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Soyuz fueling
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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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