MEMS-based solid propellant rocket array thruster with electrical feedthroughs

The prototype of a solid propellant rocket array thruster for simple attitude control of a 10 kg class micro-spacecraft was completed and tested. The prototype has 10 × 10 φ0.8 mm solid propellant micro-rockets arrayed at a pitch of 1.2 mm on a 20 × 22 mm substrate. To realize such a dense array of micro-rockets, each ignition heater is powered from the backside of the thruster through an electrical feedthrough which passes along a propellant cylinder wall. Boron/potassium nitrate propellant (NAB) is used with/without lead rhodanide/potassium chlorate/nitrocellulose ignition aid (RK). Impulse thrust was measured by a pendulum method in air. Ignition required electric power of at least 3-4 W with RK and 4-6 W without RK. Measured impulse thrusts were from 2 × 10^-5 Ns to 3 × 10^-4 Ns after the calculation of compensation for air dumping.