Improvement of Micro Solid Rocket Array Thruster for Reliable Operation in Vacuum

We are developing a micro solid propellant rocket array thruster for simple attitude control of a 10 kg class micro spacecraft. To improve the contact between the ignition heater and the ignition charge of lead thiocyanate / potassium chlorate (RK), the loading method of RK was improved. Ignition probability increased to 100 % in air and 83 % in vacuum. When the pellet diameter of boron / potassium nitrate propellant (NAB) was 1.1 mm and its density was 1.7 ~ 1.8 g/cm, it successfully burned with a 0.20 mm or 0.30 mm throat. When the pellet diameter of NAB was 0.70 mm and its density was 1.6 ~ 1.8 g/cm, it also successfully burned with a 0.063 mm throat. With epoxy adhesive bonding between the first and second layers, the micro thruster worked without fatal structural failure in the firing test.