MEMS solid propellant thruster array with micro membrane igniter

A microigniter with improved membrane for MEMS solid propellant thruster array is proposed. Although existing igniters using dielectric SiNx membranes consume low power, they cannot withstand shocks during the propellant charging process. A glass wafer is selected as the material for the igniter. A glass membrane is fabricated by the anisotropic wet etching of photosensitive glass. Platinum is used for the ignition coil. A 30–40-μm thick glass membrane exhibited sufficient strength to withstand accidental impacts during the propellant charging process. Further, the microigniter using the glass membrane had an appropriate power consumption to ignite the solid propellant. The thermal, electrical, and mechanical characteristics of the fabricated microigniter were measured. The proposed microigniter provided the sufficient heat for the propellant to be ignited with the given electric power. The fracture pressure of the glass membrane was thrice higher than the conventional microigniter. A solid propellant lead styphnate was filled into the microigniter without any additional processes. Ignition tests with fully assembly MEMS thrusters were performed successfully. Thus, it is demonstrated that a simpler, robust, and low-cost fabrication process of an igniter that performs well when assembled into a micro solid propellant thruster (MSPT) array is possible.

► Microigniter with improved membrane for MEMS solid propellant thruster array is proposed. ► A 30–40-μm thick glass membrane exhibited sufficient strength to withstand accidental impacts during the propellant charging process. ► Heating characteristics with the given electric power of the proposed microigniter were 20% lower than those of the conventional microigniter. ► Fracture pressure of the glass membrane was thrice as high as that of the conventional microigniter.