High Power Iodine Hall Thruster

ABSTRACT: A high power iodine propellant Hall Effect thruster system will be developed for orbit raising and other in-space applications. This system will include a thruster, hollow cathode, and propellant feed system. The Phase I thruster will have a power level of 1-3 kW. The Phase II thruster will be tested at up to 20-kW, enabling near-term clusters of 80 to 160 kW. The estimated specific power (kg/kW) will be 1.3 kg/kW. A 100 kW Phase III system will also be designed, with even lower specific power. The thruster will be capable of specific impulse between 1400 s and 3500 s at constant power. Based on subscale iodine testing, the efficiency will be similar to that of existing high power Xe Hall thrusters, with the possibility for significantly higher thrust to power. Based on high fidelity testing of Busek"s existing 20-kW Xe Hall thruster, the efficiency will be greater than 60% across a broad throttling range of power and specific impulse. The iodine propellant will store at a density that is 2 to 3 times greater than xenon and at approximately one thousandth of the pressure. Passive long term storage of a fully fueled system will be possible. BENEFIT: The proposed system will be used for orbit raising and other in-space applications. The thruster will meet specific mass and performance targets set forth in the topic, including a specific impulse of 1400 s to 3500 s, and efficiency greater than 60% across a broad throttling range. Higher T/P than possible with Xe may be achieved. In addition, the complete system, including iodine fuel tank, will be far smaller than a xenon system, making it more suitable for high propellant throughput applications. The system will also be storable long-term on the ground or on orbit without any active temperature control due to the condensable nature of the propellant. The system will be low cost due to the elimination of high pressure tanks normally used to store noble gases at thousands of PSI, as well as the low cost of the propellant itself. Finally, due to the condensability of the propellant, the system can be tested at high power in ground facilities that would be incapable of testing xenon thrusters in a similar power range.