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NASA NTRS2012

Laser Time-of-Flight Mass Spectrometry for Future In Situ Planetary Missions

Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) is a versatile, low-complexity instrument class that holds significant promise for future landed in situ planetary missions that emphasize compositional analysis of surface materials. Here we describe a 5kg-class instrument that is capable of detecting and analyzing a variety of analytes directly from rock or ice samples. Through laboratory studies of a suite of representative samples, we show that detection and analysis of key mineral composition, small organics, and particularly, higher molecular weight organics are well suited to this instrument design. A mass range exceeding 100,000 Da has recently been demonstrated. We describe recent efforts in instrument prototype development and future directions that will enhance our analytical capabilities targeting organic mixtures on primitive and icy bodies. We present results on a series of standards, simulated mixtures, and meteoritic samples.

Getty, S. A.↗
NASA NTRS2012

OASIS: Organics Analyzer for Sampling Icy Surfaces

Liquid chromatography mass spectrometry (LC-MS) is a well established laboratory technique for detecting and analyzing organic molecules. This approach has been especially fruitful in the analysis of nucleobases, amino acids, and establishing chirol ratios [1 -3]. We are developing OASIS, Organics Analyzer for Sampling Icy Surfaces, for future in situ landed missions to astrochemically important icy bodies, such as asteroids, comets, and icy moons. The OASIS design employs a microfabricated, on-chip analytical column to chromatographically separate liquid ana1ytes using known LC stationary phase chemistries. The elution products are then interfaced through electrospray ionization (ESI) and analyzed by a time-of-flight mass spectrometer (TOF-MS). A particular advantage of this design is its suitability for microgravity environments, such as for a primitive small body.

Getty, S. A.↗
NASA NTRS2012

Laser Ablation Mass Spectrometer (LAMS) as a Standoff Analyzer in Space Missions for Airless Bodies

A laser ablation mass spectrometer (LAMS) based on a time-of-flight (TOF) analyzer with adjustable drift length is proposed as a standoff elemental composition sensor for space missions to airless bodies. It is found that the use of a retarding potential analyzer in combination with a two-stage reflectron enables LAMS to be operated at variable drift length. For field-free drift lengths between 33 cm to 100 cm, at least unit mass resolution can be maintained solely by adjustment of internal voltages, and without resorting to drastic reductions in sensitivity. Therefore, LAMS should be able to be mounted on a robotic arm and analyze samples at standoff distances of up to several tens of cm, permitting high operational flexibility and wide area coverage of heterogeneous regolith on airless bodies.

Li, X.↗
NASA NTRS2014

Development of Genesis Solar Wind Sample Cleanliness Assessment: Initial Report on Sample 60341 Optical Imagery and Elemental Mapping

Since 2005 the Genesis science team has experimented with techniques for removing the contaminant particles and films from the collection surface of the Genesis fragments. A subset of ~40 samples have been designated as "cleaning matrix" samples. These are small samples to which various cleaning approaches are applied and then cleanliness is assessed optically, by TRXRF, SEM, ToF-SIMS, XPS, ellipsometry or other means [1-9]. Most of these sam-ples remain available for allocation, with cleanliness assessment data. This assessment allows evaluation of various cleaning techniques and handling or analytical effects. Cleaning techniques investigated by the Genesis community include acid/base etching, acetate replica peels, ion beam, and CO2 snow jet cleaning [10-16]. JSC provides surface cleaning using UV ozone exposure and ultra-pure water (UPW) [17-20]. The UPW rinse is commonly used to clean samples for handling debris between processing by different researchers. Optical microscopic images of the sample taken before and after UPW cleaning show what has been added or removed during the cleaning process.

Gonzalez, C. P.↗
NASA NTRS2015

Genesis Solar Wind Collector Cleaning Assessment: Update on 60336 Sample Case Study

To maximize the scientific return of Genesis Solar Wind return mission it is necessary to characterize and remove a crash-derived particle and thin film surface contamination. A small subset of Genesis mission collector fragments are being subjected to extensive study via various techniques. Here we present an update on the sample 60336, a Czochralski silicon (Si-CZ) based wafer from the bulk array (B/C). This sample has undergone multiple cleaning steps (see the table below): UPW spin wash, aggressive chemical cleanings (including aqua regia, hot xylene and RCA1), as well as optical and chemical (EDS, ToF-SIMS) imaging. Contamination appeared on the surface of 60336 after the initial 2007 UPW cleaning. Aqua regia and hot xylene treatment (8/13/2013) did little to remove contaminants. The sample was UPW cleaned for the third time and imaged (9/16/13). The UPW removed the dark stains that were visible on the sample. However, some features, like "the Flounder" (a large, 100 micron feature in Fig. 1b) appeared largely intact, resisting all previous cleaning efforts. These features were likely from mobilized adhesive, derived from the Post-It notes used to stabilize samples for transport from Utah after the hard landing. To remove this contamination, an RCA step 1 organic cleaning (RCA1) was employed. Although we are still uncertain on the nature of the Flounder and why it is resistant to UPW and aqua regia/hot xylene treatment, we have found RCA1 to be suitable for its removal. It is likely that the glue from sticky pads used during collector recovery may have been a source for resistant organic contamination [9]; however [8] shows that UPW reaction with crash-derived organic contamination does not make particle removal more difficult.

Goreva, Y. S.↗
NASA NTRS2016

A Fly-Through Mission Strategy Targeting Peptide as a Signature of Chemical Evolution and Possible Life in Enceladus Plumes

In situ detection of organic molecules in the extraterrestrial environment provides a key step towards better understanding the variety and the distribution of building blocks of life and it may ultimately lead to finding extraterrestrial life within the Solar System. Here we present combined results of two separate experiments that enable us to realize such in situ life signature detection from the deep habitats of the "Ocean World": a hydrothermal reactor experiment simulating complex organic synthesis and a simulated fly-through capture experiment of organic-bearing microparticles using silica aerogels, followed by subsequent analysis. Both experiments employ peptide as a plausible organics existing in Encleadus plume particles produced in its subsurface ocean. Recent laboratory hydrothermal experiments and a theoretical model on silica saturation indicated an on going hydrothermal reactions in subsurface Enceladus ocean. Given the porous chondritic origin of the core, it is likely that organic compounds originated by radiation chemistry such as amino acid precursors could have been provided, leached, and altered through widespread water-rock interactions. By using the same laboratory experimental setup from the latest water-rock interaction study, we performed amino acid polymerization experiments for 144 days and monitored the organic complexity changing over time. So far over 3,000 peaks up to the size of greater than 600 MW were observed through the analysis of capillary electrophoresis time-of-flight mass spectrometry (CE-TOF-MS) with an indication of amino acid derivatives and short peptides. Generally abiotic polymerization of enantiomeric amino acids results in forming stereoisomeric peptides with identical molecular weight and formula as opposed to homochiral biopolymers. Assuming Enceladus plume particles may contain a mixture of stereoisomeric peptides, we were able to distinguish 16 of the 17 stereoisomeric tripeptides as a test sample using capillary electrophoresis (CE) under optimized conditions. We further conducted Enceladus plume fly-through capture experiment by accelerating peptides soaked in rock particles up to a speed of 5.7 km/s and capturing with originally developed hydrophobic silica aerogels. Direct peptide extraction with acetonitrile-water followed by CE analysis led to detection of only but two stereoisomeric acidic peptide peaks, presenting the first run-through hypervelocuty impact sample analysis targeting peptides as key molecule to to understand the ongoing astrobiology on Enceladus.

organic molecules↗
NASA NTRS2017

Controlled Nitric Oxide Production via O(1D) + N2O Reactions for Use in Oxidation Flow Reactor Studies

Oxidation flow reactors that use low-pressure mercury lamps to produce hydroxyl (OH) radicals are an emerging technique for studying the oxidative aging of organic aerosols. Here, ozone (O3) is photolyzed at 254 nm to produce O(1D) radicals, which react with water vapor to produce OH. However, the need to use parts-per-million levels of O3 hinders the ability of oxidation flow reactors to simulate NOx-dependent secondary organic aerosol (SOA) formation pathways. Simple addition of nitric oxide (NO) results in fast conversion of NOx (NO+NO2) to nitric acid (HNO3), making it impossible to sustain NOx at levels that are sufficient to compete with hydroperoxy (HO2) radicals as a sink for organic peroxy (RO2) radicals. We developed a new method that is well suited to the characterization of NOx-dependent SOA formation pathways in oxidation flow reactors. NO and NO2 are produced via the reaction O(1D)+N2O->2NO, followed by the reaction NO+O3->NO2+O2. Laboratory measurements coupled with photochemical model simulations suggest that O(1D)+N2O reactions can be used to systematically vary the relative branching ratio of RO2 +NO reactions relative to RO2 +HO2 and/or RO2+RO2 reactions over a range of conditions relevant to atmospheric SOA formation. We demonstrate proof of concept using high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) measurements with nitrate (NO-3 ) reagent ion to detect gas-phase oxidation products of isoprene and -pinene previously observed in NOx-influenced environments and in laboratory chamber experiments.

Lambe, Andrew↗
NASA NTRS2018

A Compact Two-Step Laser Time-Of-Flight Mass Spectrometer for In Situ Analysis of Planetary Surfaces

Two-step laser mass spectrometry (L2MS) has proved to be a powerful tool for the analysis of aromatic organics in icy planetary simulants, meteorites, asphaltenes on Earth, and returned cometary particles from the Stardust mission. L2MS employs two lasers to separate the desorption and ionization processes of laser desorption ionization into distinct steps. In the first step, an infrared laser desorbs neutrals from a solid sample surface; in the second step, an ultraviolet laser forms molecular ions within the neutral plume through a resonance-enhanced process to minimize fragment at ion of complex species. We have recently demonstrated that the L2MS technique is compatible with a compact TOF-MS that could form the center piece of a future in situ landed planetary mission emphasizing surface chemistry or astrobiology. The increased sensitivity and selectivity offered by this technique has been demonstrated in analyses of various planetary analog mixtures and meteorite powders, and representative results of these analyses will be presented.

Getty, Stephanie A.↗
NASA NTRS2016

Spaceborne Remote Sensing of Aerosol Type: Global Distribution, Model Evaluation and Translation into Chemical Speciation

It is essential to evaluate and refine aerosol classification methods applied to passive satellite remote sensing. We have developed an aerosol classification algorithm (called Specified Clustering and Mahalanobis Classification, SCMC) that assigns an aerosol type to multi-parameter retrievals by spaceborne, airborne or ground-based passive remote sensing instruments [1]. The aerosol types identified by our scheme are pure dust, polluted dust, urban-industrialdeveloped economy, urban-industrialdeveloping economy, dark biomass smoke, light biomass smoke and pure marine. We apply the SCMC method to inversions from the ground-based AErosol RObotic NETwork (AERONET [2]) and retrievals from the space-borne Polarization and Directionality of Earths Reflectances instrument (POLDER, [3]). The POLDER retrievals that we use differ from the standard POLDER retrievals [4] as they make full use of multi-angle, multispectral polarimetric data [5]. We analyze agreement in the aerosol types inferred from both AERONET and POLDER and evaluate GEOS-Chem [6] simulations over the globe. Finally, we use in-situ observations from the SEAC4RS airborne field experiment to bridge the gap between remote sensing-inferred qualitative SCMC aerosol types and their corresponding quantitative chemical speciation. We apply the SCMC method to airborne in-situ observations from the NASA Langley Aerosol Research Group Experiment (LARGE, [7]) and the Differential Aerosol Sizing and Hygroscopicity Spectrometer Probe (DASH-SP, [8]) instruments; we then relate each coarsely defined SCMC type to a sum of percentage of individual aerosol species, using in-situ observations from the Particle Analysis by Laser Mass Spectrometry (PALMS, [9]), the Soluble Acidic Gases and Aerosol (SAGA, [10]), and the High - Resolution Time - of - Flight Aerosol Mass Spectrometer (HR ToF AMS, [11]).

airborne↗
NASA NTRS2018

Characteristics of In Situ Fine Fraction Aerosol Spectra from 300-700 nm Observed Around the Korean Peninsula During KORUS-OC

In situ aerosol extinction and absorption spectra covering the 300-700 nm range at ≤ 1 nm spectral resolution were measured aboard the R/V Onnuri during the Korea U.S. – Ocean Color (KORUS-OC) cruise around the Korean Peninsula from May 21 through June 3, 2016. Total absorption spectra were obtained from aerosols collected on glass fiber filters and subsequently placed in the center of an integrating sphere (Labsphere DRA-CA-30) attached to a dual beam spectrophotometer (Cary 100 Bio UV-Visible Spectrophotometer, 0.2 nm spectral resolution). Absorption spectra from methanol and deionized water extracts of aerosols collected on Teflon filters were measured in a liquid waveguide capillary cell (World Precision Instruments LWCC- 3100, ~0.4 nm spectral resolution). Extinction spectra were measured with a custom built instrument (SpEx, ~0.8 nm spectral resolution). The measurements were obtained at a height of ~10 m above the sea surface with an inlet that limited the measured aerosols to diameters ≤ 1.3 µm. All four sets of spectra exhibit curvature in log-log space with 2nd order polynomials providing a better fit to the measured spectra than power law fits. The deionized water extracts were also analyzed with an ion chromatograph (Dionex ICS-3000 Ion Chromatography System) and with an aerosol mass spectrometer (Aerodyne Research, Inc. HR-ToF High Resolution Aerosol Mass Spectrometer) to examine chemical composition. These data indicate the optical spectra are sensitive to differing chemical properties of the measured ambient aerosols and suggest differing sources and/or atmospheric processes influence the observed optical signatures. The measured suite of spectra are combined to examine the spectral characteristics of single scattering albedo, as well as to examine the contribution of soluble absorbing chromophores to the total absorption spectra. Additional measurements made during the affiliated Korea U.S. - Air Quality (KORUS-AQ) campaign will be used to provide further insight on the observed spectral characteristics.

Jordan, Carolyn E↗
NASA NTRS2019

Advanced Electronics for the SONTRAC Neutron Spectrometer

Solar neutrons are the tell-tale of highly energetic processes (e.g. solar flares) at the Sun in which particle acceleration is taking place over a broad range in energy. Unlike charged radiation, neutrons escape unscathed from the ambient magnetic fields, providing a view of particle acceleration unhindered by the effects of transport. High-energy neutrons are challenging to measure with the traditional double scatter technique based on time-of-flight (ToF). This technique is limited by the finite flight path and active scintillator sizes required by small satellite platforms. The new SOlar Neutron TRACking (SONTRAC) concept, based on scintillating-fiber bundles, will provide high resolution imaging of fast neutrons at energies where the bulk of solar and magnetospheric neutrons resides. Recent development of the new SONTRAC instrument concept's advanced electronics and processing algorithms are presented.

SiPM readout↗
NASA NTRS2019

The Solar Neutron TRACking (SONTRAC) Instrument for the Detection of Fast Neutrons

The detection of fast neutrons has important applications in several fields including solar, Geospace and planetary physics. Neutrons are challenging to detect and measurements of them typically suffer from high background rates. High-energy neutrons (>50 MeV) pose even more challenges, because the traditional double-scatter technique based on a time-of-flight (ToF) measurement is limited by short flight paths and small detector sizes characteristic of small satellite platforms. It is now possible to perform high-energy neutron measurements inside a large monolithic detector by imaging the recoil proton tracks, thus eliminating the need for a measure of the time-of-flight. The concept is based on a spectrometer assembled from numerous thin hydrogenous scintillating fibers that allow ionization track imaging. Fine grained readout is now possible with arrays of1-mm pitch silicon photomultipliers (SiPMs). The Solar Neutron TRACking (SONTRAC) instrument, equipped with scintillating fibers readout with SiPMs sensors, provides high-resolution, fine grained, imaging of fast (between 20-200 MeV) neutron scatters in a compact, low-power design ideal for small satellite(and aircraft) platforms. We discuss below applications of this technology and performance characteristics of the prototype SONTRAC instrument.

de Nolfo, Georgia A.↗
NASA NTRSDate not supplied

Direct Analysis of Early Solar System Aqueous Fluids

We lack fundamental information on early solar system aqueous fluids. Fluid inclusions are present in carbonates, sulfides and halides in astro materials, whose characterization is finally becoming feasible. The ordinary chondrite regolith breccias Monahans 1998 (H5) and Zag (H3-6)contain fluid inclusion-bearing halite (NaCl) crystals dated at~4.5 billion years old. Freezing studies to measure the eutectic temperature demonstrated that the brines likely contain divalent cations(Ca, Mg, Fe). Halite is effective at preservation (at least 250 MY) of organic phases and structures. Thus, compositional data on fluid inclusions in halite will reveal unique information on the origin and activity of aqueous fluids in the early solar system, and interactions with organics. To measure fluid compositions from individual fluid inclusions we performed TOF-SIMS depth profiling a tultra-high vacuum at ~110 Kusing a 30 kVBi+analysis ion beam and a1 kVO2+sputtering ion beam. Halite fluid inclusion FI1 contains H2O, K,Na,Cl and NaCl•2H2O.FI2 contains H2O, K, Na, Cl, Al, Fe,Ca,NaCl•2H2O and C-N-O-H species originating from organic molecules. Mass overlap with NaOH species prevented definitive identification of Cain FI1.

M. E Zolensky↗
NASA NTRSDate not supplied

In Situ Measurements of Ammonia In Plumes Emitted From Wildfires And Agricultural Fires in the US

Emissions of trace gases and particles from fires have a major impact on climate, visibility, air quality, and public health. Biomass burning emissions include reactive nitrogen gases, among which ammonia (NH3) plays a prominent role. NH3 is a short-lived gas that acts as precursor for secondary inorganic aerosols. This process is still poorly constrained in downwind fire plumes. In summer 2019, NASA and NOAA carried out the joint airborne FIREX-AQ (Fire Influence on Regional to global Environments and Air Quality) mission over the continental US to sample plumes from wildfires and agricultural fires. On board the NASA DC-8, we used a modified PTR-ToF-MS instrument for measuring NH3 in situ and at high time resolution. Over the course of the mission, we collected a large set of NH3 data in plumes emitted from fires differing in fuel type and burning stage. Herein, we will present the measured NH3 emissions ratios and factors, compare them with the literature, and investigate the dependence of NH3 emissions on fuel type and burning conditions.

ammonia↗
NASA NTRSDate not supplied

The Solar Neutron TRACking (SONTRAC) Instrument for the Detection of Fast Neutrons

Fast neutrons (energies >0.5 MeV) contribute to the radiation exposure of space hardware and astronaut crew, enable greater understanding of planetary atmospheric and surface compositions and allow unique measurements of solar particle acceleration. Neutrons are challenging to detect and measurements of them typically suffer from high background rates. High energy neutrons (>50 MeV) pose even more challenges, because the traditional double-scatter technique based on a time-of-flight (ToF) measurement. These measurements are challenging due to size constraints on satellites, particularly newer small satellites. The SOlar Neutron TRACking instrument (SONTRAC) is a small satellite neutron detector that utilizes fine-grained scintillating fiber bundles with 1-mm pitch silicon photomultiplier (SiPM) array readout. Signal processing is accomplished with multichannel ASICs. SONTRAC is able to image fast neutron (between 20-200 MeV) scatters in a compact scalable package. We discuss below the numerous applications of this technology and recent progress on the development and performance characteristics of the prototype instrument.

Georgia A de Nolfo↗
NASA NTRSDate not supplied

Direct Measurement of the Composition of Aqueous Fluids from the Parent Body of Asteroid 162173 Ryugu

Imaging using X-ray absorption contrast by synchrotron nano-computed tomography (47.4 nm/voxel, 7keV) of a Ryugu pyrrhotite crystal (C0002-FC012-from the second touch-down site) revealed probable fluid inclusions (Fig. 1A,B) [1]. The inclusions were completely encapsuled in pyrrhotite, suggesting the fluids were trapped in the early stages of crystal growth, and filled with low-Z material. We performed Time-of Flight-Secondary Ion Mass Spectrometry (TOF-SIMS) depth profiling and high-resolution map-ping at -120°C to exposure and measure the composition of the trapped fluids in a frozen state.

M Zolensky↗
NASA NTRSDate not supplied

Update on Measurement of the Composition of Ryugu Fluid Inclusions

Imaging using X-ray absorption contrast by synchrotron nano-computed tomography of a Ryugu pyrrhotite crystal (C0002-FC012 - from the second Hayabusa2 spacecraft touch-down site) revealed probable fluid inclusions in the center of a crystal of pyrrhotite, suggesting the parent fluids were trapped in the early stages of crystal growth on Ryugu’s parent asteroid. We previously described the performance of Time-of Flight-Secondary Ion Mass Spectrometry (TOF-SIMS) depth profiling and high-resolution mapping at -120°C to expose and measure the composition of the trapped fluids in a frozen state in two Ryugu inclusions [1,2]. Here we report results from follow-on measurements of additional inclusions in the same pyrrhotite crystal, and the initial results of measurement of standards. The ultimate goal is to reveal the quantitative composition of the fluids that caused aqueous alteration, in particular the H2O:CO2 ratio, which will also facilitate cosmochemical modeling of the alteration process.

M Zolensky↗
NASA NTRSDate not supplied

Analysis of "Stone" Samples from C-Type Asteroid Ryugu

As a part of activities of initial analysis, we analyzed eighteen Ryugu “stone” samples of 1 ~ 8mm in size: seven stones from the 1st touch down site and eleven from the 2nd touch down site. Ryugu stones were analyzed first using X-rays, UV, visible, near-infrared, mid-infrared, and muon probes for surface reflectance spectra, internal 3D structure and element distribution, crystal structures, and bulk composition of light elements such as C, N, and O. Measurements for magnetic, thermal, and physical properties using some stones were also performed. TOF-SIMS analysis of fluid inclusions as being continued. Small particles separated from some stones were analyzed by IR-CT. Based on 3D-CT images of individual stones, objects of interests were identified, separated by pFIB cutting, and exposed by polishing on the surface of epoxy disks. FE-EPMA/FE-SEM analysis was made on ~40 polished epoxy disks for chemical composition and textural observation. FIB sections and small (~15 μm in size) fragments were separated from polished surface and analyzed by TEM, STXM,XRF, and nano-CT.

T. Nakamura↗