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Soyuz fueling



 
 
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  #1  
Old July 15th 18, 07:34 PM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 1,715
Default Soyuz fueling

In article ,
says...

The NASA PR guy just mentioned the Soyuz was fueled several hours ago.

From a LOX point of view, I take it that they decided to fuel before
crew ingress (in this case, a Progress so no crew) ?

If you load the LOX hours before launch, is there a substantial cost to
replenish what you lose during those hours, or is this a minimal cost?

From a LOX density point of view, once it is loaded and starts to boil
off, does it basically remain at same density whether you launch an hour
or 3 hours later? Aka: does it warm tup to some level and then
stabilizes at that tempoerature as it boils off?


If you're going to launch (presumably hours) after fueling, keeping the
LOX below the boiling point would be very difficult. Launch vehicles
that do this typically let the LOX boil off and just continuously
replenish with liquid oxygen to make up for the boil off. Most US
launch vehicles have done it this way.

SpaceX Falcon is the exception. They sub-cool the LOX to well below its
boiling temperature to increase its density. Hence the "load and go"
timing of LOX filling.

BTW, the NASA guy now refers to Cygnus as a Northrop Grunman spacecraft.
Mentions that the Cygnus has been given the go-ahead to reboost the ISS.


Yes. NASA is finally testing reboost of ISS with Cygnus. From what
I've read, this first reboost is only about a minute long test.

Another tidbit: Today's progress will get to ISS after only 2 orbits, a
record.


Yes. A record that Russia can perform with very little investment of
hard cash. They really don't have the cash to do much of significance
these days. It's looking less and less likely that all of the planned
Russian modules will ever make it to ISS. Modules decades in the making
are still being assembled.

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.
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  #2  
Old July 16th 18, 11:42 PM posted to sci.space.policy
Fred J. McCall[_3_]
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Default Soyuz fueling

JF Mezei wrote on Mon, 16 Jul 2018
15:36:58 -0400:

On 2018-07-15 14:34, Jeff Findley wrote:

If you're going to launch (presumably hours) after fueling, keeping the
LOX below the boiling point would be very difficult. Launch vehicles
that do this typically let the LOX boil off and just continuously
replenish with liquid oxygen to make up for the boil off. Most US
launch vehicles have done it this way.


So basically, most launchers get their LOX at just under liquid
temperature and doesn't really warm up over time because the boiling off
process keeps the remaining fuel liquid ?


Basically.


In the case of SpaceX, once they have loaded supercooled LOX, does it
stay put as liquid until it warms up enough for boiling to begin? Or
does boiling happen because of the realitty of Fliorida and the sides of
the tank warming up the supercooled LOX to boiling tempoerature almopst
instantenously, but hopefully keeping the core well below that for long
enough?


The problem is that as the LOX warms it expands before it boils. So
it's not just boil off. The tank carries a reduced amount of liquid
on the way to boil off.


And if there were a delay, how long would it take before the whole tank
warms up to normal "LOX" temperature just under boiling off point?
Minutes? Tens of Minutes? an hour ? hours ?


Some small number of hours. SpaceX has aborted launches because minor
delays led to concern about having enough LOX left for the mission.


With regards to Northorp Grunman: The transaction had just been
completed. That Cygnus craft had been launched as Obrital ATK, but was
released from ISS as a Northorp Grunman craft.


Cite? It's irrelevant, but I'm curious how you arrive at that
conclusion.


There is a long period
between the time a merger is announced and the time when the paperwork
is signed and transfer/]urchases of shares executed.


Not so much, no.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
  #3  
Old July 17th 18, 04:43 AM posted to sci.space.policy
Scott M. Kozel[_2_]
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Posts: 160
Default Soyuz fueling

On Sunday, July 15, 2018 at 2:34:13 PM UTC-4, Jeff Findley wrote:

If you're going to launch (presumably hours) after fueling, keeping the
LOX below the boiling point would be very difficult. Launch vehicles
that do this typically let the LOX boil off and just continuously
replenish with liquid oxygen to make up for the boil off. Most US
launch vehicles have done it this way.

SpaceX Falcon is the exception. They sub-cool the LOX to well below its
boiling temperature to increase its density. Hence the "load and go"
timing of LOX filling.


"We sub-cool the oxygen and methane to densify it, so compared to...
propellants normally used close to their boiling point in most rockets,
in our case we actually load the propellants close to their freezing
point, and that can result in a density improvement of up to around
10 to 12 percent, which makes an enormous difference in the actual
results of the rocket."

"It also makes the... it gets rid of any cavitation risk for the
turbo pumps, and it makes it easier to feed a high pressure turbo
pump if you have very cold propellant."

https://space.stackexchange.com/ques...turbo-pumps-an
  #4  
Old July 17th 18, 05:07 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Posts: 9,773
Default Soyuz fueling

JF Mezei wrote on Mon, 16 Jul 2018
23:03:08 -0400:

On 2018-07-16 18:42, Fred J. McCall wrote:

Cite? It's irrelevant, but I'm curious how you arrive at that
conclusion.


Until the merger transaction is signed, the 2 companies remain separate
and there are a number of legal reasons, including anti-trust (until
approved, the merger cannot proceed, and the 2 companies must be able to
continue to operate as separate entities should merger be rejected).


Not what you said at all, which is why you 'cleverly' omit your
original statement. You need to learn the difference between
'announcing intent to merge' and 'announcing a merger'.


So while the merger may have been announed a long time ago, NASA would
have continued to use "Orbital ATK" in its publications because that is
the company which ran the Antares/Cygnus service that was contracted
with NASA.


Again, you need to learn the difference between 'announcing intent to
merge' and 'announcing a merger'.


The transaction closed on June 6 2018, despite being announced in
September 2017.


Bzzzt!! Thanks for playing.

snip nonsense


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
  #5  
Old July 17th 18, 09:49 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Posts: 9,773
Default Soyuz fueling

JF Mezei wrote on Tue, 17 Jul 2018
00:12:22 -0400:

On 2018-07-17 00:07, Fred J. McCall wrote:

Not what you said at all, which is why you 'cleverly' omit your
original statement.


Original statement is that NASA started to use "Northrop Grunman" as the
company building Cygnus/Antares.


Well, no. Your original claim was that Antares was launched as
Orbital ATK and reentered as Northrop Grumman. That claim was
actually true, by the way, but you then confused yourself by not
knowing the difference between announcing an INTENT to merge and
announcing an actual merger.


aka: this indicated the merger had been consumed. I don't see why you
claim I am wrong.


Consumed? I think the word you're looking for is 'consummated.


--
"It's always different. It's always complex. But at some point,
somebody has to draw the line. And that somebody is always me....
I am the law."
-- Buffy, The Vampire Slayer
  #6  
Old July 17th 18, 12:24 PM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 1,715
Default Soyuz fueling

In article ,
says...

On 2018-07-15 14:34, Jeff Findley wrote:

If you're going to launch (presumably hours) after fueling, keeping the
LOX below the boiling point would be very difficult. Launch vehicles
that do this typically let the LOX boil off and just continuously
replenish with liquid oxygen to make up for the boil off. Most US
launch vehicles have done it this way.


So basically, most launchers get their LOX at just under liquid
temperature and doesn't really warm up over time because the boiling off
process keeps the remaining fuel liquid ?


Yes.

In the case of SpaceX, once they have loaded supercooled LOX, does it
stay put as liquid until it warms up enough for boiling to begin? Or
does boiling happen because of the realitty of Fliorida and the sides of
the tank warming up the supercooled LOX to boiling tempoerature almopst
instantenously, but hopefully keeping the core well below that for long
enough?


As you can see in videos, there is some boil-off. I'm guessing due to
"hotter" areas in the stages like plumbing and etc.

And if there were a delay, how long would it take before the whole tank
warms up to normal "LOX" temperature just under boiling off point?
Minutes? Tens of Minutes? an hour ? hours ?


Google how long their launch windows are. That's your answer.

With regards to Northorp Grunman: The transaction had just been
completed. That Cygnus craft had been launched as Obrital ATK, but was
released from ISS as a Northorp Grunman craft. There is a long period
between the time a merger is announced and the time when the paperwork
is signed and transfer/]urchases of shares executed.


As far as I know, the transaction is complete, hence the reason that the
press is using the new name. According to the NASA page below, the
official acquisition date was June 6, 2018.

https://www.nasa.gov/mission_pages/s...unch/northrop-
grumman.html

From above:

Editor's note:
On June 6, 2018, Orbital ATK, one of the original commercial
resuppliers along with SpaceX, was officially acquired by
Northrop Grumman.

Official enough of a cite for you?

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #7  
Old July 17th 18, 03:06 PM posted to sci.space.policy
Fred J. McCall[_3_]
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Posts: 9,773
Default Soyuz fueling

Jeff Findley wrote on Tue, 17 Jul 2018
07:24:21 -0400:

In article ,
says...

On 2018-07-15 14:34, Jeff Findley wrote:

If you're going to launch (presumably hours) after fueling, keeping the
LOX below the boiling point would be very difficult. Launch vehicles
that do this typically let the LOX boil off and just continuously
replenish with liquid oxygen to make up for the boil off. Most US
launch vehicles have done it this way.


So basically, most launchers get their LOX at just under liquid
temperature and doesn't really warm up over time because the boiling off
process keeps the remaining fuel liquid ?


Yes.


Basic physics. Things at melting and boiling points tend to be the
same temperature throughout. That's why when you boil water on the
stove it pretty quickly comes to a full rolling boil once it starts to
boil at all.

In the case of SpaceX, once they have loaded supercooled LOX, does it
stay put as liquid until it warms up enough for boiling to begin? Or
does boiling happen because of the realitty of Fliorida and the sides of
the tank warming up the supercooled LOX to boiling tempoerature almopst
instantenously, but hopefully keeping the core well below that for long
enough?


As you can see in videos, there is some boil-off. I'm guessing due to
"hotter" areas in the stages like plumbing and etc.


Isn't most of that water vapor rather than 'boil off' LOX?

And if there were a delay, how long would it take before the whole tank
warms up to normal "LOX" temperature just under boiling off point?
Minutes? Tens of Minutes? an hour ? hours ?


Google how long their launch windows are. That's your answer.


As the LOX warms up you're going to spill around 10% of it before it
starts to boil because of the decrease in density.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw
  #8  
Old July 17th 18, 11:33 PM posted to sci.space.policy
Fred J. McCall[_3_]
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Posts: 9,773
Default Soyuz fueling

JF Mezei wrote on Tue, 17 Jul 2018
13:46:19 -0400:

On 2018-07-17 07:24, Jeff Findley wrote:

As far as I know, the transaction is complete, hence the reason that the
press is using the new name. According to the NASA page below, the
official acquisition date was June 6, 2018.


Mopuntain out of molehill. McCall started to insult me because I
reported that NASA had started to use "Northrop Grunman" when refering
to Cygnus/Antares since the merger had concluded.


You're a liar. I never "started to insult you". This isn't an
'insult', either, because it is TRUE that the preceding is a lie and
you are thus a liar.


--
"You take the lies out of him, and he'll shrink to the size of
your hat; you take the malice out of him, and he'll disappear."
-- Mark Twain
  #9  
Old July 18th 18, 12:22 AM posted to sci.space.policy
Alain Fournier[_3_]
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Posts: 354
Default Soyuz fueling

On Jul/17/2018 at 6:33 PM, Fred J. McCall wrote :
JF Mezei wrote on Tue, 17 Jul 2018
13:46:19 -0400:

On 2018-07-17 07:24, Jeff Findley wrote:

As far as I know, the transaction is complete, hence the reason that the
press is using the new name. According to the NASA page below, the
official acquisition date was June 6, 2018.


Mopuntain out of molehill. McCall started to insult me because I
reported that NASA had started to use "Northrop Grunman" when refering
to Cygnus/Antares since the merger had concluded.


You're a liar. I never "started to insult you". This isn't an
'insult', either, because it is TRUE that the preceding is a lie and
you are thus a liar.


Whether some speech is an insult or not has nothing to do with whether
it is true or false. If I would say to someone that he is an idiot, that
is an insult. Whether he is an an idiot or not doesn't change the fact
that is is an insult. It changes the fact of whether it is a lie or not
but not the fact that it is an insult.


Alain Fournier
  #10  
Old July 18th 18, 04:00 AM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 9,773
Default Soyuz fueling

Alain Fournier wrote on Tue, 17 Jul 2018
19:22:13 -0400:

On Jul/17/2018 at 6:33 PM, Fred J. McCall wrote :
JF Mezei wrote on Tue, 17 Jul 2018
13:46:19 -0400:

On 2018-07-17 07:24, Jeff Findley wrote:

As far as I know, the transaction is complete, hence the reason that the
press is using the new name. According to the NASA page below, the
official acquisition date was June 6, 2018.


Mopuntain out of molehill. McCall started to insult me because I
reported that NASA had started to use "Northrop Grunman" when refering
to Cygnus/Antares since the merger had concluded.


You're a liar. I never "started to insult you". This isn't an
'insult', either, because it is TRUE that the preceding is a lie and
you are thus a liar.


Whether some speech is an insult or not has nothing to do with whether
it is true or false.


We're going to have to agree to disagree about that.


If I would say to someone that he is an idiot, that
is an insult. Whether he is an an idiot or not doesn't change the fact
that is is an insult. It changes the fact of whether it is a lie or not
but not the fact that it is an insult.


Nope. If it's true it's called a 'description', not an 'insult'. Do
you have a point? If so, could you tell me what it is? I never said
I didn't start to insult him because what I said was true. If Mayfly
is insulted when someone questions what he says, he needs to get a lot
smarter.


--
"But if this ever changing world in which we live in
Makes you give in and cry...
Say live and let die."
-- Paul McCartney & Wings
 




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