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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 127 records · Page 7

Coaxial plasma thrusters for high specific impulse propulsion

A fundamental basis for coaxial plasma thruster performance is presented and the steady-state, ideal MHD properties of a coaxial thruster using an annular magnetic nozzle are discussed. Formulas for power usage, thrust, mass flow rate, and specific impulse are acquired and employed to assess thruster performance. The performance estimates are compared with the observed properties of an unoptimized coaxial plasma gun. These comparisons support the hypothesis that ideal MHD has an important role in coaxial plasma thruster dynamics.

Schoenberg, Kurt F.↗

Computational Investigation of the Near-Field Plasma Plume in Ion-Ion Propulsion

A two-fluid computational model of plasma flows was developed to investigate the plume of an ion-ion propulsion system. The densities of positive and negative ions, along with the associated values of net charge, electric field, and electric potential were calculated throughout the domain. The computational domain was chosen to be large enough (25 thruster diameters downstream of the accelerating grids) to examine the neutralization of the plume. The resulting plasma electric potential and charge neutrality at the downstream end of the domain are shown. The results from this simulation are compared to existing literature on ion-ion plasma thrusters.

Sankaran, K.↗

Computational Investigation of the Near-Field Plasma Plume in Ion-Ion Propulsion

A two-fluid numerical model of plasma flows was developed to investigate the plume of an ion-ion propulsion system. The densities of positive and negative ions, and the associated values of net charge, electric field, and electric potential were calculated as a function of time throughout the domain. The computational domain was chosen to be large enough (25 thruster diameters downstream of the exit plane) to allow for examining the neutralization of the plume. The resulting plasma electric potential and charge neutrality at the downstream end of the domain are shown and they indicate that it is possible to alternatively accelerate oppositely charged ions without the need for an electron-emitting neutralizer and without facing any electric potential hills that could cause stagnation. However, compared to existing literature on ion-ion plasma thrusters, the results from this simulation predict a longer length-scale for voltage decay.

Sankaran, K.↗

Some Considerations on the Pulsed Electromagnetic Acceleration of Plasma

In applying pulsed electromagnetic acceleration of plasma to space propulsion (known as pulsed plasma thrusters in the community), the mode of acceleration used has been mostly in the collisionless or near-collisionless regime. The preparation of the initial plasma is given scant attention. Collisional regime of accelerating the plasma, however, have been encountered in a variety of plasma accelerating devices. Both of these modes of acceleration are reviewed in a companion paper. In this paper, we discuss the considerations governing the controlled introduction and preparation of the initial plasma, so that the collisional mode of accelerating the plasma may be suitably enhanced.

Thio, Y. C. F.↗

Nuclear Fusion Space Propulsion Research, Experimentation, Theory Development, and Systems Analysis Efforts Led by the NASA Glenn Research Center (1994-2004)

This review paper summarizes work performed from 1994 to 2004 by a several interrelated government, academic, and industry teams led by the NASA Glenn Research Center. The nuclear fusion space propulsion system concept was predicated on a spherical torus reactor, which enabled manned missions to the outer planets in less than one year. Moderate thrust levels (1,000’s lbf)from direct nuclear fusion exhaust plasma via a magnetic nozzle enabled high thrust-to-weight. An entire vehicle conceptual design, including an artificial gravity crew habitat, was created by the NASA Glenn Research Center. The proof of concept experiment test article and facility upgrade was performed at the Ohio State University which also included staff from the Ohio Aerospace Institute and Science Applications International Corporation.The governing equations for the plasma physics theory of magnetic nozzle operation were derived by the Los Alamos National Laboratory. A preliminary investigation of a proof of concept test utilizing Coaxial Helicity Ejection as a means to supply plasma for propulsion at the National Spherical Torus Experiment reactor was outlined by the Princeton Plasma Physics Laboratory. An industry standard on nuclear fusion propulsion conceptual design was created by two AIAA teams. Despite extremely modest funding levels, significant progress was made advancing the state of the art.The result was a coordinated conceptual, theoretical, and experimental design effort to guide fusion space propulsion development.

Nuclear fusion↗

Recommended Practices in Laser-Induced Fluorescence (LIF) Diagnostics for Electric Propulsion

Laser-induced fluorescence (LIF) spectroscopy uses Doppler-shifted laser photons to excite a bound electron transition in an atom or ion, with subsequent fluorescence emission detected in order to measure the local velocity distribution function (VDF) and/or particle density. Due to its non-invasive nature, high spatial resolution, and acceptable difficulty of implementation, LIF has become a favored diagnostic for electric propulsion (EP) plasmas, particularly in the study of Hall thrusters. This paper presents recommended best practices for LIF measurements in electric thrusters, drawn from over three decades of implementation heritage in the EP community. Focusing on both single-photon LIF (typically used to measure VDFs) and two-photon LIF (TALIF, typically used to determine densities), the paper covers selection of atomic transitions to target, experimental setups, and interpretation of data. A number of special topics and advanced applications are discussed, including uncertainty analysis, techniques for high-speed measurements, and applications to a variety of propellants.

plasma plume↗

Lightweight spacecraft propulsion system selection

Various methods of significantly reducing the mass of planetary spacecraft propulsion systems were addressed. Because of the Space Shuttle Challenger accident, the availability of the Space Transportation System for planetary missions may be limited. Mounting a future planetary mission with lower-energy launch vehicles will require a significant reduction in the spacecraft mass. Smaller launch vehicles for planetary missions were considered. In this study, the assumed payload capability for the planetary missions were considered. In this study, the assumed payload capability for the planetary missions was restricted to the Delta and the Atlas-Centaur launch vehicles. Several propulsion and propulsion-related technologies for spacecraft mass reduction were investigated; ion, arcjet, resistojet, and Magneto-Plasma-Dynamic propulsion and earth-storable high-energy propulsion system thrusters were candidates. The propulsion-related technologies included a start-basket Propellant Management Device, a nitrogen tetroxide diaphragm, and a solid-cryogen cooler. Xenon-ion propulsion allowed the greatest mass reduction.

Palaszewski, B.↗

Measurements of energy distribution and wall temperature in flowing hydrogen microwave plasma systems

An electrothermal propulsion concept utilizing a microwave plasma system as the mechanism to convert electromagnetic energy into translational energy of the flowing gas is being investigated. A calorimetric experimental system has been designed and built enclosing the microwave plasma system to accurately determine the net energy transferred to the flowing gas. For a flow rate of 8900 micromoles/sec, a pressure of 7.4 torr, and an absorbed power level of 80 W, an energy transfer efficiency of 50 percent has been measured. A heat transfer model that characterizes the energy transfer processes in the plasma is developed. A wall temperature for the plasma system is calculated.

Chapman, R.↗

Physics and potentials of fissioning plasmas for space power and propulsion

A brief description of two gas core reactor concepts devised for propulsion applications is presented and recent research on the emission of radiation from nonequilibrium fissioning gases is considered. The principles of UF6 and plasma core reactor experiments are discussed. It is expected that the program of nuclear gas core reactor experiments can lead in several years to reactor operation at pressures, temperatures, and power levels of technological significance to terrestrial applications.

Thom, K.↗