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NASA NTRS1988

Environment Monitor

Viking landers touched down on Mars equipped with a variety of systems to conduct automated research, each carrying a compact but highly sophisticated instrument for analyzing Martian soil and atmosphere. Instrument called a Gas Chromatography/Mass Spectrometer (GC/MS) had to be small, lightweight, shock resistant, highly automated and extremely sensitive, yet require minimal electrical power. Viking Instruments Corporation commercialized this technology and targeted their primary market as environmental monitoring, especially toxic and hazardous waste site monitoring. Waste sites often contain chemicals in complex mixtures, and the conventional method of site characterization, taking samples on-site and sending them to a laboratory for analysis is time consuming and expensive. Other terrestrial applications are explosive detection in airports, drug detection, industrial air monitoring, medical metabolic monitoring and for military, chemical warfare agents.

Source record↗

NASA NTRS2003

Plumes and Blooms: Observations, Analysis and Modeling for SIMBIOS

The goal of the Plumes and Blooms (PnB) project is to develop, validate and apply to imagery state-of-theart ocean color algorithms for quantifying sediment plumes and phytoplankton blooms for the Case I1 environment of the Santa Barbara Channel. We conduct monthly to twice-monthly transect observations across the Santa Barbara Channel to develop an algorithm development and product validation data set. The PnB field program started in the summer of 1996. At each of the 7 PnB stations, a complete verification bio-geo-optical data set is collected. Included are redundant measures of apparent optical properties (remote sensing reflectance and diffuse attenuation spectra), as well as in situ profiles of spectral absorption, beam attenuation and backscattering coefficients. Water samples are analyzed for component in vivo absorption spectra, fluorometric chlorophyll, phytoplankton pigment (by the SDSU CHORS laboratory), and inorganic nutrient concentrations (Table 1). A primary goal is to use the PnB field data set to objectively tune semi-analytical models of ocean color for this site and apply them using available satellite imagery (SeaWiFS and MODIS). In support of this goal, we have also been addressing SeaWiFS ocean color and AVHRR SST imagery (Otero and Siegel, 2003). We also are using the PnB data set to address time/space variability of water masses in the Santa Barbara Channel and its relationship to the 1997/1998 El Niiio. However, the comparison between PnB field observations and satellite estimates of primary products has been disappointing. We find that field estimates of water-leaving radiance, LwN(h), correspond poorly to satellite estimates for both SeaWiFS and MODIS local area coverage imagery. We believe this is due to poor atmospheric correction due to complex mixtures of aerosol types found in these near-coastal regions. Last, we remain active in outreach activities.

Siegel, D. A.↗

NASA NTRS2004

Aerosol Optical Properties Measured Onboard the Ronald H. Brown During ACE Asia as a Function of Aerosol Chemical Composition and Source Region

During the ACE Asia intensive field campaign conducted in the spring of 2001 aerosol properties were measured onboard the R/V Ronald H. Brown to study the effects of the Asian aerosol on atmospheric chemistry and climate in downwind regions. Aerosol properties measured in the marine boundary layer included chemical composition; number size distribution; and light scattering, hemispheric backscattering, and absorption coefficients. In addition, optical depth and vertical profiles of aerosol 180 deg backscatter were measured. Aerosol within the ACE Asia study region was found to be a complex mixture resulting from marine, pollution, volcanic, and dust sources. Presented here as a function of air mass source region are the mass fractions of the dominant aerosol chemical components, the fraction of the scattering measured at the surface due to each component, mass scattering efficiencies of the individual components, aerosol scattering and absorption coefficients, single scattering albedo, Angstrom exponents, optical depth, and vertical profiles of aerosol extinction. All results except aerosol optical depth and the vertical profiles of aerosol extinction are reported at a relative humidity of 55 +/- 5%. An over-determined data set was collected so that measured and calculated aerosol properties could be compared, internal consistency in the data set could be assessed, and sources of uncertainty could be identified. By taking into account non-sphericity of the dust aerosol, calculated and measured aerosol mass and scattering coefficients agreed within overall experimental uncertainties. Differences between measured and calculated aerosol absorption coefficients were not within reasonable uncertainty limits, however, and may indicate the inability of Mie theory and the assumption of internally mixed homogeneous spheres to predict absorption by the ACE Asia aerosol. Mass scattering efficiencies of non-sea salt sulfate aerosol, sea salt, submicron particulate organic matter, and dust found for the ACE Asia aerosol are comparable to values estimated for ACE 1, Aerosols99, and INDOEX. Unique to the ACE Asia aerosol was the large mass fractions of dust, the dominance of dust in controlling the aerosol optical properties, and the interaction of dust with soot aerosol.

Quinn, P. K.↗

NASA NTRS2003

Plumes and Blooms: Modeling the Case II Waters of the Santa Barbara Channel

The goal of the Plumes and Blooms (PnB) project is to develop, validate and apply to imagery state-of-the-art ocean color algorithms for quantifying sediment plumes and phytoplankton blooms for the Case II environment of the Santa Barbara Channel. We conduct monthly to twice-monthly transect observations across the Santa Barbara Channel to develop an algorithm development and product validation data set. The PnB field program started in the summer of 1996. At each of the 7 PnB stations, a complete verification bio-geo-optical data set is collected. Included are redundant measures of apparent optical properties (remote sensing reflectance and diffuse attenuation spectra), as well as in situ profiles of spectral absorption, beam attenuation and backscattering coefficients. Water samples are analyzed for component in vivo absorption spectra, fluorometric chlorophyll, phytoplankton pigment (by the SDSU CHORS laboratory), and inorganic nutrient concentrations. A primary goal is to use the PnB field data set to objectively tune semi-analytical models of ocean color for this site and apply them using available satellite imagery (SeaWiFS and MODIS). In support of this goal, we have also been addressing SeaWiFS ocean color and AVHRR SST imagery. We also are using the PnB data set to address time/space variability of water masses in the Santa Barbara Channel and its relationship to the 1997/1998 El Nino. However, the comparison between PnB field observations and satellite estimates of primary products has been disappointing. We find that field estimates of water-leaving radiance, L(sub wN)(lambda), correspond poorly to satellite estimates for both SeaWiFS and MODIS local area coverage imagery. We believe this is due to poor atmospheric correction due to complex mixtures of aerosol types found in these near-coastal regions. Last, we remain active in outreach activities.

Siegel, D. A.↗

NASA NTRS2004

Plumes and Blooms: Observations, Analysis and Modeling for SIMBIOS

Maritorena, S.↗

NASA NTRS2004

Did the Pre-RNA World Rest Upon DNA Molecules?

The isolation of a DNA sequence that catalyzes the ligation of oligodeoxynucleotides via the formation of 3' - 5' phosphodiester linkage significance in selection experiments has been reported. Ball recently used this to discuss the possibility that natural DNA molecules may have formed in the primitive Earth leading to the origin of life. As noted by Ferris and Usher, if metabolic pathways evolved backwards, it could be argued that the biosynthesis of 2-deoxyribose from ribose suggests that RNA came from DNA. As summarized elsewhere, there are several properties of deoxyribose which could be interpreted to support the possibility that DNA-like molecules arose prior to the RNA world. For example, 2-deoxyribose is slightly more soluble than ribose (which may have been an advantage in a drying pool scenario), may have been more reactive under possible prebiotic conditions (it forms a nucleoside approx. 150 times faster than ribose with the alternative base urazole at 25 C), while it decomposes in solution (approximately 2.6 times more slowly than ribose at 100 C). Other advantages of DNA over RNA are that it has one fewer chiral center, has a greater stability at the 8.2 pH value of the current oceans, and does not has the 2'5' and 3'5' ambiguity in polymerizations. Yet, there is strong molecular biological and biochemical evidence that RNA was featured in the biology well before the last common ancestor. The presence of sugar acids, including both ribo- and deoxysugar acids, in the 4.6 Ga old Murchison meteorite suggest that both may have been available in the primitive Earth, derived from the accretion of extraterrestrial sources and/or from endogenous processes involving formaldehyde and its derivatives. However, the abiotic synthesis of deoxyribose, ribose, and other sugars from glyceraldehyde and acetaldehyde under alkaline conditions is inefficient and unespecific. Although sugars are labile compounds, the role of cyanamide or borate minerals in the stabilization of the cyclic forms of ribose and other pentoses has recently been demonstrated. Nonetheless, the assumption either RNA or DNA was the first genetic material needs to be supplemented by laboratory models demonstrating that the prebiotic synthesis of activated beta-D-(deoxy)ribonucleotides and their polymers was feasible. As of today such evidence is lacking, and there is no convincing synthesis of any nucleotide, since all model experiments produce complex mixtures of products in which there is no preferential synthesis of chiral D-nucleotides. This strongly suggests that both DNA and RNA may have been preceded by pairing structures much simpler than extant nucleic acids. It is doubtful that DNA molecules, or indeed other (de0xy)ribofuranoid oligonucleotides formed the basis of these as yet undescribed pre-RNA worlds.

Lazcano, Antonio↗

NASA NTRS2001

Self-assembling amphiphilic molecules: Synthesis in simulated interstellar/precometary ices

Interstellar gas and dust constitute the primary material from which the solar system formed. Near the end of the hot early phase of star and planet formation, volatile, less refractory materials were transported into the inner solar system as comets and interplanetary dust particles. Once the inner planets had sufficiently cooled, late accretionary infall seeded them with complex organic compounds [Oro, J. (1961) Nature (London) 190, 389-390; Delsemme, A. H. (1984) Origins Life 14, 51-60; Anders, E. (1989) Nature (London) 342, 255-257; Chyba, C. F. & Sagan, C. (1992) Nature (London) 355, 125-131]. Delivery of such extraterrestrial compounds may have contributed to the organic inventory necessary for the origin of life. Interstellar ices, the building blocks of comets, tie up a large fraction of the biogenic elements available in molecular clouds. In our efforts to understand their synthesis, chemical composition, and physical properties, we report here that a complex mixture of molecules is produced by UV photolysis of realistic, interstellar ice analogs, and that some of the components have properties relevant to the origin of life, including the ability to self-assemble into vesicular structures.

Meteoroids↗

NASA NTRS2003

Reactive Nitrogen in Asian Continental Outflow over the Western Pacific: Results from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P)Airborne Mission

We present here results for reactive nitrogen species measured aboard the NASA DC-8 aircraft during the Transport and Chemical Evolution over the Pacific TRACE-P) mission. The large-scale distributions total reactive nitrogen (NO(sub y,sum) = NO + NO2 + HNO3 + PAN + C(sub 1)-C(sub 5) alkyl nitrates) and O3 and CO were better defined in the boundary layer with significant degradation of the relationships as altitude increased. Typically, NO(sub y,sum) was enhanced over background levels of approx.260 pptv by 20-to-30-fold. The ratio C2H2/CO had values of 1-4 at altitudes up to 10 km and as far eastward as 150degE, implying significant vertical mixing of air parcels followed by rapid advection across the Pacific. Analysis air parcels originating from five principal Asian source regions showed that HNO3 and PAN dominated NO(sub y,sum). Correlations of NO(sub y,sum) with C2Cl4 (urban tracer) were not well defined in any of the source regions, and they were only slightly better with CH3Cl (biomass tracer). Air parcels over the western Pacific contained a complex mixture of emission sources that are not easily resolvable as shown by analysis of the Shanghai mega-city plume. It contained an intricate mixture of pollution emissions and exhibited the highest mixing ratios of NO(sub y,sum) species observed during TRACE-P. Comparison of tropospheric chemistry between the earlier PEM-West B mission and the recent TRACE-P data showed that in the boundary layer significant increases in the mixing ratios of NO(sub y,sum)species have occurred, but the middle and upper troposphere seems to have been affected minimally by increasing emissions on the Asian continent over the last 7 years.

Talbot, R.↗

NASA NTRS2003

Chemical Composition of Asian Continental Outflow over the Western Pacific: Results from Transport and Chemical Evolution over the Pacific (TRACE-P)

We characterize the chemical composition of Asian continental outflow observed during the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) mission during February-April 2001 in the western Pacific using data collected on the NASA DC-8 aircraft. A significant anthropogenic impact was present in the free troposphere and as far east as 150degE longitude reflecting rapid uplift and transport of continental emissions. Five-day backward trajectories were utilized to identify five principal Asian source regions of outflow: central, coastal, north-northwest(NNW), southeast (SE), and west-southwest (WSW). The maximum mixing ratios for several species, such as CO, C2Cl4, CH3Cl, and hydrocarbons, were more than a factor of 2 larger in the boundary layer of the central and coastal regions due to industrial activity in East Asia. CO was well correlated with C2H2, C2H6, C2Cl4, and CH3Cl at low altitudes in these two regions (r(sup 2) approx. 0.77-0.97). The NNW, WSW, and SE regions were impacted by anthropogenic sources above the boundary layer presumably due to the longer transport distances of air masses to the western Pacific. Frontal and convective lifting of continental emissions was most likely responsible for the high altitude outflow in these three regions. Photochemical processing was influential in each source region resulting in enhanced mixing ratios of O3, PAN, HNO3, H2O2, and CH3OOH. The air masses encountered in all five regions were composed of a complex mixture of photcrchemically aged air with more recent emissions mixed into the outflow as indicated by enhanced hydrocarbon ratios (C2H2/CO greater than or equal to 3 and C3H8/C2H6 greater than or equal to 0.2). Combustion, industrial activities, and the burning of biofuels and biomass all contributed to the chemical composition of air masses from each source region as demonstrated by the H6, SO2, and C2Cl4 were compared for the TRACE-P and PEM-West B missions. In the more northern regions, O3, CO, and SO2 were higher at low altitudes during TRACE-P. In general, mixing ratios were fairly similar between the two missions in the southern regions. A comparison between CO/CO2, CO/CH4, C2H6/C3H8, NO(x)/SO2, and NO(y)/(SO2 + nss-SO4) ratios for the five source regions and for the 2000 Asian emissions summary showed vay close agreement indicating that Asian emissions were well represented by the TRACE-P data and tbe emissions inventory.

Russo, R. S.↗

NASA NTRS2004

High Temperature Chemistry in the Columbia Accident Investigation

Initial estimates on the temperature and conditions of the breach in Columbia's wing focused on analyses of the slag deposits. These deposits are complex mixtures of the reinforced carbon/carbon (RCC) constituents, insulation material, and wing structural materials. However it was possible to clearly discern melted/solidified Cerachrome(R) insulation, indicating the temperatures had exceeded 1760 C. Current research focuses on the carbon/carbon in the path from the breach. Carbon morphology indicates heavy oxidation and erosion. Raman spectroscopy yielded further temperature estimates. A technique developed at Sandia National Laboratories is based on crystallite size in carbon chars. Lower temperatures yield nanocrystalline graphite; whereas higher temperatures yield larger graphite crystals. By comparison to standards the temperatures on the recovered RCC fragments were estimated to have been greater than 2700 C.

Jacobson, Nathan↗

NASA NTRS2004

Corrosion Issues for Ceramics in Gas Turbines

The requirements for hot-gas-path materials in gas turbine engines are demanding. These materials must maintain high strength and creep resistance in a particularly aggressive environment. A typical gas turbine environment involves high temperatures, rapid gas flow rates, high pressures, and a complex mixture of aggressive gases. Over the past forty years, a wealth of information on the behavior of ceramic materials in heat engine environments has been obtained. In the first part of the talk we summarize the behavior of monolithic SiC and Si3N4. These materials show excellent baseline behavior in clean, oxygen environments. However the aggressive components in a heat engine environment such as water vapor and salt deposits can be quite degrading. In the second part of the talk we discuss SiC-based composites. The critical issue with these materials is oxidation of the fiber coating. We conclude with a brief discussion of future directions in ceramic corrosion research.

Jacobson, Nathan↗

NASA NTRS2005

Followup to Columbia Investigation: Reinforced Carbon/Carbon From the Breach Location in the Wing Leading Edge Studied

Initial estimates on the temperature and conditions of the breach in the Space Shuttle Columbia's wing focused on analyses of the slag deposits. These deposits are complex mixtures of the reinforced carbon/carbon (RCC) constituents, insulation material, and wing structural materials. Identification of melted/solidified Cerachrome insulation (Thermal Ceramics, Inc., Augusta, GA) indicated that the temperatures at the breach had exceeded 1760 C.

Jacobson, Nathan S.↗

NASA NTRS2006

Miniature GC: Minicell ion mobility spectrometer (IMS) for astrobiology planetary missions

Kojiro, Daniel R.↗

NASA NTRS2002

Miniaturized GC/MS instrumentation for in situ measurements: micro gas chromatography coupled with miniature quadrupole array and paul ion trap mass spectrometers

Miniaturized chemical instrumentation is needed for in situ measurements in planetary exploration and other spaceflight applications where factors such as reduction in payload requirements and enhanced robustness are important. In response to this need, we are 'continuing to develop miniaturized GC/MS instrumentation which combines chemical separations by gas chromatography (GC) with mass spectrometry (MS) to provide positive identification of chemical compounds in complex mixtures of gases, such as those found in the International Space Station's cabin atmosphere. Our design approach utilizes micro gas chromatography components coupled with either a miniature quadrupole mass spectrometer array (QMSA) or compact, high-resolution Paul ion trap.

GC/MC miniature mass spectrometry MEMS↗

NASA NTRS2004

Miniaturized gas chromatograph-Paul ion trap system: applications to environmental monitoring

A miniature gas chromatograph (GC) and miniature Paul ion trap (PT) mass spectrometer system has been developed for identifying and quantifying chemical species present in closed environments having a complex mixture of gases.

miniature mass spectrometry↗

NASA NTRS2006

Miniature GC-Minicell Ion Mobility Spectrometer (IMS) for In Situ Measurements in Astrobiology Planetary Missions

Astrobiology flight experiments require highly sensitive instrumentation for in situ analysis of volatile chemical species and minerals present in the atmospheres and surfaces of planets, moons, and asteroids. The complex mixtures encountered place a heavy burden on the analytical instrumentation to detect and identify all species present. The use of land rovers and balloon aero-rovers place additional emphasis on miniaturization of the analytical instrumentation. In addition, smaller instruments, using tiny amounts of consumables, allow the use of more instrumentation and/or ionger mission life for stationary landers/laboratories. The miniCometary Ice and Dust Experiment (miniCIDEX), which combined Gas Chromatography (GC) with helium Ion Mobility Spectrometry (IMS), was capable of providing the wide range of analytical information required for Astrobiology missions. The IMS used here was based on the PCP model 111 IMS. A similar system, the Titan Ice and Dust Experiment (TIDE), was proposed as part of the Titan Orbiter Aerorover Mission (TOAM). Newer GC systems employing Micro Electro- Mechanical System (MEMS) based technology have greatly reduced both the size and resource requirements for space GCs. These smaller GCs, as well as the continuing miniaturization of Astrobiology analytical instruments in general, has highlighted the need for smaller, dry helium IMS systems. We describe here the development of a miniature, MEMS GC-IMS system (MEMS GC developed by Thorleaf Research Inc.), employing the MiniCell Ion Mobility Spectrometer (IMS), from Ion Applications Inc., developed through NASA's Astrobiology Science and Technology Instrument Development (ASTID) Program and NASA s Small Business Innovative Research (SBIR) Program.

Kojiro, Daniel R.↗

NASA NTRS2010

The Origins and Evolution of Molecules in Icy Solids

Astronomical observations of the past few decades have revealed the existence of a variety of molecules in extraterrestrial ices. These molecules include H2O, CO, and CO2, and organics such as CH4, CH30H, and C2H6. Some ices are dominated by polar molecules, while non-polar species appear to dominate others. Observations, mainly in the radio and IR regions, have allowed the inference of other solid-phase molecules whose formation remains difficult to explain by gas-phase chemistry alone. Several laboratory research groups have reported on extensive experiments on the solid-phase reaction chemistry of icy materials, generally as initiated by either ionizing radiation or vacuum-UV photons. These experiments not only permit molecular identifications to be made from astronomical observations, but also allow predictions of yet unidentified molecules. This laboratory approach has evolved over more than 30 years with much of the earliest work focusing on complex mixtures thought to represent either cometary or interstellar ices. Although those early experiments documented a rich solid-state photo- and radiation chemistry, they revealed few details of reactions for particular molecules, partly due to the multi-component nature of the samples. Since then, model systems have been examined that allow the chemistry of individual species and specific reactions to be probed. Reactions involving most of the smaller astronomical molecules have now been studied and specific processes identified. Current laboratory work suggests that a variety of reactions occur in extraterrestrial ices, including acid-base processes, radical dimerizations, proton transfers, oxidations, reductions, and isomerizations. This workshop presentation will focus on chemical reactions relevant to solar system and interstellar ices. While most of the work will be drawn from that to which the speaker has contributed, results from other laboratories also will be included. Suggestions for future studies will be made, with an emphasis on some present deficiencies. The speaker's work has been generously supported by these NASA research programs: Cassini Data Analysis, Exobiology, Mars Fundamental Research, Outer Planets Research, Planetary Atmospheres, Planetary Geology and Geophysics, and the NASA Astrobiology Institute.

Hudson, Reggie L.↗

NASA NTRS2011

Search for Chemical Biomarkers on Mars Using the Sample Analysis at Mars Instrument Suite on the Mars Science Laboratory

One key goal for the future exploration of Mars is the search for chemical biomarkers including complex organic compounds important in life on Earth. The Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) will provide the most sensitive measurements of the organic composition of rocks and regolith samples ever carried out in situ on Mars. SAM consists of a gas chromatograph (GC), quadrupole mass spectrometer (QMS), and tunable laser spectrometer to measure volatiles in the atmosphere and released from rock powders heated up to 1000 C. The measurement of organics in solid samples will be accomplished by three experiments: (1) pyrolysis QMS to identify alkane fragments and simple aromatic compounds; pyrolysis GCMS to separate and identify complex mixtures of larger hydrocarbons; and (3) chemical derivatization and GCMS extract less volatile compounds including amino and carboxylic acids that are not detectable by the other two experiments.

Glavin, D. P.↗