 plumes versus three much larger ones for example, if it is out in the open versus not viewable. 


Perhaps I am reading too much into it though.


Is it likely that the new test stand will replace tests on the old beal one (making it essentially obsolete?)  Or will separate programs use them separately?  example: F5 on the beal one instead of the new one.


Do any of you Texans know if construction has begun yet? 

[Jim]

"To fire all 27 engines at the same time, which is required to lift the massive rocket, a test stand will be built deep into the earth."

And that doesn't say foundation to you?

[dcporter]

You're probably reading too much into it. =)  Maybe hiding the test plume in a flame trench might be useful in some odd future, but SpaceX has been very forthcoming about its propellant choices on announced products to date.  (And they seem to announce things well before they show up on test stands.)  In this case the simplest explanation is probably the right one - they're trying to dampen sound on behalf of the neighbors (enlightened self-interest).

I have no particular knowledge but I would guess that the difference in cost between building a taller stand and a deeper trench is in the noise for a rocket company.

Regarding flame trench vs. underground testing bunker, Chris's quote effectively answered that.

By the way I believe the Stratolaunch rocket is down to 4 engines at last count.

[wolfpack]

 

2) If there is a switch from RP-1 to a different fuel, the hue of the plume could be analyzed if it is visible to all of the neighbours.  If it isn't visible to all of the neighbours, then it can't be.  Also, it is might be obvious if all of the smoke and noise is coming from 27 plumes versus three much larger ones for example, if it is out in the open versus not viewable. 

There are myriad other ways to determine what rocket fuel they're using. It comes in trucks. Those trucks need hazmat permits from the State of Texas. Fuel has to be stored. The storage facility needs permits. Local FD's need to have plans in place for every contingency. When the government wants to be secret, they can, by speaking those two powerful words -  "national security". Private companies aren't afforded that same luxury. Either you buy up an entire west Texas county, wall it in, and provide your own infrastructure for EVERYTHING, or you cooperate with local officials whose work will inevitably be FOIA-able.

Literally hundreds of ways to deduce what's going on without looking at an exhaust plume!

[go4mars]

There are myriad other ways to determine what rocket fuel they're using.

  I assume there are already natural gas lines to the facility.  Hard to tell if the RP-1 would be for grasshopper or other uses.  Perhaps a really good scout could crack it by tracking all that data.  But it's a bit like locking your door.  Keeps the lazier, less determined crooks out.  Also:

it might be obvious if all of the smoke and noise is coming from 27 plumes versus three much larger ones for example, if it is out in the open versus not viewable. 

But in general, I agree.  They have been very open with their plans.  Even the "musing" and "maybe" types of plans.   I love that they do that!   

I concede unlikelyhood of mysterious uses, but assert that it could be propitious for future developments depending on how it is built. 

[Nate_Trost]

A more interesting question to me is, if they plan on testing a complete Falcon Heavy 3-core configuration in Texas, what does building that test capability do to the Falcon Heavy development schedule?

[go4mars]

A more interesting question to me is, if they plan on testing a complete Falcon Heavy 3-core configuration in Texas, what does building that test capability do to the Falcon Heavy development schedule?

Depends on a few things:
Whether it is needed for a cross-fed version or non-cross-fed version or both.

What the timeframe is for building the stand.