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"believed" versus "noted". |
"believed" versus "noted". |
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* Nobody knows what someone once believed. That's definitely the wrong word. |
* Nobody knows what someone once believed. That's definitely the wrong word. |
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:The fact that they wrote stuff down supports this position that they believed it :-) ''Noted'' has ''connotations'', for example you talk about 'noted researchers'. It sort of implies correctness/importance etc. which is not really true in this case. It's like I once refered to a serving lady as a 'wench', when she was giving me some lip. Whilst formally correct, the other connotations (which I didn't mean at all) could have got me into a lot of trouble :-) Connotations are important. [[User:Wolfkeeper|WolfKeeper]] |
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* The correctness of hydrogen being "ideal": I agree, no propellant is ideal, so the problem word here is "ideal". How about "Many early rocket theorists noted that hydrogen would be a marvellous propellant, since it gives the highest [[specific impulse]]." |
* The correctness of hydrogen being "ideal": I agree, no propellant is ideal, so the problem word here is "ideal". How about "Many early rocket theorists noted that hydrogen would be a marvellous propellant, since it gives the highest [[specific impulse]]." |
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:That would be ok.[[User:Wolfkeeper|WolfKeeper]] |
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"whilst being very energy dense and lightweight" |
"whilst being very energy dense and lightweight" |
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* This is what high specific impulse means, so this phrase is redundant. |
* This is what high specific impulse means, so this phrase is redundant. |
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:not precisely, they are not truly equivalent, but I don't feel strongly.[[User:Wolfkeeper|WolfKeeper]] |
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"where a hydrogen stage's low fuel mass" |
"where a hydrogen stage's low fuel mass" |
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* I do not want to confuse Isp and mass. Helium cold-gas thrusters have low fuel mass too, but they have crummy Isp. Isp is what matters, not (directly) mass. |
* I do not want to confuse Isp and mass. Helium cold-gas thrusters have low fuel mass too, but they have crummy Isp. Isp is what matters, not (directly) mass. |
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:No, that's not correct. For a given stage's ''delta-v'' and for a given payload mass a hydrogen fuelled stage happens to weigh less than say, a kerosene one. That's mainly why they use it I believe, because the whole launch vehicle gets a lower GLOW, and hence ends up cheaper. But the fact that hydrogen gives a high Isp is significant, but not on its own enough. For example a theoretical fuel with an Isp 1 second less than hydrogen, but with several times higher density could easily give the same delta-v, but the stage would weigh less due to the better mass fraction.[[User:Wolfkeeper|WolfKeeper]] |
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"in practice" |
"in practice" |
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* Hydrogen is bulky in theory too. Even slush hydrogen is bulky in theory. |
* Hydrogen is bulky in theory too. Even slush hydrogen is bulky in theory. |
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:Without in any way trying to be evasive: it depends on the theory. A theory is just a model of reality; models always leave things out.[[User:Wolfkeeper|WolfKeeper]] |
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* There are no other proposed hydrogen storage systems besides cryogenic storage. That makes it the only practical storage system. Would you quibble with the phrase "remotely practical"? |
* There are no other proposed hydrogen storage systems besides cryogenic storage. That makes it the only practical storage system. Would you quibble with the phrase "remotely practical"? |
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:Yes. GOX for example has been used on Buran. There's no obvious reason why GH2 couldn't be used for similar purposes; it's much heavier that way, but that doesn't always matter, and gaseous propellants are easily space storable, liquid hydrogen is rather difficult.[[User:Wolfkeeper|WolfKeeper]] |
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I'm leaving your edits up for now so we can talk about this and resolve it. But I don't agree with all of them. |
I'm leaving your edits up for now so we can talk about this and resolve it. But I don't agree with all of them. |
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Greek: Ά ά Έ έ Ή ή Ί ί Ό ό Ύ ύ Ώ ώ Α α Β β Γ γ Δ δ Ε ε Ζ ζ Η η Θ θ Ι ι Κ κ Λ λ Μ μ Ν ν Ξ ξ Ο ο Π π Ρ ρ Σ σ ς Τ τ Υ υ Φ φ Χ χ Ψ ψ Ω ω {{Polytonic|}}
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