[So Cal Rocket]

The proposed system takes bleed air off of the engine, compresses it through a gas separation membrane, splitting off a good portion of the oxygen content and sends the de-oxygenated air (nitrogen enhanced) into the fuel tank.

[HangThemHigh]

This sounds like a membrane separation system where oxygen is essentially filtered out by passing pressurized air through a membrane. This gives an enriched nitrogen atmosphere (but some oxygen gets through). Anybody know for sure?