Abstract: A method and apparatus for measuring the amount of fuel aboard a spacecraft under weightless conditions utilize at least one orifice, at least one flow latch valve for the selection of an orifice to be used, and at least one control valve for releasing a stream of a pressurizing gas from at least one high-pressure tank in order to restore pressure in a fuel tank following a pressure reduction due to withdrawal of fuel. The amount of fuel remaining in the fuel tank is determined based on the time required to restore fuel tank pressure by a flow of gas from the high pressure tank to the fuel tank, via the orifice.

Abstract: A method and apparatus for measuring the amount of fuel aboard a spacecraft under weightless conditions utilize at least one orifice, at least one flow latch valve for the selection of an orifice to be used, and at least one control valve for releasing a stream of a pressurizing gas from at least one high-pressure tank in order to restore pressure in a fuel tank following a pressure reduction due to withdrawal of fuel. The amount of fuel remaining in the fuel tank is determined based on the time required to restore fuel tank pressure bv a flow of gas from the high pressure tank to the fuel tank, via the orifice.