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At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS2022

Compressed CO2 Hard Rock Drill for Mars

We have developed a down-the-hole (DTH) rotary-percussive drill prototype that could operate on compressed Mars atmospheric CO2 gas with a wireline drilling approach. This technology addresses a need for more aggressive sampling and drilling techniques, for both scientific purposes and to obtain In-Situ Resource Utilization (ISRU) resources for future NASA missions and human crew support. Using a spool of lightweight, high-pressure capillary, a DTH drill assembly would be moved in and out of the hole that could be a kilometer or more in depth. The CO2 drill is designed so that Mars atmospheric CO2 could be collected, compressed, and supplied down the hole and routed through microducts, valves, and reservoirs for the purpose of controlling miniature mechanical actuation in the assembly. By using compressed CO2, the drill system avoids the need for heavy electrical cabling and actuator systems or a liquid media for carrying away particulates as is typically used in terrestrial drilling systems. Instead, the liquid CO2 that powers the drill expands to a gas and could be channeled around the drill housing to carry cuttings to be collected in a bailing bucket. Where terrestrial systems often use drill depth vs time as a metric, a Mars drilling system would need to be extremely low mass, but would have no need to perform under tight schedules. In this paper, we will document our trade studies, progression for the design of microduct logic verified through multiple generations of prototypes, and provide predictive performance data on energy consumption, hole depth, and drill time.

Wilcox, Brian↗
NASA NTRS2026

Equivalent System Mass Comparison of ECLSS CO2 Removal Technologies

This project employs equivalent system mass (ESM) analyses to evaluate and compare state-of-the-art spacecraft CO2 removal systems. The ESM methodology converts sizing characteristics such as volume, power, and cooling requirements into a unified metric of mass, allowing for simple quantitative comparison of equipment impacts on a system level. Comparison of six high TRL technologies – the Carbon Dioxide Removal System (CDRS), Thermal Amine Scrubber (TAS), Carbon Dioxide Removal Assembly (CDRA), Four-Bed CO2 Scrubber (4BCO2), CO2 and Humidity Control Swing Bed (CHC), and the Carbon Dioxide Removal by Ionic Liquid Sorbent (CDRILS) – was achieved using an existing ESM spreadsheet tool that formerly ranked such technologies for consideration on Gateway. Fidelity of the tool was increased through revision with the most up-to-date sizing and performance data for each technology. ESM values were then estimated using NASA-supplied Lunar, Martian, and low-Earth orbit habitat infrastructure costs. This paper details the ESM approach used, lists major performance variables for each CO2 removal option, and summarizes conclusions of the technology comparison. The results are intended to act as a guide to assist programs in their selection of CO2 technologies best suited for a specific vehicle or mission.

Madeleine C Oliver↗
NASA NTRS2017

The Effect of the Spin-Forbidden Co((sup 1) Sigma plus) plus O((sup 3) P) Yields CO2 (1 Sigma (sub G) plus) Recombination Reaction on Afterbody Heating of Mars Entry Vehicles

Vibrationally excited CO2, formed by two-body recombination from CO((sup 1) sigma plus) and O((sup 3) P) in the wake behind spacecraft entering the Martian atmosphere reaction, is potentially responsible for the higher than anticipated radiative heating of the backshell, compared to pre-flight predictions. This process involves a spin-forbidden transition of the transient triplet CO2 molecule to the longer-lived singlet. To accurately predict the singlet-triplet transition probability and estimate the thermal rate coefficient of the recombination reaction, ab initio methods were used to compute the first singlet and three lowest triplet CO2 potential energy surfaces and the spin-orbit coupling matrix elements between these states. Analytical fits to these four potential energy surfaces were generated for surface hopping trajectory calculations, using Tully's fewest switches surface hopping algorithm. Preliminary results for the trajectory calculations are presented. The calculated probability of a CO((sup 1) sigma plus) and O((sup 3) P) collision leading to singlet CO2 formation is on the order of 10 (sup -4). The predicted flowfield conditions for various Mars entry scenarios predict temperatures in the range of 1000 degrees Kelvin - 4000 degrees Kelvin and pressures in the range of 300-2500 pascals at the shoulder and in the wake, which is consistent with a heavy-particle collision frequency of 10 (sup 6) to 10 (sup 7) per second. Owing to this low collision frequency, it is likely that CO((sup 1) sigma plus) molecules formed by this mechanism will mostly be frozen in a highly nonequilibrium rovibrational energy state until they relax by photoemission.

CO2 recombination↗
NASA NTRS2012

Co2(nu2)-o Quenching Rate Coefficient Derived from Coincidental SABER-TIMED and Fort Collins Lidar Observations of the Mesosphere and Lower Thermosphere

Among the processes governing the energy balance in the mesosphere and lower thermosphere (MLT), the quenching of CO2(nu2) vibrational levels by collisions with O atoms plays an important role. However, there is a factor of 3-4 discrepancy between the laboratory measurements of the CO2-O quenching rate coefficient, k(sub VT),and its value estimated from the atmospheric observations. In this study, we retrieve k(sub VT) in the altitude region85-105 km from the coincident SABER/TIMED and Fort Collins sodium lidar observations by minimizing the difference between measured and simulated broadband limb 15 micron radiation. The averaged k(sub VT) value obtained in this work is 6.5 +/- 1.5 X 10(exp -12) cubic cm/s that is close to other estimates of this coefficient from the atmospheric observations.However, the retrieved k(sub VT) also shows altitude dependence and varies from 5.5 1 +/-1 10(exp -12) cubic cm/s at 90 km to 7.9 +/- 1.2 10(exp -12) cubic cm/s at 105 km. Obtained results demonstrate the deficiency in current non-LTE modeling of the atmospheric 15 micron radiation, based on the application of the CO2-O quenching and excitation rates, which are linked by the detailed balance relation. We discuss the possible model improvements, among them accounting for the interaction of the non-thermal oxygen atoms with CO2 molecules.

SABER/TIMED↗
NASA NTRS2016

The Effect of CO2 Ice Cap Sublimation on Mars Atmosphere

Sublimation of the polar CO2 ice caps on Mars is an ongoing phenomenon that may be contributing to secular climate change on Mars. The transfer of CO2 between the surface and atmosphere via sublimation and deposition may alter atmospheric mass such that net atmospheric mass is increasing despite seasonal variations in CO2 transfer. My study builds on previous studies by Kahre and Haberle that analyze and compare data from the Phoenix and Viking Landers 1 and 2 to determine whether secular climate change is happening on Mars. In this project, I use two years worth of temperature, pressure, and elevation data from the MSL Curiosity rover to create a program that allows for successful comparison of Curiosity pressure data to Viking Lander pressure data so a conclusion can be drawn regarding whether CO2 ice cap sublimation is causing a net increase in atmospheric mass and is thus contributing to secular climate change on Mars.

CO2↗
NASA NTRS2018

Efficacy of FTIR Analysis in Determining CO2 Loading on Diglycolamine

In support of advanced air revitalization technologies to enable human spaceflight beyond low earth orbit, performance studies have been conducted using a liquid amine, Diglycolamine (DGA) between teams at NASA's Johnson Spaceflight Center (JSC) and Ames Research Center (ARC). Liquid amines have been used in regenerable earth-based systems to remove CO2 from industrial systems as well as for closed-environment air revitalization because they can be regenerated at lower temperatures than solid sorbent systems. As an additional advantage to solid sorbent-based systems, liquid sorbents can be cycled between an adsorbing contactor and degassing chamber, thereby reducing system complexity by operation in a continuous loop. In an effort to inform a regeneration system design for micro-gravity applications, ARC has performed a number of tests to characterize the degas mechanics of DGA. In order to accurately measure the amount of CO2 captured or released by the amine, methods such as gravimetric weighing and chemical desorption are reasonable, however the first iteration test setup for a scaled down degas system required analysis on small sample sizes. Fourier-transform infrared spectroscopy (FTIR) analysis was experimentally evaluated to analyze CO2 concentration because it can produce measurements with sample sizes on the order of 100's of μL. Calibration against chemical desorption showed relatively good correlation and test data showed reasonable adherence to expected trends, however more extensive testing should be conducted to fully validate the usage of FTIR to determine CO2 loading on DGA.

Diglycolamine↗
NASA NTRS1972

Laboratory CO2 photolysis studies related to planetary atmospheres

The CO(a 3II) state, the upper state of the Cameron bands, was characterized with respect to its average radiative lifetime and its quenching coefficients for a series of simple molecules. The CO2 recombination reaction (O(3P) + CO + M yields CO2 + M) was studied as a function of temperature. For M = CO, the rate constant can be expressed as k = 6.5 x 10/33 exp(-4340 plus or minus 550/RT) cm to the 6th power molec/2 sec/1, whereas the rate for M = CO2, the pertinent species in the planetary atmospheres, is 1.6 times greater. The quantum yield for CO2 photodissociation was measured in the 1200-1500 A region, using atomic line sources. The yield throughout this spectral region was much lower than that measured at 1470 A, the lowest value obtained being 8% at 1304 A.

Slanger, T. G.↗
NASA NTRS1972

Lifetime and quenching of CO /a super 3 pi/ produced by recombination of CO2 ions in a helium afterglow.

Demonstration that rapid dissociative recombination of CO2(+) in a flowing, helium afterglow is an efficient source of CO in the a super 3 pi metastable state. Ions produced by mixing CO2 with He(2 super 3 S) recombine to produce a CO metastable afterglow with a number density as great as 10 to the 9th per sq cm. Monitoring of the (a super 3 pi-X super 1 sigma) Cameron transition in CO was used to study the lifetime and quenching of CO (a super 3 pi) by CO2, N2, NO, and He. Recombination of CO2(+) also produces CO in the d super 3 delta and a' super 3 sigma states.

Wauchop, T. S.↗
NASA NTRS1974

Exchange of adsorbed H2O and CO2 between the regolith and atmosphere of Mars caused by changes in surface insolation

Estimates have been made of the capacity of the Martian regolith to exchange adsorbed H2O and CO2 with the atmosphere-plus-cap system (APCS). These estimates are based upon measured isotherms for H2O and CO2 adsorption on pulverized basalt at low temperatures and on theoretical considerations. A unit column (1 sq cm) of regolith with a deep subsurface temperature of -77 C, considered average for the disk, will contain about 0.4 g of adsorbed CO2 and about 1 g of adsorbed H2O per meter of depth. Under favorable circumstances the top 3 cm can exchange much more H2O with the lower atmosphere each day than is necessary to produce the diurnal brightening. The process appears to be seasonally reversible. The total regolith may contain, in the adsorbed phase alone, as much as 1% of the H2O and 5% of the CO2 surface inventories expected for a hypothetical Mars that has experienced degassing as intensive as that of earth.

Fanale, F. P.↗
NASA NTRS1975

High dispersion observations of Venus during 1972. The CO2 band at 7820 angstrom

Photographic plates of Venus which show the spectrum of the carbon dioxide band at 7820A were obtained at Table Mountain Observatory in September-October 1972. These spectra showed a semi-regular 4-day variation in the CO2 abundance over the disk of the planet. Evidence for temporal variations in the rotational temperature of this band and temperature variations over the disk was found. The two quantities, CO2 abundance and temperature, do not show any obvious relationship; however, an increase in the temperature usually is accompanied by a decrease in the abundance of CO2. The average temperature, found from a curve of growth analysis assuming a constant CO2 line of width, is 249 plus or minus 1.4 K (one standard deviation).

Young, L. D. G.↗
NASA NTRS1975

Comparison of simultaneous CO2 and H2O observations of Venus

Results are reported for 115 pairs of CO2 and H2O abundance determinations made with the coude scanner of a 2.7 m reflector. The pairs of observations were made over the same area of the illuminated disk of Venus with the guiding, seeing and slit-placement errors less than 15 per cent of the disk diameter. A correlation analysis of the pairs of observations grouping them into eight periods of time which corresponded to telescope observing runs or periods of similar phase angle shows a lack of correlation in all except one period. For this set, the H2O abundances were positively correlated with the relative CO2 line strengths for measurements of the 8689-A and 7820-A CO2 bands made on the same day. Comparison of abundances on some 25 individual days shows a positive correlation on one day and a marginal negative correlation on two days, with no correlation on the remaining 22 days. On the basis of the lack of correlations, it is concluded that either the H2O level of line formation does not fluctuate in phase with the observed CO2 absorption fluctuations or the horizontal distribution of the H2O vapor must be inhomogeneous.

Barker, E. S.↗
NASA NTRS1975

Carbon dioxide-water clathrate as a reservoir of CO2 on Mars

It has been suggested that the residual polar caps of Mars contain a resorvoir of permanently frozen carbon dioxide which is controlling the atmospheric pressure. However, observational data and models of the polar heat balance suggest that the temperatures of the Martian poles are too high for solid CO2 to survive permanently. On the other hand, the icelike compound carbon dioxide-water clathrate could function as a CO2 reservoir instead of solid CO2, because it is stable at higher temperatures. This paper shows that the permanent polar caps may contain several millibars of CO2 in the form of clathrate, and discusses the implications of this permanent clathrate reservoir for the present and past atmospheric pressure on Mars.

Dobrovolskis, A.↗
NASA NTRS1977

Flight prototype CO2 and humidity control system

A regenerable CO2 and humidity control system is presently being developed for potential use on the space shuttle as an alternative to the baseline lithium hydroxide system. The system utilizes a sorbent material (designated HS-C) to adsorb CO2 and water vapor from the cabin atmosphere and desorb the CO2 and water vapor overboard when exposed to a space vacuum. Continuous operation is achieved by utilizing two beds which are alternately cycled between adsorption and desorption. A shuttle vehicle integration study showed that the HS-C system offers substantial weight advantages compared to the baseline shuttle orbiter expendable lithium hydroxide CO2 removal system for extended missions beyond the nominal design of four men for seven days. This study defined a system packaging envelope in the area presently occupied by the LiOH cartridges.

Rudy, K. M.↗
NASA NTRS1979

Flight prototype CO2 and humidity control system

A regenerable CO2 and humidity control system is presently being developed for potential use on shuttle as an alternative to the baseline lithium hydroxide system. The system utilizes a sorbent material (designated HS-C) to adsorb CO2 and the latent heat load from the cabin atmosphere and desorb the CO2 and water vapor overboard when exposed to a space vacuum, thus reducing the overall vehicle heat rejection load. Continuous operation is achieved by utilizing two beds which are alternatively cycled between adsorption and desorption. The HS-C material process was verified. Design concepts for the auxiliary components for the HS-C prototype system were generated. Performance testing verified system effectiveness in controlling CO2 partial pressure and humidity.

Rudy, K. M.↗
NASA NTRS1979

Nuclear-pumped CO2 laser

The He-3 (n,p)T reaction was examined as an energy source for a CO2 laser. For this purpose He-3 was added to a functioning CO2 electrically excited laser. Initially the laser was run electrically with 12 torr total pressure. The gas mixture was 1:1:8, CO2:N2:He. At zero reactor power, the laser was tested in place next to the core of the Georgia Tech. Research Reactor. After verification of laser action He-3 was added to the system. The He-3 partial pressures of 10 torr, 50 torr, and 300 torr were added in three separate reactor runs. Reactor power ranged from zero to 5 million watts, which corresponds to a peak flux of 10 to the 14th power/sq cm. At reactor powers greater than 10 kW, gain of up to 30 percent was shown. However, indications are this may be due to gamma excitation rather than caused by the He-3 (n,p)T reaction. These results do agree with the data of past CO2 nuclear pumped laser experiments.

Rowe, M.↗
NASA NTRS1979

Optical properties of solid CO2 - Application to Mars

Using a special low-temperature cell, thick layers of solid CO2 are grown on an infrared-transparent window. The transmission spectra of solid CO2 is measured from 4000 to 360 kaysers (2.5-27.8 microns). The complex index of refraction is derived for samples of different thicknesses. Scattering in the samples is the major source of error. Away from the major absorption bands the imaginary index is very low. The absorption coefficient is of the order of 1 kayser. The emissivity in the Viking IRTM 20-micron band of a solid surface of CO2 is estimated at 0.72 + 0.17 or -0.10. Snowlike deposits have similar or lower emissivity. The results of this paper relieve the need for exceptional meteorology to explain Martian brightness temperatures below the CO2 frost point.

Ditteon, R.↗
NASA NTRS1979

Mars - CO2 adsorption and capillary condensation on clays: Significance for volatile storage and atmospheric history

Results on the adsorbate-adsorbent system CO2-nontronite are reported at 230, 196, and 158 deg K, covering the range of subsurface regolith temperature on Mars. A three-part regolith-atmosphere-cap model reveals that cold nontronite, and expanding clays in general, are far better but far more complex CO2 adsorbers than cold pulverized basalt. In addition, the layered terrain, and possibly the adjacent debris mantle, contains about 2% or more by mass of atmosphere-exchangeable CO2 and the total regolith inventory of available adsorbed CO2 is estimated to be 400 g/ sq cm.

Fanale, F. P.↗
NASA NTRS1980

The factors influencing the formation of Li2CO3 from LiOH and CO2

LiOH is used to remove CO2 from the atmosphere in three environmental control systems of the Shuttle program, and the investigation of the performance dependent parameters for the CO2 reaction with LiOH is reported. Emphasis is placed on LiOH quality acceptance criteria and on identifiying the relationships between the reaction rate and the following independent parameters: temperature, CO2 partial pressure (PP), H2O concentration in the solid, amount of remaining LiOH and the porosity of the LiOH pellets. Results showed that the reaction rate is proportional to the CO2 PP for PP at least as high as 40 mm Hg (5330 N/sq m). It is also noted that a significant difference in the reactivity of wet and dry LiOH was not detected.

Davis, S. H., Jr.↗