Structural and Thermal Response of 30 Cm Diameter Ion Thruster Optics PDF Download

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722806453
Category :
Languages : en
Pages : 30

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Book Description
Tabular and graphical data are presented which are intended for use in calibrating and validating structural and thermal models of ion thruster optics. A 30 cm diameter, two electrode, mercury ion thruster was operated using two different electrode assembly designs. With no beam extraction, the transient and steady state temperature profiles and center electrode gaps were measured for three discharge powers. The data showed that the electrode mount design had little effect on the temperatures, but significantly impacted the motion of the electrode center. Equilibrium electrode gaps increased with one design and decreased with the other. Equilibrium displacements in excess of 0.5 mm and gap changes of 0.08 mm were measured at 450 W discharge power. Variations in equilibrium gaps were also found among assemblies of the same design. The presented data illustrate the necessity for high fidelity ion optics models and development of experimental techniques to allow their validation. Macrae, G. S. and Zavesky, R. J. and Gooder, S. T. Glenn Research Center RTOP 506-42-31...

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781724980434
Category :
Languages : en
Pages : 34

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A thermal analytic model for a 30-cm engineering model mercury-ion thruster was developed and calibrated using the experimental test results of tests of a pre-engineering model 30-cm thruster. A series of tests, performed later, simulated a wide range of thermal environments on an operating 30-cm engineering model thruster, which was instrumented to measure the temperature distribution within it. The modified analytic model is described and analytic and experimental results compared for various operating conditions. Based on the comparisons, it is concluded that the analytic model can be used as a preliminary design tool to predict thruster steady-state temperature distributions for stage and mission studies and to define the thermal interface bewteen the thruster and other elements of a spacecraft. Oglebay, J. C. Glenn Research Center NASA-TM-X-3541, E-9064 RTOP 506-22...

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781723146473
Category :
Languages : en
Pages : 112

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Performance data are presented for the NASA/Hughes 30-cm-diam 'common' thruster operated over the power range from 600 W to 4.6 kW. At the 4.6-kW power level, the thruster produces 172 mN of thrust at a specific impulse of just under 4000 s. Xenon pressure and temperature measurements are presented for a 6.4-mm-diam hollow cathode operated at emission currents ranging from 5 to 30 A and flow rates of 4 sccm and 8 sccm. Highly reproducible results show that the cathode temperature is a linear function of emission current, ranging from approx. 1000 C to 1150 C over this same current range. Laser-induced fluorescence (LIF) measurements obtained from a 30-cm-diam thruster are presented, suggesting that LIF could be a valuable diagnostic for real-time assessment of accelerator-arid erosion. Calibration results of laminar-thin-film (LTF) erosion badges with bulk molybdenum are presented for 300-eV xenon, krypton, and argon sputtering ions. Facility-pressure effects on the charge-exchange ion current collected by 8-cm-diam and 30-cm-diam thrusters operated on xenon propellant are presented to show that accel current is nearly independent of facility pressure at low pressures, but increases rapidly under high-background-pressure conditions. Beattie, J. R. and Matossian, J. N. Glenn Research Center ELECTRIC PROPULSION; ION PROPULSION; PLASMA PROPULSION; ROCKET THRUST; PRESSURE MEASUREMENT; PRESSURE EFFECTS; SPECIFIC IMPULSE; THIN FILMS; ION CURRENTS; ION ENGINES; CHARGE TRANSFER; PLASMA ENGINES; PROPELLANTS; TEMPERATURE MEASUREMENT; LASER INDUCED FLUORESCENCE; FLOW VELOCITY...

Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781726673877
Category : Science
Languages : en
Pages : 42

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A 40 cm ion thruster is being developed at the NASA Glenn Research Center to obtain input power and propellant throughput capabilities of 10 kW and 550 kg. respectively. The technical approach here is a continuation of the "derating" technique used for the NSTAR ion thruster. The 40 cm ion thruster presently utilizes the NSTAR ion optics aperture geometry to take advantage of the large database of lifetime and performance data already available. Dome-shaped grids were chosen for the design of the 40 cm ion optics because this design is naturally suited for large-area ion optics. Ion extraction capabilities and electron backstreaming limits for the 40 cm ion optics were estimated by utilizing NSTAR 30 cm ion optics data. A preliminary service life assessment showed that the propellant throughput goal of 550 kg of xenon may be possible with molybdenum 40 cm ion optics. One 40 cm ion optics' set has been successfully fabricated to date. Additional ion optics' sets are presently being fabricated. Preliminary performance tests were conducted on a laboratory model 40 cm ion thruster. Soulas, George C. Glenn Research Center; Marshall Space Flight Center NASA/TM-2001-211275, E-13074, IEPC-01-090, NAS 1.15:211275

Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781724087355
Category : Science
Languages : en
Pages : 40

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The success of the NASA Deep Space I spacecraft has demonstrated that ion propulsion is a viable option for deep space science missions. More aggressive missions such as Comet Nuclear Sample Return and Europa lander will require higher power, higher propellant throughput and longer thruster lifetime than the NASA Solar Electric Propulsion Technology Application Readiness (NSTAR) engine. Presented here are thruster plume and discharge plasma measurements of an NSTAR-type thruster operated from 0.5 kW to 5 kW. From Faraday plume sweeps, beam divergence was determined. From Langmuir probe plume measurements on centerline, low energy ion production on axis due to charge-exchange and direct ionization was assessed. Additionally, plume plasma potential measurements made on axis were used to determine the upper energy limits at which ions created on centerline could be radially accelerated. Wall probes flush-mounted to the thruster discharge chamber anode were used to assess plasma conditions. Langmuir probe measurements at the wall indicated significant differences in the electron temperature in the cylindrical and conical sections of the discharge chamber. Foster, John E and Soulas, George C. and Patterson, Michael J. Glenn Research Center NASA/TM-2000-210382, E-12438, AIAA Paper 2000-3812, NAS 1.15:210382

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721297078
Category :
Languages : en
Pages : 34

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NASA's Hall thruster program has base research and focused development efforts in support of the Advanced Space Transportation Program, Space-Based Program, and various other programs. The objective of the base research is to gain an improved understanding of the physical processes and engineering constraints of Hall thrusters to enable development of advanced Hall thruster designs. Specific technical questions that are current priorities of the base effort are: (1) How does thruster life vary with operating point? (2) How can thruster lifetime and wear rate be most efficiently evaluated? (3) What are the practical limitations for discharge voltage as it pertains to high specific impulse operation (high discharge voltage) and high thrust operation (low discharge voltage)? (4) What are the practical limits for extending Hall thrusters to very high input powers? and (5) What can be done during thruster design to reduce cost and integration concerns? The objective of the focused development effort is to develop a 50 kW-class Hall propulsion system, with a milestone of a 50 kW engineering model thruster/system by the end of program year 2006. Specific program wear 2001 efforts, along with the corporate and academic participation, are described. Jankovsky, Robert S. and Jacobson, David T. and Rawlin, Vincent K. and Mason, Lee S. and Mantenieks, Maris A. and Manzella, David H. and Hofer, Richard R. and Peterson, Peter Y. Glenn Research Center NASA/TM-2001-211215, E-13067, NAS 1.15:211215, AIAA Paper 2001-3888

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721531929
Category :
Languages : en
Pages : 30

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NASA's Glenn Research Center has been selected to lead development of NASA's Evolutionary Xenon Thruster (NEXT) system. The central feature of the NEXT system is an electric propulsion thruster (EPT) that inherits the knowledge gained through the NSTAR thruster that successfully propelled Deep Space 1 to asteroid Braille and comet Borrelly, while significantly increasing the thruster power level and making improvements in performance parameters associated with NSTAR. The EPT concept under development has a 40 cm beam diameter, twice the effective area of the Deep-Space 1 thruster, while maintaining a relatively-small volume. It incorporates mechanical features and operating conditions to maximize the design heritage established by the flight NSTAR 30 cm engine, while incorporating new technology where warranted to extend the power and throughput capability. The NASA Hall thruster program currently supports a number of tasks related to high power thruster development for a number of customers including the Energetics Program (formerly called the Space-based Program), the Space Solar Power Program, and the In-space Propulsion Program. In program year 2002, two tasks were central to the NASA Hall thruster program: 1.) the development of a laboratory Hall thruster capable of providing high thrust at high power; 2.) investigations into operation of Hall thrusters at high specific impulse. In addition to these two primary thruster development activities, there are a number of other on-going activities supported by the NASA Hall thruster program, These additional activities are related to issues such as thruster lifetime and spacecraft integration. Domonkos, Matthew T. and Patterson, Michael J. and Jankovsky, Robert S. Glenn Research Center NASA/TM-2002-211969, NAS 1.15:211969, E-13612, IMECE-2002-34444

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721532490
Category :
Languages : en
Pages : 32

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Outer solar system missions will have propulsion system lifetime requirements well in excess of that which can be satisfied by ion thrusters utilizing conventional hollow cathode technology. To satisfy such mission requirements, other technologies must be investigated. One possible approach is to utilize electrodeless plasma production schemes. Such an approach has seen low power application less than 1 kW on earth-space spacecraft such as ARTEMIS which uses the rf thruster the RIT 10 and deep space missions such as MUSES-C which will use a microwave ion thruster. Microwave and rf thruster technologies are compared. A microwave-based ion thruster is investigated for potential high power ion thruster systems requiring very long lifetimes. Foster, John E. and Patterson, Michael J. Glenn Research Center NASA/TM-2002-211877, NAS 1.15:211877, E-13559, AIAA Paper 2002-3837

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721671724
Category :
Languages : en
Pages : 34

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Book Description
Carbon has a sputter erosion rate about an order of magnitude less than that of molybdenum, over the voltages typically used in ion thruster applications. To explore its design potential, 30 cm pyrolytic carbon ion thruster optics have been fabricated geometrically similar to the molybdenum ion optics used on NSTAR. They were then installed on an NSTAR Engineering Model thruster, and experimentally evaluated over much of the original operating envelope. Ion beam currents ranged from 0.51 to 1.76 Angstroms, at total voltages up to 1280 V. The perveance, electron back-streaming limit, and screen-grid transparency were plotted for these operating points, and compared with previous data obtained with molybdenum. While thruster performance with pyrolytic carbon was quite similar to that with molybdenum, behavior variations can reasonably be explained by slight geometric differences. Following all performance measurements, the pyrolytic carbon ion optics assembly was subjected to an abbreviated vibration test. The thruster endured 9.2 g(sub rms) of random vibration along the thrust axis, similar to DS 1 acceptance levels. Despite significant grid clashing, there was no observable damage to the ion optics assembly. Haag, Thomas and Soulas, George C. Glenn Research Center NASA/TM-2004-213178, E-14673, AIAA Paper 2003-4557

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721507290
Category :
Languages : en
Pages : 26

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Book Description
With recent success of the NSTAR ion thruster on Deep Space 1, there is continued interest in long term, high propellant throughput thrusters to perform energetic missions. This requires flight qualified thrusters that can operate for long periods at high beam density, without degradation in performance resulting from sputter induced grid erosion. Carbon-based materials have shown nearly an order of magnitude improvement in sputter erosion resistance over molybdenum. NASA Glenn Research Center (GRC) has been active over the past several years pursuing carbon-based grid development. In 1995, NASA GRC sponsored work performed by the Jet Propulsion Laboratory to fabricate carbon/carbon composite grids using a machined panel approach. In 1999, a contract was initiated with a commercial vendor to produce carbon/carbon composite grids using a chemical vapor infiltration process. In 2001, NASA GRC purchased pyrolytic carbon grids from a commercial vendor. More recently, a multi-year contract was initiated with North Carolina A&T to develop carbon/carbon composite grids using a resin injection process. The following paper gives a brief overview of these four programs. Haag, Thomas and Patterson, Michael and Rawlin, Vince and Soulas, George Glenn Research Center; Jet Propulsion Laboratory; Marshall Space Flight Center NASA/TM-2002-211501, NAS 1.15:211501, IEPC-01-94, E-13241