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Future human exploration missions to Mars are being studied by NASA, industry and academia. Many approaches to the Mars mission are being examined that use various types of propulsion for the different phases of the mission. The choice and implementation of propulsion system options can be optimally determined based on specific mission criteria suc...
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... SLS Block 2B performance was assumed for all 2017 study trades. Useful payload system mass (PSM) was taken from the SLS Program Mission Planner's Guide-Version 2. 5 Figure 4 shows the NASA SLS useful payload mass used in the AR SEP cargo study. Useful PSM is the sum of the payload attachment system mass and payload mass. ...
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This study examines the impact of the launch capabilities provided by the planned Space Launch System (SLS) Block 2 vehicle on the solar electric propulsion (SEP) power levels required for large cargo prepositioning missions to Mars orbit. Our analysis shows that the additional launch capability planned for the SLS vehicle enables a dramatic reduct...
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The use of krypton in the field of electric propulsion has become a key research topic owing to its high specific impulse and high reserves. However, because krypton has features such as a small ionization cross section and high ionization energy, its ionization performance is relatively low, thereby increasing the actual specific impulse loss of the krypton Hall thruster in comparison with its theoretical value. Therefore, to use of krypton as the propellant of the Hall thruster instead of xenon, it is necessary to study the optimization of its ionization process. In this study, a gas distributor with a rotating propellant supply mode is designed, considering factors such as the velocity and density of the velocity of neutral atoms, which affects the ionization process. The distribution of neutral atom parameters in the discharge channel is changed by the rotation; and its influences on the propellant ionization and other performance parameters of the Hall thruster are experimentally analyzed with respect to the magneto-ampere, volt-ampere, and flow rate-ampere characteristics. The results demonstrate that the rotating propellant supply reduces the axial velocity of neutral atoms, increases the density and circumferential motion distance, and thus improves the ionization efficiency of the krypton Hall thruster. Furthermore, the performance parameters, such as thrust and efficiency, are also improved, and the plume divergence angle is reduced. When the discharge voltage is 450 V and the anode flow rate is 60 sccm, the rotating propellant supply can increase the anode efficiency of the axial propellant supply mode from 46.2% to 53.2%. However, the plume divergence half-angle reduces from 39.2° to 35.5°. In addition, an increase in the anode flow rate and discharge voltage continuously increases the performance promotion in the rotating propellant supply mode.
