SN7.1 not snuffed in Boca Chica squall

Stayed up through the attempt to get SN7.1 to fail. After the scrub,
just before I shutdown my screen, I thought I saw SN7.1 being craned
back onto the launchstand with the thrust simulator, and I thought the
LabPadre steam yesterday showed it there, but currently SN7.1 seems to
be back on the transport stand. Next attempt on the 21st (9pm CDT 0200
UTC).

Did I really see the move? If so, this is probably because the
transport stand or the improvised GSE needed repairs. NSF reported
that the LN2 feed was not directly from the tank farm, but via Pad A
(to the left in the usual views, not the stand with the thrust
simulator). There was a lot vapor clouds during the start-up of the
two loading attempts on the 17th; they must not have interfered with
SpaceX's view, but for us viewers it sure produced a lot of gasps.

The second attempt was apparently stopped due to a visible spark,
speculated to be a cable being wind-whipped over some upper-ring
fittings.

The downpour may have reached a level to obscure SpaceX's view, as they
didn't attempt another load after the rain came in buckets, even though
there may have been enough time left in the window.

/dps

--
Ieri, oggi, domani

JF Mezei blurted out:
On 2020-09-19 18:33, Snidely wrote:

The downpour may have reached a level to obscure SpaceX's view, as they
didn't attempt another load after the rain came in buckets, even though
there may have been enough time left in the window.


If you're going to inflate a tank till it explodes, I would think they
would want to have high quality cameras all around the tank to be able
to see in extreme slow motion and high resolution the spot where the
first failure/split happens and how it unfolds.

Doing these tests at night seems to be counter intuitive since you'd
expect to want as much light on the shiny beer keg as you can get.

I can understand road closures easier at night. But still, as a test, I
would think video footage is as important as detecting at what pressure
it fails.

Considering what images we were getting from about 1.5 miles with high
/consumer/ equipment, I would be confident that SpaceX's cameras at
roughly a tenth of that distance were up to the job.

I know some pressure was put in it because one "kink" became smooth
early on. But I suspect that it was only has that was blowin in and
they didn't really fill it with liquid.

I would have LOVED to see it explode during the rain. Elon would have
created snow in texas in summer :-)

More likely to get a hiss. Which could still produce snow, but not so
much like shaking a snow globe.

/dps

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In case of fire, exit the building before tweeting about it.
(Sighting reported by Adam F)

JF Mezei blurted out:
On 2020-09-20 14:07, Snidely wrote:

Considering what images we were getting from about 1.5 miles with high
/consumer/ equipment, I would be confident that SpaceX's cameras at
roughly a tenth of that distance were up to the job.

If you want to analyze failure, you want 4K at highest frame rate as
possible and that only works with a lot of light.



More likely to get a hiss. Which could still produce snow, but not so
much like shaking a snow globe.


If they truly test a tank to failure, I have to assume that at such high
pressure any crack will quickly propagate and cause "catastrophic"
failure instead of just a leak.


Remember that while it looks like a beer keg, this is meant to be a
spacship and mass still matters, so I don't think they can afford to
have much overbuild with steel.

Elon has not tweeted about it. Had the tank exceeded some target by so
much without bursting that they stopped the test, I suspect Mr Musk
would have tweeted about the success. Staying silent points to likely
some really stupid small problem that didn't allow the test to go far.
(nobody saw frost on tank).

So tune in tonight. And you did notice they had lots of lights around
the pad area, didn't you? Any even though it's sunny there now, the
Gulf could provide a squall line on short notice, I'm sure.

/dps

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The presence of this syntax results from the fact that SQLite is really
a Tcl extension that has escaped into the wild.
http://www.sqlite.org/lang_expr.html

With a quizzical look, Snidely observed:
JF Mezei blurted out:
On 2020-09-20 14:07, Snidely wrote:

Considering what images we were getting from about 1.5 miles with high
/consumer/ equipment, I would be confident that SpaceX's cameras at
roughly a tenth of that distance were up to the job.

If you want to analyze failure, you want 4K at highest frame rate as
possible and that only works with a lot of light.



More likely to get a hiss. Which could still produce snow, but not so
much like shaking a snow globe.


If they truly test a tank to failure, I have to assume that at such high
pressure any crack will quickly propagate and cause "catastrophic"
failure instead of just a leak.


Remember that while it looks like a beer keg, this is meant to be a
spacship and mass still matters, so I don't think they can afford to
have much overbuild with steel.

Elon has not tweeted about it. Had the tank exceeded some target by so
much without bursting that they stopped the test, I suspect Mr Musk
would have tweeted about the success. Staying silent points to likely
some really stupid small problem that didn't allow the test to go far.
(nobody saw frost on tank).

So tune in tonight. And you did notice they had lots of lights around the
pad area, didn't you? Any even though it's sunny there now, the Gulf could
provide a squall line on short notice, I'm sure.

Perhaps even Tropical Storm Beta.

/dps

--
I have always been glad we weren't killed that night. I do not know
any particular reason, but I have always been glad.
_Roughing It_, Mark Twain

Snidely presented the following explanation :
Stayed up through the attempt to get SN7.1 to fail. After the scrub, just
before I shutdown my screen, I thought I saw SN7.1 being craned back onto
the launchstand with the thrust simulator, and I thought the LabPadre steam
yesterday showed it there, but currently SN7.1 seems to be back on the
transport stand. Next attempt on the 21st (9pm CDT 0200 UTC).

Did I really see the move? If so, this is probably because the transport
stand or the improvised GSE needed repairs. NSF reported that the LN2 feed
was not directly from the tank farm, but via Pad A (to the left in the usual
views, not the stand with the thrust simulator). There was a lot vapor
clouds during the start-up of the two loading attempts on the 17th; they must
not have interfered with SpaceX's view, but for us viewers it sure produced a
lot of gasps.

The second attempt was apparently stopped due to a visible spark, speculated
to be a cable being wind-whipped over some upper-ring fittings.

The downpour may have reached a level to obscure SpaceX's view, as they
didn't attempt another load after the rain came in buckets, even though there
may have been enough time left in the window.

Popped on the third night of testing. In contrast to SN7, SN7.1 popped
at the top, like a champagne bottle.

URL:https://youtu.be/CkFFgngw6Q4

/dps

--
"I'm glad unicorns don't ever need upgrades."
"We are as up as it is possible to get graded!"
_Phoebe and Her Unicorn_, 2016.05.15

JF Mezei explained on 9/23/2020 :
On 2020-09-23 17:24, Snidely wrote:

Popped on the third night of testing. In contrast to SN7, SN7.1 popped
at the top, like a champagne bottle.


It was a nice show. Quite interesting that in the previous nights, while
the geeks were proclaiming that it was being filled and frost forming,
yesterday made it clear that it hadn't happened in previous nights.

There was also a big difference with previous nights: the venting
started from the top of dome yesterday whereas in previous nights, it
came out of the big pipe near the skin on the hidden portion of the beer
keg.

My guess is that they first tested it with gaseous nitrogen and they
likely found leaks which they had to fix and once fixed, they then
filled it from the bottom with liquid N2 for yesterday's test.

Remember this tank did a cryo proof test including thrust simulator.

My bet is on problems with improvised GSE.


What got mu curious though is all the fog that was being created only in
the back of the beer keg during the final phases of test. Wondering if
this was a leak or planned release. If it had been atmpspheric, it would
have been from all around, not just from the back.


BTW, after it blew its top, there was an overflow of nitrogen which
behaved like a foam as it overflowed over the rim and then moved down.
Would liquid nitrogen, let loose, behave as a foam as it forms bubbles
inside as it tried to boil with little heat available?

That's LN2, GN2 boil off, and atmospheric moisture forming the foam.
Open a soda bottle, a beer bottle, or champagne bottle where the CO2
stops being dissolved for a smaller demonstration, or ask someone with
an LN2 tank (used for various purposes, primarily rapid chilling) to
partially fill a small open dewar.

I had access to LN2 in high school (at an off-campus science center)
and the popular thing was to put some in a plastic chemistry bottle
(normally used for lab spirits (alcohol) and similar cleaners) and toss
it out the door into the parking lot.

/dps

--
"That’s where I end with this kind of conversation: Language is
crucial, and yet not the answer."
Jonathan Rosa, sociocultural and linguistic anthropologist,
Stanford.,2020

In article mn.bb607e49969c869c.127094@snitoo,
says...

Snidely presented the following explanation :
Stayed up through the attempt to get SN7.1 to fail. After the scrub, just
before I shutdown my screen, I thought I saw SN7.1 being craned back onto
the launchstand with the thrust simulator, and I thought the LabPadre steam
yesterday showed it there, but currently SN7.1 seems to be back on the
transport stand. Next attempt on the 21st (9pm CDT 0200 UTC).

Did I really see the move? If so, this is probably because the transport
stand or the improvised GSE needed repairs. NSF reported that the LN2 feed
was not directly from the tank farm, but via Pad A (to the left in the usual
views, not the stand with the thrust simulator). There was a lot vapor
clouds during the start-up of the two loading attempts on the 17th; they must
not have interfered with SpaceX's view, but for us viewers it sure produced a
lot of gasps.

The second attempt was apparently stopped due to a visible spark, speculated
to be a cable being wind-whipped over some upper-ring fittings.

The downpour may have reached a level to obscure SpaceX's view, as they
didn't attempt another load after the rain came in buckets, even though there
may have been enough time left in the window.

Popped on the third night of testing. In contrast to SN7, SN7.1 popped
at the top, like a champagne bottle.

URL:https://youtu.be/CkFFgngw6Q4

The closeups of the aftermath look pretty good to me. It looks like it
didn't rip at the welds, which means they've gotten really good at that.
This is quite a good sign. That and the switch to a different variant
of stainless steel are signs that they're really "dialing in" their
manufacturing methods.

The goal here is to be able to inexpensively produce a veritable fleet
of Starships and Super Boosters, not one every year and a half like SLS
cores.

Jeff
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