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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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NASA NTRS1991

Hubble Space Telescope images and follow-up spectroscopy of the Orion nebula

Recently published HST images of the Orion nebula reveal elephant-trunk structures, an apparent jet of material, and fine-scale structure in the Herbig-Haro object HH2, which is located at the base of an elephant trunk. High-resolution spectroscopy shows that the apparent jet is actually an ionization front seen edge-on. HH2 shows a complex structure in the several stages of ionization observed. There seem to be two velocity systems characterized by a bright central region and an accompanying shell-like emission. These two systems are most likely to be the result of a bow shock and corresponding Mach disk formed from the interaction of a collimated jet and the ambient gas of the nebula.

O'Dell, C. R.↗

NASA NTRS2004

Atomic Oxygen Durability Evaluation of a UV Curable Ceramer Protective Coating

The exposure of most silicones to atomic oxygen in low Earth orbit (LEO) results in the oxidative loss of methyl groups with a gradual conversion to oxides of silicon. Typically there is surface shrinkage of oxidized silicone protective coatings which leads to cracking of the partially oxidized brittle surface. Such cracks widen and branch crack with continued atomic oxygen exposure ultimately allowing atomic oxygen to reach any hydrocarbon polymers under the silicone coating. A need exists for a paintable silicone coating that is free from such surface cracking and can be effectively used for protection of polymers and composites in LEO. A new type of silicone based protective coating holding such potential was evaluated for atomic oxygen durability in an RF atomic oxygen plasma exposure facility. The coating consisted of a UV curable inorganic/organic hybrid coating, known as a ceramer, which was fabricated using a methyl substituted polysiloxane binder and nanophase silicon-oxo-clusters derived from sol-gel precursors. The polysiloxane was functionalized with a cycloaliphatic epoxide in order to be cured at ambient temperature via a cationic UV induced curing mechanism. Alkoxy silane groups were also grafted onto the polysiloxane chain, through hydrosilation, in order to form a network with the incorporated silicon-oxo-clusters. The prepared polymer was characterized by H-1 and Si-29 NMR, FT-IR, and electrospray ionization mass spectroscopy. The paper will present the results of atomic oxygen protection ability of thin ceramer coatings on Kapton H as evaluated over a range of atomic oxygen fluence levels.

Banks, Bruce A.↗

NASA NTRS1984

The laboratory simulation of unmagnetized supernova remnants Absence of a blast wave

Supernova remnants are experimentally simulated by irradiating spherical targets with eight-beam carbon dioxide laser in a chamber containing finite amounts of neutral gas, the gas being ionized by radiation from the hot target. The expansion velocities of the target plasmas are approximately the same as the expansion velocities of supernova ejecta and the experiment is successfully scaled to the case of a supernova remnant in an unmagnetized, low-density, interstellar medium. No sweep-up of the ambient plasma is detected, indicating that no hydrodynamic shock wave is formed to couple the target ejecta to the ambient gas. The experiment implies that if supernova ejecta couple to the interstellar medium, magnetic-field effects may be crucial to the physical description.

Borovsky, J. E.↗

NASA NTRS1989

He 2-104: A link between symbiotic stars and planetary nebulae

Ultraviolet, optical and infrared observations of He 2-104 are presented, and estimates for some of the physical properties of the nebular shell are made. It is argued that He 2-104 is in transition between the D-type symbiotic star and bipolar planetary nebula phases and, as such, represents a link between subclasses of these two types of objects. The model includes a binary system with a Mira variable and a hot, evolved star. Previous mass loss has resulted in the formation of a disk of gas and dust around the whole system, while the hot star has an accretion disk which produces the observed highly ionized emission line spectrum. Emission lines from cooler, lower density gas is also observed to come from the nebula. In addition, matter is flowing out of the system in a direction perpendicular to the disk with a high velocity and is impacting upon the previously-ejected red giant wind and/or the ambient interstellar medium.

Lutz, Julie H.↗

NASA NTRS1989

He 2-104 - A link between symbiotic stars and planetary nebulae?

Lutz, Julie H.↗

NASA NTRS2004

Lunar and Planetary Science XXXV: Astrobiology

The presentations in this session are: 1. A Prototype Life Detection Chip 2. The Geology of Atlantis Basin, Mars, and Its Astrobiological Interest 3. Collecting Bacteria Together with Aerosols in the Martian Atmosphere by the FOELDIX Experimental Instrument Developed with a Nutrient Detector Pattern: Model Measurements of Effectivity 4. 2D and 3D X-ray Imaging of Microorganisms in Meteorites Using Complexity Analysis to Distinguish Field Images of Stromatoloids from Surrounding Rock Matrix in 3.45 Ga Strelley Pool Chert, Western Australia 4. Characterization of Two Isolates from Andean Lakes in Bolivia Short Time Scale Evolution of Microbiolites in Rapidly Receding Altiplanic Lakes: Learning How to Recognize Changing Signatures of Life 5. The Effect of Salts on Electrospray Ionization of Amino Acids in the Negative Mode 6. Determination of Aromatic Ring Number Using Multi-Channel Deep UV Native Fluorescence 7. Microbial D/H Fractionation in Extraterrestrial Materials: Application to Micrometeorites and Mars 8. Carbon Isotope Characteristics of Spring-fed Iron-precipitating Microbial Mats 9. Amino Acid Survival Under Ambient Martian Surface UV Lighting Extraction of Organic Molecules from Terrestrial Material: Quantitative Yields from Heat and Water Extractions 10. Laboratory Detection and Analysis of Organic Compounds in Rocks Using HPLC and XRD Methods 11. Thermal Decomposition of Siderite-Pyrite Assemblages: Implications for Sulfide Mineralogy in Martian Meteorite ALH84001 Carbonate Globules 12. Determination of the Three-Dimensional Morphology of ALH84001 and Biogenic MV-1 Magnetite: Comparison of Results from Electron Tomography and Classical Transmission Electron Microscopy 13. On the Possibility of a Crypto-Biotic Crust on Mars Based on Northern and Southern Ringed Polar Dune Spots 14. Comparative Planetology of the Terrestrial Inner Planets: Implications for Astrobiology 15. A Possible Europa Exobiology 16. A Possible Biogeochemical Model for Titan

Source record↗

NASA NTRS1976

Twilight helium 10,830-A calculations and observations

The 10,830-A column emission rates from metastable He(2 3S) atoms in the upper atmosphere are calculated and compared with other calculations and observations. It is shown that the calculated emission rates agree well with the observed emission rates provided that the cross sections for loss of He(2 3S) by Penning ionization on atomic oxygen is near 5 A 2 and not 44 A 2 as previously measured. It is assumed that the local and conjugate photoelectron fluxes above 300 km are about double those calculated. The dawn/dusk intensity ratio observed in New Mexico, Brazil and Peru is accounted for by changes in the ambient thermal electron concentration in Brazil and Peru and by changes in plasmasphere opacity to conjugate point electrons for New Mexico and to some extent for Brazil. The rate at which He-4 would escape from the earth if sufficient energy were imparted to the He-4 atoms during the Penning reaction was recalculated and found to be inadequate by an order of magnitude to balance the terrestrial production.

Tinsley, B. A.↗

NASA NTRS2017

Mass Spectra Deconvolution of Gaseous Mixtures Containing Volatile Organic Compounds

The Spacecraft Atmosphere Monitor (S.A.M.) analyzes all gaseous pollutants in the 1-150Th mass-to-charge range based on their positive-ion mass spectra. Of particular interest is the Trace Gas Analysis (TGA) mode of operation in which S.A.M detects minute amounts of volatile organic compounds (VOC). Pollutant component of the ambient air is sampled on demand in twenty full mass spectra per second. All spectra is accumulated in two-second intervals by an on-board Field Programmable Gate Arrays (FPGA) unit. Mass spectra represents the number of detected fragment ions in a given mass-to-charge ratio channel. Electron impact ionization of neutral molecules results in creation of numerous fragment ions and most of organic compounds will contribute several identical fragments. Despite the presence of these molecular isobars, we developed the deconvolution algorithm capable of identifying target species based on their characteristic fragmentation patterns. We investigate the efficiency of deconvolution algorithm as a function of mass resolution with which mass spectrum is acquired. Higher the mass resolution, better the chances are to distinguish between stereoisomers using their fragmentation propensities, but also results in higher data volumes to be processed by a set of small footprint software stacks hosted by an on-board computer. Finding the balance between deconvolution accuracy and generated data volume under time constrains and limited computing resources is the main topic of this study.

Darrach, M.↗

NASA NTRS1978

Heating of the ambient ionosphere by an artificially injected electron beam

An electrostatic analyzer on the electron accelerator of the Electron Echo 2 experiment showed that the electrons of the background plasma were heated to 10,000 K or more within 8 ms of the start of gun pulses. The degree of heating was dependent on the orientation of the rocket with respect to the magnetic field but was not measurably dependent on ambient electron density, neutral atmosphere density, or on the pitch angle at which the 40-keV electron beam was injected. This heating was also accompanied by an increase of plasma density. No evidence was found for an ion-free region around the rocket during gun pulses. These observations show that significant amounts of ionization are taking place around the rocket. During part of the flight a two-temperature electron distribution was found. It is believed that the high-temperature part of these distributions represents secondaries produced by the beam.

Cartwright, D. G.↗

NASA NTRS1979

The impact of gas-surface reactions on mass spectrometric measurements of atomic nitrogen

The paper presents a simplified model of the ion source chemistry, explains several details of the data reduction method used in obtaining atomic-nitrogen (N) densities from OSS data, and discusses implications of gas-surface reactions for the design of future satellite-borne mass spectrometers. Because of various surface reactions, N appears in three different forms in the ion source, as N, NO, and NO2. Considering the rather small spin modulation of NO and NO2 in the semi-open ionization chamber used in the OSS instrument, it is not surprising that these reaction products have not been previously identified in closed source instruments as a measure of the presence of atomic nitrogen. Warmup and/or outgassing of the ion source are shown to drastically reduce the NO2 concentration, thereby making possible reliable measurement of ambient N densities.

Engebretson, M. J.↗

NASA NTRS1991

An experimental investigation of hollow cathode-based plasma contactors

Experimental results are presented which describe operation of the plasma environment associated with a hollow cathod-based plasma contactor collecting electrons from or emitting them to an ambient, low density Maxwellian plasma. A one-dimensional, phenomenological model of the near-field electron collection process, which was formulated from experimental observations, is presented. It considers three regions, namely, a plasma cloud adjacent to the contactor, an ambient plasma from which electrons are collected, and a double layer region that develops between the contactor plasma cloud and the ambient plasma regions. Results of the electron emission experiments are also presented. An important observation is made using a retarding potential analyzer (RPA) which shows that high energy ions generally stream from a contactor along with the electrons being emitted. A mechanism for this phenomenon is presented and it involves a high rate of ionization induced between electrons and atoms flowing together from the hollow cathode orifice. This can result in the development of a region of high positive potential. Langmuir and RPA probe data suggest that both electrons and ions expand spherically from this hill region. In addition to experimental observations, a one-dimensional model which describes the electron emission process and predicts the phenomena just mentioned is presented and shown to agree qualitatively with these observations.

Williams, John D.↗

NASA NTRS2011

The EUV Emission in Comet-Solar Corona Interactions

The Atmospheric Imaging Assembly (AlA) on the Solar Dynamics Observatory (SDO) viewed a comet as it passed through the solar corona on 2011 July 5. This was the first sighting of a comet by a EUV telescope. For 20 minutes, enhanced emission in several of the AlA wavelength bands marked the path of the comet. We explain this EUV emission by considering the evolution of the cometary atmosphere as it interacts with the ambient solar atmosphere. Water ice in the comet rapidly sublimates as it approaches the Sun. This water vapor is then photodissociated, primarily by Ly-alpha, by the solar radiation field to create atomic Hand O. Other molecules present in the comet also evaporate and dissociate to give atomic Fe and other metals. Subsequent ionization of these atoms can be achieved by a number of means, including photoionization, electron impact, and charge exchange with coronal protons and other highly-charged species. Finally, particles from the cometary atmosphere are thermalized to the background temperature of the corona. Each step could cause emission in the AlA bandpasses. We will report here on their relative contribution to the emission seen in the AlA telescopes.

Bryans, Paul↗

NASA NTRS1976

Quantitative observation of light flash sensations experiment MA-106

Light flashes caused by the interaction of cosmic particles with the visual apparatus have been observed by astronauts on all space missions since Apollo 11. This Apollo Soyuz Test Project experiment compared measurements of the observer's visual sensitivity with measurements of the ambient radiation environment and with the frequency and character of the flashes observed. The data obtained reveal a latitude dependence of the frequency of observed flashes. This distribution of flashes is correlated with the distribution of cosmic particles with stopping power greater than 15 keV/ micrometers in the eye. The interaction of dark adaptation, specific ionization, and range of particles in the retina as factors in the visualization of particle passage is discussed.

Budinger, T. F.↗

NASA NTRS1990

Natural vacuum electronics

The ambient natural vacuum of space is proposed as a basis for electron valves. Each valve is an electron controlling structure similiar to a vacuum tube that is operated without a vacuum sustaining envelope. The natural vacuum electron valves discussed offer a viable substitute for solid state devices. The natural vacuum valve is highly resistant to ionizing radiation, system generated electromagnetic pulse, current transients, and direct exposure to space conditions.

Leggett, Nickolaus↗

NASA NTRS2003

The High-Excitation Planetary Nebula NCG 246: Optical and Near-Ultraviolet Observations and Two-dimensional Numerical Models

We have imaged the planetary nebula (PN) NGC 246 in the near-ultraviolet wavelengths [Ne v] 342.6 nm, the Bowen fluorescence line of 0 111 at 344.4 nm, and a nearby line-free region centered on 338.6 nm, as well as H(alpha), [O III] 500.7 nm, and [S II] 673.0 and 671.5 nm. Imaging in the 344.4 nm line is necessary to deconvolve contamination of the [Ne v] images by O III 342.9 nm. The emission from the shell and inner parts of the nebula is detected in [Ne v]. The radial profiles of the [Ne v] brightness decrease with radius from the exciting star, indicating that the bulk of the emission from this ion is due to the hard UV stellar radiation field, with a (probably) marginal contribution from collisional ionization in a shock between the PN shell and the interstellar medium (ISM). In contrast, the radial profiles of the emission in H(alpha), [0 III] 500.7 nm, and [S II] are flatter and peak at the location of the shell. The emission of [S II] probably traces the interaction of the PN with the ambient ISM. We also present two-dimensional numerical simulations for this PN-ISM interaction. The simulations consider the stellar motion with respect to the ambient ISM, with a velocity of 85 km/s , and include the time evolution of the wind parameters and UV radiation field from the progenitor star.

Szentgyorgyi, Andrew↗

NASA NTRS1975

Photoelectron escape from the ionosphere of Jupiter

Photoelectron escape fluxes and ambient electron heating from the Jovian ionosphere are computed as a function of local time and latitude. Several differences for the fluxes expected from a hydrogen atmosphere, rather than a terrestrial type of atmosphere, are described, including an increase in structure in the energy spectra due to the paucity of ionic states entering the photo-ionization processes and lower escape fluxes above 10 eV than were expected from a simple scaling of earth fluxes.

Swartz, W. E.↗

NASA NTRS2015

Design and Demonstration of the Mars Organic Molecule Analyzer (MOMA) on the ExoMars 2018 Rover

The Mars Organic Molecule Analyzer (MOMA) investigation is a key astrobiology experiment scheduled to launch on the joint ESA-Roscosmos ExoMars 2018 rover mission. MOMA will examine the chemical composition of geological samples acquired from depths of up to two meters below the martian surface, where fragile organic molecules may be protected from destructive cosmic radiation and/or oxidative chemical reactions. The heart of the MOMA mass spectrometer subsystem (i.e., MOMA-MS) is a miniaturized linear ion trap (LIT) that supports two distinct modes of operation to detect: i) volatile and semi-volatile, low-to-moderate mass organics (less than or equal to 500 Da) via pyrolysis coupled with gas chromatography mass spectrometry (pyr/GCMS); and, ii) more refractory, moderate-to-high mass compounds (up to 1000 Da) via laser desorption (LDMS) at ambient Mars pressures. Additionally, the LIT mass analyzer enables selective ion trapping via multi-frequency waveform ion excitation (e.g., stored waveform inverse Fourier transform, or SWIFT), and structural characterization of complex molecules using tandem mass spectrometry (MSIMS). A high-fidelity Engineering Test Unit (ETU) of MOMAMS, including the LIT subassembly, dual-gun electron ionization source, micropirani pressure gauge, solenoid-driven aperture valve, redundant detection chains, and control electronics, has been built and tested at NASA GSFC under relevant operational conditions (pressure, temperature, etc.). Spaceflight qualifications of individual hardware components and integrated subassemblies have been validated through vibration, shock, thermal, lifetime, and performance evaluations. The ETU serves as a pathfinder for the flight model buildup, integration and test, as the ETU meets the form, fit and function of the flight unit that will be delivered to MPS in late 2015. To date, the ETU of MOMA-MS has been shown to meet or exceed all functional requirements, including mass range, resolution, accuracy, instrumental drift, and Iimit-of-detection specifications, thereby enabling the primary science objectives of the MOMA investigation and ExoMars 2018 mission.

Mars Organic Molecule Analyzer↗

NASA NTRS1985

Artificial plasma density structures produced by energetic electron beams from rockets and spacecraft

Recent rocket and Space Shuttle experiments have demonstrated the capability to launch electron beams of moderate power (100 W to 10 kW) into the earth's ionosphere and magnetosphere. This letter describes how such beams, when fired from rockets or satellites, can create significant ionization in the E- and F-regions of the ionosphere. Through proper selection of beam-related parameters, an interesting variety of plasma density structures, including plasma sheets and plasma filaments, can be created and studied over periods of 30 minutes to 1 hour, depending on the rate of plasma recombination and the density of the ambient plasma. Observations of these structures can give new information relating to the physics of plasma density structures in the ionosphere, and the effects these features have upon the scattering of radio waves. It is also possible that observations of the density structures will provide a new means for studying neutral winds and electrodynamic phenomena in the ionosphere.

Banks, P. M.↗