Design and Characterization of a 3D-Printed Attitude Control Thruster for an Interplanetary 6U CubeSat

This paper describes the design and testing of a miniature, 3D-printed cold gas attitude control thruster for the NASA Ames Research Center BioSentinel mission, an interplanetary small spacecraft that will be launched on the EM-1 flight of SLS. Earth-orbiting small satellites typically use magnetic torque rods for momentum unloading, but these cannot be employed in interplanetary space due to the lack of a strong external magnetic field. ACS thrusters can be used to unload reaction wheels or used directly for attitude control, regardless of the external environment. By 3D printing the propellant tanks, pipes, and nozzles into a single component, the complexity and cost of the thruster are reduced. The use of 3D printing also allows the thruster to better utilize its allocated volume to store more propellant. This is especially important for strictly volume-constrained spacecraft, such as CubeSats. The thruster has seven nozzles that are printed directly into the surface of the structure. The BioSentinel thruster has been tested at the Georgia Institute of Technology by the Space Systems Design Lab. The thrust of each nozzle has been measured to be approximately 50 milliNewtons, with a specific impulse of approximately 31 seconds.