[lepton]

tanks are not metal, they are made of wrapping composite, tape, which I think is to be fiberglass, into a sphere, making a tough, light tank.

I know that most are, but was of the impression that some of the tanks which held non-corrosive small-molecule materials like Helium were metal, as it diffuses through many other materials - and it looked like there were two materials, one which burned, and another which maintained its coppery color.

Ah-well.

[XBob]

I am unaware of that, particularly, of any use of helium (an inert gas), period, except for testing.

helium and hydrogen atoms are so small, they leak through anything, period, no matter what the composition.

helium is used for testing equipment, most comes from Texas, and is shipped and stored in very very thick walled tanks on rail cars, in banks of tanks which look like big pipe racks. and even then they they leak. Hydrogen is made nearby in a hydrogen plant, as needed for each flight.

However, it could be. There are a lot of tanks, for a lot of things, and I am not familiar with the components of each.