2) NEXT Ion Thruster Analysis: As discussed in class, the NASA Evolutionary Xenon Thruster (NEXT) is...

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2) NEXT Ion Thruster Analysis: As discussed in class, the NASA Evolutionary Xenon Thruster (NEXT) is being developed by NASA for the DART mission. Let's do a simple performance analysis of the NEXT thruster by following the steps below. Assume only singly charged xenon ions and that the beam is has zero divergence. a. The beam voltage is 1800 V, the beam current is 3.52 A, and the energy required by the plasma to generate a beam ion (the discharge loss, ɛ³) is 130 eV/ion. The thruster's cathodes and supporting equipment require a power of 66 W. Determine the electrical efficiency, ŋe, of the thruster. Note: 1 eV/ion = 1 W/A. b. C. Calculate the ideal Isp and thrust for this device by assuming that only ions are ejected by the thruster (i.e., no neutrals are lost through the grids). In an actual ion thruster, you must consider that some of the propellant will escape through thruster grids as neutrals instead of ions. i. If we know that the thruster has a discharge propellant utilization efficiency, ŋud, of 0.89, determine the actual thruster Isp compared to the value found above. Assume that the neutral propellant escapes the thruster at a thermal velocity corresponding to 300°C. Find the approximate thrust produced by the escaping neutrals and compare that to the thrust produced by the ions by finding the ratio of the thrusts (Tneut/Tion) ii. d. Prove that nT = nenud using the formulas for ion thruster efficiencies. 2) NEXT Ion Thruster Analysis: As discussed in class, the NASA Evolutionary Xenon Thruster (NEXT) is being developed by NASA for the DART mission. Let's do a simple performance analysis of the NEXT thruster by following the steps below. Assume only singly charged xenon ions and that the beam is has zero divergence. a. The beam voltage is 1800 V, the beam current is 3.52 A, and the energy required by the plasma to generate a beam ion (the discharge loss, ɛ³) is 130 eV/ion. The thruster's cathodes and supporting equipment require a power of 66 W. Determine the electrical efficiency, ŋe, of the thruster. Note: 1 eV/ion = 1 W/A. b. C. Calculate the ideal Isp and thrust for this device by assuming that only ions are ejected by the thruster (i.e., no neutrals are lost through the grids). In an actual ion thruster, you must consider that some of the propellant will escape through thruster grids as neutrals instead of ions. i. If we know that the thruster has a discharge propellant utilization efficiency, ŋud, of 0.89, determine the actual thruster Isp compared to the value found above. Assume that the neutral propellant escapes the thruster at a thermal velocity corresponding to 300°C. Find the approximate thrust produced by the escaping neutrals and compare that to the thrust produced by the ions by finding the ratio of the thrusts (Tneut/Tion) ii. d. Prove that nT = nenud using the formulas for ion thruster efficiencies.

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