PERFORMANCE OF THERMAL PLUME IN SOLAR THERMAL-ELECTRIC PROPULSION SYSTEM

A solar thermal-electric propulsion (STEP) system which combined thermal and electric thrusters in a tandem arrangement has been installed for demonstrating a new rocket engine with medium ranges of specific impulse and thrust. The STEP system consists of a solar thermal and a magnetoplasmadynamic (MPD) thrusters. In the thermal channel, the propellant gas is heated up to 2000 K by an argon arc-lamp solar simulator. Without the DC power on the MPD electrodes, the system merely produces a thermal plume of argon gas. An insitu technique, Pilot tube method, is used to measure the total and static pressure of the core flow of the plume in steady-state operation in order to characterize and benchmark so that any increment of thrust and specific impulse resulted from the MPD acceleration can be determined later. The data are compared with the results of CET93 computer code developed at NASA Lewis Research Center (LeRC). An increase of the total pressure, therefor the thrust was found in preliminary run with the MPD accelerator.