PPT Development for Nanosatellite Applications: Experimental Results
In this paper, the design and performances of a pulsed plasma thruster (PPT) for nanosatellite applications will be presented. The breadboard model PPT presented in this paper will be a part of six PPTs propulsion system designed to provide attitude and translational control for a 20-kg nanosatellite for a total delta-V of 40 m/s. The thruster performances have been characterized in terms of electrical parameters, mass bit, impulse bit, and specific impulse. The thruster was found to be compliant with the mission requirement. Moreover, preliminary electromagnetic noise interference measurements have been performed. The spark plug discharge was found to be the main source of noise as already found by previous authors. From the collected data, it can be inferred that the noise is mostly radiated.
Preliminary Measurements of an Integrated Prototype of the CubeSat Ambipolar Thruster
An integrated engineering unit of the CubeSat Ambipolar Thruster (CAT) was tested at power levels up to 43 W. With the incorporation of a closed loop cooling system CAT was able to operate for hours, and steady state measurements indicated that the electrical efficiency was ∼ 50%. Plume oscillations measured with a Langmuir probe showed a maximum peak-to-peak floating potential oscillation of 150 mV and implying that RF compensation of probes is not required. Angular ion current density profiles were measured a various distances downstream of the thruster exit plane, demonstrating the ion current closely follows the magnetic nozzle geometry. A parameter study of the peak ion density and plume divergence half angle was conducted. The peak current density increased and the plume divergence half angle decreased with decreasing propellant mass flow rate, while the peak current density increased and the plume divergence half angle was insensitive to increasing input power. Indirect thrust measurements indicated a thrust improvement over the corresponding cold gas thrust. However, these results are degraded by the prevalence of scattering collisions due to high background pressure during operation. A discussion on considerations for indirect thrust measurements is included. Improvements to the CAT architecture and future experiments are discussed.
Pulsed plasma thruster of the erosion type for a geostationary artificial Earth satellite
Abstract Analysis is made for the possibility of erosion pulsed plasma thruster (PPT) application while solving the task of maintaining the point sustaining a long-operating geostationary artificial Earth satellite. The concept of an erosion PPT with a pulse energy of 200–300 J, designed for holding the attitude of a satellite of 500 kg mass over 10 years is presented. The thruster, with a lifetime of 2–3 × 10 7 pulses, produces a total pulse of 2.5 × 10 5 Ns, consuming up to 13 kg of propellant (Teflon). Estimations have shown that the thruster total mass will not exceed 50–60 kg for the flying PPT. Even in the case of a two-fold redundancy the thruster set mass should comprise no more than 0.20-0.25 of the satellite mass. The prospect of a rail design for the PPT discharge chamber with lateral propellant feeding is experimentally examined.