Breathing mode oscillations of a xenon 600 W Hall effect thruster have been studied using temporally resolved experimental data and numerical modeling. Fluctuations in xenon neutral near infrared (810–835 nm) emission in the near field thruster plume have been measured at 1-μs resolution using a high speed, phase-matched intensified charge coupled device. Oscillations in electron temperature, 3...

Ion current density and electron number density profiles were measured in the very-nearfield plume of a 1.35 kW stationary plasma thruster (SPT-100) loaned from Space Systems/Loraland Fakel Enterprises. In order to take these measurements without significantly disturbing plasma flow while data were collected, a small Faraday probe and a single Langmuir probe were constructed and used with high-...

The finite pressure present in vacuum chamber testing of space propulsion systems such as Hall thrusters can have a number of undesirable effects. For example, the thrust generated by the thruster is higher and the plume divergence angle larger in ground tests in comparison to space operation. To try to quantify these effects, the direct simulation Monte Carlo method is applied to model a cold ...

Microsatellite technology has become increasingly popular in recent years as it can offer significant cost savings, higher reliability, and is generally more affordable for a large variety of commercial applications. Since many microsatellite missions require considerable propulsion capabilities, miniaturization of the propulsion subsystem is critical in the design of most miniature spacecraft....

We present the initial results from a cavity ring-down sensor for measuring the density of sputtered boron atoms originating from the discharge channel of a 6-kW Hall thruster. The sensor traps 250 nm light in a high-finesse cavity to greatly increase its sensitivity to boron atoms. Measurements were obtained with the thruster operating at seven conditions spanning discharge voltages from 150 t...

Computational analysis of the transport of boron eroded from the walls of a Hall thruster is performed by implementing sputter yields of hexagonal boron nitride and velocity distribution functions of boron within the hybrid-PIC model HPHall. The model is applied to simulate NASA’s HiVHAc Hall thruster at a discharge voltage of 500V and discharge powers of 1–3 kW. The number densities of grounda...

Minimizing the modal vibration induced by on-off thrusters is a challenging problem for designers of flexible spacecraft. This thesis presents the first study of PulseWidth, Pulse-Frequency (PWPF) modulated thruster control using the method of command input shaping. Input shaping for systems with linear actuators has been successfully developed to reduce modal vibrations. Recently, this method ...

Assessment of thruster induced contamination of critical surfaces is the important and necessary stage of International Space Station (ISS) component design. Plume contamination models aimed at the prediction of the spatial distribution of contaminant mass fluxes have been developed in the recent years for various ISS thrusters based on vacuum chamber and space flight experiments and empirical ...

Hall Effect Thrusters (HET) are known to exhibit many high-speed oscillations that are indicative of thruster performance. Azimuthal ionization oscillations, called spokes, have been investigated extensively but the mechanisms governing their behavior are still poorly understood. Most experimentation has been done with single-channel Hall thrusters but evidence exists that a nested-channel Hall...