Meanings of conserve precious in English

To conserve precious gas while on the surface, Rolland disabled his rebreather's automatic oxygen injector.

They seek to conserve precious little.

To conserve precious plutonium, researchers simulated the metal using similarly dense depleted uranium, which posed far less of a radiological threat.

The Orion, which originally was to land on land has now reverted to an Apollo splash-down style landing in order to conserve precious mass.