Since the Russian launch of the Zond-2 satellite in 1964 there have been over fifty years of research dedicated to the understanding of the first electric propulsion device to be flown in space, the Pulsed Plasma Thruster. The Pulsed Plasma Thruster originates from the evolution of the vacuum arc switch, but due to its microsecond operation time, the internal dynamics and nature of operation ha...

The University of Michigan and United States Air Force Research Laboratory have jointly created a cluster composed of two P5 Hall effect thrusters. The P5 is a 5 kW class laboratory model Hall thruster developed to investigate a thruster similar to that specified by Integrated High Payoff Rocket Propulsion Technology (IHPRT) goals. In this study, the performance characteristics of each of the P...

A colloid thruster functions by electrostatically generating and accelerating sub-micron droplets of propellant to high velocities. The technology is attractive because of the weight and size of the integrated package, its high efficiency, low power consumption and inert propellant. The development of the thruster prototype at Stanford University is aimed for a proof-of-concept flight-testing o...

A spatiotemporal study of neutral gas temperature during the first 100 s of operation for a radio-frequency electrothermal plasma micro-thruster operating on nitrogen at 60 W and 1.5 Torr is performed to identify the heating mechanisms involved. Neutral gas temperature is estimated from rovibrational band fitting of the nitrogen second positive system. A set of baffles are used to restrict the ...

The ion energy distribution of each ion species in the SPT-100 plume was obtained at various angles off thruster axis at 1 m and 50 cm from the thruster exit using an ExB probe. Each peak of the measured ExB probe traces were fitted using a model based on the kinetic theory of gases, and the energy distribution functions f(Ei) were obtained. From the fitting parameters, Eb (the beam energy) and...

The Hall thruster cluster is an attractive propulsion approach for spacecraft requiring very high-power electric propulsion systems. Plasma density, electron temperature, and plasma potential data collected with a combination of triple langmuir probes and floating emissive probes in the plume of a low-power, four-engine Hall thruster cluster are presented. Simple analytical formulas are introdu...

PURPOSE To verify the positional accuracy of a novel x-ray-image-based dynamic tumor-tracking (DTT) irradiation technique using the gimbaled MV x-ray head of a Vero4DRT (MHI-TM2000). METHODS Verification of the x-ray-image-based DTT was performed using three components: a three-dimensional moving phantom with a steel ball target, a laser displacement gauge, and an orthogonal kV x-ray imaging ...

In order to fully characterize the performance of the colloid thruster system the electrospray (ES) beam must itself be fully characterized. This may be achieved by measuring various properties such as flow rate, current, droplet/ion charge to mass ratio and current profile. Beam properties of both standard electrospray mass spectrometry (ESMS) emitters and arrays of custom made micro-fabricate...

Measurements of the most probable time-averaged axial ion velocities and plasma potential within the acceleration channel and in the plume of a straightchanneled cylindrical cusped field thruster operating on xenon are presented. Ion velocities for the thruster are derived from laser-induced fluorescence measurements of the 5d[4]7/2 −6p[3]5/2 xenon ion excited state transition centered at λ = 8...