Author Topic: Pad 39B to gain new Flame Deflector and Trench upgrade  (Read 21326 times)


Offline GClark

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #1 on: 02/06/2015 06:32 AM »
And a fine piece of journalism it is, sir.

I doff my hat in your general direction (I would hit your tip jar, if you had one).

Offline Martin FL

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #2 on: 02/06/2015 11:32 AM »
Really enjoy infrastructure articles! That was another great read.

And a fine piece of journalism it is, sir.

I doff my hat in your general direction (I would hit your tip jar, if you had one).


If you don't already have it, get L2! That's the site's tip jar, with massive benefits! :)

Offline spacenut

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #3 on: 02/06/2015 01:44 PM »
Will the new flame deflector take a higher pressure for future larger rockets?

Offline chrisking0997

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #4 on: 02/06/2015 05:24 PM »
Did I understand correctly that they are removing (some of) the brick from the trench or just the old flame deflector?
Tried to tell you, we did.  Listen, you did not.  Now, screwed we all are.

Offline Halidon

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #5 on: 02/06/2015 05:31 PM »
Thanks for the article, Chris. From an outsider's perspective, I would think that a flame deflector that can handle the heat/pressure from SLS could do the job for most smaller vehicles as well, provided they don't have an unusual configuration like STS. Would I be wrong in that assumption?

Offline AS_501

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #6 on: 02/06/2015 05:34 PM »
Did I understand correctly that they are removing (some of) the brick from the trench or just the old flame deflector?

If so, we can presume they will apply lessons learned after STS-124 blew out some of the bricks lining the trench.  Foot note:  Still hard to image any rocket engines generating as much blast force as five F-1s.

Offline Jim

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #7 on: 02/06/2015 05:52 PM »
Still hard to image any rocket engines generating as much blast force as five F-1s.

One 5 segment SRB is more than 2 F-1s and has a more blast force during ignition.  Much easier to build flame deflector for F-1s than SRB's

Offline PahTo

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #8 on: 02/06/2015 07:44 PM »

To answer spacenut's and Halidon's queries, as well as follow-on to AS_501 and Jim, the trench and deflector is being fabricated to specs for "advanced boosters"--that is, fiber wound case (FWC) units that have even higher over-pressure than the 5-segs (which are much higher than even the "tuned up" 4-seg boosters used on STS-124).  It should be noted that the F-1s ramped up in thrust (and acoustical energy) over a number of seconds, while the SRBs exert a massive amount of OP at ignition (see transient overpressure vs MEOP [Mean Effective Operating Pressure]).
One of the coating materials used in lieu of the old bricks to withstand the OP and heat is "fondue fyre".  I can't imagine another rocket that will create the same sonic, thermal and OP as the notional FWC, or even the 5 segs, but we'll see (at least from 39B, a-hem).  Any other rocket that flies from 39B would only be constrained by orientation, not output.
I'm still of a mind the first launch of SLS (should it actually come to pass) will prove to be a learning experience re: pad substrate, structure and MLP/LUT.

Offline PahTo

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #9 on: 02/06/2015 08:02 PM »

Oh, and sorry to double-post, but I am curious if they're going to "split" the SRB exhaust (one N and one S) or mimic the STS and have RS-25s flow S and both SRBs flow N (and thus under the MLP).  It would seem to make more sense to try to split evenly/distribute those forces, but those calculations Chris mentioned are critical to understanding flow patterns, waves that cancel and waves that amplify...
btw, thanks for the article on infrastructure, Chris!

Offline newpylong

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #10 on: 02/06/2015 08:08 PM »
Exhaust will not be split. All to the north.

Offline AS_501

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #11 on: 02/06/2015 08:13 PM »
Still hard to image any rocket engines generating as much blast force as five F-1s.

One 5 segment SRB is more than 2 F-1s and has a more blast force during ignition.  Much easier to build flame deflector for F-1s than SRB's

Interesting, thanks.  Do SRBs create a "sand-blasting" effect (from any un-burnt propellent?) on the trench that liquid engines do not?

Offline AS_501

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #12 on: 02/06/2015 08:41 PM »

To answer spacenut's and Halidon's queries, as well as follow-on to AS_501 and Jim, the trench and deflector is being fabricated to specs for "advanced boosters"--that is, fiber wound case (FWC) units that have even higher over-pressure than the 5-segs (which are much higher than even the "tuned up" 4-seg boosters used on STS-124).  It should be noted that the F-1s ramped up in thrust (and acoustical energy) over a number of seconds, while the SRBs exert a massive amount of OP at ignition (see transient overpressure vs MEOP [Mean Effective Operating Pressure]).
One of the coating materials used in lieu of the old bricks to withstand the OP and heat is "fondue fyre".  I can't imagine another rocket that will create the same sonic, thermal and OP as the notional FWC, or even the 5 segs, but we'll see (at least from 39B, a-hem).  Any other rocket that flies from 39B would only be constrained by orientation, not output.
I'm still of a mind the first launch of SLS (should it actually come to pass) will prove to be a learning experience re: pad substrate, structure and MLP/LUT.

Fascinating perspectives, thanks.  Probably a silly point here, but I wonder if there would be any value in staging some trench materials behind an SRB test motor in Utah, without compromising SRB test objectives.  Also, any indication if they will conduct an FRF on the first SLS?

Offline PahTo

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #13 on: 02/08/2015 08:55 PM »
Fascinating perspectives, thanks.  Probably a silly point here, but I wonder if there would be any value in staging some trench materials behind an SRB test motor in Utah, without compromising SRB test objectives.  Also, any indication if they will conduct an FRF on the first SLS?

I know there are all kinds of evaluation hardware sensors all over the place, and beyond that, neighbors in the area have had direct experiences with erosive and corrosive by-products of motor firings (see threads covering DM testing); and I don't know, respectively.

Offline Jim

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #14 on: 02/08/2015 08:59 PM »


Interesting, thanks.  Do SRBs create a "sand-blasting" effect (from any un-burnt propellent?) on the trench that liquid engines do not?

Not just unburnt but the primary fuel is aluminum, so it is very corrosive.

Offline TomH

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #15 on: 02/09/2015 02:11 AM »
Not just unburnt but the primary fuel is aluminum, so it is very corrosive.

The advanced solid boosters will have greater pressure, but do we know enough yet about their formula to know whether they will be more/less corrosive, more/less toxic?

Offline Jim

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #16 on: 02/09/2015 02:56 AM »
That would be splitting hairs.

Offline MP99

That would be splitting hairs.
Chlorine can have that effect. :-)

Cheers, Martin

Offline Lobo

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #18 on: 02/09/2015 09:54 PM »
Exhaust will not be split. All to the north.

Wasn't Saturn V's exhaust split?  I'd assume so as 39A and B were built with both north and south flame duts.  If so, why wouldn't SLS's be split too then?

Offline PahTo

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Re: Pad 39B to gain new Flame Deflector and Trench upgrade
« Reply #19 on: 02/09/2015 10:08 PM »
Exhaust will not be split. All to the north.

Wasn't Saturn V's exhaust split?  I'd assume so as 39A and B were built with both north and south flame duts.  If so, why wouldn't SLS's be split too then?

Note newlylong's response was re: SRB exhaust only per the context.  I expect the RS-25 exhaust will be directed S (same as it was for STS).  The geometry of the RS-25s might mean something different (a split of 2x2 N/S) but expect it to mimic STS.

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