The first solid propellant is formed to have a columnar shape so as for a combustion surface to move to a first direction, and to have an end surface exposed to a combustion space. The surface of first solid propellant except for the end surface is covered with a barrier membrane. The position of combustion surface in the first direction is detected by a position sensor device in an always-on measurement or a fixed-point measurement. Based on the detected result, the consumption amount of the first solid propellant is estimated.

The first solid propellant is formed to have a columnar shape so as for a combustion surface to move to a first direction, and to have an end surface exposed to a combustion space. The surface of first solid propellant except for the end surface is covered with a barrier membrane. The position of combustion surface in the first direction is detected by a position sensor device in an always-on measurement or a fixed-point measurement. Based on the detected result, the consumption amount of the first solid propellant is estimated.

The first solid propellant is formed to have a columnar shape so as for a combustion surface to move to a first direction, and to have an end surface exposed to a combustion space. The surface of first solid propellant except for the end surface is covered with a barrier membrane. The position of combustion surface in the first direction is detected by a position sensor device in an always-on measurement or a fixed-point measurement. Based on the detected result, the consumption amount of the first solid propellant is estimated.

The first solid propellant is formed to have a columnar shape so as for a combustion surface to move to a first direction, and to have an end surface exposed to a combustion space. The surface of first solid propellant except for the end surface is covered with a barrier membrane. The position of combustion surface in the first direction is detected by a position sensor device in an always-on measurement or a fixed-point measurement. Based on the detected result, the consumption amount of the first solid propellant is estimated.

A gas generator includes an outer propellant, an inner propellant arranged inside the outer propellant, and a barrier membrane which isolates the outer propellant from the inner propellant. A forward end surface of the inner propellant faces a combustion space. A side surface of the inner propellant is isolated from the combustion space.

A multi-pulse gas generator includes a pressure vessel, an outer propellant arranged in the pressure vessel and which has a tubular shape, an intermediate propellant arranged inside the outer propellant and which has a tubular shape, an inner propellant arranged inside the intermediate propellant and which has a tubular shape, an internal structure arranged inside the inner propellant and fixed to the pressure vessel, a first barrier membrane arranged between the outer propellant and the intermediate propellant so as to isolate the outer propellant and the intermediate propellant from each other, and a second barrier membrane arranged between the intermediate propellant and the inner propellant so as to isolate the intermediate propellant and the inner propellant from each other. The outer propellant is supported on its outer surface by the pressure vessel. The inner propellant is supported on its inner surface by the internal structure.

A multi-pulse gas generator includes a pressure vessel, an outer propellant arranged in the pressure vessel and which has a tubular shape, an intermediate propellant arranged inside the outer propellant and which has a tubular shape, an inner propellant arranged inside the intermediate propellant and which has a tubular shape, an internal structure arranged inside the inner propellant and fixed to the pressure vessel, a first barrier membrane arranged between the outer propellant and the intermediate propellant so as to isolate the outer propellant and the intermediate propellant from each other, and a second barrier membrane arranged between the intermediate propellant and the inner propellant so as to isolate the intermediate propellant and the inner propellant from each other. The outer propellant is supported on its outer surface by the pressure vessel. The inner propellant is supported on its inner surface by the internal structure.