[kortex]

Nice writeup! Former chemist here. Helium is indeed poorly soluble in most liquids. It's actually used to sparge (purge by bubbling through) solvents to drive out other dissolved gasses.

This is because Helium has very weak intermolecular forces due to its electronic symmetry. For that same reason, it's also as close to an ideal gas, giving you the most pressure/volume bang for your mass buck (only hydrogen is better, and that's bad for oxidizer tanks for obvious reasons).

But this also limits the ability to cryogenically condense helium, which would improve storage density. But you really don't need much in turbopump fed engines.