The VHITAL Program to Demonstrate the Performance and Lifetime of a Bismuth-Fueled Very High Isp Hall Thruster

Abstract

In the Very High Isp Thruster with Anode Layer (VHITAL) Program the performance, plume and lifetime capability of the radiatively-cooled two stage, bismuth-fueled VHITAL-160 will be characterized in the U.S. and Russia. The demonstration and further characterization of this technology is motivated by its excellent performance, unique propellant attributes and potentially significant mass and trip time savings over chemical and ion thruster systems for NEP missions. This Russian-developed electric propulsion technology $rill be improved from its previously tested state over 1-5 ycrrs ago with an advanced feed system, novel erosion and plume diagnostics and models of the thruster performance, lifetime and plume interactions with the spacecraft. The VHITAL-160 design documentation has been completed with thermal and structural analysis showing the capability of this thruster to operate in a self-heated mode at 25 and 36 kW. The previously existing TAL-160 was refurbished at TsNllMASH and recently demonstrated operation in a discharge mode and the functionality of the thruster support systems. An all-carbon AIAA 2005-4564This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States.resistively heated prototype vaporizer with porous plug was successfully demonstrated for the flight-like feed system. Hydrodynamic models of the first and second stages of the discharge have been developed with good agreement with experimental results. Significant progress has been made in the development and demonstrations of the thruster diagnostics. I walls. This attribute of the propellant significantly relaxes the pumping speed requirements placed on facilities used for testing bismuth fueled thrusters, which is a significant factor when testing at increasingly high power levels for high power electric thruster performance and lifetime assessments. Two stage TALs operating on Bi propellant could be tested at power levels exceeding 100 kW in existing facilities. Multiple thrusters could be tested in existing facilities at total power levels exceeding 1 MW. Additional attributes of the bismuth propellant include its low ionization potential and high mass, enabling high efficiency thruster operation. It is also environmentally friendly and non-toxic.The VHITAL Program P-I is Dr. Mark Cappelli of Stanford University. He is also leading the thruster lifetime assessment element. He is responsible for implementing the near-field plume diagnostics and leading the near-field plume characterization and the assessment of the thruster lifetime. Anita Sengupta, a Co-1. is the VHITAL Program Manager at JPL. Dr. Colleen Marrese-Reading is a Co-1 as the technical lead of the thruster support system technology development and the thruster performance assessment at JPL. Drs. Sergey Tverdokhlebov and Sasha Sememkin, at TsNIIMASH, are responsible for the thruster, cathode and a feed system. Dr. lain Boyd, at the University of Michigan, is also a Co-1 who will lead the spacecraft contamination-ass...

Performance Comparison between a Magnesium- and Xenon-fueled 2 kW Hall Thruster

“…In the early 2000s research on bismuth propellant occurred in the United States [3][4][5][6][7][8][9][10][11][12][13]. Bismuth thrusters required components to be heated to temperatures in excess of 800 °C such that catastrophic component failures were common [7].…”

Modeling a Two-Stage High-Power Anode Layer Thruster and its Plume

“…Recently an interest in development of high-power Hall thrusters was renewed due to the fact that TAL technology has wide technical capabilities and range of parameters [11][12][13]. In Hall thrusters, a substantial fraction of the ions is directed toward the channel wall.…”

Demonstration of an Automated Mass Flow Control System for Condensable Propellant Hall-effect Thrusters

“…In 2005 NASA researchers attempted to resurrect the TsNIIMASH thruster in the Very High Isp Thruster with Anode Layer (VHITAL) program. 5 As part of the program, a feed system was developed which used an electromagnetic pump to feed liquid bismuth into a porous carbon vaporizer. 6 This method was demonstrated by Polzin et al and was able to provide up to 6 mg/s of bismuth vapor, but the results were not reproducible and the mass flow control system was never integrated with a Hall thruster.…”