[G Larry]

I suffer from the presumption that a hydraulic system is a CLOSED SYSTEM….and shouldn’t “run out”!!

[Vince Ferrer]

I suffer from the presumption that a hydraulic system is a CLOSED SYSTEM….and shouldn’t “run out”!!

I don't understand hydraulics either, but it seems there is an "open" loop and "closed" loop, and the rocket uses an "open" loop and ran out of fluid.