Author Topic: Solid production - Booster segments readying for opening SLS launches  (Read 1209 times)

Online Chris Bergin

Feature article by Philip Sloss:

https://www.nasaspaceflight.com/2017/06/solid-production-booster-segments-sls-launches/

Includes his photos and one specially sent from Orbital ATK and of course Nathan Koga L2 render work.

And yes, there are no swooshes on the actual SLS boosters.

Offline Khadgars

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Excellent write up as usual.  I see no reason to move to composite boosters when the current versions are so well understood and reliable.   

Offline MATTBLAK

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I provisionally agree with you. But the steel segments cannot be easily or cheaply produced anymore. They will have to go to composites if this vehicle ends up going more than 9 or 10 launches - the steel segments will be used up. Besides; it's hard to resist the performance increase the proposed 'Dark Knights' solid boosters will bring.
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Offline Khadgars

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I provisionally agree with you. But the steel segments cannot be easily or cheaply produced anymore. They will have to go to composites if this vehicle ends up going more than 9 or 10 launches - the steel segments will be used up. Besides; it's hard to resist the performance increase the proposed 'Dark Knights' solid boosters will bring.

Is it really impossible to restart steel casing production?  I guess if its significantly cheaper to produce composites...

Offline MATTBLAK

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That is why I hedged my answer a bit - there are people who might be reading this; space professionals - who will tell you that it's very impractical and therefore for all intents and purposes impossible to restart the steel case segment production. Others might say "They just don't wanna make more". Both viewpoints can't be correct - So I'm using occam's razor for the answer. They represent a major component of the Shuttle infrastructure which has been either modified or shut down completely. I can't give you published figures, but conversations I've had in the last year with former Shuttle program personnel and a former Shuttle Commander informs me that it would be in the spirit of throwing 'good money after bad' to resurrect steel SRBs once the current crop of old segments is used. It would be only negligibly more expensive to develop and manufacture the 'Dark Knights'. After all - the develop program for the 'new' 5 segment boosters has been a long and relatively expensive road to now.

With a couple of years still to go... :(
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Offline Coastal Ron

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I provisionally agree with you. But the steel segments cannot be easily or cheaply produced anymore. They will have to go to composites if this vehicle ends up going more than 9 or 10 launches - the steel segments will be used up. Besides; it's hard to resist the performance increase the proposed 'Dark Knights' solid boosters will bring.

Is it really impossible to restart steel casing production?  I guess if its significantly cheaper to produce composites...

Anything like those casings can be built, so it's more a matter of cost I would think. And I would think that steel casings like these would not be that hard to make, since large steel "tubes" seem to be popular in lots of projects.

Changing subjects, the article went into very good detail about how each segment is constructed, and that started me to wonder how that process has changed since the Shuttle days?

Also, as of 2002 NASA was paying about $69M per SRM flight set, and it will be interesting to find out what NASA is paying for SLS flight sets - no doubt higher because the have extra segments, but also because of the far lower flight rate (the Shuttle contract was for about 7 sets/year).
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Online Eerie

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And yes, there are no swooshes on the actual SLS boosters.

Scandalous! The swooshes are the best part of the boosters! :-)

Offline laszlo

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I find it interesting that we actually have reuse of reused boosters from another spacecraft family. It's too bad they're not getting reused on this program, otherwise we could have reused reused reused boosters : :D

Offline tea monster

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10 launches with this vehicle is a decade-long flight program  :o :-\

Offline Rik ISS-fan

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STS launched ~3x annually, so 3x 8 = 24 casings. So I guess fixed cost per segment increased by a factor of > 3.
I read the article, and I thought; with expendable solids only this facility is required. If they replace the cleaning booths and insulation applying boots, with:
- a mold assembly area,
- a filement winding area and
- a mold removal area.
They have a facility where they can build 12-24 carbon segments.

Now they also need a RSRM disassembly and cleaning facility. Because of the hydrogen - chloride combustion products, the cleaning requires scalp suites. Very nasty and expensive work.
Composite casings can be produced a lot faster and isolation can be applied automatically, with the filement winding equipment. Thus composite casings are a lot cheaper than metal casings. The lower weight is a side benifit. (This is my non-expert judgement.)

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