The specific impulse achieved by low power arcjets must increase from the 500-600 second range to the 600-700 second range to meet the mission requirements of next generation satellites. Reaching these performance goals will require operation at significantly higher specific energies than present electrode materials can tolerate. Numerical tools, with the assistance of high fidelity diagnostics, are rapidly maturing and may be able to provide a sufficient understanding of the internal arcjet plasma dynamics to develop new thermal management strategies. An essential ingredient of these models is the accurate description of mass and energy transport within the arcjet. This paper describes recent improvements achieved by incorporating the effects of species diffusion in a single-fluid arcjet performance model. A comparison of the preliminary simulation results with low power hydrogen arcjet velocity and temperature data indicates that these improvements better represent the important plasma physics. With these comparisons taken as starting point, the sensitivity of key arcjet physical processes to diffusive transport of mass and energy are also explored.
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