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Towards routine, reusable space launch.



 
 
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  #1  
Old June 16th 18, 03:38 PM posted to sci.astro,sci.physics,sci.space.policy
Jeff Findley[_6_]
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Default Towards routine, reusable space launch.

In article ,
says...

On 2018-06-15 07:52, Jeff Findley wrote:

True, but that's essentially still the state of the art today.
Composite layup machines have been around for decades.


Wasn't aware of that. If that is the case, then you are correct.

fiber layup, so I'd count that as new, whenever it was first done. I'm
not a materials engineer, so I don't know when that would be for glass
fiber and aluminum.


Developped by/for Airbus as part of many years og R&D un mid/late 1990s
when Airbus wanted to make the A380 but knew it woudln't be economical
(too heavy) with current tech. It wasn't till they solved a number of
weight and landing gear problems that they could launch the project
formally.

BFR/BFS may have similar scalability problems since weight is also a big
issue. But they won't have to worry about landing pad being strong
enough for it since they can build their own.


X-33 attempted to do just that. It failed due to the complex geometry.
BFR/BFS is sticking with traditional cylindrical tanks, which is a
proven geometry for carbon fiber composites. They're being pretty
conservative as far as their use of carbon fiber goes, IMHO.


Had forgotten about the odd shape for X33 tanks being reason for failure.

From what I've read, they'll be sticking with traditional techniques to
minimize development risks. I fully expect them to cure it in an
autoclave.


Yet, that BFR all composite tank is at a scale nobody has productized
before. Just because they seem to have been able to build/test it
doesn't mean that it is "conventional" in design or using off-the-shelf
resin.


They already built the thing and it's stitting inside a tent at the
BFR/BFS production facility:

SpaceX moving fast on Mars rocket development, BFR tent spied with more
tooling

https://www.teslarati.com/spacex-bfr...ocket-tooling-
molds/

It's big, but others have build quite large autoclaves:

ASC Process Systems Manufactured the World's Largest Autoclave System.
http://www.aschome.com/index.php/en/...rol-systems/2-
uncategorised/327-world-s-largest-composites-autoclave

From above:

Inside working diameter: 30ft. (9.26M)
Inside working length: 76 ft. (23.5M)

From Orbital ATK's arsenal:

https://en.wikipedia.org/wiki/Castor_(rocket_stage)

Scroll down to Castor-600, which is to be used for OmegA:

Based on a 2-segment Space Shuttle SRB, the Castor 600 measures
860 inches (22 m) in length and 146.1 inches (3.71 m) in
diameter, and it weighs approximately 600,000 pounds (270,000
kg). Instead of using a D6AC steel case and PBAN binder like
the Space Shuttle SRB, it will instead use the technology
derived from the GEM motors which have carbon composite cases
and HTPB binder. The carbon composite design eliminates the
factory joint common on all Space Shuttle SRBs.

If Orbital ATK can made SRB casings out of carbon composites (very large
size and pressures inside an SRB casing), then making a few tanks for
BFR/BFS out of carbon composites will be a lot eaiser.

This stuff really isn't as uncommon as you think.

Jeff
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These posts do not reflect the opinions of my family, friends,
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  #2  
Old June 17th 18, 10:16 AM posted to sci.astro,sci.physics,sci.space.policy
Fred J. McCall[_3_]
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Default Towards routine, reusable space launch.

JF Mezei wrote on Sat, 16 Jun 2018
17:51:21 -0400:

On 2018-06-16 10:38, Jeff Findley wrote:

They already built the thing and it's stitting inside a tent at the
BFR/BFS production facility:


Just because they already built it doesn't negate the potential for them
to have needed breaktrough to scale this not only for size but also
repeated cryo load/unload cycles.


Yes, they could always discover that magical unicorns are attracted to
it to **** on it and that breaks it, but having run full pressure
tests and burst tests that's pretty damned unlikely.


Just because they built test articles using conventional stuff available
from yor local hardware store doesn't mean that the final product will
not be highly propriettary with new version of fibres and resin.


Yes, because engineering organizations always build **** that isn't
representative of what they're actually building.


Quickly building one with available composites allows them to make
initial tests on strength and then do the fatique tests quickly, see
if/how it fails and then develop what is needed to make this long
lasting tanks.


Not how engineering works. Can you really be this clueless?


The fact that SpaceX is tight lipped about how it built its tanks points
to them already beyond using already commercial available materials and
process. There is more to a picture of a mandrel in making a large
composite cylinder.


Hogwash!


Also note: neither SpaceX nor orbital ATK have this in production yet.
Either could hit stumbling blocks on the way.


Yes, and monkeys might fly out your butt.


Using composite for room temperature + very hot SRBs is not the same as
a tank that goes from room temperature to very cold in cryo to very hot
once expose to sun in space.


What makes you think the case on an SRB gets all that hot? Tanks only
get exposed to sun in space if you plan on peeling the shell of the
spacecraft off. I don't know of any spacecraft that do that.


--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
  #3  
Old June 17th 18, 09:52 PM posted to sci.astro,sci.physics,sci.space.policy
Jeff Findley[_6_]
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Posts: 2,307
Default Towards routine, reusable space launch.

In article ,
says...

On 2018-06-17 05:16, Fred J. McCall wrote:

Not how engineering works. Can you really be this clueless?



Engineering tries to PREDICT how a structure will behave.

snip?

I snipped the rest of your rambling post. You really should stop
telling engineers how you think engineering works.

Also, you act like they've done zero cryogenic testing on this composite
cryogenic tank design. This is utterly false. Here is a cite from
Composites Manufacturing Magazine:

SpaceX Successfully Tests Carbon Fiber Tank for Mars Spaceship
Evan Milberg, November 29, 2016
http://compositesmanufacturingmagazi...-successfully-
tests-carbon-fiber-tank-mars-spaceship/

You seem to keep assuming SpaceX engineers don't perform any sort of
ground testing and just "wing it" every time they fly. The facts do not
support that assertion.

Note also that this article was from November 29, 2016. It's quite
likely SpaceX has performed other tests between then and now, nearly two
years later. But, since they're a private company, they don't *have* to
tell us anything, now do they?

Jeff
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These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #4  
Old June 18th 18, 02:26 AM posted to sci.astro,sci.physics,sci.space.policy
Fred J. McCall[_3_]
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Default Towards routine, reusable space launch.

JF Mezei wrote on Sun, 17 Jun 2018
15:49:50 -0400:

On 2018-06-17 05:16, Fred J. McCall wrote:

Not how engineering works. Can you really be this clueless?


Engineering tries to PREDICT how a structure will behave.


Like I said, not how engineering works. You really don't understand
any of this except in the most simplistic ways, do you?

snip idiocy


--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
  #5  
Old June 18th 18, 08:05 AM posted to sci.astro,sci.physics,sci.space.policy
Fred J. McCall[_3_]
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Posts: 10,018
Default Towards routine, reusable space launch.

JF Mezei wrote on Mon, 18 Jun 2018
02:44:03 -0400:

On 2018-06-17 16:52, Jeff Findley wrote:

Also, you act like they've done zero cryogenic testing on this composite
cryogenic tank design. This is utterly false. Here is a cite from
Composites Manufacturing Magazine:


I mentioned that they built one, filled it succesfully, then
destructively tested it to see at what pressure it failed. I did not
ignore this. The article you linked is older and doesn't mention the
destructive test SpaceX did (which I mentioned).


You also claimed that what they built and tested wasn't representative
of what they intend to build as a final article and fly, which is just
a stupid assertion.


These tests do not mean the tank is ready. There are other tests they
need to do, in particulat measure how many fill/empty cycles can be made
before flaws start to appear. And if that number if below expectations,
fix the design to add longevity.

This is a normal part of development. Nothing nefarious about it. But
just because they did 2 tests doesn't mean that they did all the tests.


Just because they only told you about two tests doesn't mean they
didn't do any others.



You seem to keep assuming SpaceX engineers don't perform any sort of
ground testing and just "wing it" every time they fly. The facts do not
support that assertion.


I was responding to McCall who claimed engineers can build stuff that
works (in response to my arguments they need to test to validate the
designs and in doing so, can possibly find problems that need to be fixed.


Apparently your deficiency in knowledge of engineering is only
surpassed by your defective English skills, since I said no such
thing. My responses were replies to your massively stupid assertion
that they just built any old tank and tested that without any idea at
all of what they're actually going to build.


--
"Ordinarily he is insane. But he has lucid moments when he is
only stupid."
-- Heinrich Heine
  #6  
Old June 19th 18, 03:39 AM posted to sci.astro,sci.physics,sci.space.policy
Fred J. McCall[_3_]
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Posts: 10,018
Default Towards routine, reusable space launch.

JF Mezei wrote on Mon, 18 Jun 2018
14:27:11 -0400:

On 2018-06-18 03:05, Fred J. McCall wrote:

You also claimed that what they built and tested wasn't representative
of what they intend to build as a final article and fly, which is just
a stupid assertion.


I did no such thing. I claimed that it was not necessarily what the
final would be because during testing, they discovery problems that
require changes.


Of course you did. You said that they built their test tank out of
existing resins using existing processes but that would not be what
they built the 'real' tank using.



Just because they only told you about two tests doesn't mean they
didn't do any others.


And just because of that, you can't claim they performed those tests
succesfully either.

My point is that you can't claim "mission accomplished" on those tanks
just because of 2 tests that SpaceX chose to make public.


They've made more than two of them public. Your perpetual
underinformed state is your personal problem.


--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
 




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