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NASA NTRSDate not supplied

The Comet Astrobiology Exploration Sample Return (CAESAR) Mission

The Comet Astrobiology Exploration Sample Return (CAESAR) mission will acquire and return to Earth for laboratory analysis a minimum of 80 grams of surface material from the nucleus of comet 67P/Chur-yumov-Gerasimenko (67P). CAESAR will characterize the surface region sampled, preserve the collected sample in a pristine state, and return evolved volatiles by capturing them in a separate gas reservoir. NASA Goddard Space Flight Center provides project management, systems engineering, safety and mission assurance, contamination control, mission operations, and many other important functions. Northrop Grumman Space Systems will build the spacecraft, based on Dawn mission heritage, which like CAESAR, uses solar electric propulsion. CAESAR was selected by for Phase A study in the New Frontiers 4 Competition and will be proposed to New Frontiers 5.Collection of a sample from the surface of comet 67P is facilitated by a set of cameras that together provide images to support sample site selection, perform optical navigation, and document the sample before, during, and after col-lection. The sample is collected at the end of an arm during a 5-second touch-and-go (TAG) maneuver with the Sample Acquisition System (SAS)designed by Honeybee Robotics for the surface properties of comet 67P observed by the Rosetta mission. After sample collection, and while the sample is still cold (< -80°C), the TAG Arm inserts the sample container into the Sample Containment System (SCS) mounted inside the Sample Return Capsule (SRC). The SCS is sealed, preventing the sample from escaping into space. The sample is slowly warmed inside the SCS to enable sublimation of volatiles, which are collected in the Gas Containment System (GCS), a passively cooled gas reservoir. Separating the volatiles from the solid sample protects the solid sample from alteration. Once all sublimated H2O is transferred to the GCS, the GCS is sealed to capture the volatile sit contains, and the SCS is vented to space to maintain the solid sample under vacuum. The SCS vent is closed before Earth entry to prevent atmospheric contamination. Detailed laboratory analyses of the sample from 67P will trace the history of volatile reservoirs, delineate the chemical pathways that led from simple interstellar species to complex molecules, constrain the evolution of the comet, and evaluate the role of comets in delivering water and prebiotic organics to the early Earth. CAESAR will achieve these goals by carrying out coordinated sample analyses that will link macroscopic properties of the comet with microscale mineralogy, chemistry, and isotopic studies of volatiles and solids. Most of the sample (≥75%) will be set aside for analyses by generations of scientists using continually advancing tools and methods, yielding an enduring scientific treasure that only sample return can provide. This presentation will review development conducted during NF4 Phase A and discuss the NF5 mission concept.

A G Hayes↗
NASA NTRS1983

Improving Hydrocarbon Separation In Gas Chromatography

Modified solica spheres enhance chromatographic separation. Commercially available silica spheres are modified by reacting them with molecules containing isocyante and isothiocyanate groups. Applications of surface derivatized spheres that result from reaction include analysis of samples prouced by atmospheric or soil probes.

Pollock, G. E.↗
NASA NTRS2013

Multiphase Transport in Porous Media: Gas-Liquid Separation Using Capillary Pressure Gradients International Space Station (ISS) Flight Experiment Development

Advances in the understanding of multiphase flow characteristics under variable gravity conditions will ultimately lead to improved and as of yet unknown process designs for advanced space missions. Such novel processes will be of paramount importance to the success of future manned space exploration as we venture into our solar system and beyond. In addition, because of the ubiquitous nature and vital importance of biological and environmental processes involving airwater mixtures, knowledge gained about fundamental interactions and the governing properties of these mixtures will clearly benefit the quality of life here on our home planet. The techniques addressed in the current research involving multiphase transport in porous media and gas-liquid phase separation using capillary pressure gradients are also a logical candidate for a future International Space Station (ISS) flight experiment. Importantly, the novel and potentially very accurate Lattice-Boltzmann (LB) modeling of multiphase transport in porous media developed in this work offers significantly improved predictions of real world fluid physics phenomena, thereby promoting advanced process designs for both space and terrestrial applications.This 3-year research effort has culminated in the design and testing of a zero-g demonstration prototype. Both the hydrophilic (glass) and hydrophobic (Teflon) media Capillary Pressure Gradient (CPG) cartridges prepared during the second years work were evaluated. Results obtained from ground testing at 1-g were compared to those obtained at reduced gravities spanning Martian (13-g), Lunar (16-g) and zero-g. These comparisons clearly demonstrate the relative strength of the CPG phenomena and the efficacy of its application to meet NASAs unique gas-liquid separation (GLS) requirements in non-terrestrial environments.LB modeling software, developed concurrently with the zero-g test effort, was shown to accurately reproduce observed CPG driven gas-liquid separation phenomena. The design and fabrication of a micropost plate-lamina Hele-Shaw (HS) cell was performed which served as a computationally attainable geometric structure facilitating direct comparison between physical phenomena observed in our laboratory and the LB software predictions.

Wheeler, Richard R., Jr.↗
NASA NTRS2008

Gas Strut Separation Alternative for Ares I

This paper presents a design alternative and the rationale for a stage separation system based on Metering Adiabatic Gas Struts (MAG Struts) for the Ares 1 launch vehicle. The MAG Strut separation system was proposed as an alternative to the current Ares 1 separation system, which relies on small solid rocket motors to provide the main separation force. This paper will describe technical issues that were addressed during the trade study and present a conceptual design of the strut system that best resolved the issues. Needed development testing and programmatic considerations will be addressed as part of the paper.

Floyd, Brian↗
NASA NTRS1973

Separation of gas from liquid in a two-phase flow system

Separation system causes jets which leave two-phase nozzles to impinge on each other, so that liquid from jets tends to coalesce in center of combined jet streams while gas phase is forced to outer periphery. Thus, because liquid coalescence is achieved without resort to separation with solid surfaces, cycle efficiency is improved.

Hayes, L. G.↗
NASA NTRS1978

Variable-temperature cryogenic trap for the separation of gas mixtures

The paper describes a continuous variable-temperature U-shaped cold trap which can both purify vacuum-line combustion products for subsequent stable isotopic analysis and isolate the methane and ethane constituents of natural gases. The canister containing the trap is submerged in liquid nitrogen, and, as the gas cools, the gas mixture components condense sequentially according to their relative vapor pressures. After the about 12 min required for the bottom of the trap to reach the liquid-nitrogen temperature, passage of electric current through the resistance wire wrapped around the tubing covering the U-trap permits distillation of successive gas components at optimal temperatures. Data on the separation achieved for two mixtures, the first being typical vacuum-line combustion products of geochemical samples such as rocks and the second being natural gas, are presented, and the thermal behavior and power consumption are reported.

Des Marais, D. J.↗
NASA NTRS2012

Microgravity Passive Phase Separator

A new invention disclosure discusses a structure and process for separating gas from liquids in microgravity. The Microgravity Passive Phase Separator consists of two concentric, pleated, woven stainless- steel screens (25-micrometer nominal pore) with an axial inlet, and an annular outlet between both screens (see figure). Water enters at one end of the center screen at high velocity, eventually passing through the inner screen and out through the annular exit. As gas is introduced into the flow stream, the drag force exerted on the bubble pushes it downstream until flow stagnation or until it reaches an equilibrium point between the surface tension holding bubble to the screen and the drag force. Gas bubbles of a given size will form a front that is moved further down the length of the inner screen with increasing velocity. As more bubbles are added, the front location will remain fixed, but additional bubbles will move to the end of the unit, eventually coming to rest in the large cavity between the unit housing and the outer screen (storage area). Owing to the small size of the pores and the hydrophilic nature of the screen material, gas does not pass through the screen and is retained within the unit for emptying during ground processing. If debris is picked up on the screen, the area closest to the inlet will become clogged, so high-velocity flow will persist farther down the length of the center screen, pushing the bubble front further from the inlet of the inner screen. It is desired to keep the velocity high enough so that, for any bubble size, an area of clean screen exists between the bubbles and the debris. The primary benefits of this innovation are the lack of any need for additional power, strip gas, or location for venting the separated gas. As the unit contains no membrane, the transport fluid will not be lost due to evaporation in the process of gas separation. Separation is performed with relatively low pressure drop based on the large surface area of the separating screen. Additionally, there are no moving parts, and there are no failure modes that involve fluid loss. A patent application has been filed.

Paragano, Matthew↗
NASA NTRS2002

Membrane Separation Processes at Low Temperatures

The primary focus of Kennedy Space Center's gas separation activities has been for carbon dioxide, nitrogen, and argon used in oxygen production technologies for Martian in-situ resource utilization (ISRU) projects. Recently, these studies were expanded to include oxygen for regenerative life support systems. Since commercial membrane systems have been developed for separation of carbon dioxide, nitrogen, and oxygen, initially the studies focused on these membrane systems, but at lower operating temperatures and pressures. Current investigations art examining immobilized liquids and solid sorbents that have the potential for higher selectivity and lower operating temperatures. The gas separation studies reported here use hollow fiber membranes to separate carbon dioxide, nitrogen, and argon in the temperature range from 230 to 300 K. Four commercial membrane materials were used to obtain data at low feed and permeate pressures. These data were used with a commercial solution-diffusion modeling tool to design a system to prepare a buffer gas from the byproduct of a process to capture Martian carbon dioxide. The system was designed to operate, at 230 K with a production rate 0.1 sLpm; Feed composition 30% CO2, 44% N2, and 26% Ar; Feed pressure 104 kPa (780); and Permeate pressure 1 kPa (6 torr); Product concentration 600 ppm CO2. This new system was compared with a similar system designed to operate at ambient temperatures (298 K). The systems described above, along with data, test apparatus, and models are presented.

Parrish, Clyde↗
NASA NTRS1992

The separation between gas and dust filaments at the edge of the expanding shell in Eridanus

Observations obtained from IRAS for a 120 sq deg region at the boundary of a large expanding shell in Eridanus are presented. It is found that the separation between the structures in the H I and IR emission is not due to a transition of the gas into molecular hydrogen at the location of the IR filaments. The molecular hydrogen column density of these filaments is at least two orders of magnitude below what is typically seen in high-latitude molecular clouds. As the H I and dust in this region are associated with a large expanding shell (or superbubble), the action of shocks and radiation fields may be responsible for the separations of gas and dust. Unless the gas and dust structures are resolved and lie in a favorable viewing geometry, the effect tends to be hidden. The results indicate that it is not always evident, from observations with spatial resolutions coarser than a few arcminutes, how interstellar gas and dust are related.

Verschuur, G. L.↗
NASA NTRS1984

Gas chromatographic separation of nitrogen, oxygen, argon, and carbon monoxide using custom-made porous polymers from high purity divinylbenzene

Existing porous polymers were surveyed for their ability to separate the subject gases. Certain products that showed more promise than others were synthesized and the existing synthetic procedures studied and modified to produce new polymers with enhanced ability to separate the subject gases. Evaluation of the porous polymers was carried out practically by gas chromatography at ambient temperature. The modified synthetic procedures were somewhat simpler than the originals. The new porous polymers made with high purity divinylbenzene enabled use of shorter columns to obtain the separations desired.

Pollock, G. E.↗
NASA NTRS1964

Helium tube separates nitrogen gas from liquid nitrogen

To prevent a boiloff problem, liquid nitrogen flowing from a storage tank to a container, is separated into liquid and gaseous components. This is accomplished by centrifugal and venting action, using a section of perforated helical aluminum tubing.

Stephens, J. B.↗
NASA NTRS2009

Amorphous Silk Fibroin Membranes for Separation of CO2

Amorphous silk fibroin has shown promise as a polymeric material derivable from natural sources for making membranes for use in removing CO2 from mixed-gas streams. For most applications of silk fibroin, for purposes other than gas separation, this material is used in its highly crystalline, nearly natural form because this form has uncommonly high tensile strength. However, the crystalline phase of silk fibroin is impermeable, making it necessary to convert the material to amorphous form to obtain the high permeability needed for gas separation. Accordingly, one aspect of the present development is a process for generating amorphous silk fibroin by treating native silk fibroin in an aqueous methanol/salt solution. The resulting material remains self-standing and can be prepared as thin film suitable for permeation testing. The permeability of this material by pure CO2 has been found to be highly improved, and its mixed-gas permeability has been found to exceed the mixed-gas permeabilities of several ultrahigh-CO2-permeable synthetic polymers. Only one of the synthetic polymers poly(trimethylsilylpropyne) [PTMSP] may be more highly permeable by CO2. PTMSP becomes unstable with time, whereas amorphous silk should not, although at the time of this reporting this has not been conclusively proven.

Aberg, Christopher M.↗
NASA NTRS1992

Modeling of membrane processes for air revitalization and water recovery

Gas-separation and reverse-osmosis membrane models are being developed in conjunction with membrane testing at NASA JSC. The completed gas-separation membrane model extracts effective component permeabilities from multicomponent test data, and predicts the effects of flow configuration, operating conditions, and membrane dimensions on module performance. Variable feed- and permeate-side pressures are considered. The model has been applied to test data for hollow-fiber membrane modules with simulated cabin-air feeds. Results are presented for a membrane designed for air drying applications. Extracted permeabilities are used to predict the effect of operating conditions on water enrichment in the permeate. A first-order reverse-osmosis model has been applied to test data for spiral wound membrane modules with a simulated hygiene water feed. The model estimates an effective local component rejection coefficient under pseudosteady-state conditions. Results are used to define requirements for a detailed reverse-osmosis model.

Lange, Kevin E.↗
NASA NTRS1981

Noble-gas-rich separates from the Allende meteorite

Predominantly carbonaceous HF/HCl-resistant residues from the Allende meteorite are studied. Samples are characterized by SEM/EDXA, X-ray diffraction, INAA, C, S, H, N, and noble gas analyses. Isotopic data for carbon show variations no greater than 5%, while isotopic data from noble gases confirm previously established systematics. Noble gas abundances correlate with those of C and N, and concomitant partial loss of C and normal trapped gas occur during treatments with oxidizing acids. HF/HCl demineralization of bulk meteorite results in similar fractional losses of C and trapped noble gases, which leads to the conclusion that various macromolecular carbonaceous substances serve as the main host phase for normal trapped noble gases and anomalous gases in acid-resistant residues, and as the carrier of the major part of trapped noble gases lost during HF/HCl demineralization. Limits on the possible abundances of dense mineralic host phases in the residues are obtained, and considerations of the nucleogenetic origin for CCF-XE indicate that carbonaceous host phases and various forms of organic matter in carbonaceous meteorites may have a presolar origin.

Ott, U.↗
NASA NTRS2015

The Two-Phase Flow Separator Experiment Breadboard Model: Reduced Gravity Aircraft Results

Life support systems in space depend on the ability to effectively separate gas from liquid. Passive cyclonic phase separators use the centripetal acceleration of a rotating gas-liquid mixture to carry out phase separation. The gas migrates to the center, while gas-free liquid may be withdrawn from one of the end plates. We have designed, constructed and tested a breadboard that accommodates the test sections of two independent principal investigators and satisfies their respective requirements, including flow rates, pressure and video diagnostics. The breadboard was flown in the NASA low-gravity airplane in order to test the system performance and design under reduced gravity conditions.

phase separation↗
NASA NTRS2013

Ongoing Development of a Series Bosch Reactor System

Future manned missions to deep space or planetary surfaces will undoubtedly require highly robust, efficient, and regenerable life support systems that require minimal consumables. To meet this requirement, NASA continues to explore a Bosch‐based carbon dioxide reduction system to recover oxygen from CO2. In order to improve the equivalent system mass of Bosch systems, we seek to design and test a "Series Bosch" system in which two reactors in series are optimized for the two steps of the reaction, as well as to explore the use of in situ materials as carbon deposition catalysts. Here we report recent developments in this effort including assembly and initial testing of a Reverse Water‐Gas Shift reactor (RWGSr) and initial testing of two gas separation membranes. The RWGSr was sized to reduce CO2 produced by a crew of four to carbon monoxide as the first stage in a Series Bosch system. The gas separation membranes, necessary to recycle unreacted hydrogen and CO2, were similarly sized. Additionally, we report results of preliminary experiments designed to determine the catalytic properties of Martian and Lunar regolith simulant for the carbon deposition step.

Abney, Morgan↗
NASA NTRS2013

Ongoing Development of a Series Bosch Reactor System

Future manned missions to deep space or planetary surfaces will undoubtedly incorporate highly robust, efficient, and regenerable life support systems that require minimal consumables. To meet this requirement, NASA continues to explore a Bosch-based carbon dioxide reduction system to recover oxygen from CO2. In order to improve the equivalent system mass of Bosch systems, we seek to design and test a "Series Bosch" system in which two reactors in series are optimized for the two steps of the reaction, as well as to explore the use of in situ materials as carbon deposition catalysts. Here we report recent developments in this effort including assembly and initial testing of a Reverse Water-Gas Shift reactor (RWGSr) and initial testing of two gas separation membranes. The RWGSr was sized to reduce CO2 produced by a crew of four to carbon monoxide as the first stage in a Series Bosch system. The gas separation membranes, necessary to recycle unreacted hydrogen and CO2, were similarly sized. Additionally, we report results of preliminary experiments designed to determine the catalytic properties of Martian regolith simulant for the carbon formation step.

Abney, Morgan B↗