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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Lithium-ion cell technology demonstration for future NASA applications

NASA requires lightweight rechargeable batteries for future missions to Mars and the outer planets that are capable of operating over a wide range of temperatures, with high specific energy and energy densities. Due to their attractive performance characteristics, lithium-ion batteries have been identified as the battery chemistry of choice for a number of future applications, including planetary orbiters, rovers and landers. For example, under the Mars Surveyor Program MSP 01 lithium-ion batteries were developed by Lithion (each being 28 V, 25 Ah, 8-cells. and 9 kg) and fully qualified prior to mission cancellation. In addition to the requirement of being able to supply at least 90 cycles on the surface of Mars, the battery demonstrated operational capability (both charge and discharge) over a large temperature range (-2O'C to +4OoC), with tolerance to non-operational excursions to -30nd 50Currently, JPL is implementing lithium-ion technology on the 2003 Mars Exploration Rover (MER), which will be coupled with a solar array. This mission has similar performance requirements to that of the 2001 Lander in that high energy density and a wide operating temperature range are necessitated. In addition to planetary rover and lander applications, we are also engaged in determining the viability of using lithium-ion technology for orbiter applications that require exceptionally long life (>20,000 cydes at partial depth of discharge). To assess the viabili of lithium-ion cells for these applications, a number of performance characterization tests have been performed (at the cell and battery level) on state-of-art prototype lihium- ion cells, induding: assessing the cycle life performance (at varying DODs), life characteristics at extreme temperatures (< -10nd >+4OoC), rate capability as a function of temperature (-30' to 4OoC), pulse capability, self-discharge and storage characteristics, as well as, mission profile capability. This paper will describe the current and future NASA missions that are considering lithium ion batteries and will contain results of the cell testing conducted to-date to validate the technology for these missions.

lithium-ion batteries Mars landers Mars rovers↗
NASA NTRS1985

A comparison of Doppler lidar wind sensors for Earth-orbit global measurement applications

Now, there are four Doppler lidar configurations which are being promoted for the measurement of tropospheric winds: (1) the coherent CO2 Lidar, operating in the 9 micrometer region using a pulsed, atmospheric pressure CO2 gas discharge laser transmitter, and heterodyne detection; (2) the coherent Neodymium doped YAG or Glass Lidar, operating at 1.06 micrometers, using flashlamp or diode laser optical pumping of the solid state laser medium, and heterodyne detection; (3) the Neodymium doped YAG/Glass Lidar, operating at the doubled frequency (at 530 nm wavelength), again using flashlamp or diode laser pumping of the laser transmitter, and using a high resolution tandem Fabry-Perot filter and direct detection; and (4) the Raman shifted Xenon Chloride Lidar, operating at 350 nm wavelength, using a pulsed, atmospheric pressure XeCl gas discharge laser transmitter at 308 nm, Raman shifted in a high pressure hydrogen cell to 350 nm in order to avoid strong stratospheric ozone absorption, also using a high resolution tandem Fabry-Perot filter and direct detection. Comparisons of these four systems can include many factors and tradeoffs. The major portion of this comparison is devoted to efficiency. Efficiency comparisons are made by estimating the number of transmitted photons required for a single pulse wind velocity estimate of + or - 1 m/s accuracy in the middle troposphere, from an altitude of 800 km, which is assured to be reasonable for a polar orbiting platform.

Menzies, Robert T.↗
NASA NTRS2009

Efficient Ionization Investigation for Flow Control and Energy Extraction

Nonequilibrium ionization of air by nonthermal means is explored for hypersonic vehicle applications. The method selected for evaluation generates a weakly ionized plasma using pulsed nanosecond, high-voltage discharges sustained by a lower dc voltage. These discharges promise to provide a means of energizing and sustaining electrons in the air while maintaining a nearly constant ion/neutral molecule temperature. This paper explores the use of short approx.5 nsec, high-voltage approx.12 to 22 kV, repetitive (40 to 100 kHz) discharges in generating a weakly ionized gas sustained by a 1 kV dc voltage in dry air at pressures from 10 to 80 torr. Demonstrated lifetimes of the sustainer discharge current approx.10 to 25 msec are over three orders of magnitude longer than the 5 nsec pulse that generates the electrons. This life is adequate for many high speed flows, enabling the possibility of exploiting weakly ionized plasma phenomena in flow-fields such as those in hypersonic inlets, combustors, and nozzles. Results to date are obtained in a volume of plasma between electrodes in a bell jar. The buildup and decay of the visible emission from the pulser excited air is photographed on an ICCD camera with nanosecond resolution and the time constants for visible emission decay are observed to be between 10 to 15 nsec decreasing as pressure increases. The application of the sustainer voltage does not change the visible emission decay time constant. Energy consumption as indicated by power output from the power supplies is 194 to 669 W depending on pulse repetition rate.

Schneider, Steven J.↗
NASA NTRS1979

Electrical discharges in the atmosphere of Venus

Data received from Venera 11 and 12 experiments involving the electrical activity of the atmosphere of Venus show that the electrical discharges occur in the cloud layer. Their energy is roughly the same as in terrestrial lightning, but with a pulse repetition frequency of the discharges which is much greater.

Ksanfomaliti, L. V.↗
NASA NTRS1972

Terminated capacitor-discharge firing of electroexplosive devices.

By terminating the discharge of energy into an insensitive electroexplosive device, firing-energy parameters can be determined. A simple capacitor-discharge system providing exponential pulses terminated at an adjustable width is described. Basic theory and application to testing are discussed.

Rosenthal, L. A.↗
NASA NTRS1981

Acoustic power dissipation on radiation through duct terminations - Experiments

An acoustic impulse technique is used to study the acoustic transmission characteristics of ducts, nozzles, orifices, and perforated plates. High intensity pulses were generated by discharging a capacitor across a spark gap for both heated and unheated flows, with and without simulated flights. The effect of a termination geometry on power absorption for high acoustic intensities was observed, showing the existence of power absorption at low frequencies for the duct, nozzles, orifice plates, and perforated plates at a no flow condition; the amount of power absorption was controlled primarily by the open area at the exit. Power conservation with flow was similar to that for no flow: Power absorption initially increased for the duct and conical nozzles and then decreased with increasing Mach number. Power absorption results for the suppressor nozzle were similar to those for the conical nozzle, and the nonlinear effect was found to be insignificant in the presence of flow. A power imbalance was noted for heated jets, with a greater power loss at low frequencies than for unheated jets. Low frequency power absorption increased with the simulated flight, and a small amount of low frequency power absorption was found even for low intensity sound. A typical schlieren photograph of vortex formation (Whiffen and Ahuja, 1981) helped to confirm that sound energy can be converted into vortical energy and may account for low frequency power losses.

Salikuddin, M.↗
NASA NTRS1983

Spontaneous Raman scattering as a high resolution XUV radiation source

A type of high resolution XUV radiation source is described which is based upon spontaneous anti-Stokes scattering of tunable incident laser radiation from atoms excited to metastable levels. The theory of the source is summarized and two sets of experiments using He (1s2s)(1)S atoms, produced in a cw hollow cathode and in a pulsed high power microwave discharge, are discussed. The radiation source is used to examine transitions originating from the 3p(6) shell of potassium. The observed features include four previously unreported absorption lines and several sharp interferences of closely spaced autoionizing lines. A source linewidth of about 1.9 cm(-1) at 185,000 cm(-1) is demonstrated.

Rothenberg, J. E.↗
NASA NTRS1983

Time-resolved study of the laser optogalvanic effect in I2

A time-resolved study of the optogalvanic effect in a pure iodine discharge is reported for pulsed dye laser irradiation at 585 nm. By varying both the spatial location and pulse energy of the laser probe, several contributions to the time evolution of the optogalvanic signal are identified and their origin discussed.

Haner, D. A.↗
NASA NTRS1983

Spontaneous Raman scattering as a high-resolution XUV radiation source

A type of high resolution XUV radiation source is described which is based upon spontaneous anti-Stokes scattering of tunable incident laser radiation from atoms excited to metastable levels. The theory of the source is summarized and two sets of experiments using He (1s2s)(1)S atoms, produced in a CW hollow cathode and in a pulsed high power microwave discharge, are discussed. The radiation source is used to examine transitions originating from the 3p(6) shell of potassium. The observed features include four previously unreported absorption lines and several sharp interferences of closely spaced autoionizing lines. A source linewidth of about 1.9 cm(-1) at 185,000 cm(-1) is demonstrated. Previously announced in STAR as N83-18422

Rothenberg, J. E.↗
NASA NTRS1995

Lightning driven EMP in the upper atmosphere

Large lightning discharges can drive electromagnetic pulses (EMP) that cause breakdown of the neutral atmosphere between 80 and 95 km leading to order of magnitude increases in the plasma density. The increase in the plasma density leads to increased reflection and absorption, and limits the pulse strength that propagates higher into the ionosphere.

Rowland, H. L.↗
NASA NTRS1994

Laser optogalvanic wavelength calibration with a commercial hollow cathode iron - neon discharge lamp

351 optogalvanic transitions have been observed in the 337 - 598 nm wavelength region using an iron - neon hollow cathode discharge lamp and a pulsed tunable dye laser. 223 of these have been identified as transitions associated with neon energy levels. These optogalvanic transitions have allowed, in conjunction with interference fringes recorded concomitantly with an etalon, the calibration of the dye laser wavelength with 0.3/cm accuracy.

Zhu, Xinming↗
NASA NTRS2013

Inductive Pulsed Plasma Thruster Development and Testing at NASA-MSFC

THE inductive pulsed plasma thruster (IPPT) is an electrodeless space propulsion device where a capacitor is charged to an initial voltage and then discharged producing a high current pulse through a coil. The field produced by this pulse ionizes propellant, inductively driving current in a plasma located near the face of the coil. Once the plasma is formed it can be accelerated and expelled at a high exhaust velocity by the electromagnetic Lorentz body force arising from the interaction of the induced plasma current and the magnetic field produced by the current in the coil. In the present work, we present a summary of the IPPT research and development conducted at NASA's Marshall Space Flight Center (MSFC). As a higher-power, still relatively low readiness level system, there are many issues associated with the eventual deployment and use of the IPPT as a primary propulsion system on spacecraft that remain to be addressed. The present program aimed to fabricate and test hardware to explore how these issues could be addressed. The following specific areas were addressed within the program and will be discussed within this paper. a) Conical theta-pinch IPPT geometry thruster configuration. b) Repetition-rate multi-kW thruster pulsing. c) Long-lifetime pulsed gas valve. d) Fast pulsed gas valve driver and controller. e) High-voltage, repetitive capacitor charging power processing unit. During the course of testing, a number of specific tests were conducted, including several that, to our knowledge, have either never been previously conducted (such as multi-KW repetition-rate operation) or have not been performed since the early 1990s (direct IPPT thrust measurements).2 Conical theta-pinch IPPT thrust stand measurements are presented in Fig. 1 while various time-integrated and time

Polzin, Kurt A.↗
NASA NTRS1993

The PIT MkV pulsed inductive thruster

The pulsed inductive thruster (PIT) is an electrodeless, magnetic rocket engine that can operate with any gaseous propellant. A puff of gas injected against the face of a flat (spiral) coil is ionized and ejected by the magnetic field of a fast-rising current pulse from a capacitor bank discharge. Single shot operation on an impulse balance has provided efficiency and I(sub sp) data that characterize operation at any power level (pulse rate). The 1-m diameter MkV thruster concept offers low estimated engine mass at low powers, together with power capability up to more than 1 MW for the 1-m diameter design. A 20 kW design estimate indicates specific mass comparable to Ion Engine specific mass for 10,000 hour operation, while a 100,000 hour design would have a specific mass 1/3 that of the Ion Engine. Performance data are reported for ammonia and hydrazine. With ammonia, at 32 KV coil voltage, efficiency is a little more than 50 percent from 4000 to more than 8000 seconds I(sub sp). Comparison with data at 24 and 28 kV indicates that a wider I(sub sp) range could be achieved at higher coil voltages, if required for deep space missions.

Dailey, C. Lee↗
NASA NTRS2012

Dielectric Barrier Discharge Plasma Actuator for Flow Control

This report is Part II of the final report of NASA Cooperative Agreement contract no. NNX07AC02A. It includes a Ph.D. dissertation. The period of performance was January 1, 2007 to December 31, 2010. Part I of the final report is the overview published as NASA/CR-2012- 217654. Asymmetric dielectric barrier discharge (DBD) plasma actuators driven by nanosecond pulses superimposed on dc bias voltage are studied experimentally. This produces non-self-sustained discharge: the plasma is generated by repetitive short pulses, and the pushing of the gas occurs primarily due to the bias voltage. The parameters of ionizing pulses and the driving bias voltage can be varied independently, which adds flexibility to control and optimization of the actuators performance. The approach consisted of three elements coupled together: the Schlieren technique, burst mode of plasma actuator operation, and 2-D numerical fluid modeling. During the experiments, it was found that DBD performance is severely limited by surface charge accumulation on the dielectric. Several ways to mitigate the surface charge were found: using a reversing DC bias potential, three-electrode configuration, slightly conductive dielectrics, and semi conductive coatings. Force balance measurements proved the effectiveness of the suggested configurations and advantages of the new voltage profile (pulses+bias) over the traditional sinusoidal one at relatively low voltages. In view of practical applications certain questions have been also addressed, such as electrodynamic effects which accompany scaling of the actuators to real size models, and environmental effects of ozone production by the plasma actuators.

Opaits, Dmitry, F.↗
NASA NTRS2007

Design of an Integrated-System FARAD Thruster

Pulsed inductive plasma accelerators are spacecraft propulsion devices in which energy is stored in a capacitor and then discharged through an inductive coil. The device is electrodeless, inducing a current s heet in a plasma located near the face of the coil. The propellant is accelerated and expelled at a high exhaust velocity (order of 10 km/s) through the interaction of the plasma current and the induced magne tic field, The Faraday Accelerator with RF-Assisted Discharge (FARAD) thruster is a type of pulsed inductive plasma accelerator in which t he plasma is preionized by a mechanism separate from that used to for m the current sheet and accelerate the gas. Employing a separate preionization mechanism allows for the formation of an inductive current s heet at much lower discharge energies and voltages than those used in previous pulsed inductive accelerators like the Pulsed Inductive Thr uster (PIT). In this paper, we present the design of a benchtop FARAD thruster with all the subsystems (mass injection, preionization, and acceleration) integrated into a single unit. Design of the thruster follows the guidelines and similarity performance parameters presented elsewhere. The system is designed to use the ringing, RF-frequency s ignal produced by a discharging Vector Inversion Generator (VIG) to p reionize the gas. The acceleration stage operates on the order of 100 J/pulse and can be driven by several different pulsed powertrains. These include a simple capacitor coupled to the system, a Bernardes and Merryman configuration, and a pulsecompression circuit that takes a temporally broad, low current pulse and transforms it into a short, h igh current pulse. A set of applied magnetic field coils are integrated into the system to guide the preionized propellant as it spreads ov er the face of the inductive acceleration coil. The coils are operate d in a pulsed mode, and the thruster can be operated without using the coils to determine if there is a performance improvement gain realiz ed when an applied field is present.

Polzin, K.A.↗
NASA NTRS1977

The electric fields produced by lightning stepped leaders

The electric fields produced by stepped and dart-stepped leaders which immediately precede return strokes in lightning discharges to the ground have been recorded in Florida and Arizona. The mean interval time between normal steps is about 16 microsec, and the mean interval between dart steps is 6-8 microsec. The amplitudes of leader pulses in Florida increase just prior to the return stroke, the largest usually being about 10% of the return-stroke peak. In Arizona the leader pulse amplitudes are smaller than those in Florida, in relation to the return stroke, and are not as easy to identify. The shapes of the fields produced by normal steps are similar to dart steps, and the dart steps are very similar to regular sequences of pulses produced by many intracloud discharges. The 10-90% rise times of individual step wave forms are often less than 0.3 microsec, and the full width at half maximum of a step pulse is typically 0.4-0.5 microsec under conditions where the propagation distortion is minimal. The amplitudes and the shapes of leader step wave forms suggest that the peak step current is at least 2000-8000 A close to the ground and that the maximum rate of change of step current is 6-24 kA/microsec or larger. A rough estimate of the minimum charge lowered during the formation of a step is 0.001 to 0.004 C.

Krider, E. P.↗
NASA NTRS1980

Control of XeF laser output by pulse injection

Injection locking is investigated as a means for control of optical pulse duration and polarization in a XeF laser. Intense short-pulse generation in the ultraviolet is achieved by injection of a low-level 1-ns optical pulse into a XeF oscillator. Control of laser output polarization by injection locking is demonstrated and studied as a function of injected signal level. Enhancement of XeF electric-discharge laser efficiency by injection pulse 'priming' is observed.

Pacala, T. J.↗
NASA NTRS2010

Design of a Microwave Assisted Discharge Inductive Plasma Accelerator

A new plasma accelerator concept that employs electrodeless plasma preionization and pulsed inductive acceleration is presented. Preionization is achieved through an electron cyclotron resonance discharge that produces a weakly-ionized plasma at the face of a conical theta pinch-shaped inductive coil. The presence of the preionized plasma allows for current sheet formation at lower discharge voltages than those found in other pulsed inductive accelerators. The location of an electron cyclotron resonance discharge can be controlled through the design of the applied magnetic field in the thruster. A finite-element model of the magnetic field was used as a design tool, allowing for the implementation of an arrangement of permanent magnets that yields a small volume of preionized propellant at the coil face. This allows for current sheet formation at the face of the inductive coil, minimizing the initial inductance of the pulse circuit and maximizing the potential efficiency of the new accelerator.

Hallock, Ashley K.↗