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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 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Comets in other planetary systems?

Comets in our solar system appear to have provided a bridge between the cold, volatile-rich outer solar system, and the warm, but volatile-poor inner solar system. Excluding tidal and possible extinct radionuclide heating sources, only in the inner solar system are temperatures high enough for liquid water, and therefore life as we know it, to exist for times comparable to the age of the solar system. Comets may have been crucial for providing biogenic volatiles and perhaps organic molecules to this warm environment. It is therefore interesting from an exobiological point of view to ask if comets exist in other planetary systems. Most attempts to detect comets around other stars or in interstellar space have failed. However, there is growing spectroscopic evidence for comet-like bodies orbiting the star Beta Pictoris.

Chyba, C. F.↗
NASA NTRS1974

Communication system for the Viking mission to Mars

The Viking communications system discussed comprises a UHF relay link and an S-band communication link. The design of both links was guided by the design of the mission itself and its constraints. The most important of these are: the available launch opportunities; the effect of interplanetary distances on the power and bandwidth of the S-band link; weight; reliability and survival in the Martian environment; the up-link command philosophy; the landing problem; and the requirements for planetary quarantine and cleanliness. The Viking mission, with its orbits and trajectories, launch and landing sequences is described and illustrated.

Brown, I.↗
NASA NTRS1982

The Venus environment; Proceedings of the International Conference, Palo Alto, CA, November 1-6, 1981

Attention is given to noble gases in planetary atmospheres, the photochemistry of the stratosphere of Venus, the chemistry of metastable species in the Venusian ionosphere, the Venus ionosphere at grazing incidence of solar radiation, disappearing ionospheres on the nightside of Venus, and the observed composition of the ionosphere of Venus. Other investigations considered are concerned with the predicted electrical conductivity between 0 and 80 km in the Venusian atmosphere, sulfuric acid vapor and other cloud-related gases in the Venus atmosphere, the composition and vertical structure of the lower cloud deck on Venus, amorphous sulfur as the ultraviolet absorber on Venus, and polarization studies of the Venus UV contrasts. A description is provided of topics related to temporal variability of ultraviolet cloud features in the Venus stratosphere, zonal mean circulation at the cloud level on Venus, the influence of thermospheric winds on exospheric hydrogen on Venus, and an analysis of Venus gravity data.

Source record↗
NASA NTRS1985

Terrestrial Analogs for Planetary Wrinkle Ridges

Wrinkle ridges are common physiographic features on the terrestrial planets. Their origin has remained enigmatic, although two different types of models, volcanic and tectonic, have been proposed. The major impediment to deciphering the origin of wrinkle ridges has been the lack of a terrestrial analog. Seven terrestrial analogs were discussed, two in detail. Their implications for the origin for planetary wrinkle ridges were considered. All of the terrestrial analogs were formed in compressional environments and are the surface breaks of thrust faults.

Plescia, J. B.↗
NASA NTRS1988

Aeolian weathering of Venusian surface materials - Preliminary results from laboratory simulations

An attempt is made to duplicate the atmospheric temperature, pressure, and approximate gas composition of all surface elevations on Venus by means of a simulator environment in which particles are impacted against rock targets as a way of studying planetary aeolian processes. While particles are abraded even at the low impact velocities envisioned for Venus, the same particles do not generate basaltic rock abrasion for impact velocities lower than 1 m/sec; comminution debris is instead transferred onto rock surfaces to form an accretion layer. These phenomena are seen as functions of the greater than 660 K temperatures encountered.

Marshall, John R.↗
NASA NTRS1988

The effects of high energy particles on planetary missions

Researchers review the background and motivation for the detailed study of the variability and uncertainty of the particle environment from a space systems planning perspective. The engineering concern raised by each environment is emphasized rather than the underlying physics of the magnetosphere or the sun. Missions now being planned span the short term range of one to three years to periods over ten years. Thus the engineering interest is beginning to stretch over periods of several solar cycles. Coincidentally, detailed measurements of the environment are now becoming available over that period of time. Both short term and long term environmental predictions are needed for proper mission planning. Short term predictions, perhaps based on solar indices, real time observations, or short term systematics, are very useful in near term planning -- launches, EVAs (extravehicular activities), coordinated observations, and experiments which require the magnetosphere to be in a certain state. Long term predictions of both average and extreme conditions are essential to mission design. Engineering considerations are many times driven by the worst case environment. Knowledge of the average conditions and their variability allows trade-off studies to be made, implementation of designs which degrade gracefully under multi-stress environments.

Robinson, Paul A., Jr.↗
NASA NTRS1990

A methodology for choosing candidate materials for the fabrication of planetary space suit structures

A study of space suit structures and materials is under way at NASA Ames Research Center, Moffett Field, CA. The study was initiated by the need for a generation of lightweight space suits to be used in future planetary Exploration Missions. This paper provides a brief description of the Lunar and Mars environments and reviews what has been done in the past in the design and development of fabric, metal, and composite suit components in order to establish criteria for comparison of promising candidate materials and space suit structures. Environmental factors and mission scenarios will present challenging material and structural requirements; thus, a program is planned to outline the methodology used to identify materials and processes for producing candidate space suit structures which meet those requirements.

Jacobs, Gilda↗
NASA NTRS1994

The circumplanetary nebular environment: A possible source region for chondrules

Hypotheses for the origin of chondrules fall into two broad groups: nebular and planetary. Arguments against the latter have prevailed in recent years such that, by default, the less testable nebular setting for chondrule formation is now generally favored. However, the recognition in ordinary chondrites of igneous clasts that probably formed on, or in, small planetoids hints that some parent bodies were still accreting after others had evolved magmatically and lost material to space, presumably by impact. If melting of planetoids can predate accretion, could the same early melting even be related to chondrule production? My affirmative response to this interesting question is expanded here in a chondrule-forming scenario, which incorporates both planetary and nebular features.

Sanders, I. S.↗
NASA NTRS1997

Instrumentation for Mars Environments

The main portion of the project was to support the "MAE" experiment on the Mars Pathfinder mission and to design instrumentation for future space missions to measure dust deposition on Mars and to characterize the properties of the dust. A second task was to analyze applications for photovoltaics in new space environments, and a final task was analysis of advanced applications for solar power, including planetary probes, photovoltaic system operation on Mars, and satellite solar power systems.

Landis, Geoffrey A.↗
NASA NTRS2001

Development of Electronics for Low-Temperature Space Missions

Electronic systems that are capable of operating at cryogenic temperatures will be needed for many future NASA space missions, including deep space probes and spacecraft for planetary surface exploration. In addition to being able to survive the harsh deep space environment, low-temperature electronics would help improve circuit performance, increase system efficiency, and reduce payload development and launch costs. Terrestrial applications where components and systems must operate in low-temperature environments include cryogenic instrumentation, superconducting magnetic energy storage, magnetic levitation transportation systems, and arctic exploration. An ongoing research and development project for the design, fabrication, and characterization of low-temperature electronics and supporting technologies at NASA Glenn Research Center focuses on efficient power systems capable of surviving in and exploiting the advantages of low-temperature environments. Supporting technologies include dielectric and insulating materials, semiconductor devices, passive power components, optoelectronic devices, and packaging and integration of the developed components into prototype flight hardware. An overview of the project is presented, including a description of the test facilities, a discussion of selected data from component testing, and a presentation of ongoing research activities being performed in collaboration with various organizations.

Patterson, Richard L.↗
NASA NTRS2002

Optical Scattering Characterization for the Glennan Microsystems Microscale Particulate Classifier

Small sensors that are tolerant to mechanically and thermally harsh environments present the possibility for in-situ particle characterization in propulsion, industrial, and planetary science applications. Under a continuing grant from the Glennan Microsystems Initiative to the Microgravity Fluids Physics Branch of the NASA-Glenn Research Center, a Microscale Particle Classifier (MiPAC) instrument is being developed. The MiPAC instrument will be capable of determining the size distribution of airborne particles from about 1 nm to 30 micrometers, and will provide partial information as to the concentration, charge state, shape, and structure of the particles, while being an order of magnitude smaller in size and lighter in weight than presently commercially available instruments. The portion of the instrument that will characterize the nm-range particles will employ electrical mobility techniques and is being developed under a separate grant to Prof. David Pui of the University of Minnesota. The portion of the instrument that will characterize the micrometer-size particles such as dirt, pollens, spores, molds, soot, and combustion aerosols will use light scattering techniques. The development of data analysis techniques to be employed in the light scattering portion of the instrument is covered by this grant.

Lock, James A.↗
NASA NTRS1998

Formation of Jupiter and Saturn

An overview of current theories of the formation of our Solar System, with emphasis on giant planets, is presented. The most detailed models are based upon observations of planets and smaller bodies within our own Solar System and of young stars and their environments. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth as do terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. Larger disk mass allows for faster growth of solid planetary bodies. The ability of a solid planet to trap gas from the protoplanetary disk increases rapidly as its mass increases (because the depth of its gravitational potential well increases), but decreases as the planetesimal accretion rate is increased (as it becomes hotter). The net effect of increasing disk mass is that gas giant planets form more rapidly, but with larger core masses. Observations of circumstellar disks suggest an upper bound on the time available prior to dissipation of the gas, and planetary models place upper limits on core sizes. Together, these constraints suggest that Jupiter and Saturn formed in 1-10 million years, and the density of solids in the region of their formation was a few times as large as the lower bound provided by the traditional minimum mass nebula.

Lissauer, Jack J.↗
NASA NTRS1998

Formation of Jupiter and Saturn

An overview of current theories of the formation of our Solar System, with emphasis on giant planets, is presented. The most detailed models are based upon observations of planets and smaller bodies within our own Solar System and of young stars and their environments. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth as do terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. Larger disk mass allows for faster growth of solid planetary bodies. The ability of a solid planet to trap gas from the protoplanetary disk increases rapidly as its mass increases (because the depth of its gravitational potential well increases), but decreases as the planetesimal accretion rate is increased (as it becomes hotter). The net effect of increasing disk mass is that gas giant planets form more rapidly, but with larger core masses. Observations of circumstellar disks suggest an upper bound on the time available prior to dissipation of the gas, and planetary models place upper limits on core sizes. Together, these constraints suggest that Jupiter and Saturn formed in 1 - 10 million years, and the density of solids in the region of their formation was a few times as large as the lower bound provided by the traditional minimum mass nebula.

Lissauer, Jack J.↗
NASA NTRS2005

Planet Formation - Overview

Modern theories of star and planet formation are based upon observations of planets and smaller bodies within our own Solar System, exoplanets &round normal stars and of young stars and their environments. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth as do terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. These models predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. A potential hazard to planetary systems is radial decay of planetary orbits resulting from interactions with material within the disk. Planets more massive than Earth have the potential to decay the fastest, and may be able to sweep up smaller planets in their path.

Lissauer, Jack J.↗
NASA NTRS2006

Observations of Shock Diffusion and Interactions in Supersonic Freestreams with Counterflowing Jets

One of the technical challenges in long-duration space exploration and interplanetary missions is controlled entry and re-entry into planetary and Earth atmospheres, which requires the dissipation of considerable kinetic energy as the spacecraft decelerates and penetrates the atmosphere. Efficient heat load management of stagnation points and acreage heating remains a technological challenge and poses significant risk, particularly for human missions. An innovative approach using active flow control concept is proposed to significantly modify the external flow field about the spacecraft in planetary atmospheric entry and re-entry in order to mitigate the harsh aerothermal environments, and significantly weaken and disperse the shock-wave system to reduce aerothermal loads and wave drag, as well as improving aerodynamic performance. To explore the potential benefits of this approach, we conducted fundamental experiments in a trisonic blow down wind tunnel to investigate the effects of counterflowing sonic and supersonic jets against supersonic freestreams to gain a better understanding of the flow physics of the interactions of the opposing flows and the resulting shock structure.

Daso, Endwell O.↗
NASA NTRS2010

PDS Lunar Data Node Restoration of Apollo In-Situ Surface Data

The Apollo missions between 1969 and 1972 deployed scientific instruments on the Moon's surface which made in-situ measurements of the lunar environment. Apollo II had the short-term Early Apollo Surface Experiments Package (EASEP) and Apollos 12, 14, 15, 16, and 17 each set up an Apollo Lunar Surface Experiments Package (ALSEP). Each ALSEP package contained a different suite of instruments which took measurements and radioed the results back to Earth over periods from 5 to 7 years until they were turned off on 30 September 1977. To this day the ALSEP data remain the only long-term in-situ information on the Moon's surface environment. The Lunar Data Node (LDN) has been formed under the auspices of the Planetary Data System (PDS) Geosciences Node to put relevant, scientifically important Apollo data into accessible digital form for use by researchers and mission planners. We will report on progress made since last year and plans for future data restorations.

Williams, David R.↗
NASA NTRS2010

Metabolic Costs and Biomechanics of Inclined Ambulation and Exploration Tasks in a Planetary Suit

Observations from Apollo lunar surface extravehicular activities (EVAs) and a few studies conducted in partial-gravity simulation environments have helped us understand suited human performance in reduced-gravity environments. The Constellation Program EVA Systems Project Office initiated a series of tests aimed at increasing our understanding of human performance and suit kinematics under various simulated lunar EVA conditions, including matched unsuited controls, to identify the specific metabolic costs and biomechanics of the prototype Mark III Advanced Spacesuit Technology Demonstrator. A primary goal of the series is to provide evidence-based recommendations for suit mass, center of gravity, pressure, and suit kinematic constraints that optimize human performance in partial-gravity environments. Results will be combined with studies in other lunar analogs to evaluate the effectiveness and limitations of these environments. As our understanding of suited human performance matures, different combinations of variables can be evaluated to determine whether significant interactions exist between parameters. This report provides an overview of key findings of Integrated Suit Test (IST)-2. As future tests are completed, focusing on other suit factors, analog environments, or different suits, study results will be combined and reevaluated. The series of tests comprising IST-2 was conducted from June 13, 2007 through October 24, 2007.

Aerospace environments↗
NASA NTRS2012

Radiation Tests of Highly Scaled, High-Density, Commercial, Nonvolatile NAND Flash Memories - Update 2012

The space radiation environment poses a certain risk to all electronic components on Earth-orbiting and planetary mission spacecraft. In recent years, there has been increased interest in the use of high-density, commercial, nonvolatile flash memories in space because of ever-increasing data volumes and strict power requirements. They are used in a wide variety of spacecraft subsystems. At one end of the spectrum, flash memories are used to store small amounts of mission-critical data such as boot code or configuration files and, at the other end, they are used to construct multi-gigabyte data recorders that record mission science data. This report examines single-event effect (SEE) and total ionizing dose (TID) response in single-level cell (SLC) 32-Gb, multi-level cell (MLC) 64-Gb, and Triple-level (TLC) 64-Gb NAND flash memories manufactured by Micron Technology with feature size of 25 nm.

Irom, Farokh↗