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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Preliminary results of the scientific experiments on the Kosmos-936 biosatellite

The scientific equipment and experiments on the Kosmos-936 biosatellite are described, including various ground controls and the lab unit for studies at the descent vehicle landing site. Preliminary results are presented of the physiological experiment with rats, biological experiments with drosophila and higher and lower plants, and radiation physics and radiobiology studies for the planning of biological protection on future space flights. The most significant conclusion from the preliminary data is that rats tolerate space flight better with an artificial force of gravity.

Source record↗
NASA NTRS1966

Applications in physics

Application of Lie series to various physics problems - rigid body mechanics, electricity, gravity gradient stabilization of artificial satellites, and particle motion in synchrotron

LIE GROUP↗
NASA NTRS1979

Development and analysis of a twelfth degree and order gravity model for Mars

Satellite geodesy techniques previously applied to artificial earth satellites have been extended to obtain a high-resolution gravity field for Mars. Two-way Doppler data collected by 10 Deep Space Network (DSN) stations during Mariner 9 and Viking 1 and 2 missions have been processed to obtain a twelfth degree and order spherical harmonic model for the martian gravitational potential. The quality of this model was evaluated by examining the rms residuals within the fit and the ability of the model to predict the spacecraft state beyond the fit. Both indicators show that more data and higher degree and order harmonics will be required to further refine our knowledge of the martian gravity field. The model presented shows much promise, since it resolves local gravity features which correlate highly with the martian topography. An isostatic analysis based on this model, as well as an error analysis, shows rather complete compensation on a global (long wavelength) scale. Though further model refinements are necessary to be certain, local (short wavelength) features such as the shield volcanos in Tharsis appear to be uncompensated. These are interpreted to place some bounds on the internal structure of Mars.

Christensen, E. J.↗
NASA NTRS2016

PowerCells Payload on EuCROPIS - Measuring Synthetic Biology in Space

NASA’s PowerCell payload on the DLR (Deutsches Zentrum fur Luft- und Raumfahrt, i.e. German Aerospace Center) Eu:CROPIS satellite will compare the effect of multiple simulated gravity regimes on basic processes required for synthetic biology in space including growth, protein production, and genetic transformation of the bacterium Bacillus subtilis. In addition, it will pioneer the use of a cyanobacterially-produced feedstock for microbial growth in space, a concept we call “PowerCell.” The PowerCell experiment system will be integrated using the Spaceflight Secondary Payload System with the German Space Agency's (DLR's) Euglena and Combined Regenerative Organic-food Production In Space (Eu:CROPIS) satellite, to be launched during the summer of 2017. In order to simulate the gravitational gradient of different celestial bodies, the Eu:CROPIS satellite will establish artificial microgravity, lunar, and Martian gravity levels prior to conducting each set of biological experiments, with experimental results compared to ground controls. Experiments will be carried out in microfluidics cards with experimental progress measured through absorbance as detected by the LED-based optical system. Here we describe the ground studies that led to these experiments, along with a description of the flight hardware and its performance. The results of this mission will provide foundational data for the use and production of genetically engineered organisms for extraterrestrial missions.

PowerCell experiment system↗
NASA NTRS1977

Electrophoresis

Ground-based techniques for electrophoresis take account of the need either to circumvent the effects of gravity to prevent convection, or to use gravity for fluid stabilization through artificial density gradients. The microgravity environments of orbiting spacecraft provides a new alternative for electrophoresis by avoiding the need for either of these two approaches. The paper presents some theoretical considerations concerning electrophoresis, examines certain experimental techniques (zone and high density gel electrophoresis, isoelectric focusing and isotachophoresis), and examines the electrophoresis of living cells.

Bier, M.↗
NASA NTRS1975

Navigational assignment of scientific measurements

Some problems are considered in the navigational assignment of scientific measurements (the calculation of the position of the center of a spacecraft mass in space) as it applies to the Interkosmos series of artificial satellites. Possible models of disturbing forces and the corresponding perturbations in the orbits are analyzed. The following forces and their effect on artificial satellites are discussed: earth's gravity, atmospheric drag, the moon's gravity, the sun's gravity, and light pressure.

Elyasberg, P. Y.↗
NASA NTRS1986

The implementation of two satellite programs in a microcomputer environment

This paper describes the implementation of two computer programs that predict the motion of artificial satellites. The two programs are developed in a microcomputer environment. The particular microcomputer used is an IBM AT system. The programs can predict the orbital behavior of artificial satellites under the influence of gravity harmonics up to a 21 by 21 field, luni-solar gravity, drag, and solar radiation pressure. One program uses Cowell's method and the other uses variation of parameters with a singly averaging technique. Both programs use commercially available software to post-process trajectory information and to generate graphics display. The programs reside on floppy disks and are available to the general public through NASA's Computer Software Management and Information Center (COSMIC).

Kwok, J. H.↗
NASA NTRS2000

Cardiovascular response to lower body negative pressure stimulation before, during, and after space flight

BACKGROUND: It is well known that space travel cause post-flight orthostatic hypotension and it was assumed that autonomic cardiovascular control deteriorates in space. Lower body negative pressure (LBNP) was used to assess autonomic function of the cardiovascular system. METHODS: LBNP tests were performed on six crew-members before and on the first days post-flight in a series of three space missions. Additionally, two of the subjects performed LBNP tests in-flight. LBNP mimics fluid distribution of upright posture in a gravity independent way. It causes an artificial sequestration of blood, reduces preload, and filtrates plasma into the lower part of the body. Fluid distribution was assessed by bioelectrical impedance and anthropometric measurements. RESULTS: Heart rate, blood pressure, and total peripheral resistance increased significantly during LBNP experiments in-flight. The decrease in stroke volume, the increased pooling of blood, and the increased filtration of plasma into the lower limbs during LBNP indicated that a plasma volume reduction and a deficit of the interstitial volume of lower limbs rather than a change in cardiovascular control was responsible for the in-flight response. Post-flight LBNP showed no signs of cardiovascular deterioration. The still more pronounced haemodynamic changes during LBNP reflected the expected behaviour of cardiovascular control faced with less intravascular volume. In-flight, the status of an intra-and extravascular fluid deficit increases sympathetic activity, the release of vasoactive substances and consequently blood pressure. Post-flight, blood pressure decreases significantly below pre-flight values after restoration of volume deficits. CONCLUSION: We conclude that the cardiovascular changes in-flight are a consequence of a fluid deficit rather than a consequence of changes in autonomic signal processing.

manned↗
NASA NTRS1979

Mars gravity field model from Mariner 9, Viking 1 and 2 data

Earth artificial satellite methods are extended by means of two way Doppler data, to the computation of very accurate orbiter trajectories around another planet, and to the determination of its gravity field. It is reported that in the case of Mars, all observations collected by 10 Deep Space Network stations located at three different sites during the Mariner 9 and Viking 1 and 2 missions have been processed and used to compute a full twelfth degree and order spherical harmonic model of the gravitational potential. It is concluded that the aeroid derived from the model shows very large correlations with the Martian topography, raising questions as to the deep structure of the planet which cannot be interpreted on the basis of topographic and isostatic considerations alone.

Balmino, G.↗
NASA NTRSDate not supplied

Using Artificial Intelligence (AI) and Machine Learning (ML) to conduct Space Missions Solid Waste Management Survey

The National Aeronautics and Space Administration (NASA) Solid Waste Management team has been focusing on technologies that can operate in microgravity. NASA aims to conduct both short and long-term transit and planetary missions on the lunar and Mars surfaces. Therefore, an updated waste survey is needed to explore technologies for operation in microgravity for transit missions and partial gravity for planetary missions. This paper will utilize Artificial Intelligence and Machine Learning techniques to conduct the survey and generate knowledge graphs for Spacecraft Waste Management.

Artificial Intelligence↗
DOE OSTI2024

Numerical challenges in modeling gravothermal collapse in Self-Interacting Dark Matter halos

When dark matter has a large cross section for self scattering, halos can undergo a process known as gravothermal core collapse, where the inner core rapidly increases in density and temperature. To date, several methods have been used to implement Self-Interacting Dark Matter (SIDM) in N-body codes, but there has been no systematic study of these different methods or their accuracy in the core-collapse phase. In this paper, we compare three different numerical implementations of SIDM, including the standard methods from the GIZMO and Arepo codes, by simulating idealized dwarf halos undergoing significant dark matter self interactions (σ/m = 50 cm 2 /g). When simulating these halos, we also vary the mass resolution, time-stepping criteria, and gravitational force-softening scheme. The various SIDM methods lead to distinct differences in a halo's evolution during the core-collapse phase, as each results in spurious scattering rate differences and energy gains/losses. The use of adaptive force softening for gravity can lead to numerical heating that artificially accelerates core collapse, while an insufficiently small simulation time step can cause core evolution to stall or completely reverse. Additionally, particle numbers must be large enough to ensure that the simulated halos are not sensitive to noise in the initial conditions. Even for the highest-resolution simulations tested in this study (10 6 particles per halo), we find that variations of order 10% in collapse time are still present. Here, the results of this work underscore the sensitivity of SIDM modeling on the choice of numerical implementation and motivate a careful study of how these results generalize to halos in a cosmological context.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1975

Poisson equations of rotational motion for a rigid triaxial body with application to a tumbling artificial satellite

A mathematical model is developed for studying the effects of gravity gradient torque on the attitude stability of a tumbling triaxial rigid satellite. Poisson equations are used to investigate the rotation of the satellite (which is in elliptical orbit about an attracting point mass) about its center of mass. An averaging method is employed to obtain an intermediate set of differential equations for the nonresonant, secular behavior of the osculating elements which describe the rotational motions of the satellite, and the averaged equations are then integrated to obtain long-term secular solutions for the osculating elements.

Liu, J. J. F.↗
NASA NTRS2014

ATLAS LTCS Vertically Challenged System Lessons Learned

Re-planning of LTCS TVAC testing and supporting RTA (Receiver Telescope Assembly) Test Plan and Procedure document preparation. The Laser Thermal Control System (LTCS) is designed to maintain the lasers onboard Advanced Topographic Laser Altimeter System (ATLAS) at their operational temperatures. In order to verify the functionality of the LTCS, a thermal balance test of the thermal hardware was performed. During the first cold start of the LTCS, the Loop Heat Pipe (LHP) was unable to control the laser mass simulators temperature. The control heaters were fully on and the loop temperature remained well below the desired setpoint. Thermal analysis of the loop did not show these results. This unpredicted behavior of the LTCS was brought up to a panel of LHP experts. Based on the testing and a review of all the data, there were multiple diagnostic performed in order to narrow down the cause. The prevailing theory is that gravity is causing oscillating flow within the loop, which artificially increased the control power needs. This resulted in a replan of the LTCS test flow and the addition of a GSE heater to allow vertical operation.

Loop Heat Pipe↗
NASA NTRS2006

Diffusion Limited Supercritical Water Oxidation (SCWO) in Microgravity Environments

Tests designed to quantify the gravitational effects on thermal mixing and reactant injection in a Supercritical Water Oxidation (SCWO) reactor have recently been performed in the Zero Gravity Facility (ZGF) at NASA s Glenn Research Center. An artificial waste stream, comprising aqueous mixtures of methanol, was pressurized to approximately 250 atm and then heated to 450 C. After uniform temperatures in the reactor were verified, a controlled injection of air was initiated through a specially designed injector to simulate diffusion limited reactions typical in most continuous flow reactors. Results from a thermal mapping of the reaction zone in both 1-g and 0-g environments are compared. Additionally, results of a numerical model of the test configuration are presented to illustrate first order effects on reactant mixing and thermal transport in the absence of gravity.

Hicks, M. C.↗
NASA NTRS2001

Numerical Study of Buoyancy and Different Diffusion Effects on the Structure and Dynamics of Triple Flames

Numerical simulations of 2-D triple flames under gravity force have been implemented to identify the effects of gravity on triple flame structure and propagation properties and to understand the mechanisms of instabilities resulting from both heat release and buoyancy effects. A wide range of gravity conditions, heat release, and mixing widths for a scalar mixing layer are computed for downward-propagating (in the same direction with the gravity vector) and upward-propagating (in the opposite direction of the gravity vector) triple flames. Results of numerical simulations show that gravity strongly affects the triple flame speed through its contribution to the overall flow field. A simple analytical model for the triple flame speed, which accounts for both buoyancy and heat release, is developed. Comparisons of the proposed model with the numerical results for a wide range of gravity, heat release and mixing width conditions, yield very good agreement. The analysis shows that under neutral diffusion, downward propagation reduces the triple flame speed, while upward propagation enhances it. For the former condition, a critical Froude number may be evaluated, which corresponds to a vanishing triple flame speed. Downward-propagating triple flames at relatively strong gravity effects have exhibited instabilities. These instabilities are generated without any artificial forcing of the flow. Instead disturbances are initiated by minute round-off errors in the numerical simulations, and subsequently amplified by instabilities. A linear stability analysis on mean profiles of stable triple flame configurations have been performed to identify the most amplified frequency in spatially developed flows. The eigenfunction equations obtained from the linearized disturbance equations are solved using the shooting method. The linear stability analysis yields reasonably good agreements with the observed frequencies of the unstable triple flames. The frequencies and amplitudes of disturbances increase with the magnitude of the gravity vector. Moreover, disturbances appear to be most amplified just downstream of the premixed branches. The effects of mixing width and differential diffusion are investigated and their roles on the flame stability are studied.

Chen, Jyh-Yuan↗
NASA NTRSDate not supplied

NASA Crew Health & Performance Capability Development for Exploration: 2021 to 2022 Overview

Radiation, reduced gravity, distance from earth, isolation and confinement, and habitation within artificially created and controlled life support environments are hazards that present risk to human space explorers. In many cases, research is required to characterize those risks and help identify risk mitigation strategies. Where new capabilities are necessary to maintain crew health and performance (CHP) during exploration missions, a multi-step process is followed: 1) a Capability Gap is defined; 2) a plan or “roadmap” to develop that capability is established based on agency priorities and anticipated mission development timelines; and 3) work defined on the roadmap is then initiated as resources allow, with the objective that the capability will be available in time to support the future mission. Over the past year, significant progress has occurred in CHP technology development, ground testbed development, ground-based testing, and in preparations for ISS technology demonstrations. This paper provides a development update in the following capability areas: crew health countermeasures, EVA physiology and performance, food and nutrition, exploration medical capabilities, and radiation. Project overviews will include descriptions of CHP development activities over the past year, the human system risks and capability gaps being targeted, as well as planned follow-on activities and anticipated program infusion points.

Andrew F J Abercromby↗