Highly Integrated Solid Propellant Micro-Thrusters Using SOI Wafers

With the development of micro- and nano-spacecrafts, propulsion systems need to be miniaturized in order to reach smaller dimensions, volumes and weights. To reach this goal, we are developing a micropropulsion system composed of an array of solid-propellant micro-thrusters to be integrated in a nanosatellite. The highly integrated thrusters array is composed of suspended Joule heating silicon igniters with integrated nozzles made using silicon-on-insulator wafers. The igniter/nozzle part is bonded to a micromachined chamber made of Foturan glass previously filled with a solid-propellant, zirconium potassium perchlorate (ZPP). The integration of the igniter and nozzle part in the same wafer simplifies the processing, assembling and propellant filling procedures compared to the work previously reported in this field. Moreover, the combination of this thruster’s architecture with the ZPP propellant has allowed reducing the diameter of a single thruster’s cell to 0.5 mm. The successful ignition, in a constant current mode, of the propellant was achieved at a total power of 225 to 400 mW with an ignition time of 5–20 ms. A thrust pulse was generated with a combustion time of 20–30 ms.