System and method for protecting a pressure vessel from excessive differential pressure

A method for protecting a pressure vessel of an aerospace vehicle from excessive differential pressure between an internal pressure and an external pressure, comprising:

• providing a pressure vessel protection system that includes:
• a gas container configured to be coupled to the pressure vessel, the gas container capable of supplying a gas or liquid to the pressure vessel to increase the internal pressure of the pressure vessel;
• a relief valve coupled to the pressure vessel, the relief valve configured to release the gas or liquid from the pressure vessel when the internal pressure substantially exceeds the external pressure;
• and
• a supply valve coupled to the gas container, the supply valve configured to allow the gas or liquid from the gas container into the pressure vessel to increase the internal pressure of the pressure vessel until the internal pressure of the pressure vessel substantially equals the external pressure of the pressure vessel;
• when the internal pressure substantially exceeds the external pressure while the aerospace vehicle ascends from underwater until becoming airborne, triggering the relief valve to release the gas or liquid from the pressure vessel, thus decreasing the internal pressure of the pressure vessel;
• and
• when the external pressure substantially exceeds the internal pressure while the aerospace vehicle descends during deployment underwater, triggering the supply valve to release the gas or liquid from the gas container to the pressure vessel until the internal pressure of the pressure vessel substantially equals the external pressure of the pressure vessel.

A system, comprising:

• a pressure vessel that is a hull of an aerospace vehicle;
• a gas cylinder configured to be coupled to the pressure vessel, the gas cylinder capable of supplying a gas or liquid to the pressure vessel to increase an internal pressure of the pressure vessel;
• a relief valve coupled to the pressure vessel, the relief valve configured to release the gas or liquid from the pressure vessel when the internal pressure exceeds an external pressure of the pressure vessel;
• and
• a diaphragm valve coupled to the gas cylinder, the diaphragm valve configured to allow the gas or liquid from the gas cylinder into the pressure vessel to increase the internal pressure of the pressure vessel until the internal pressure of the pressure vessel equals the external pressure of the pressure vessel.