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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

Space Test of Bare-Wire Anode Tethers

An international team, lead by Tokyo Metropolitan University, is developing a mission concept for a suborbital test of orbital-motion-limited (OML) bare-wire anode current collection for application to electrodynamic tether propulsion. The tether is a tape with a 50-mm width, 0.05-mm thickness, and 1-km length. This will be the first space test of the OML theory. In addition, by being an engineering demonstration (of space tethers), the mission will demonstrate electric beam generation for "sounding" determination of the neutral density profile in the ionospheric "E-layer." If selected by the Institute of Space and Astronautical Science/Japanese Aerospace Exploration Agency (JAXA), the mission will launch in early 2009 using an $520 Sounding Rocket. During ascent, and above =100 km in attitude, the 1-km tape tether will be deployed at a rate of 8 m/s. Once deployed, the tape tether will serve as an anode, collecting ionospheric electrons. The electrons will be expelled into space by a hollow cathode device, thereby completing the circuit and allowing current to flow.This paper will describe the objectives of the proposed mission, the technologies to be employed, and the application of the results to future space missions using electrodynamic tethers for propulsion or power generation.

Johnson, L.↗
NASA NTRS2004

Very High Isp Thruster with Anode Layer (VHITAL): An Overview

This article describes the two stage bismuth fueled Hall thruster technology that was developed at TsNIIMASH [1] and the Very High Isp Thruster with Anode Layer (VHITAL) technology assessment program that is funded by NASA Exploration Systems Mission Directorate (ESMD)' Prometheus program. The overall objective of this program is to evaluate the potential for this Russian-developed thruster technology to enable near-term, Nuclear Electric Propulsion (NEf)-enabled ESMD missions to the outer planets. This 2.5 year program will provide the technology basis for the development of even higher power anode layer thrusters for rapid outer planet exploration missions and, ultimately, human exploration of the solar system. The first 6 month phase is currently in progress. If this phase is successful, the second (1 year) and third (1 year) phase of the proposed program will follow.

Hall thrusters↗
NASA NTRS1995

Arcjet anode

There is disclosed an anode for an arcjet thruster which resists erosion during start-up on constriction during steady-state operation. The anode includes a converging upstream portion, a diverging downstream portion and a constricted portion disposed therebetween. In one embodiment of the invention, rails formed in the constricted portion accelerate the passage of an arc during start-up reducing erosion. In a second embodiment, a higher strength material resists bulging as a result of the thermal gradient within the nozzle.

Lichon, Paul G.↗
NASA NTRS2008

Fortissimo: A Japanese Space Test Of Bare Wire Anode Tethers

A Japanese led international team is developing a suborbital test of orbital-motion-limited (OML) bare wire anode current collection for application to electrodynamic tether (EDT) propulsion. The tether is a tape with a width of 25 mm, thickness of 0.05 mm, and is 300 m in length. This will be the first space test of OML theory. The mission will launch in the summer of 2009 using an S520 Sounding Rocket. During ascent, and above approx. 100 km in attitude, the tape tether will be deployed at a rate of approx. 8 m/s. Once deployed, the tape tether will serve as an anode, collecting ionospheric electrons. The electrons will be expelled into space by a hollow cathode device, thereby completing the circuit and allowing current to flow. The total amount of current collected will be used to assess the validity of OML theory. This paper will describe the objectives of the proposed mission, the technologies to be employed, and the application of the results to future space missions using EDTs for propulsion or power generation.

Johnson, Les↗
NASA NTRS2006

Single-Wall Carbon Nanotube Anodes for Lithium Cells

In recent experiments, highly purified batches of single-wall carbon nanotubes (SWCNTs) have shown promise as superior alternatives to the graphitic carbon-black anode materials heretofore used in rechargeable thin-film lithium power cells. The basic idea underlying the experiments is that relative to a given mass of graphitic carbon-black anode material, an equal mass of SWCNTs can be expected to have greater lithium-storage and charge/discharge capacities. The reason for this expectation is that whereas the microstructure and nanostructure of a graphitic carbon black is such as to make most of the interior of the material inaccessible for intercalation of lithium, a batch of SWCNTs can be made to have a much more open microstructure and nanostructure, such that most of the interior of the material is accessible for intercalation of lithium. Moreover, the greater accessibility of SWCNT structures can be expected to translate to greater mobilities for ion-exchange processes and, hence, an ability to sustain greater charge and discharge current densities.

Hepp, Aloysius F.↗
NASA NTRS2010

Carbon Cryogel Silicon Composite Anode Materials for Lithium Ion Batteries

A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 10 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-4,9 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

Woodworth James↗
NASA NTRS2010

Silicon Composite Anode Materials for Lithium Ion Batteries Based on Carbon Cryogels and Carbon Paper

A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nanofoams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

Woodworth, James↗
NASA NTRS2010

Carbon Cryogel and Carbon Paper-Based Silicon Composite Anode Materials for Lithium-Ion Batteries

A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 6 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-5 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

Woodworth, James↗
NASA NTRS2011

Li Anode Technology for Improved Performance

A novel, low-cost approach to stabilization of Li metal anodes for high-performance rechargeable batteries was developed. Electrolyte additives are selected and used in Li cell electrolyte systems, promoting formation of a protective coating on Li metal anodes for improved cycle and safety performance. Li batteries developed from the new system will show significantly improved battery performance characteristics, including energy/power density, cycle/ calendar life, cost, and safety.

Chen, Tuqiang↗
NASA NTRS2014

Development of Large-Format Lithium-Ion Cells with Silicon Anode and Low Flammable Electrolyte

NASA is developing safe, high energy and high capacity lithium-ion cell designs and batteries for future missions under NASAs Advanced Space Power System (ASPS) project. Advanced cell components, such as high specific capacity silicon anodes and low-flammable electrolytes have been developed for improving the cell specific energy and enhancing safety. To advance the technology readiness level, we have developed large-format flight-type hermetically sealed battery cells by incorporating high capacity silicon anodes, commercially available lithium nickel, cobalt, aluminum oxide (NCA) cathodes, and low-flammable electrolytes. In this report, we will present the performance results of these various battery cells. In addition, we will also discuss the post-test cell analysis results as well.

lithium-ion cell↗
NASA NTRS2015

Development of Nanosized/Nanostructured Silicon as Advanced Anodes for Lithium-Ion Cells

NASA is developing high energy and high capacity Li-ion cell and battery designs for future exploration missions under the NASA Advanced Space Power System (ASPS) Program. The specific energy goal is 265 Wh/kg at 10 C. center dot Part of effort for NASA advanced Li-ion cells  Anode: Silicon (Si) as an advanced anode.  Electrolyte: advanced electrolyte with flame-retardant additives for enhanced performance and safety (NASA JPL).

silicon↗
NASA NTRS2015

Silicon Whisker and Carbon Nanofiber Composite Anode

Phase II Objectives: Demonstrate production levels of grams per batch; Achieve full cell anode capacity of greater than 1,000 mAh/g at a charge rate of 10 (C/10) and 0 degree C; Establish a full cell cycle life of over 300 cycles; Display an operating temperature of negative 30 degrees C to plus 30 degrees C; Demonstrate a rate capability of C/5 or higher; Deliver to NASA three 2.5 Ah cells (energy density greater than 220 Wh/kg); Exhibit the safety features of the anode and full cells; Design a 1 kWh prismatic battery pack.

Lang, Christopher M.↗
NASA NTRS2015

Mesoporous Silicon-Based Anodes

For high-capacity, high-performance lithium-ion batteries. A new high-capacity anode composite based on mesoporous silicon is being developed. With a structure that resembles a pseudo one-dimensional phase, the active anode material will accommodate significant volume changes expected upon alloying and dealloying with lithium (Li).

Peramunage, Dharmasena↗
NASA NTRS1995

Fabrication and Performance of Planar Schottky Diodes with T-gate-like Anodes in 200 GHz Subharmonically-Pumped Waveguide Mixers

A T-gate-like structure has been developed, fabricated and tested as the anode for millimeter and submillimeter-wave Schottky diodes. The low parasitics of the T-anode diodes yield extremely high cutoff frequencies, making the diodes useable at frequencies well beyond 1 THz. The diodes were tested as an antiparallel-pair, integrated monolithically with microstrip circuitry on a quartz substrate, in a subharmonically pumped waveguide mixer. A double sideband noise temperature of 600 K with a conversion loss of 4.7 dB were measured at 200 GHz. This is believed to be the lowest noise temperature ever reported for a room temperature subharmonically-pumped Schottky diode mixer at this frequency.

Planar↗
NASA NTRSDate not supplied

Multiscale Modeling of the Uptake of Hydrogen Chloride on Anodized Aluminum in Relevance to Spacecraft Fire Safety

Fire safety is a critical component of space missions. An electrical fire within the spacecraft often produces gaseous hydrogen chloride (HCl) from the smoldering of wire insulation. These gases tend to stick to the interior materials of the spacecraft, which is often comprised of treated aluminum. Determining the rate of uptake for HCl by aluminum helps the safe design of the spacecraft to reduce catastrophic mission risk. Our previous studies showed that a one-step global reaction model for adsorption of HCl on aluminum is incapable of predicting the experimentally measured HCl uptake of anodized aluminum, compared to other treatments with thinner oxide layers. X-ray photoelectron spectroscopy revealed that aluminum chloride is found deep in the oxide layer of the anodized aluminum, implying that the transport of HCl within the oxide layer covering the aluminum surface must be considered. This work uses a multiscale modeling approach to predict the uptake of HCl. A pore model is developed wherein the HCl reacts with the aluminum oxide pore walls to create an aluminum chloride layer. The HCl then diffuses through that layer for further reaction, until the diffusion resistance grows too large, and the surface is said to be saturated. The pore model is then coupled with the reactor-scale model to predict overall HCl uptake. Results show that this new multiscale approach predicts the uptake of HCl far more accurately than previously used single-scale models.

Modeling↗