Engineering topics

Ruyten, W. M.

Publications and source records attributed to Ruyten, W. M..

8 records

NASA NTRS1995

EPOP: The Electric Propulsion Orbital Platform

This paper describes the results of a one-year feasibility study for an Electric Propulsion Orbital Platform (EPOP), whose primary objective is to provide an instrumented platform for testing electric propulsion devices in space. The first flight, EPOP-1, is planned aboard the Shuttle-deployed Wake Shield Facility in March 1995, and will be designed around a commercial 1.8 kW, 0.5 hydrazine arcjet system. Specific subsystems are described, namely the arcjet and the power conditioning unit, the propellant and power systems, and Wake Shield Facility. Also, system engineering and integration issues are discussed. In an accompanying paper, the diagnostics and data acquisition and control systems are described in more detail.

Friedly, V. J.↗

NASA NTRS1995

EPOP Diagnostics and Data Acquisition

This paper describes the diagnostics that have been selected for the first flight of the Electric Propulsion Orbital Platform (EPOP-1), in which a 1.8 kW hydrazine arcjet will be flown and tested on the Wake Shield Facility. These diagnostics are: Langmuir probe measurements and video of the arcjet plume; three types of electromagnetic noise measurements; measurement of the voltage-current characteristic of the arc at different feed pressures; and measurement of other performance parameters such as pressures and temperatures of arcjet system components, thrust, and specific impulse. Also, the approach to data acquisition and control of the experiment is described.

Ruyten, W. M.↗

NASA NTRS1995

Electric Propulsion: Experimental Research

This paper describes experimental electric propulsion research which was carried out at the University of Tennessee Space Institute with support from the Center for Space Transportation and Applied Research. Specifically, a multiplexed LIF technique for obtaining vector velocities, Doppler temperatures, and relative number densities in the exhaust plumes form electric propulsion devices is described, and results are presented that were obtained on a low power argon arcjet. Also, preliminary Langmuir probe measurements on an ion source are described, and an update on the vacuum facility is presented.

Ruyten, W. M.↗

NASA NTRS1993

Anomalous optogalvanic line shapes of argon metastable transitions in a hollow cathode lamp

Anomalous optogalvanic line shapes were observed in a commercial hollow cathode lamp containing argon buffer gas. Deviations from Gaussian line shapes were particularly strong for transitions originating from the 3P2 metastable level of argon. The anomalous line shapes can be described reasonably well by the assumption that two regions in the discharge are excited simultaneously, each giving rise to a purely Gaussian line shape, but with different polarities, amplitudes, and linewidths.

Ruyten, W. M.↗

NASA NTRS1993

Spectroscopic investigation of a low-power arcjet plume

We report the results of spectroscopic measurements on the exhaust plume from a 1 kW NASA Lewis arcjet operated on simulated ammonia. In particular, we analyze emissions from the Balmer lines of atomic hydrogen and from one of the rotational bands of the NH radical. We find that exit plane temperatures are in the range 2000 to 3500 K, depending on the measurement method, and that the electron density upstream of the exit plane is on the order of 1.5 x 10 exp 14/cu cm as determined by the Stark width of the Balmer-alpha line. Also, we have determined that the average velocity of atomic hydrogen at the exit plane is about 4 km/sec, and that strong acceleration (to 5.5 km/sec) of the flow occurs just beyond the exit plane.

Ruyten, W. M.↗

NASA NTRS1993

Spectroscopic investigations of beam-plasma interactions in an ion plume

We report the results of spectroscopic investigations of beam-plasma interactions in the plume from a 3 cm ion source operated on argon. Ion-electron, ion-neutral, and electron-neutral scattering are identified by studying the dependence of neutral and ion emission intensities on chamber pressure and mass flow rate, and by analyzing the emission lineshapes at a non-orthogonal angle to the plume axis. Through the Doppler shift, we are able to separate contributions from fast beam ions and fast charge-exchange neutrals on the one hand, and of slow neutrals and slow ions on the other. We discuss the application of this new technique to the characterization of beam plasma interactions in the downstream region of ion thruster engines, and its potential for identifying the processes which lead to grid erosion.

Ruyten, W. M.↗

NASA NTRS1992

Characterization of electric thruster plumes using multiplexed laser induced fluorescence measurements

The use of laser-induced fluorescence to obtain spatially resolved measurements of propellant velocities and temperatures in electric thruster plumes is discussed, with emphasis on two innovations of the technique, namely simultaneous recording of the optogalvanic signal in a hollow cathode lamp for the purpose of calibrating Doppler shifts, and two-beam multiplexing to allow the measurement of two velocity components at once. It is also shown how information on plume fluctuations can be obtained from the multiplxed LIF data. The techniques are demonstrated on the plume from a low power arcjet, operated on argon, and its extension to the measurement of ion velocities in electrostatic ion thrusters and stationary plasma thrusters is discussed.

Ruyten, W. M.↗

NASA NTRS1992

EPOP - Toward the realization of an Electric Propulsion Orbital Platform

This paper describes the results of a feasibility study for an Electric Propulsion Orbital Platform (EPOP), whose primary objective is to provide an instrumented platform for testing electric propulsion devices in space. It is anticipated that the first flight, EPO-1, will take place on the Shuttle-deployed Wake Shield Facility in 1996, and will be designed around a modified version of a commercial 1.8 kW hydrazine arcjet system, to be operated on gaseous hydrogen propellant. Specific subsystems are described, including the arcjet system, the propellant and power systems, and the diagnostics systems. Also, system engineering and integration issues are discussed.

Friedly, V. J.↗