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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Space debris - Electrodynamic effects

It is shown that electrodynamic forces play a crucial role in the orbital dynamics of the small Al2O3 particles that are injected into the terrestrial magnetosphere during solid rocket propellant burns. Due to the simplified model that is used to describe the plasma distribution in the magnetosphere, the present results are necessarily preliminary. Even so, it appears that the smallest particles (a = 0.1 micron) will be rapidly eliminated from the magnetosphere. Evaluation of the fate of the somewhat larger (a = 1 micron) particles awaits the construction of a more complete and realistic model of the magnetospheric plasma.

Horanyi, M.↗
NASA NTRS2000

Guns and High Gas Output Devices Panel: Introduction

A new panel known as the Guns and High Gas Output Panel was organized in 1999 under the auspices of the JANNAF Propellant and Characterization SubCommittee (PDCS). This is an introduction to our first meeting, purpose of the panel, and the scope of activities to be covered. The primary purpose of the panel is very simple: to provide a single focal point for interfacing Government Laboratories (Department of Defense and Department of Energy) and commercial industry researchers to share R&D activities and findings (i.e. facilitate the exchange of information) specifically aimed at gun-launched propulsion and high-gas output devices (gas generators and air bag inflators). Specific areas of interest included in the Panel's scope (and the Technical Data Base) are the following: (1) new propellant formulations and chemistry, (2) new ingredients, (3) ballistic effects of the new formulations and ingredients, (4) new processing methods unique to gun propellants, (5) thermochemistry of new ingredients, (6) unique physical and mechanical properties, (7) burning rates of new propellants and small scale closed bomb testing, (8) plasma effects on the propellant, and (9) unique safety and insensitive munitions properties.

Simmons, Ronald L.↗
NASA NTRS2011

Variability of Thermosphere and Ionosphere Responses to Solar Flares

We investigated how the rise rate and decay rate of solar flares affect the thermosphere and ionosphere responses to them. Model simulations and data analysis were conducted for two flares of similar magnitude (X6.2 and X5.4) that had the same location on the solar limb, but the X6.2 flare had longer rise and decay times. Simulated total electron content (TEC) enhancements from the X6.2 and X5.4 flares were 6 total electron content units (TECU) and approximately 2 TECU, and the simulated neutral density enhancements were approximately 15% -20% and approximately 5%, respectively, in reasonable agreement with observations. Additional model simulations showed that for idealized flares with the same magnitude and location, the thermosphere and ionosphere responses changed significantly as a function of rise and decay rates. The Neupert Effect, which predicts that a faster flare rise rate leads to a larger EUV enhancement during the impulsive phase, caused a larger maximum ion production enhancement. In addition, model simulations showed that increased E x B plasma transport due to conductivity increases during the flares caused a significant equatorial anomaly feature in the electron density enhancement in the F region but a relatively weaker equatorial anomaly feature in TEC enhancement, owing to dominant contributions by photochemical production and loss processes. The latitude dependence of the thermosphere response correlated well with the solar zenith angle effect, whereas the latitude dependence of the ionosphere response was more complex, owing to plasma transport and the winter anomaly.

Qian, Liying↗
NASA NTRS1995

Electrostatic Plasma Accelerator (EPA)

The application of electric propulsion to communications satellites, however, has been limited to the use of hydrazine thrusters with electric heaters for thrust and specific impulse augmentation. These electrothermal thrusters operate at specific impulse levels of approximately 300 s with heater powers of about 500 W. Low power arcjets (1-3 kW) are currently being investigated as a way to increase specific impulse levels to approximately 500 s. Ion propulsion systems can easily produce specific impulses of 3000 s or greater, but have yet to be applied to communications satellites. The reasons most often given for not using ion propulsion systems are their high level of overall complexity, low thrust with long burn times, and the difficulty of integrating the propulsion system into existing commercial spacecraft busses. The Electrostatic Plasma Accelerator (EPA) is a thruster concept which promises specific impulse levels between low power arcjets and those of the ion engine while retaining the relative simplicity of the arcjet. The EPA thruster produces thrust through the electrostatic acceleration of a moderately dense plasma. No accelerating electrodes are used and the specific impulse is a direct function of the applied discharge voltage and the propellant atomic mass.

Brophy, John R.↗
NASA NTRS2001

Life Testing of the Hollow Cathode Plasma Contactor for the ProSEDS Mission

The Propulsive Small Expendable Deployer System (ProSEDS) mission is designed to provide an on-orbit demonstration of the electrodynamic propulsion capabilities of tethers in space. The ProSEDS experiment will be a secondary payload on a Delta 11 unmanned expendable booster. A 5-km conductive tether is attached to the Delta 11 second stage and collects current from the low Earth orbit (LEO) plasma. A hollow cathode plasma contactor emits the collected electrons from the Delta II, completing the electrical circuit with the ambient plasma. The current flowing through the tether generates thrust based on the Lorentz Force Law. The thrust will be generated opposite to the velocity vector, slowing down the spacecraft and causing it to de-orbit in approximately 14 days compared to the normal 6 months. A 10-km non-conductive tether is between the conductive tether and an endmass containing several scientific instruments. The ProSEDS mission lifetime was set at I day because most of the primary objectives can be met in that time. The extended ProSEDS mission will be for as many days as possible, until the Delta 11 second stage burns up or the tether is severed by a micrometeoroid or space debris particle. The Hollow Cathode Plasma Contactor (HCPC) unit has been designed for a 12-day mission. Because of the science requirements to measure the background ambient plasma, the HCPC must operate on a duty cycle. Later in the ProSEDS mission, the HCPC is operated in a manner to allow charging of the secondary battery. Due to the unusual operating requirements by the ProSEDS mission, a development unit of the HCPC was built for thorough testing. This developmental unit was tested for a simulated ProSEDS mission, with measurements of the ability to start and stop during the duty cycle. These tests also provided valuable data for the ProSEDS software requirements. Qualification tests of the HCPC flight hardware are also discussed.

Vaughn, Jason A.↗
NASA NTRS1988

Spacelab 2 Upper Atmospheric Modification experiment over Arecibo. I - Neutral gas dynamics

The Orbital Maneuvering Subsystem engines of the Space Shuttle were used to inject H2, CO2, H2O and other combustion products into the upper atmosphere over the Arecibo Observatory. Images of the airglow enhancements that resulted from chemical reactions between the exhaust gases and the F-layer plasma showed that the exhaust vapor trail came to rest 80 km downstream from the center of the burn. A computer simulation of the gas dynamics shows that the region of the burn was dominated by a 'snow plow' effect sweeping out a corridor in the atmosphere and collisionally heating the injected vapors.

Bernhardt, P. A.↗
NASA NTRS1992

Container Prevents Oxidation Of Metal Powder

Sealed high-vacuum container holds metal powder required free of contamination by oxygen from point of manufacture to point of use at vacuum-plasma-spraying machine. Container protects powder from air during filling, storage, and loading of spraying machine. Eliminates unnecessary handling and transfer of powder from one container to another. Stainless-steel container sits on powder feeder of vacuum-plasma-spraying machine.

Woodford, William H.↗
NASA NTRS1995

Stochastic charging of dust grains in planetary rings: Diffusion rates and their effects on Lorentz resonances

Dust grains in planetary rings acquire stochastically fluctuating electric charges as they orbit through any corotating magnetospheric plasma. Here we investigate the nature of this stochastic charging and calculate its effect on the Lorentz resonance (LR). First we model grain charging as a Markov process, where the transition probabilities are identified as the ensemble-averaged charging fluxes due to plasma pickup and photoemission. We determine the distribution function P(t;N), giving the probability that a grain has N excess charges at time t. The autocorrelation function tau(sub q) for the strochastic charge process can be approximated by a Fokker-Planck treatment of the evolution equations for P(t; N). We calculate the mean square response to the stochastic fluctuations in the Lorentz force. We find that transport in phase space is very small compared to the resonant increase in amplitudes due to the mean charge, over the timescale that the oscillator is resonantly pumped up. Therefore the stochastic charge variations cannot break the resonant interaction; locally, the Lorentz resonance is a robust mechanism for the shaping of etheral dust ring systems. Slightly stronger bounds on plasma parameters are required when we consider the longer transit times between Lorentz resonances.

Schaffer, L.↗
NASA NTRS1975

Nuclear system that burns its own wastes shows promise

A nuclear fission energy system, capable of eliminating a significant amount of its radioactive wastes by burning them, is described. A theoretical investigation of this system conducted by computer analysis, is based on use of gaseous fuel nuclear reactors. Gaseous core reactors using a uranium plasma fuel are studied along with development for space propulsion.

Atchison, K.↗
NASA NTRS2022

“The Goose” Pulsar Wind Nebula of PSR J1016–5857: The Birth of a Plerion

We report the results of X-ray (CXO) and radio (ATCA) observations of the pulsar wind nebula(PWN) powered by the young pulsar PSR J1016–5857, which we dub “the Goose” PWN. In bothbands the images reveal a tail-like PWN morphology which can be attributed to pulsar’s motion. Bycomparing archival and newCXOobservations, we measure the pulsar’s proper motionμ= 28.8±7.3mas yr−1, yielding a projected pulsar velocityv≈440±110 km s−1(atd= 3.2 kpc); its direction isconsistent with the PWN shape. Radio emission from the PWN is polarized, with the magnetic fieldoriented along the pulsar tail. The radio tail connects to a larger radio structure (not seen in X-rays)which we interpret as a relic PWN (also known as a plerion). The spectral analysis of theCXOdatashows that the PWN spectrum softens from Γ = 1.7 to Γ≈2.3−2.5 with increasing distance fromthe pulsar. The softening can be attributed to the rapid synchrotron burn-off, which would explainthe lack of X-ray emission from the older relic PWN. In addition to non-thermal PWN emission, wedetected thermal emission from a hot plasma which we attribute to the host SNR. The radio PWNmorphology and the proper motion of the pulsar suggest that the reverse shock passed through thepulsar’s vicinity and pushed the PWN to one side.

Pulsars↗
NASA NTRS2012

Contamination Control and Hardware Processing Solutions at Marshall Space Flight Center

The Contamination Control Team of Marshall Space Flight Center's Materials and Processes Laboratory supports many Programs/ Projects that design, manufacture, and test a wide range of hardware types that are sensitive to contamination and foreign object damage (FOD). Examples where contamination/FOD concerns arise include sensitive structural bondline failure, critical orifice blockage, seal leakage, and reactive fluid compatibility (liquid oxygen, hydrazine) as well as performance degradation of sensitive instruments or spacecraft surfaces such as optical elements and thermal control systems. During the design phase, determination of the sensitivity of a hardware system to different types or levels of contamination/FOD is essential. A contamination control and FOD control plan must then be developed and implemented through all phases of ground processing, and, sometimes, on-orbit use, recovery, and refurbishment. Implementation of proper controls prevents cost and schedule impacts due to hardware damage or rework and helps assure mission success. Current capabilities are being used to support recent and on-going activities for multiple Mission Directorates / Programs such as International Space Station (ISS), James Webb Space Telescope (JWST), Space Launch System (SLS) elements (tanks, engines, booster), etc. The team also advances Green Technology initiatives and addresses materials obsolescence issues for NASA and external customers, most notably in the area of solvent replacement (e.g. aqueous cleaners containing hexavalent chrome, ozone depleting chemicals (CFC s and HCFC's), suspect carcinogens). The team evaluates new surface cleanliness inspection and cleaning technologies (e.g. plasma cleaning), and maintains databases for processing support materials as well as outgassing and optical compatibility test results for spaceflight environments.

Burns, DeWitt H.↗
NASA NTRS2003

Plasma Interactions with a Negative Biased Electrodynamic Tether

The ProSEDS conductive tether design incorporates two distinct types of tethers from a plasma interaction viewpoint. The 200 m closest to the Delta 11 spacecraft is insulated from the plasma, and the remaining 5000 m is semi-bare. This latter portion is semi-bare because it has a conductive coating applied to the wires to permit electron collection while also regulating the overall tether temperature. Because the tether possesses these two distinct types of tethers, a transition point exists between the two types that form a triple point with the space plasma. Insulated tethers can suffer from a second plasma interaction if the insulation is weakened or breached, such as by pinholes caused by small particle debris strikes. Because electrodynamic tethers are typically long, they have a high probability of such impacts. These impacting particles may not be of sufficient size to severe the tether, but they can easily be of sufficient size to damage the tether insulation. Samples of both the ProSEDS tether transition region and the insulated tether section (with various degrees of pinhole damage) were placed into the MSFC plasma chamber and biased to typical ProSEDS open circuit tether potentials (-500 V to -1600 V). The results of the testing showed that the transition region of the tether (i.e. the triple point) arced and burned the tether in two at -900 V, and the damaged insulated sections arced and burned in two between -1000 V and -1600, depending on the pinhole damage geometry. tether design and make the tether ready for flight. To reduce the pinhole arcing risk, ProSEDS mission operations were changed to eliminate the negative potential on the tether. The results of the testing campaign and the design changes implemented to ensure a successful flight will be described.

Vaughn, Jason A.↗
NASA NTRS1994

Charged dust in planetary magnetospheres: Hamiltonian dynamics and numerical simulations for highly charged grains

We use a combination of analytical and numerical methods to investigate the dynamics of charged dust grains in planetary magnetospheres. Our emphasis is on obtaining results valid for particles that are not necessarily dominated either by gravitational or electromagnetic forces. A Hamiltonian formulation of the problem yields exact results, for all values of charge-to-mass ratio, when we introduce two constraints: particles remain in the equatorial plane and the magnetic field is taken as axially symmetric. In particular, we obtain locations of equilibrium points, the frequencies of stable periodic orbits, the topology of separatrices in phase space, and the rate of longitudinal drift. These results are significant for specific applications: motion in the nearly aligned dipolar field of Saturn, and the trajectories of arbitrarily charged particles in complex magnetic fields for limited periods of time after ejection from parent bodies. Since the model is restrictive, we also use numerical integrations of the full three-dimensional equations of motion and illustrate under what conditions the constrained problem yields reasonable results. We show that a large fraction of the intermediately charged and highly charged (gyrating) particles will always be lost to a planet's atmosphere within a few hundred hours, for motion through tilted-dipole magnetic fields. We find that grains must have a very high charge-to-mass ratio in order to be mirrored back to the ring plane. Thus, except perhaps at Saturn where the dipole tilt is very small, the likely inhabitants of the dusty ring systems are those particles that are either nearly Keplerian (weakly charged) grains or grains whose charges place them in the lower end of the intermediate charge zone. Fianlly, we demonstrate the effect of plasma drag on the orbits of gyrating particles to be a rapid decrease in gyroradius followed by a slow radial evolution of the guiding center.

Schaffer, L.↗
NASA NTRS2015

Suzaku Observation of the Classical Nova V2491 Cyg in Quiescence

We present Suzaku XIS observation of V2491 Cyg (Nova Cyg 2008 No. 2) obtained in quiescence, more than two years after the outburst. The nova was detected as a very luminous source in a wide spectral range from soft to hard X-rays. A very soft blackbody-like component peaking at 0.5 keV indicates that either we observe remaining, localized hydrogen burning on the surface of the white dwarf, or accretion onto a magnetized polar cap. In the second case, V2491 Cyg is a candidate "soft intermediate polar". We obtained the best fit for the X-ray spectra with several components: two of thermal plasma, a blackbody and a complex absorber. The later is typical of intermediate polars. The X-ray light-curve shows a modulation with an approximately 38 min period. The amplitude of this modulation is strongly energy dependent and reaches maximum in the 0.8-2.0 keV range. We discuss the origin of the X-ray emission and pulsations, and the likelihood of the intermediate polar scenario.

cataclysmic variables: general aEuro" nova: indivi↗
NASA NTRS1998

Research on Orbital Plasma Electro-Dynamics (ROPE)

This report spans activities covering approximately 13 years. This period includes both the TSS1 and 1R missions. As is well known the TSS1 mission was not successful due to the tether hanging in the reelout mechanism. This resulted in the approval of a reflight mission. TSS1-R. The reel mechanism did work on the reflight however the tether arced, burned through and flew away just as maximum length was being obtained. Thus only a few of the planned objectives were carried out. The good news is that all items delivered under this contract worked as planned. In addition the contract was completed on time and in scope with no overruns. Several publications have resulted even under these non-optimum conditions.

Source record↗
NASA NTRS1993

Vacuum Plasma Spraying Of Copper Onto Titanium

Vacuum plasma spraying successful in depositing tenacious copper coat on flanges and other selected areas of titanium valve housing. Oxidation and concomitant brittleness eliminated.

Power, Chris↗
NASA NTRS1982

Evaluation of present thermal barrier coatings for potential service in electric utility gas turbines

The resistance of present-day thermal barrier coatings to combustion gases found in electric utility turbines was assessed. The plasma sprayed coatings, both duplex and graded types, were primarily zirconia-based, although a calcium silicate was also evaluated. Both atmospheric burner rig tests and high pressure tests (135 psig) showed that several present-day thermal barrier coatings have a high potential for service in gas turbines burning the relatively clean GT No. 2 fuel. However, coating improvements are needed for use in turbines burning lower grade fuel such as residual oil. The duplex ZrO2.8Y2O3/NiCrA1Y coating was ranked highest and selected for near-term field testing, with Ca2SiO4/NiCrA1Y ranked second. Graded coatings show potential for corrosive turbine operating conditions and warrant further development. The coating degradation mechanisms for each coating system subjected to the various environmental conditions are also described.

Bratton, R. J.↗