Feasibility study of mini RF-helicon-Double-Layer plasma thruster for microsatelite attitude control

Thrusters for micro satellite are currently developed mainly based on FEEP Hall effect concepts and PPTS. This paper is focused on an innovative type of thruster firstly proposed by Australian National University (ANU) based on helicon plasma source and Double-layer effect. The study has been focused on establishing the performances of the helicon thruster in the low power regime ( <40 W) in term of thruster and specific impulse to verify the possibility of using it as actuators for microsatellite attitude control subsystem. The paper deals with the possibility of applying the helicon Double-Layer thruster, as experimental payload, to the attitude control system of a UNISAT microsatellite in order to evaluate its effective performances. A model of the thruster has firstly been built, control algorithms for achievable maneuvers have been identified combining the thruster model with the UNISAT attitude dynamics model. UNISAT satellites are designed, built and operate in orbit by students, researchers and professors of GAUSS (Group of Astrodynamics of University “La Sapienza”) at School of Aerospace Engineering. In the framework of this program four satellite have already been launched (2 years apart one from the other, starting in 2000) by the Baykonour Cosmodrome and a fifth satellite is scheduled to be launched in the 2008. The thruster simulation has been performed through three codes combined together. A global code simulating the plasma source and a one dimensional PIC (PPDL) code simulating the plasma exhaust through the magnetic nozzle. Finally a 2-D PIC code has been applied to analyze plasma detachment. These two codes have been combined through a genetic optimization algorithms in order to identify the best thruster configuration defined as a trade-off among performances , total mass and total volume.