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Book Advanced Diagnostics for Millimeter Scale Micro Pulsed Plasma Thrusters

Download or read book Advanced Diagnostics for Millimeter Scale Micro Pulsed Plasma Thrusters written by and published by . This book was released on 2002 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: A class of Micro-Pulsed Plasma Thrusters (MicroPPTs) is being developed by the Air Force Research Laboratory (AFRL) to provide precise attitude control and stationkeeping ability to 25-kg class satellites. Operating by means of a surface discharge across a Teflon(TM) propellant fuel bar only a few millimeters in diameter, the MicroPPT delivers a thrust-to-power ratio of 5 - 10 microN-s/J. Due to the low pulse energy and size, the MicroPPT produces a spatially-confined and diffuse plasma plume that is difficult to analyze with material probes. Efforts to characterize MicroPPT plume are underway. To this end, a Herriott Cell interferometer is introduced to establish the plume electron and neutral densities. Comparison of the measured electron density with modeling predictions shows close agreement. Additionally, a Pockels cell has been developed to provide a zero-impedance MicroPPT breakdown voltage measurement. Current research focuses on an infrared-emission measurement capability to determine propellant surface temperature during thruster operation.

Book Microsecond Timescale Surface Temperature Measurements in Micro Pulsed Plasma Thrusters

Download or read book Microsecond Timescale Surface Temperature Measurements in Micro Pulsed Plasma Thrusters written by and published by . This book was released on 2003 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: A time-resolved surface temperature diagnostic for ablation-controlled arcs is in development at the Air Force Research Laboratory at Edwards AFB. The diagnostic draws on heritage from the experimental dynamic crack propagation community which has used photovoltaic infrared detectors to measure temperature rise in materials in the process of fracture. The microsecond time scales involved in the fracture process suggest that such detectors may be applicable to the ablation-controlled discharges in pulsed plasma thrusters as a direct measurement of surface temperature during and after the arc. HgCdTe detectors are evaluated for use on the surface of a micro-pulsed plasma thruster invented at the AFRL. Evaluation of the diagnostic focuses on development of valid calibration methodology and application of the detector in the presence of a plasma. Current calibration techniques are reviewed with physical limitations discussed. Detector response to an operating thruster is examined and future studies involving surface roughness changes are investigated.

Book High order Modeling of Micro pulsed Plasma Thrusters

Download or read book High order Modeling of Micro pulsed Plasma Thrusters written by Guang Lin and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Pulsed Plasma Thrusters for Micropropulsion

Download or read book Pulsed Plasma Thrusters for Micropropulsion written by Daniel H. Simon and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Optimization of Pulsed Plasma Thrusters for Micro satellite Propulsion

Download or read book Optimization of Pulsed Plasma Thrusters for Micro satellite Propulsion written by P. J. Turchi and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Advanced Pulsed Plasma Thruster Electrical Components

Download or read book Advanced Pulsed Plasma Thruster Electrical Components written by Scott W. Benson and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Progress in Development of Modeling Capabilities for a Micro pulsed Plasma Thruster

Download or read book Progress in Development of Modeling Capabilities for a Micro pulsed Plasma Thruster written by Michael Keidar and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Evaluation of Pulsed Plasma Thruster Micropulsing

Download or read book Evaluation of Pulsed Plasma Thruster Micropulsing written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-21 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper evaluates the concept of pulsed plasma thruster (PPT) micropulsing. Micropulsing was a premise behind a power processing unit (PPU) and an energy storage unit (ESU) design that for certain mission profiles, it was advantageous to operate a PPT at lower energy but higher frequency rather than at a higher energy but lower frequency. This premise allows for reductions in the ESU volume and mass without paying a penalty in thrust. To complete the evaluation, an independent spark plug initiation unit, a high voltage power supply and a variety of mica foil capacitors at 2.6, 5, 10, and 20 capacitance were used to conduct a series of tests on a single PPT to map performance levels of thrust, impulse bit, efficiency and specific impulse over a comparable power range. Testing at NASA Glenn Research Center was conducted with breadboard PPT hardware. The test results showed that operating in the lower energy ESU micropulsing mode produced similar thrust levels to a higher energy ESU operating at high power level. Further testing however showed a reduction in specific impulse and efficiency when the smaller capacitances were used at the highest power levels. This would require more fuel mass for a mission that was predominately high power, potentially negating the ESU mass savings. Therefore, micropulsing is advantageous where most of a mission profile occurs at low power, but retains the ability to conduct high thrust maneuvers when necessary. Arrington, Lynn Glenn Research Center NASA/CR-2004-213209, AIAA Paper 2004-3458, E-14717

Book Fundamentals of Electric Propulsion

Download or read book Fundamentals of Electric Propulsion written by Dan M. Goebel and published by John Wiley & Sons. This book was released on 2008-12-22 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout most of the twentieth century, electric propulsion was considered the technology of the future. Now, the future has arrived. This important new book explains the fundamentals of electric propulsion for spacecraft and describes in detail the physics and characteristics of the two major electric thrusters in use today, ion and Hall thrusters. The authors provide an introduction to plasma physics in order to allow readers to understand the models and derivations used in determining electric thruster performance. They then go on to present detailed explanations of: Thruster principles Ion thruster plasma generators and accelerator grids Hollow cathodes Hall thrusters Ion and Hall thruster plumes Flight ion and Hall thrusters Based largely on research and development performed at the Jet Propulsion Laboratory (JPL) and complemented with scores of tables, figures, homework problems, and references, Fundamentals of Electric Propulsion: Ion and Hall Thrusters is an indispensable textbook for advanced undergraduate and graduate students who are preparing to enter the aerospace industry. It also serves as an equally valuable resource for professional engineers already at work in the field.

Book Theoretical Investigation of Pulsed Plasma Thrusters

Download or read book Theoretical Investigation of Pulsed Plasma Thrusters written by P. J. Turchi and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Assessment of the Plume Characteristics of a Miniaturized Pulsed Plasma Thurster

Download or read book Assessment of the Plume Characteristics of a Miniaturized Pulsed Plasma Thurster written by Richard Henry [Verfasser] Sypniewski Jr. and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Pulsed Plasma Thrusters are one of the most simplistic constructions in the electric propulsion family and are categorized among the electromagnetic class of thrusters. This classification of electromagnetics deals with the underlying physics of the pulsed plasma thruster and is much more complex with less understanding then other electric propulsion systems. However, due to the mechanical simplicity, wide range of specific impulses, non-toxic propellant, and the numerous applications, these thrusters are an ideal candidate for integrating into CubeSats. CubeSats are nanosatellites that are designed in three typical standard sizes (1 Unit, 2 Unit, and 3 Unit), each with standardized footprints. The smallest volumetric dimensions are the 1 Unit CubeSat, which is 10 x 10 x 10 cm. The volume and mass of CubeSats are quite small and therefore the miniaturization of the Pulsed Plasma Thruster is necessary to adhere to these constraints. Current research has shown that when miniaturization of a Pulsed Plasma Thruster there is a tendency for the thruster to work and perform in the electrothermal regime rather than in the electromagnetic one. Understanding which regime the thruster is operating in is critical for understanding how to optimize the design. For example, a thruster operates with higher efficiencies in the electromagnetic regime because there is much less loss from Ohmic heating. Preliminary testing of the Micro-Pulsed Plasma Thruster design was performed by the research company called FOTEC and determined a thruster chamber design. To understand thoroughly the Micro-Pulsed Plasma Thruster, characterization of the thruster and its plume will be conducted experimentally. This characterization will determine parametric features such as current/voltage waveform, electron temperatures, electron densities, and exhaust velocities. Performing the initial characterizations will give insight into the Micro-Pulsed Plasma Thruster and will provide further understanding into the regime that the thruster is operating in. The characteristics that resulted from this thesis concluded that the Micro-Pulsed Plasma Thruster is operating in the electromagnetic regime. This was concluded based on several characteristic traits that only conclude for electromagnetic acceleration mechanisms. These were that the peak currents reached were approximately 5,000 A and the exhaust velocity was in the 50 km/sec range. Further information was measured and the total resistance and inductance was calculated to be 13 m and 24 nH. Details on this information and how it was calculated is discussed in this thesis.*****Pulsed Plasma Thrusters are one of the most simplistic constructions in the electric propulsion family and are categorized among the electromagnetic class of thrusters. This classification of electromagnetics deals with the underlying physics of the pulsed plasma thruster and is much more complex with less understanding then other electric propulsion systems. However, due to the mechanical simplicity, wide range of specific impulses, non-toxic propellant, and the numerous applications, these thrusters are an ideal candidate for integrating into CubeSats. CubeSats are nanosatellites that are designed in three typical standard sizes (1 Unit, 2 Unit, and 3 Unit), each with standardized footprints. The smallest volumetric dimensions are the 1 Unit CubeSat, which is 10 x 10 x 10 cm. The volume and mass of CubeSats are quite small and therefore the miniaturization of the Pulsed Plasma Thruster is necessary to adhere to these constraints. Current research has shown that when miniaturization of a Pulsed Plasma Thruster there is a tendency for the thruster to work and perform in the electrothermal regime rather than in the electromagnetic one. Understanding which regime the thruster is operating in is critical for understanding how to optimize the design. For example, a thruster operates with higher efficiencies in the electromagne

Book Nonequilibrium Diagnostics of Plasma Thrusters

Download or read book Nonequilibrium Diagnostics of Plasma Thrusters written by and published by . This book was released on 1990 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes possible techniques by which the state of plasma thruster operation for space propulsion can be determined from a minimum set of experimental data in the laboratory. The kinetic properties of the nonequilibrium plasma plume usually can not be directly related to the observed radiation; hence, appropriate nonequilibrium diagnostic techniques must be employed. A newly developed multithermal, multichemical equilibrium method is discussed that uses measured line emission intensities and N equations to solve for N unknowns. The effect of arbitrarily changing the number of selected N unknowns and how one determines the optimum (minimum) number to be used for a given composition is also presented. The chemical nonequilibrium aspects and the application to molecular species have not yet been published. The important conclusions are that (1) complete thermodynamic systems in nonequilibrium can be described by relatively few variables if appropriate choices and filtering methods are used, (2) a few radiation measurements can yield valid kinetic properties, and (3) the major question in the relations to be used is in the form of the law of mass action. The results are substantiated in the laboratory by additional alternative methods of measurement of some of the kinetic properties. 13 refs., 1 fig.