* Presented as Paper IEPC-03-0069 at the 28 International Electric Propulsion Conference, Toulouse, France, March 17 – 21, 2003. Published by the Electric Rocket Propulsion Society with permission. † Graduate Student, Aerospace Engineering, [email protected]. ‡ Graduate Student, Aerospace Engineering. § Associate Professor and Laboratory Director. A method for delivering a symmetric double ...

A new electric propulsion device concept takes advantage of residual helium gas that is trapped in the chemical propellant feed system and currently unused at end of life. The helium ion thruster provides additional propellant resources to extend satellite lifetimes and transfer geostationary orbit space assets to ultrasafe disposal orbits. The predicted capability, if fully allotted to the dis...

This paper presents a recent characterization of the thrust efficiency and specific impulse of a low power, linear-geometry (non-coaxial) Hall thruster with an open electron-drift current. The thruster was constructed with a boron-nitride insulating channel surrounded by a magnetic circuit served by four electromagnet coils, and was designed to operate in the 100-Watt power class. A survey of t...

This paper considers thruster dead zones and saturation limits in fine motion control of underwater robots. Thruster dead zones and saturation limits are major nonlinear elements that make fine motion control of underwater robots difiicult. If the vehicle is designed with a redundant thruster configuration, the dead zone and the nonlinear region around it can be completely avoided by implementi...

The ffx code was used to investigate the lifetime and propellant throughput capability of the High Power Electric Propulsion (HiPEP) thruster ion optics as part of NASA’s Project Prometheus. Erosion predictions are presented as a function of beamlet current, accel grid voltage, and propellant utilization efficiency. These predictions were then compared to the lifetime goals of the thruster, and...

A compact high-speed reciprocating probe system has been developed in order to perform measurements of the plasma parameters by means of electrostatic probes in the discharge and the plume of a Hall thruster. The system is based on a piezoelectric linear drive that can achieve a speed of up to 350 mm/s over a travel range of 90 mm. Due to the high velocity of the linear drive the probe can be r...

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-...

Introduction Experiments were conducted to develop a As the development of Hall effect plasma thrusters comprehensive plume model for Hall effect plasma continues, potential missions beyond basic north-south thrusters. The purpose of the plume model developed in and east-west station keeping are being considered for this this paper is to give system integrators a guide to follow type of thruste...

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....

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 ...