I see the Falcon 9 launch was delayed because of a Helium leak in the rocket. Why is Helium used in liquid fuel rockets?

Just curious,

David

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Helium is used to pressurize LOX because it is not inclined to mix with it or be reactive. I use it too.

BTW helium leaks through solid steel tubes, so it leaks period.

I do too. For party balloons.

I may be wrong, but it seems like I have read that we have a pretty finite supply of Helium on Earth. Are there alternatives to using Helium for LOX pressurization?

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I used to have super powers, but then one day, my Therapist took them away from me.

NAR #96285

SoAR #503

My Low Power Rocket Fleet

Level 1 (2-22-2014) GRITS Winternationals
Level 2 TBD
Level 3 TBD

Nope, no alternatives. Especially when LH2 is involved. Besides, the amount of helium used on space vehicles is minuscule compared to other world uses.

And it has to be clean helium. Bolloons different.

It's all in TX owned by the Japanese. The supply is 80% exhausted and demand is dramatically reduced.

Russia buys our helium and we buy their titanium.

Jerry

Plus, helium is the only gas that isn't liquefied by liquid hydrogen temperatures... therefore used to pressurize LH2 tanks, as well as bubbling through the propellant lines in launch vehicles to prevent temperature stratification of the propellants in the lines...

Some rockets use more helium than others... helium is also commonly used for spinup of turbines during engine start, and for purge on some systems after shutdown (like SSME). The RS-68's on Delta IV's are pretty big helium hogs, although I think they've reworked some stuff to cut down on helium use during startup...

Later! OL JR

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And once liquified, would be a liquid all the way down to absolute zero unless pressurized. I was visiting the University of Wisconsin-Madison once where they produced solid helium for some experiment. You couldn't see it (any light would contribute too much heat), and the professor explained how it was nearly impossible to tell if you had liquid or solid via any measurable physical property. However, they were sure they had it for the purposes of the experiment at hand.

Cool...

I was reading something here while back about SOLID METALLIC hydrogen as rocket fuel...

Interesting stuff... could make SSTO (with decent payload) a reality, if it ever becomes possible...

Later! OL JR

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