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