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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Detection of the J-10 Manifold of the Pure Rotational Band of Phosphine on Saturn

The detection of the J = 10 manifold of the pure rotational band of PH3 on Saturn is reported. The observations were made from the far-infrared cooled grating spectrometer. The wavelengths and observed brightness temperatures for the full disk plus rings are 89 + or - 3 K at 97.04 micrometer, 77 + or - 3 K at 102.72 micrometer, 77 + or - 3 K at 102.94 micrometer, and 83 + or - 3 K at 105.12 micrometers. The points of 97.04 and 105.12 micrometers establish the continuum level and the two points near 103 micrometers measure the depth of the PH3 manifold. After the flux due to the rings is subtracted, the depth of the feature is 16 + or - 6 K relative to the nearby 102 K continuum. These results are compared to theoretical models which parameterize the PH3 mixing ratio as x = x sub zero (P/P sub zero)(alpha) for P P sub zero and as x = x sub zero for P or = P, where P is the total pressure and alpha = H/h is the ratio of the dynamical scale height (H) and the scale height for decreasing the PH3 mixing ratio (h). The parameters x sub zero, P sub zero, and h were varied, as well as the H/He mixing ratio and the pressure-temperature profile. The data are well fitted using pressure-temperature profiles. The preferred values of h, P sub zero, and x sub zero imply that there is little or no PH3 above the thermal inversion and that the mixing ratio below the inversion is consistent with PH3 being 1 to 4 times overabundant relative to the solar P/H ratio.

Haas, M. R.↗
NASA NTRS1987

Mass spectrometric studies of phosphine pyrolysis and OMVPE growth of InP

The mechanism of PH3 decomposition was studied by using D2 as a carrier gas and analyzing the reaction products with a mass spectrometer. The effects of InP and silica surfaces were investigated. The only gaseous product below 600 C is H2. Since any gas-phase H atoms would produce HD, the reaction occurs entirely on the surface. The slow step is the unimolecular removal of the first hydrogen atom, with an activation energy of 36.0 kcal/mole on InP surfaces. The reaction on InP is first-order for PH3 concentrations as high as 15 percent, so the surface is not saturated at those conditions. When trimethylindium (TMIn) is added to the gas mixture, the mechanism changes dramatically, probably proceeding via an unstable intermediate adduct of TMIn and PH3 which eliminates CH4 upon formation. This concerted reaction lowers the pyrolysis temperatures of both PH3 and TMIn.

Larsen, C. A.↗
NASA NTRS1995

Synthesis of low color, atomic oxygen resistant polyimides

The purpose of this project was to develop low color, atomic oxygen resistant polyimides for potential applications on spacecraft in low earth orbit. The material is needed in order to protect satellites and spacecraft from the gases and radiation found at those altitudes. Phosphorous containing polyimides have been shown to be especially resistant to corrosion and weight loss under oxygen plasma. Unfortunately the color of these phosphorous containing polyimides is still too high for them to be good heat insulators. While they are not as effective as teflon, the current material of choice. polyimides are much less dense than teflon and would be especially valuable if they could be made with low color. The approach taken was to synthesize a monomer which would contain the elements needed for giving the final polyimide its desired properties. In particular the monomer should incorporate phosphine or phosphine oxides and have bulky side groups to block any color forming charge transfer structures. The target molecule, 3,5-di-(trifluoromethylphenyl)-bis(3-aminophenyl) phosphine oxide, (containing both a phosphine oxide group and a bulky ditrifluoromethylphenyl group) was synthesized via three reactions in overall yield of 21 percent. In addition, a model compound, bis(3-phenylamine) phenyl phosphine oxide, was synthesized two different ways in order to establish the conditions for the nitration of phosphine oxides and their reduction to the amine. Finally, a trisubstituted phosphine oxide was synthesized. In all, seven phosphorus containing organic compounds were synthesized, purified and characterized. The model compound was reacted with oxydiphthalic anhydride to form a polyamic acid with inherent viscosity of 0.34. This material was cast into a film and heated, forming a normally colored fairly strong polyimide with a Tg of 240 C. The target compound was reacted with 6-fluorodiphthalic anhydride to give a polyamic acid with inherent viscosity of 0.19 and cast to give a heavily cracked colored film with a Tg of 230 C.

MacInnes, Dave↗
NASA NTRS1973

Interaction of some extreme-pressure type lubricating compounds with an iron surface

An iron surface was exposed to the extreme-pressure type lubricant benzyl chloride, dichlorophenyl phosphine, dichlorophenyl phosphine sulfide, ophenyl phosphine oxide. Iron, in the sputter-cleaned state, was exposed to these materials statically and during dynamic friction experiments. With benzyl chloride only chlorine adsorbed to the surface, and with dichlorophenyl phosphine no adsorption occurred, while the addition of sulfur to that same molecular structure resulted in the promotion of carbon and chlorine adsorption. substitution of oxygen for sulfur in the dichlorobenzyl phosphine molecule resulted in carbon, chlorine, and oxygen adsorption. With none of the phosphorus containing molecules was phosphorus detected on the surface. Sliding in an atmosphere of benzyl chloride promoted adsorption of chlorine to the iron surface. Increases in load resulted in a decrease in the surface concentration of iron chloride.

Buckley, D. H.↗
NASA NTRS1994

High Efficiency InP Solar Cells from Low Toxicity Tertiarybutylphosphine

Large scale manufacture of phosphide based semiconductor devices by organo-metallic vapor phase epitaxy (OMVPE) typically requires the use of highly toxic phosphine. Advancements in phosphine substitutes have identified tertiarybutylphosphine (TBP) as an excellent precursor for OMVPE of InP. High quality undoped and doped InP films were grown using TBP and trimethylindium. Impurity doped InP films were achieved utilizing diethylzinc and silane for p and n type respectively. 16 percent efficient solar cells under air mass zero, one sun intensity were demonstrated with Voc of 871 mV and fill factor of 82.6 percent. It was shown that TBP could replace phosphine, without adversely affecting device quality, in OMVPE deposition of InP thus significantly reducing toxic gas exposure risk.

Hoffman, Richard W., Jr.↗
NASA NTRS1996

Evaluation of Degradation Inhibitors in Poly(Hexafluoropropene Oxide) Fluids

The action of various alloys: 440C steel, M-50 steel, Pyrowear 675, Cronidur 30 and Ti(4Al,4Mn); the effect of decradation inhibitors: mono- and diphospha-s-triazines, diphosphatetraazacyclooctatetraene, phosphate esters, phosphate/ diester rust inhibiting mixtures, and a phosphine were evaluated in two poly(hexafluoropropene oxide) fluids (143AC and 16256). The degradation promoting action of the ferrous alloys in 16256 fluid were comparable; Ti(4Al,4Mn) alloy was significantly more detrimental. The overall rating of the additives was: phosphates (greater than) phosphate/diester mixture (greater than) phosphine (greater than or equal to) phospha-s-triazines. The 16256 fluid was less responsive to additive inhibition than 143AC. Phosphate esters were fully effective over 24 hour exposure in the 16256/440C steel and the 16256/Ti(4Al,4Mn) systems at 330 C. In general, the phosphine was less effective in the presence of ferrous alloys than the phosphates and phospha-s-triazines.

Jones, William R., Jr.↗
NASA NTRS2010

Cassini/CIRS Observations of Saturn's "Storm Alley"

In the Voyager era storms on Saturn were observed predominantly in the northern hemisphere, however, in recent years storm activity has been confined to a narrow range of latitudes referred to as "storm alley" (approx.40degS planetographic latitude). Throughout Cassini's prime mission storms have been detected by two independent instruments: ISS through dayside images and RPWS using radio emissions from Saturn Electrostatic Discharges (SED's) (Dyudina et al. 2007). Analysis of these storms indicates that the cloud tops are in the 200 - 500rnbar altitude range. During Saturn's Equinox, in August 2009, lSS imaged lightning on the night side in storm alley when ring-shine was at a minimum (Dyudina et al. 2010). This study indicates that lightning may have originated as deep as the water cloud. Decently, Cassini/CIRS was targeted at storm alley while a storm, originally detected by amateurs, was ongoing (March 2010). Phosphine can be used as a tracer of vertical transport because it is a disequilibrium species that falls off with altitude in the upper troposphere. CIRS can measure temperature and phosphine abundance independently in the altitude range where these cloud tops occur. Early analysis of these data shows stronger phosphine absorption at storm longitudes. This is an indication that powerful updrafts were dredging material upward into the upper troposphere. The results of the analysis of the March 2010 CIRS observations of storm alley will be presented.

Hesman, Brigette E.↗
NASA NTRS2024

The Thermal Structure and Composition of Jupiter's Great Red Spot From JWST/MIRI

Jupiter's Great Red Spot (GRS) was mapped by the James Webb Space Telescope (JWST)/Mid-Infrared Instrument (4.9–27.9 μm) in July and August 2022. These observations took place alongside a suite of visual and infrared observations from; Hubble, JWST/NIRCam, Very Large Telescope/VISIR and amateur observers which provided both spatial and temporal context across the jovian disc. The stratospheric temperature structure retrieved using the NEMESIS software revealed a series of hot-spots above the GRS. These could be the consequence of GRS-induced wave activity. In the troposphere, the temperature structure was used to derive the thermal wind structure of the GRS vortex. These winds were only consistent with the independently determined wind field by JWST/NIRCam at 240 mbar if the altitude of the Hubble-derived winds were located around 1,200 mbar, considerably deeper than previously assumed. No enhancement in ammonia was found within the GRS but a link between elevated aerosol and phosphine abundances was observed within this region. North-south asymmetries were observed in the retrieved temperature, ammonia, phosphine and aerosol structure, consistent with the GRS tilting in the north-south direction. Finally, a small storm was captured north-west of the GRS that displayed a considerable excess in retrieved phosphine abundance, suggestive of vigorous convection. Despite this, no ammonia ice was detected in this region. The novelty of JWST required us to develop custom-made software to resolve challenges in calibration of the data. This involved the derivation of the “FLT-5” wavelength calibration solution that has subsequently been integrated into the standard calibration pipeline.

Jake Harkett↗
NASA NTRS2021

Venus' Mass Spectra Show Signs of Disequilibria in the Middle Clouds

We present a re‐examination of mass spectral data obtained from the Pioneer Venus Large Probe Neutral Mass Spectrometer. Our interpretations of differing trace chemical species are suggestive of redox disequilibria in Venus' middle clouds. Assignments to the data (at 51.3 km) include phosphine, hydrogen sulfide, nitrous acid, nitric acid, carbon monoxide, hydrochloric acid, hydrogen cyanide, ethane, and potentially ammonia, chlorous acid, and several tentative PxOy species. All parent ions were predicated upon assignment of corresponding fragmentation products, isotopologues, and atomic species. The data reveal parent ions at varying oxidation states, implying the presence of reducing power in the clouds, and illuminating the potential for chemistries yet to be discovered. When considering the hypothetical habitability of Venus' clouds, the assignments reveal a potential signature of anaerobic phosphorus metabolism (phosphine), an electron donor for anoxygenic photosynthesis (nitrite), and major constituents of the nitrogen cycle (nitrate, nitrite, ammonia, and N2).

disequilibria↗
NASA NTRS1979

The role of phosphorus in the upper atmosphere of Jupiter

The reaction of elemental phosphorus and H atoms to form PH3 was observed and should be a major factor in the recycling of PH3 in the stratosphere of Jupiter. The formation of PH3 in this manner should predominate at high altitudes where, due to the very low temperatures, reactions that require higher activation energies than these atom reactions cannot occur. At lower altitudes, in the troposphere, the rapid formation of H atoms from the strong absorption of light by NH3 will contribute to phosphine production also in this same manner. Recent experiments have also shown that elemental phosphorus reacts readily with aqueous ammonia to form PH3. This reaction may also be important in the recycling of PH3 in the upper troposphere of Jupiter if water-ammonia clouds, as had been previously thought, exist. Considerations of the coloration of the Great Red Spot have been made based upon the nature of the phosphorus obtained by decomposition of the phosphine.

Howland, G. R.↗
NASA NTRS1983

Phosphorus-containing imide resins

Bis- and tris-imides derived from tris (m-aminophenyl) phosphine oxides by reaction with maleic anhydride or its derivatives, and addition polymers of such imides, including a variant in which a mono-imide is condensed with a dianhydride and the product is treated with a further quantity of maleic anhydride. Such monomers or their oligomes may be used to impregnate fibers and fabrics which when cured, are flame resistant. Also an improved method of producing tris (m-aminophenyl) phosphine oxides from the nitro analogues by reduction with hydrazine hydrate using palladized charcoal or Raney nickel as the catalyst is described.

Varma, I. K.↗
NASA NTRS1985

Phosphorus-containing imide resins

Cured polymers of bis and tris-imides derived from tris(m-aminophenyl) phosphine oxides by reaction with maleic anhydride or its derivatives, and addition polymers of such imides, including a variant in which a monoimide is condensed with a dianhydride and the product is treated with a further quantity of maleic anhydride prior to curing are disclosed and claimed. Such polymers are flame resistant. Also disclosed are an improved method of producing tris(m-aminophenyl) phosphine oxides from the nitro analogues by reduction with hydrazine hydrate using palladized charcoal or Raney nickel as the catalyst and fiber reinforced cured resin composites.

Varma, I. K.↗
NASA NTRS1984

Phosphorus-containing imide resins - Modification by elastomers

The syntheses and general features of addition-type maleimide resins based on bis(m-aminophenyl)phosphine oxide and tris(m-aminophenyl)phosphine oxide have been reported previously. These resins have been used to fabricate graphite cloth laminates having excellent flame resistance. These composites did not burn even in pure oxygen. However, these resins were somewhat brittle. This paper reports the modification of these phosphorus-containing resins by an amine-terminated butadiene-acrylonitrile copolymer (ATBN) and a perfluoroalkylene diaromatic amine elastomer (3F). An approximately two-fold increase in short beam shear strength and flexural strength was observed at 7 percent ATBN concentration. The tensile, flexural, and shear strengths were reduced when 18 percent ATBN was used. Anaerobic char yields of the resins at 800 C and the limiting oxygen indexes of the laminates decreased with increasing ATBN concentration. The perfluorodiamine (3F) was used with both imide resins at 6.4 percent concentration. The shear strength was doubled in the case of the bisimide with no loss of flammability characteristics. The modified trisimide laminate also had improved properties over the unmodified one. The dynamic mechanical analysis of a four-ply laminate indicated a glass transition temperature above 300 C. Scanning electron micrographs of the ATBN modified imide resins were also recorded.

Varma, I. K.↗
NASA NTRS1986

Spectroscopic observations of the planets

The first phase of a program to determine D/H in the atmospheres of all of the major planets and Titan was completed. D/H on Titan and Uranus is significantly higher than on Jupiter and Saturn. Titan has the highest value, consistent with the possibility for hydrogen escape. These measurements were all made in terms of CH3D/CH4. They suggest that at least two reservoirs for deuterium exist in the outer solar system - a large one in hydrogen and a much smaller one in hydrogen-containing compounds that have not isotopically equilibrated with the hydrogen. This result also demonstrates that a large fraction of the carbon in the outer solar nebula was in the form of methane and it supports the nucleation model for the formation of the outer planets. Other studies included an investigation of the phosphine abundance over the Great Red Spot (GRS) of Jupiter, pre-Voyager determination of the amount of acetylene on Uranus, and the carbon isotope ratio in Halley's Comet. UV spectra of the GRS obtained with the IUE show no evidence of the enhancement of phosphine that would be expected if the red color of this object is caused by P4.

Owen, T.↗
NASA NTRS1994

Poly(arylene ether)s That Resist Atomic Oxygen

Novel poly(arylene ether)s containing phosphine oxide (PAEPO's) made via aromatic nucleophilic displacement reactions of activated aromatic dihalides (or, in some cases, activated aromatic dinitro compounds) with new bisphenol monomers containing phosphine oxide. Exhibited favorable combination of physical and mechanical properties and resistance to monatomic oxygen in oxygen plasma environment. Useful as adhesives, coatings, films, membranes, moldings, and composite matrices.

Connell, John W.↗
NASA NTRS2011

Trace Species Identified in Saturn's Northern Storm Region

The massive storm at 40degN on Saturn that began in December 2010 has produced significant and lasting effects in the northern hemisphere on temperature and species abundances [I}. The northern storm region was observed at 0.5/cm spectral resolution in March 2011 by Cassini's Composite Infrared Spectrometer (CIRS). Temperatures in the stratosphere as high as 190 K were derived from CIRS spectra in warm regions referred to as "beacons". Other longitudes exhibit cold temperatures in the upper troposphere. These unusual conditions allow us to identify rare species such as C4H2, C3H4, and CO2 in the stratosphere, as well as to measure changes in the abundance of phosphine (PH3) in the troposphere. Phosphine is a disequilibrium species whose abundance is a tracer of upwelling from the deep atmosphere.

Bjoraker, Gordon L.↗