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NASA NTRS2005

Measurements of Trace Gases Using a Tunable Diode Laser

This report is the final report for "Measurements of Trace Gases Using a Tunable Diode Laser." The tasks outlined in the proposal are listed below with a brief comment. The publications and the conference presentations are listed. Finally, the important publications are attached. The Cooperative Agreement made possible a research effort to produce high- precision and high-accuracy in-situ measurements of carbon monoxide, methane and nitrous oxide on the WB-57 during the CRYSTAL-FACE and pre-AVE field campaigns and to analyze these measurements. These measurements of CO and CH4 were of utmost importance to studies of the radiative effects of clouds. Some important results of the CRYSTAL-FACE program were contained in two scientific papers (attached). This Cooperative Agreement allowed the participation of the Argus instrument in the program and the analysis of the data.

Jost, Hans-Juerg↗

NASA NTRS2005

Precision ADCS of a spinning spacecraft for the Mars Aeronomy Explorer Mission

This paper discusses a precision attitude and control technique for meeting these requirements utilizing a similar architecture that was adopted for the Laboratory of Atmospheric and Space Physics (LASP) SNOE (Student Nitrous Oxide Explorer) spinning spacecraft; SNOE has been operating with its ADCS architecture in low earth orbit (LEO) for over two years.

Mars Aeronomy Explorer (MAX)↗

NASA NTRS2006

Early Validation Analyses of Atmospheric Profiles from EOS MLS on the Aura Satellite

We present results of early validation studies using retrieved atmospheric profiles from the Earth Observing System Microwave Limb Sounder (MLS) instrument on the Aura satellite. 'Global' results are presented for MLS measurements of atmospheric temperature, ozone, water vapor, hydrogen chloride, nitrous oxide, nitric acid, and carbon monoxide, with a focus on the January-March 2005 time period. These global comparisons are made using long-standing global satellites and meteorological datasets, as well as some measurements from more recently launched satellites. Comparisons of MLS data with measurements from the Ft. Sumner, NM, September 2004 balloon flights are also presented. Overall, good agreeement is obtained, often within 5% to 10%, but we point out certain issues to resolve and some larger systematic differences; some artifacts in the first publicly released MLS (version 1.5) dataset are noted.We comment briefly on future plans for validation and software improvements.

Atmospheric retrievals↗

NASA NTRS2010

Nitrous Oxide/Paraffin Hybrid Rocket Engines

Nitrous oxide/paraffin (N2OP) hybrid rocket engines have been invented as alternatives to other rocket engines especially those that burn granular, rubbery solid fuels consisting largely of hydroxyl- terminated polybutadiene (HTPB). Originally intended for use in launching spacecraft, these engines would also be suitable for terrestrial use in rocket-assisted takeoff of small airplanes. The main novel features of these engines are (1) the use of reinforced paraffin as the fuel and (2) the use of nitrous oxide as the oxidizer. Hybrid (solid-fuel/fluid-oxidizer) rocket engines offer advantages of safety and simplicity over fluid-bipropellant (fluid-fuel/fluid-oxidizer) rocket en - gines, but the thrusts of HTPB-based hybrid rocket engines are limited by the low regression rates of the fuel grains. Paraffin used as a solid fuel has a regression rate about 4 times that of HTPB, but pure paraffin fuel grains soften when heated; hence, paraffin fuel grains can, potentially, slump during firing. In a hybrid engine of the present type, the paraffin is molded into a 3-volume-percent graphite sponge or similar carbon matrix, which supports the paraffin against slumping during firing. In addition, because the carbon matrix material burns along with the paraffin, engine performance is not appreciably degraded by use of the matrix.

Zubrin, Robert↗

NASA NTRS2010

More About N2O-Based Propulsion and Breathable-Gas Systems

A concept was evaluated of using nitrous oxide as (1) a monopropellant in thrusters for space suits and spacecraft and (2) a source of breathable gas inside space suits and spacecraft, both by exploiting the controlled decomposition of N2O into N2 and O2. Relative to one prior monopropellant hydrazine, N2O is much less toxic, yet offers comparable performance. N2O can be stored safely as a liquid at room temperature and unlike another prior monopropellant hydrogen peroxide does not decompose spontaneously. A prototype N2O-based thruster has been demonstrated. It has also been proposed to harness N2O-based thrusters for generating electric power and to use the N2 + O2 decomposition product as a breathable gas. Because of the high performance, safety, and ease of handling of N2O, it can be expected to be economically attractive to equip future spacecraft and space suits with N2O-based thrusters and breathable-gas systems.

Zubrin, Robert↗

NASA NTRS2009

Aerojet - AJ10-137 Apollo Service Module Engine

The general configuration of the SPS engine was 20,000 pounds of thrust, with a chamber pressure of 100 psi and specific impulse (Isp) of 314.5. The very large nozzle had an area ratio of 62.5:1 (exit area to throat area). The propellants were nitrogen tetroxide (also known as N2O4 and nitrous oxide) and A-50. A-50 was a hydrazine family fuel. Aerojet developed it for the Titan Missile Program when they went with Titan II, to store it in the launch silos. They wanted the highest performance they could get. N2H4 was just pure hydrazine, which doesn't take low temperature very well. In fact, it freezes about like water. We started adding unsymmetrical-dimethylhydrazine (UDMH) to the hydrazine until such time as it would meet the environmental specifications the Air Force needed for Titan II. It turned out it s roughly a fifty-fifty mix. We still had to be careful with that fuel because the two fluids didn't mix very well chemically. We had to spray the two fluids through some special nozzles to get them to emulsify with each other into a single fluid. If we ever got it too cold or froze it, the hydrazine separated back out. Then, if we tried to run the engine, things could go boom in the night. The inlet pressure was only 165 pounds per square inch absolute (psia), but we needed at least forty psi pressure drop across the injector just to get some kind of stable flow. It was a whole new game for some of us. We didn't have much supply pressure to work with. It had the aluminum injector to keep the weight down. That was a couple feet in diameter, and we didn't have a lot of propellant to cool it. In fact, we had to use both propellants to keep the injector cool. There were twenty-two ring channels in the injector. Specification required 750 seconds duration, or fifty engine restarts during a flight. There were several first flight things we accomplished with the engine. It was the first ablative thrust chamber of any size to fly. (See Slide 6, Appendix G) There were no liners in it. It was just straight ablative material. It took us a while to figure that out. It was a throat-gimbaled engine, and it was the first engine to fly with columbium (also known as niobium, used as an alloying element in steels and superalloys) in the nozzle.

Boyce, Clay↗

NASA NTRS2010

Modeling the Frozen-In Anticyclone in the 2005 Arctic Summer Stratosphere

Immediately following the breakup of the 2005 Arctic spring stratospheric vortex, a tropical air mass, characterized by low potential vorticity (PV) and high nitrous oxide (N2O), was advected poleward and became trapped in the easterly summer polar vortex. This feature, known as a "Frozen-In Anticyclone (FrIAC)", was observed in Earth Observing System (EOS) Aura Microwave Limb Sounder (MLS) data to span the potential temperature range from approximately 580 to 1100 K (approximately 25 to 40 km altitude) and to persist from late March to late August 2005. This study compares MLS N2O observations with simulations from the Global Modeling Initiative (GMI) chemistry and transport model, the GEOS-5/MERRA Replay model, and the VanLeer Icosahedral Triangular Advection isentropic transport model to elucidate the processes involved in the lifecycle of the FrIAC which is here divided into three distinct phases. During the "spin-up phase" (March to early April), strong poleward flow resulted in a tight isolated anticyclonic vortex at approximately 70-90 deg N, marked with elevated N2O. GMI, Replay, and VITA all reliably simulted the spin-up of the FrIAC, although the GMI and Replay peak N2O values were too low. The FrIAC became trapped in the developing summer easterly flow and circulated around the polar region during the "anticyclonic phase" (early April to the end of May). During this phase, the FrIAC crossed directly over the pole between the 7th and 14th of April. The VITA and Replay simulations transported the N2O anomaly intact during this crossing, in agreement with MLS, but unrealistic dispersion of the anomaly occurred in the GMI simulation due to excessive numerical mixing of the polar cap. The vortex associated with the FrIAC was apparently resistant to the weak vertical hear during the anticyclonic phase, and it thereby protected the embedded N20 anomaly from stretching. The vortex decayed in late May due to diabatic processes, leaving the N2O anomaly exposed to horizontal and vertical wind shears during the "shearing phase" (June to August). The observed lifetime of the FrIAC during this phase is consistent with time-scales calculated from the ambient horizontal and vertical wind shear. Replay maintained the horizontal structure of the N2O anomaly similar to NILS well into August. The VITA simulation also captured the horizontal structure of the FrIAC during this phase, but VITA eventually developed fine-scale N2O structure not observed in MLS data.

Allen, D. R.↗

NASA NTRS2012

Miniaturized Hollow-Waveguide Gas Correlation Radiometer (GCR) for Trace Gas Detection in the Martian Atmosphere

Gas correlation radiometry (GCR) has been shown to be a sensitive and versatile method for detecting trace gases in Earth's atmosphere. Here, we present a miniaturized and simplified version of this instrument capable of mapping multiple trace gases and identifying active regions on the Mars surface. Reduction of the size and mass of the GCR instrument has been achieved by implementing a lightweight, 1 mm inner diameter hollow-core optical fiber (hollow waveguide) for the gas correlation cell. Based on a comparison with an Earth orbiting CO2 gas correlation instrument, replacement of the 10 meter mUltipass cell with hollow waveguide of equivalent pathlength reduces the cell mass from approx 150 kg to approx 0.5 kg, and reduces the volume from 1.9 m x 1.3 m x 0.86 m to a small bundle of fiber coils approximately I meter in diameter by 0.05 m in height (mass and volume reductions of >99%). This modular instrument technique can be expanded to include measurements of additional species of interest including nitrous oxide (N2O), hydrogen sulfide (H2S), methanol (CH3OH), and sulfur dioxide (SO2), as well as carbon dioxide (CO2) for a simultaneous measure of mass balance.

Wilson, Emily L.↗

NASA NTRS2012

Miniaturized Gas Correlation Radiometer for the Detection of Trace Gases in the Martian Atmosphere

We present a miniaturized and simplified version of a gas correlation radiometer (GCR) capable of simultaneously mapping multiple trace gases and identifying active regions on the Mars surface. Gas correlation radiometry (GCR) has been shown to be a sensitive and versatile method for detecting trace gases in Earth's atmosphere. Reduction of the size and mass of the GCR was achieved by implementing compact, light-weight 1 mm inner diameter hollow-core optical fibers (hollow waveguides) as the gas correlation cells. In a comparison with an Earth orbiting CO2 GCR instrument, exchanging the 10 m multipass cells with hollow waveguide gas correlation cells of equivalent path length reduces the mass from approximately 150 kg to approximately 0.5 kg, and reduces the volume from 1.9 m x 1.3 m x 0.86 m to a small bundle of fiber coils approximately 1 meter in diameter by 0.05 m in height (mass and volume reductions of greater than 99%). A unique feature of this instrument is its stackable module design, with a single module for each trace gas. Each of the modules is self-contained, and fundamentally identical; differing by the bandpass filter wavelength range and gas mixtures inside the hollow-waveguide absorption cells. The current configuration contains four stacked modules for simultaneous measurements of methane (CH4), formaldehyde (H2CO), water vapor (H2O), and deuterated water vapor (HDO) but could easily be expanded to include measurements of additional species of interest including nitrous oxide (N2O), hydrogen sulfide (H2S), methanol (CH3OH), and sulfur dioxide (SO2), as well as carbon dioxide (CO2) for a simultaneous measure of mass balance. Preliminary results indicate that a 1 ppb detection limit is possible for both formaldehyde and methane with one second of averaging. Using non-optimized components, we have demonstrated an instrument sensitivity equivalent to approximately 30 ppb for formaldehyde, and approximately 500 ppb for methane. We expect custom bandpass filters and 6 m long waveguides to significantly improve these promising results. Ongoing testing is being conducted on water vapor and deuterated water vapor.

Melroy, Hilary R.↗

NASA NTRS2012

The Multiple Use Plug Hybrid for NanoSats (MUPHyN) Miniature Thruster

The Multiple Use Plug Hybrid (for) Nanosats is a prototype thruster is being developed to fill a niche application for NanoSat-scale spacecraft propulsion. When fully developed, the MUPHyN thruster will provide an effective and low-risk propulsive capability that could enable multiple NanoSats to be independently re-positioned after deployment from a parent launch vehicle. Because the environmentally benign, chemically-stable propellants are mixed only within the combustion chamber after ignition and the flow rate of the fuel is determined by a pyrolysis mechanism that is nearly independent of pressure or fuel grain defects, the system is inherently safe and can be piggy-backed near a secondary payload with little or no overall mission risk increase to the primary payload. The MUPHyN thruster uses safe-handling and inexpensive nitrous oxide (N2O) and acrylonitrile-butadiene-styrene (ABS) as propellants. Fused Deposition Modeling (FDM), a direct digital manufacturing process, is used to fabricate short-form-factor solid fuel grains with multiple helical combustion ports from ABS thermoplastic. This manufacturing process allows for the rapid development and manufacture of complex fuel grain geometries that are not possible to extrude or cast using conventional methods. This technology enables the construction of fuel grains with length-to-diameter ratios appropriate for incorporation into CubeSats while maintaining high surface areas and regression rates that allow the system to maintain a near optimal oxidizer to fuel ratio. The MUPHyN system provides attitude control torques by using secondary-injection thrust vectoring on a truncated aerospike nozzle. This configuration allows large impulse delta V burns and small impulse attitude control firings to be performed with the same system. To ensure survivability during extend duration burns, the MUPHyN incorporates a novel regenerative cooling design where the N2O oxidizer flows through a cooling path embedded in the aerospike nozzle before being injected into the combustion chamber near the nozzle base.

Eilers, Shannon D.↗

NASA NTRS2012

NASA Environmentally Responsible Aviation Projects Propulsion Technology Phase I Overview and Highlights of Accomplishments

The NASA Environmentally Responsible Aviation (ERA) Project is focused on developing and demonstrating integrated systems technologies to TRL 4-6 by 2020 that enable reduced fuel burn, emissions, and noise for futuristic air vehicles. The specific goals aim to simultaneously reduce fuel burn by 50%, reduce Landing and Take-off Nitrous Oxides emissions by 75% relative to the CAEP 6 guidelines, and reduce cumulative noise by 42 Decibels relative to the Stage 4 guidelines. These goals apply to the integrated vehicle and propulsion system and are based on a reference mission of 3000nm flight of a Boeing 777-200 with GE90 engines. This paper will focus primarily on the ERA propulsion technology portfolio, which consists of advanced combustion, propulsor, and core technologies to enable these integrated air vehicle systems goals. An overview of the ERA propulsion technologies will be described and highlights of the results obtained during the first phase of ERA will be presented.

jet propulsion↗

NASA NTRS2013

Net Influence of an Internally Generated Guasi-biennial Oscillation on Modelled Stratospheric Climate and Chemistry

A Goddard Earth Observing System Chemistry- Climate Model (GEOSCCM) simulation with strong tropical non-orographic gravity wave drag (GWD) is compared to an otherwise identical simulation with near-zero tropical non-orographic GWD. The GEOSCCM generates a quasibiennial oscillation (QBO) zonal wind signal in response to a tropical peak in GWD that resembles the zonal and climatological mean precipitation field. The modelled QBO has a frequency and amplitude that closely resembles observations. As expected, the modelled QBO improves the simulation of tropical zonal winds and enhances tropical and subtropical stratospheric variability. Also, inclusion of the QBO slows the meridional overturning circulation, resulting in a generally older stratospheric mean age of air. Slowing of the overturning circulation, changes in stratospheric temperature and enhanced subtropical mixing all affect the annual mean distributions of ozone, methane and nitrous oxide. Furthermore, the modelled QBO enhances polar stratospheric variability in winter. Because tropical zonal winds are easterly in the simulation without a QBO, there is a relative increase in tropical zonal winds in the simulation with a QBO. Extratropical differences between the simulations with and without a QBO thus reflect the westerly shift in tropical zonal winds: a relative strengthening of the polar stratospheric jet, polar stratospheric cooling and a weak reduction in Arctic lower stratospheric ozone.

stratosphere↗

NASA NTRS2012

Overview of the NASA Environmentally Responsible Aviation Project's Propulsion Technology Portfolio

aircraft engines↗

NASA NTRS2014

Surface Nitrification: A Major Uncertainty in Marine N2O Emissions

The ocean is responsible for up to a third of total global nitrous oxide (N2O) emissions, but uncertainties in emission rates of this potent greenhouse gas are high (approaching 100%). Here we use a marine biogeochemical model to assess six major uncertainties in estimates of N2O production, thereby providing guidance in how future studies may most effectively reduce uncertainties in current and future marine N2O emissions. Potential surface N2O production from nitrification causes the largest uncertainty in N2O emissions (estimated up to approximately 1.6 Tg N/yr (sup -1) or 48% of modeled values), followed by the unknown oxygen concentration at which N2O production switches to N2O consumption (0.8 Tg N/yr (sup -1)or 24% of modeled values). Other uncertainties are minor, cumulatively changing regional emissions by less than 15%. If production of N2O by surface nitrification could be ruled out in future studies, uncertainties in marine N2O emissions would be halved.

N2O↗

NASA NTRS2014

Climate Change in New York State Updating the 2011 ClimAID Climate Risk Information Supplement to NYSERDA Report 11-18 (Responding to Climate Change in New York State)

In its 2013-2014 Fifth Assessment Report (AR5), the Intergovernmental Panel on Climate Change (IPCC) states that there is a greater than 95 percent chance that rising global average temperatures, observed since the mid-20th century, are primarily due to human activities. As had been predicted in the 1800s, the principal driver of climate change over the past century has been increasing levels of atmospheric greenhouse gases associated with fossil-fuel combustion, changing land-use practices, and other human activities. Atmospheric concentrations of the greenhouse gas carbon dioxide are now approximately 40 percent higher than in preindustrial times. Concentrations of other important greenhouse gases, including methane and nitrous oxide, have increased rapidly as well.

New York↗

NASA NTRS2013

Miniaturized Laser Heterodyne Radiometer for Measurements of CO2 in the Atmospheric Column

We have developed a low-cost, miniaturized laser heterodyne radiometer for highly sensitive measurements of carbon dioxide (CO2) in the atmospheric column. In this passive design, sunlight that has undergone absorption by CO2 in the atmosphere is collected and mixed with continuous wave laser light that is step-scanned across the absorption feature centered at 1,573.6 nm. The resulting radio frequency beat signal is collected as a function of laser wavelength, from which the total column mole fraction can be de-convolved. We are expanding this technique to include methane (CH4) and carbon monoxide (CO), and with minor modifications, this technique can be expanded to include species such as water vapor (H2O) and nitrous oxide (N2O).

CO2↗

NASA NTRS2015

Analysis of Process Gases and Trace Contaminants in Membrane-Aerated Gaseous Effluent Streams.

In membrane-aerated biofilm reactors (MABRs), hollow fibers are used to supply oxygen to the biofilms and bulk fluid. A pressure and concentration gradient between the inner volume of the fibers and the reactor reservoir drives oxygen mass transport across the fibers toward the bulk solution, providing the fiber-adhered biofilm with oxygen. Conversely, bacterial metabolic gases from the bulk liquid, as well as from the biofilm, move opposite to the flow of oxygen, entering the hollow fiber and out of the reactor. Metabolic gases are excellent indicators of biofilm vitality, and can aid in microbial identification. Certain gases can be indicative of system perturbations and control anomalies, or potentially unwanted biological processes occurring within the reactor. In confined environments, such as those found during spaceflight, it is important to understand what compounds are being stripped from the reactor and potentially released into the crew cabin to determine the appropriateness or the requirement for additional mitigation factors. Reactor effluent gas analysis focused on samples provided from Kennedy Space Center's sub-scale MABRs, as well as Johnson Space Center's full-scale MABRs, using infrared spectroscopy and gas chromatography techniques. Process gases, such as carbon dioxide, oxygen, nitrogen, nitrogen dioxide, and nitrous oxide, were quantified to monitor reactor operations. Solid Phase Microextraction (SPME) GC-MS analysis was used to identify trace volatile compounds. Compounds of interest were subsequently quantified. Reactor supply air was examined to establish target compound baseline concentrations. Concentration levels were compared to average ISS concentration values and/or Spacecraft Maximum Allowable Concentration (SMAC) levels where appropriate. Based on a review of to-date results, current trace contaminant control systems (TCCS) currently on board the ISS should be able to handle the added load from bioreactor systems without the need for secondary mitigation.

Gaseous Effluent Streams↗

NASA NTRS2014

Assessing Non-CO2 Climate-Forcing Emissions and Mitigation in Sub-Saharan Africa

There are few direct measurements of anthropogenic climate-forcing emissions in Africa, making it difficult to accurately assess current emissions and to anticipate changes in future emissions. Emissions databases suggest that sub-Saharan Africa (SSA), home to less than 15 of the world's population, is responsible for 11 of anthropogenic methane (CH4) and 18 of anthropogenic nitrous oxide (N2O) emissions globally, though this includes substantial emissions from biomass burning that would occur in the absence of contemporary anthropogenic activity, and which may be over-estimated. SSA is also an important source of precursors to the greenhouse gas tropospheric ozone, and of mineral dust, which has a range of impacts on climate. Eliminating food insecurity and poverty is likely to take priority over greenhouse gas mitigation in the region, so innovations in mitigation must focus on ways to reduce emissions as an ancillary benefit of improving livelihoods.

Africa↗