Here in Falcon 1 user guide, in table 2-1 in page 8, heated Helium is mentioned as used for tank pressurisation. What will be the temperature of such He and why is heated He used?

Location in the linked article for reference.

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    $\begingroup$ Sorry Karthik, didn't notice you were asking about the first reference to it, added an image to avoid confusion. $\endgroup$ Sep 17, 2018 at 17:34
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    $\begingroup$ If you haven't already read all of the answers to questions like Why does the Falcon 9 require a helium pressurization system? and How does tank pressurization work? and Why Use Helium? and Why do pressure-fed systems have to be pressurized with helium or nitrogen? this might be a good time. To "why is heated He used?" isn't the answer just that that's what generates the pressure? $\endgroup$
    – uhoh
    Sep 17, 2018 at 18:10
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    $\begingroup$ @uhoh I take the question to mean "why heated helium." $\endgroup$ Sep 17, 2018 at 18:53
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    $\begingroup$ @WayneConrad as do I. Isn't the heating the helium what causes the helium to become pressurized, "the heating" being the thing that actually "generates the pressure?" A tank of liquid helium at its 1 bar boiling point will have a slow boil-off rate, nothing close to enough to help the tons per second of propellants out of the tank. Isn't the heating of the helium the thing that does the propellant-helping? $\endgroup$
    – uhoh
    Sep 17, 2018 at 19:05
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    $\begingroup$ If gaseous helium is stored in a high pressure tank, its temperature will drop a lot during expansion. To compensate the temperature drop and to get more volume per mass, the helium is heated after expansion. $\endgroup$
    – Uwe
    Sep 17, 2018 at 22:21


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