Aeolian geomorphology from the global perspective

NASA Technical Reports Server (NTRS)

Greeley, R.

1985-01-01

Any planet or satellite having a dynamic atmosphere and a solid surface has the potential for experiencing aeolian (wind) processes. A survey of the Solar System shows at least four planetary objects which potentially meet these criteria: Earth, Mars, Venus, and possibly Titan, the largest satellite of Saturn. While the basic process is the same among these four objects, the movement of particles by the atmosphere, the aeolian environment is drastically different. It ranges from the hot (730 K), dense atmosphere of Venus to the extremely cold desert (218 K) environment of Mars where the atmospheric surface pressure is only approximately 7.5 mb. In considering aeolian processes in the planetary perspective, all three terrestrial planets share some common areas of attention for research, especially in regard to wind erosion and dust storms. Relevant properties of planetary objects potentially subject to aeolian processes are given in tabular form.

Twenty-Fourth Lunar and Planetary Science Conference. Part 2: G-M

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1993-01-01

The topics covered include the following: meteorites, meteoritic composition, geochemistry, planetary geology, planetary composition, planetary craters, the Moon, Mars, Venus, asteroids, planetary atmospheres, meteorite craters, space exploration, lunar geology, planetary surfaces, lunar surface, lunar rocks, lunar soil, planetary atmospheres, lunar atmosphere, lunar exploration, space missions, geomorphology, lithology, petrology, petrography, planetary evolution, Earth surface, planetary surfaces, volcanology, volcanos, lava, magma, mineralogy, minerals, ejecta, impact damage, meteoritic damage, tectonics, etc. Separate abstracts have been prepared for articles from this report.

Laser-based mass spectrometry for in situ chemical composition analysis of planetary surfaces

NASA Astrophysics Data System (ADS)

Frey, Samira; Neuland, Maike B.; Grimaudo, Valentine; Moreno-García, Pavel; Riedo, Andreas; Tulej, Marek; Broekmann, Peter; Wurz, Peter

2016-04-01

Mass spectrometry is an important analytical technique in space research. The chemical composition of planetary surface material is a key scientific question on every space mission to a planet, moon or asteroid. Chemical composition measurements of rocky material on the surface are of great importance to understand the origin and evolution of the planetary body.[1] A miniature laser ablation/ionisation reflectron- type time-of-flight mass spectrometer (instrument name LMS) was designed and built at the University of Bern for planetary research.[2] Despite its small size and light weight, the LMS instrument still maintains the same capabilities as large laboratory systems, which makes it suitable for its application on planetary space missions.[3-5] The high dynamic range of about eight orders of magnitude, high lateral (μm-level) and vertical (sub-nm level) resolution and high detection sensitivity for almost all elements (10 ppb, atomic fraction) make LMS a versatile instrument for various applications. LMS is a suitable instrument for in situ measurements of elemental and isotope composition with high precision and accuracy. Measurements of Pb- isotope abundances can be used for dating of planetary material. Measurements of bio-relevant elements allow searching for past or present life on a planetary surface. The high spatial resolution, both in lateral and vertical direction, is of considerable interest, e.g. for analysis of inhomogeneous, extraterrestrial samples as well as weathering processes of planetary material. References [1] P. Wurz, D. Abplanalp, M. Tulej, M. Iakovleva, V.A. Fernandes, A. Chumikov, and G. Managadze, "Mass Spectrometric Analysis in Planetary Science: Investigation of the Surface and the Atmosphere", Sol. Sys. Res., 2012, 46, 408. [2] U. Rohner, J.A. Whitby, P. Wurz, "A miniature laser ablation time of flight mass spectrometer for in situ planetary exploration" Meas. Sci. Tch., 2003, 14, 2159. [3] M. Tulej, A. Riedo, M.B. Neuland, S. Meyer, P. Wurz, N. Thomas, V. Grimaudo, P. Moreno-García, P. Broekmann, A. Neubeck and M. Ivarsson, "CAMAM: A miniature laser ablation ionisation mass spectrometer and microscope-camera system for in situ investigation of the composition and morphology of extraterrestrial materials", Geostand. Geoanal. Res., 2014, 38, 441. [4] A. Riedo, M. Neuland, S. Meyer, M. Tulej and P. Wurz, "Coupling of LMS with a fs-laser ablation ion source: elemental and isotope composition measurements", J. Anal. At. Spectrom., 2013, 28, 1256. [5] A. Riedo, S. Meyer, B. Heredia, M. Neuland, A. Bieler, M. Tulej, I. Leya, M. Iakovleva, K. Mezger and P. Wurz, "Highly accurate isotope composition measurements by a miniature laser ablation mass spectrometer designed for in situ investigations on planetary surfaces", Planet. Space Sci., 2013, 87, 1.

Europlanet-RI IDIS - A Data Network in Support of Planetary Research

NASA Astrophysics Data System (ADS)

Schmidt, Walter; Capria, Maria Teresa; Chanteur, Gérard

2010-05-01

The "Europlanet Research Infrastructure - Europlanet RI", supported by the European Commission's Framework Program 7, aims at integrating major parts of the distributed European Planetary Research infrastructure with as diverse components as space exploration, ground-based observations, laboratory experiments and numerical modeling teams. A central part of Europlanet RI is the "Integrated and Distributed Information Service" (IDIS), a network of data and information access facilities in Europe via which information relevant for planetary research can be easily found and retrieved. This covers the wide range from contact addresses of possible research partners, laboratories and test facilities to the access of data collected with space missions or during laboratory or simulation tests and to model software useful for their interpretation. During the following three years the capabilities of the network will be extended to allow the combination of many different data sources for comperative studies including the results of modeling calculations and simulations of instrument observations. Together with the access to complex databases for spectra of atmospheric molecules and planetary surface material IDIS will offer a versatile working environment for making the scientific exploitation of the resources put into planetary research in the past and future more effective. Many of the mentioned capabilities are already available now. List of contact web-sites: Technical node for support and management aspects: http://www.idis.europlanet-ri.eu/ Planetary Surfaces and Interiors node: http://www.idis-interiors.europlanet-ri.eu/ Planetary Plasma node: http://www.idis-plasma.europlanet-ri.eu/ Planetary Atmospheres node: http://www.idis-atmos.europlanet-ri.eu/ Small Bodies and Dust node: http://www.idis-sbdn.europlanet-ri.eu/ Planetary Dynamics and Extraterrestrial Matter node: http://www.idis-dyn.europlanet-ri.eu/

The Threatening Magnetic and Plasma Environment of the TRAPPIST-1 Planets

NASA Astrophysics Data System (ADS)

Garraffo, Cecilia; Drake, Jeremy J.; Cohen, Ofer; Alvarado-Gómez, Julian D.; Moschou, Sofia P.

2017-07-01

Recently, four additional Earth-mass planets were discovered orbiting the nearby ultracool M8 dwarf, TRAPPIST-1, making a remarkable total of seven planets with equilibrium temperatures compatible with the presence of liquid water on their surface. Temperate terrestrial planets around an M-dwarf orbit close to their parent star, rendering their atmospheres vulnerable to erosion by the stellar wind and energetic electromagnetic and particle radiation. Here, we use state-of-the-art 3D magnetohydrodynamic models to simulate the wind around TRAPPIST-1 and study the conditions at each planetary orbit. All planets experience a stellar wind pressure between 103 and 105 times the solar wind pressure on Earth. All orbits pass through wind pressure changes of an order of magnitude and most planets spend a large fraction of their orbital period in the sub-Alfvénic regime. For plausible planetary magnetic field strengths, all magnetospheres are greatly compressed and undergo much more dynamic change than that of the Earth. The planetary magnetic fields connect with the stellar radial field over much of the planetary surface, allowing the direct flow of stellar wind particles onto the planetary atmosphere. These conditions could result in strong atmospheric stripping and evaporation and should be taken into account for any realistic assessment of the evolution and habitability of the TRAPPIST-1 planets.

The Stability of Orbital Configurations and the Ultimate Configurations of Planetary and Satellite Systems

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.; Duncan, Martin J.

2004-01-01

The contents include the following: 1) Dynamical Evolution of the Earth-Moon Progenitors. 2) Dynamical Connections between Giant and Terrestrial Planets. 3) Dynamics of the Upsilon Andromedae Planetary System. 4) Dynamics of the Planets Orbiting GJ 876. and 5) Integrators for Planetary Accretion in Binaries.

Contamination Mitigation Strategies for Long Duration Human Spaceflight Missions

NASA Technical Reports Server (NTRS)

Lewis, Ruthan; Lupisella, Mark; Bleacher, Jake; Farrell, William

2017-01-01

Contamination control issues are particularly challenging for long-term human spaceflight and are associated with the search for life, dynamic environmental conditions, human-robotic-environment interaction, sample collection and return, biological processes, waste management, long-term environmental disturbance, etc. These issues impact mission success, human health, planetary protection, and research and discovery. Mitigation and control techniques and strategies may include and integrate long-term environmental monitoring and reporting, contamination control and planetary protection protocols, habitation site design, habitat design, and surface exploration and traverse pathways and area access planning.

NASA's Space Lidar Measurements of Earth and Planetary Surfaces

NASA Technical Reports Server (NTRS)

Abshire, James B.

2010-01-01

A lidar instrument on a spacecraft was first used to measure planetary surface height and topography on the Apollo 15 mission to the Moon in 1971, The lidar was based around a flashlamp-pumped ruby laser, and the Apollo 15-17 missions used them to make a few thousand measurements of lunar surface height from orbit. With the advent of diode pumped lasers in the late 1980s, the lifetime, efficiency, resolution and mass of lasers and space lidar all improved dramatically. These advances were utilized in NASA space missions to map the shape and surface topography of Mars with > 600 million measurements, demonstrate initial space measurements of the Earth's topography, and measured the detailed shape of asteroid. NASA's ICESat mission in Earth orbit just completed its polar ice measurement mission with almost 2 billion measurements of the Earth's surface and atmosphere, and demonstrated measurements to Antarctica and Greenland with a height resolution of a few em. Space missions presently in cruise phase and in operation include those to Mercury and a topographic mapping mission of the Moon. Orbital lidar also have been used in experiments to demonstrate laser ranging over planetary distances, including laser pulse transmission from Earth to Mars orbit. Based on the demonstrated value of the measurements, lidar is now the preferred measurement approach for many new scientific space missions. Some missions planned by NASA include a planetary mission to measure the shape and dynamics of Europa, and several Earth orbiting missions to continue monitoring ice sheet heights, measure vegetation heights, assess atmospheric CO2 concentrations, and to map the Earth surface topographic heights with 5 m spatial resolution. This presentation will give an overview of history, ongoing work, and plans for using space lidar for measurements of the surfaces of the Earth and planets.

Faults and Fractures in the Subseafloor Environment tell a Different Story than They do at the Seafloor

NASA Astrophysics Data System (ADS)

Hayman, N. W.

2018-05-01

Planetary studies can benefit from a lesson learned in the research of Mid-Ocean Ridges, wherein the subsurface view of faulting and fracturing contrasts with surface observations, important for the dynamics and chemistry of hydrothermal systems.

Editorial Introduction: Fourth Planetary Dunes Workshop Special Issue

NASA Astrophysics Data System (ADS)

Chojnacki, Matthew; Telfer, Matt W.

2017-06-01

The Fourth International Planetary Dunes Workshop: Integrating Models, Remote Sensing, and Field Data was held May 19-22, 2015 in Boise, Idaho (see Final Announcement). More than 60 researchers and students participated in two and a half days of presentations and lively discussion, plus a full day field trip to Bruneau Dunes State Park. The workshop focused on the many landforms and deposits created by the dynamic interactions between granular material and airflow (aeolian processes). These processes are known to occur on several planetary bodies, including Earth, Mars, Titan, Venus, and possibly, cometary surfaces. The overarching purpose of this workshop was to provide a forum for discussion and the exchange of new ideas and approaches to gaining new insights into planetary aeolian processes. Meeting programs, abstracts, and E-Posters are all available at the workshop website (http://www.hou.usra.edu/meetings/dunes2015/)

On the Interactions Between Planetary and Mesoscale Dynamics in the Oceans

NASA Astrophysics Data System (ADS)

Grooms, I.; Julien, K. A.; Fox-Kemper, B.

2011-12-01

Multiple-scales asymptotic methods are used to investigate the interaction of planetary and mesoscale dynamics in the oceans. We find three regimes. In the first, the slow, large-scale planetary flow sets up a baroclinically unstable background which leads to vigorous mesoscale eddy generation, but the eddy dynamics do not affect the planetary dynamics. In the second, the planetary flow feels the effects of the eddies, but appears to be unable to generate them. The first two regimes rely on horizontally isotropic large-scale dynamics. In the third regime, large-scale anisotropy, as exists for example in the Antarctic Circumpolar Current and in western boundary currents, allows the large-scale dynamics to both generate and respond to mesoscale eddies. We also discuss how the investigation may be brought to bear on the problem of parameterization of unresolved mesoscale dynamics in ocean general circulation models.

The dynamical core of the Aeolus 1.0 statistical-dynamical atmosphere model: validation and parameter optimization

NASA Astrophysics Data System (ADS)

Totz, Sonja; Eliseev, Alexey V.; Petri, Stefan; Flechsig, Michael; Caesar, Levke; Petoukhov, Vladimir; Coumou, Dim

2018-02-01

We present and validate a set of equations for representing the atmosphere's large-scale general circulation in an Earth system model of intermediate complexity (EMIC). These dynamical equations have been implemented in Aeolus 1.0, which is a statistical-dynamical atmosphere model (SDAM) and includes radiative transfer and cloud modules (Coumou et al., 2011; Eliseev et al., 2013). The statistical dynamical approach is computationally efficient and thus enables us to perform climate simulations at multimillennia timescales, which is a prime aim of our model development. Further, this computational efficiency enables us to scan large and high-dimensional parameter space to tune the model parameters, e.g., for sensitivity studies.Here, we present novel equations for the large-scale zonal-mean wind as well as those for planetary waves. Together with synoptic parameterization (as presented by Coumou et al., 2011), these form the mathematical description of the dynamical core of Aeolus 1.0.We optimize the dynamical core parameter values by tuning all relevant dynamical fields to ERA-Interim reanalysis data (1983-2009) forcing the dynamical core with prescribed surface temperature, surface humidity and cumulus cloud fraction. We test the model's performance in reproducing the seasonal cycle and the influence of the El Niño-Southern Oscillation (ENSO). We use a simulated annealing optimization algorithm, which approximates the global minimum of a high-dimensional function.With non-tuned parameter values, the model performs reasonably in terms of its representation of zonal-mean circulation, planetary waves and storm tracks. The simulated annealing optimization improves in particular the model's representation of the Northern Hemisphere jet stream and storm tracks as well as the Hadley circulation.The regions of high azonal wind velocities (planetary waves) are accurately captured for all validation experiments. The zonal-mean zonal wind and the integrated lower troposphere mass flux show good results in particular in the Northern Hemisphere. In the Southern Hemisphere, the model tends to produce too-weak zonal-mean zonal winds and a too-narrow Hadley circulation. We discuss possible reasons for these model biases as well as planned future model improvements and applications.

The Threatening Magnetic and Plasma Environment of the TRAPPIST-1 Planets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garraffo, Cecilia; Drake, Jeremy J.; Cohen, Ofer

2017-07-10

Recently, four additional Earth-mass planets were discovered orbiting the nearby ultracool M8 dwarf, TRAPPIST-1, making a remarkable total of seven planets with equilibrium temperatures compatible with the presence of liquid water on their surface. Temperate terrestrial planets around an M-dwarf orbit close to their parent star, rendering their atmospheres vulnerable to erosion by the stellar wind and energetic electromagnetic and particle radiation. Here, we use state-of-the-art 3D magnetohydrodynamic models to simulate the wind around TRAPPIST-1 and study the conditions at each planetary orbit. All planets experience a stellar wind pressure between 10{sup 3} and 10{sup 5} times the solar windmore » pressure on Earth. All orbits pass through wind pressure changes of an order of magnitude and most planets spend a large fraction of their orbital period in the sub-Alfvénic regime. For plausible planetary magnetic field strengths, all magnetospheres are greatly compressed and undergo much more dynamic change than that of the Earth. The planetary magnetic fields connect with the stellar radial field over much of the planetary surface, allowing the direct flow of stellar wind particles onto the planetary atmosphere. These conditions could result in strong atmospheric stripping and evaporation and should be taken into account for any realistic assessment of the evolution and habitability of the TRAPPIST-1 planets.« less

Numerical simulation of an experimental analogue of a planetary magnetosphere

NASA Astrophysics Data System (ADS)

Liao, Andy Sha; Li, Shule; Hartigan, Patrick; Graham, Peter; Fiksel, Gennady; Frank, Adam; Foster, John; Kuranz, Carolyn

2015-12-01

Recent improvements to the Omega Laser Facility's magneto-inertial fusion electrical discharge system (MIFEDS) have made it possible to generate strong enough magnetic fields in the laboratory to begin to address the physics of magnetized astrophysical flows. Here, we adapt the MHD code AstroBEAR to create 2D numerical models of an experimental analogue of a planetary magnetosphere. We track the secular evolution of the magnetosphere analogue and we show that the magnetospheric components such as the magnetopause, magnetosheath, and bow shock, should all be observable in experimental optical band thermal bremsstrahlung emissivity maps, assuming equilibrium charge state distributions of the plasma. When the magnetosphere analogue nears the steady state, the mid-plane altitude of the magnetopause from the wire surface scales as the one-half power of the ratio of the magnetic pressure at the surface of the free wire to the ram pressure of an unobstructed wind; the mid-plane thickness of the magnetosheath is directly related to the radius of the magnetopause. This behavior conforms to Chapman and Ferraro's theory of planetary magnetospheres. Although the radial dependence of the magnetic field strength differs between the case of a current-carrying wire and a typical planetary object, the major morphological features that develop when a supersonic flow passes either system are identical. Hence, this experimental concept is an attractive one for studying the dynamics of planetary magnetospheres in a controlled environment.

The Hottest Hot Jupiters May Host Atmospheric Dynamos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, T. M.; McElwaine, J. N.

2017-06-01

Hot Jupiters have proven themselves to be a rich class of exoplanets that test our theories of planetary evolution and atmospheric dynamics under extreme conditions. Here, we present three-dimensional magnetohydrodynamic simulations and analytic results that demonstrate that a dynamo can be maintained in the thin, stably stratified atmosphere of a hot Jupiter, independent of the presumed deep-seated dynamo. This dynamo is maintained by conductivity variations arising from strong asymmetric heating from the planets’ host star. The presence of a dynamo significantly increases the surface magnetic field strength and alters the overall planetary magnetic field geometry, possibly affecting star–planet magnetic interactions.

Remote microscopy and volumetric imaging on the surface of icy satellites

NASA Astrophysics Data System (ADS)

Soto, Alejandro; Nowicki, Keith; Howett, Carly; Feldkhun, Daniel; Retherford, Kurt D.

2017-10-01

With NASA PIDDP support we have applied recent advancements in Fourier-domain microscopy to develop an instrument capable of microscopic imaging from meter-scale distances for use on a planetary lander on the surface of an icy satellite or other planetary bodies. Without moving parts, our instrument projects dynamic patterns of laser light onto a distant target using a lightweight large-aperture reflector, which then collects the light scattered or fluoresced by the target on a fast photon-bucket detector. Using Fourier Transform based techniques, we reconstruct an image from the detected light. The remote microscope has been demonstrated to produce 2D images with better than 15 micron lateral resolution for targets at a distance of 5 meters and is capable of linearly proportionally higher resolution at shorter distances. The remote microscope is also capable of providing three-dimensional (3D) microscopic imaging capabilities, allowing future surface scientists to explore the morphology of microscopic features in surface ices, for example. The instrument enables microscopic in-situ imaging during day or night without the use of a robotic arm, greatly facilitating the surface operations for a lander or rover while expanding the area of investigation near a landing site for improved science targeting. We are developing this remote microscope for in-situ planetary exploration as a collaboration between the Southwest Research Institute, LambdaMetrics, and the University of Colorado.

Fourier transform spectroscopy for future planetary missions

NASA Astrophysics Data System (ADS)

Brasunas, John C.; Hewagama, Tilak; Kolasinski, John R.; Kostiuk, Theodor

2015-11-01

Thermal-emission infrared spectroscopy is a powerful tool for exploring the composition, temperature structure, and dynamics of planetary atmospheres; and the temperature of solid surfaces. A host of Fourier transform spectrometers (FTS) such as Mariner IRIS, Voyager IRIS, and Cassini CIRS from NASA Goddard have made and continue to make important new discoveries throughout the solar system.Future FTS instruments will have to be more sensitive (when we concentrate on the colder, outer reaches of the solar system), and less massive and less power-hungry as we cope with decreasing resource allotments for future planetary science instruments. With this in mind, NASA Goddard was funded via the Planetary Instrument Definition and Development Progrem (PIDDP) to develop CIRS-lite, a smaller version of the CIRS FTS for future planetary missions. Following the initial validation of CIRS-lite operation in the laboratory, we have been acquiring atmospheric data in the 8-12 micron window at the 1.2 m telescope at the Goddard Geophysical and Astronomical Observatory (GGAO) in Greenbelt, MD. Targets so far have included Earth's atmosphere (in emission, and in absorption against the moon), and Venus.We will present the roadmap for making CIRS-lite a viable candidate for future planetary missions.

Planetary Surface Instruments Workshop

NASA Technical Reports Server (NTRS)

Meyer, Charles (Editor); Treiman, Allan H. (Editor); Kostiuk, Theodor (Editor)

1996-01-01

This report on planetary surface investigations and planetary landers covers: (1) the precise chemical analysis of solids; (2) isotopes and evolved gas analyses; (3) planetary interiors; planetary atmospheres from within as measured by landers; (4) mineralogical examination of extraterrestrial bodies; (5) regoliths; and (6) field geology/processes.

Our evolving understanding of aeolian bedforms, based on observation of dunes on different worlds

NASA Astrophysics Data System (ADS)

Diniega, Serina; Kreslavsky, Mikhail; Radebaugh, Jani; Silvestro, Simone; Telfer, Matt; Tirsch, Daniela

2017-06-01

Dunes, dune fields, and ripples are unique and useful records of the interaction between wind and granular materials - finding such features on a planetary surface immediately suggests certain information about climate and surface conditions (at least during the dunes' formation and evolution). Additionally, studies of dune characteristics under non-Earth conditions allow for ;tests; of aeolian process models based primarily on observations of terrestrial features and dynamics, and refinement of the models to include consideration of a wider range of environmental and planetary conditions. To-date, the planetary aeolian community has found and studied dune fields on Mars, Venus, and the Saturnian moon Titan. Additionally, we have observed candidate ;aeolian bedforms; on Comet 67P/Churyumov-Gerasimenko, the Jovian moon Io, and - most recently - Pluto. In this paper, we hypothesize that the progression of investigations of aeolian bedforms and processes on a particular planetary body follows a consistent sequence - primarily set by the acquisition of data of particular types and resolutions, and by the maturation of knowledge about that planetary body. We define that sequence of generated knowledge and new questions (within seven investigation phases) and discuss examples from all of the studied bodies. The aim of such a sequence is to better define our past and current state of understanding about the aeolian bedforms of a particular body, to highlight the related assumptions that require re-analysis with data acquired during later investigations, and to use lessons learned from planetary and terrestrial aeolian studies to predict what types of investigations could be most fruitful in the future.

The effect of latent heat release on synoptic-to-planetary wave interactions and its implication for satellite observations: Theoretical modeling

NASA Technical Reports Server (NTRS)

Branscome, Lee E.; Bleck, Rainer; Obrien, Enda

1990-01-01

The project objectives are to develop process models to investigate the interaction of planetary and synoptic-scale waves including the effects of latent heat release (precipitation), nonlinear dynamics, physical and boundary-layer processes, and large-scale topography; to determine the importance of latent heat release for temporal variability and time-mean behavior of planetary and synoptic-scale waves; to compare the model results with available observations of planetary and synoptic wave variability; and to assess the implications of the results for monitoring precipitation in oceanic-storm tracks by satellite observing systems. Researchers have utilized two different models for this project: a two-level quasi-geostrophic model to study intraseasonal variability, anomalous circulations and the seasonal cycle, and a 10-level, multi-wave primitive equation model to validate the two-level Q-G model and examine effects of convection, surface processes, and spherical geometry. It explicitly resolves several planetary and synoptic waves and includes specific humidity (as a predicted variable), moist convection, and large-scale precipitation. In the past year researchers have concentrated on experiments with the multi-level primitive equation model. The dynamical part of that model is similar to the spectral model used by the National Meteorological Center for medium-range forecasts. The model includes parameterizations of large-scale condensation and moist convection. To test the validity of results regarding the influence of convective precipitation, researchers can use either one of two different convective schemes in the model, a Kuo convective scheme or a modified Arakawa-Schubert scheme which includes downdrafts. By choosing one or the other scheme, they can evaluate the impact of the convective parameterization on the circulation. In the past year researchers performed a variety of initial-value experiments with the primitive-equation model. Using initial conditions typical of climatological winter conditions, they examined the behavior of synoptic and planetary waves growing in moist and dry environments. Surface conditions were representative of a zonally averaged ocean. They found that moist convection associated with baroclinic wave development was confined to the subtropics.

Energy Balance Models and Planetary Dynamics

NASA Technical Reports Server (NTRS)

Domagal-Goldman, Shawn

2012-01-01

We know that planetary dynamics can have a significant affect on the climate of planets. Planetary dynamics dominate the glacial-interglacial periods on Earth, leaving a significant imprint on the geological record. They have also been demonstrated to have a driving influence on the climates of other planets in our solar system. We should therefore expect th.ere to be similar relationships on extrasolar planets. Here we describe a simple energy balance model that can predict the growth and thickness of glaciers, and their feedbacks on climate. We will also describe model changes that we have made to include planetary dynamics effects. This is the model we will use at the start of our collaboration to handle the influence of dynamics on climate.

Expanding the Planetary Analog Test Sites in Hawaii - Planetary Basalt Manipulation

NASA Astrophysics Data System (ADS)

Kelso, R.

2013-12-01

The Pacific International Space Center for Exploration Systems (PISCES) is one of the very few planetary surface research test sites in the country that is totally funded by the state legislature. In recent expansions, PISCES is broadening its work in planetary test sites to include much more R&D work in the planetary surface systems, and the manipulation of basalt materials. This is to include laser 3D printing of basalt, 'lunar-concrete' construction in state projects for Hawaii, renewable energy, and adding lava tubes/skylights to their mix of high-quality planetary analog test sites. PISCES Executive Director, Rob Kelso, will be providing program updates on the interest of the Hawaii State Legislature in planetary surface systems, new applied research initiatives in planetary basalts and interests in planetary construction.

Demarcating Circulation Regimes of Synchronously Rotating Terrestrial Planets within the Habitable Zone

NASA Astrophysics Data System (ADS)

Haqq-Misra, Jacob; Wolf, Eric. T.; Joshi, Manoj; Zhang, Xi; Kopparapu, Ravi Kumar

2018-01-01

We investigate the atmospheric dynamics of terrestrial planets in synchronous rotation within the habitable zone of low-mass stars using the Community Atmosphere Model. The surface temperature contrast between the day and night hemispheres decreases with an increase in incident stellar flux, which is opposite the trend seen in gas giants. We define three dynamical regimes in terms of the equatorial Rossby deformation radius and the Rhines length. The slow rotation regime has a mean zonal circulation that spans from the day to the night sides, which occurs for planets around stars with effective temperatures of 3300–4500 K (rotation period > 20 days), with both the Rossby deformation radius and the Rhines length exceeding the planetary radius. Rapid rotators have a mean zonal circulation that partially spans a hemisphere and with banded cloud formation beneath the substellar point, which occurs for planets orbiting stars with effective temperatures of less than 3000 K (rotation period < 5 days), with the Rossby deformation radius less than the planetary radius. In between is the Rhines rotation regime, which retains a thermally direct circulation from the day side to the night side but also features midlatitude turbulence-driven zonal jets. Rhines rotators occur for planets around stars in the range of 3000–3300 K (rotation period ∼5–20 days), where the Rhines length is greater than the planetary radius but the Rossby deformation radius is less than the planetary radius. The dynamical state can be observationally inferred from a comparison of the morphologies of the thermal emission phase curves of synchronously rotating planets.

Dependence of the Onset of the Runaway Greenhouse Effect on the Latitudinal Surface Water Distribution of Earth-Like Planets

NASA Astrophysics Data System (ADS)

Kodama, T.; Nitta, A.; Genda, H.; Takao, Y.; O'ishi, R.; Abe-Ouchi, A.; Abe, Y.

2018-02-01

Liquid water is one of the most important materials affecting the climate and habitability of a terrestrial planet. Liquid water vaporizes entirely when planets receive insolation above a certain critical value, which is called the runaway greenhouse threshold. This threshold forms the inner most limit of the habitable zone. Here we investigate the effects of the distribution of surface water on the runaway greenhouse threshold for Earth-sized planets using a three-dimensional dynamic atmosphere model. We considered a 1 bar atmosphere whose composition is similar to the current Earth's atmosphere with a zonally uniform distribution of surface water. As previous studies have already showed, we also recognized two climate regimes: the land planet regime, which has dry low-latitude and wet high-latitude regions, and the aqua planet regime, which is globally wet. We showed that each regime is controlled by the width of the Hadley circulation, the amount of surface water, and the planetary topography. We found that the runaway greenhouse threshold varies continuously with the surface water distribution from about 130% (an aqua planet) to 180% (the extreme case of a land planet) of the present insolation at Earth's orbit. Our results indicate that the inner edge of the habitable zone is not a single sharp boundary, but a border whose location varies depending on planetary surface condition, such as the amount of surface water. Since land planets have wider habitable zones and less cloud cover, land planets would be good targets for future observations investigating planetary habitability.

Lunar and Planetary Science XXXV: Outer Solar System

NASA Technical Reports Server (NTRS)

2004-01-01

The session "Outer Solar System" included the following reports:New Data About Seasonal Variations of the North-South Asymmetry of Polarized Light of Jupiter; Appearance of Second Harmonic in the Jupiter Spectrum; Dynamics of Confined Liquid Mass, Spreading on Planet Surface; "Cassini" will Discover 116 New Satellites of Saturn!; Jupiter's Light Reflection Law;and Internal Structure Modelling of Europa.

Study on the optimization of the deposition rate of planetary GaN-MOCVD films based on CFD simulation and the corresponding surface model

PubMed Central

Fei, Ze-yuan; Xu, Yi-feng; Wang, Jie; Fan, Bing-feng; Ma, Xue-jin; Wang, Gang

2018-01-01

Metal-organic chemical vapour deposition (MOCVD) is a key technique for fabricating GaN thin film structures for light-emitting and semiconductor laser diodes. Film uniformity is an important index to measure equipment performance and chip processes. This paper introduces a method to improve the quality of thin films by optimizing the rotation speed of different substrates of a model consisting of a planetary with seven 6-inch wafers for the planetary GaN-MOCVD. A numerical solution to the transient state at low pressure is obtained using computational fluid dynamics. To evaluate the role of the different zone speeds on the growth uniformity, single factor analysis is introduced. The results show that the growth rate and uniformity are strongly related to the rotational speed. Next, a response surface model was constructed by using the variables and the corresponding simulation results. The optimized combination of the matching of different speeds is also proposed as a useful reference for applications in industry, obtained by a response surface model and genetic algorithm with a balance between the growth rate and the growth uniformity. This method can save time, and the optimization can obtain the most uniform and highest thin film quality. PMID:29515883

Study on the optimization of the deposition rate of planetary GaN-MOCVD films based on CFD simulation and the corresponding surface model.

PubMed

Li, Jian; Fei, Ze-Yuan; Xu, Yi-Feng; Wang, Jie; Fan, Bing-Feng; Ma, Xue-Jin; Wang, Gang

2018-02-01

Metal-organic chemical vapour deposition (MOCVD) is a key technique for fabricating GaN thin film structures for light-emitting and semiconductor laser diodes. Film uniformity is an important index to measure equipment performance and chip processes. This paper introduces a method to improve the quality of thin films by optimizing the rotation speed of different substrates of a model consisting of a planetary with seven 6-inch wafers for the planetary GaN-MOCVD. A numerical solution to the transient state at low pressure is obtained using computational fluid dynamics. To evaluate the role of the different zone speeds on the growth uniformity, single factor analysis is introduced. The results show that the growth rate and uniformity are strongly related to the rotational speed. Next, a response surface model was constructed by using the variables and the corresponding simulation results. The optimized combination of the matching of different speeds is also proposed as a useful reference for applications in industry, obtained by a response surface model and genetic algorithm with a balance between the growth rate and the growth uniformity. This method can save time, and the optimization can obtain the most uniform and highest thin film quality.

Study on the optimization of the deposition rate of planetary GaN-MOCVD films based on CFD simulation and the corresponding surface model

NASA Astrophysics Data System (ADS)

Li, Jian; Fei, Ze-yuan; Xu, Yi-feng; Wang, Jie; Fan, Bing-feng; Ma, Xue-jin; Wang, Gang

2018-02-01

Metal-organic chemical vapour deposition (MOCVD) is a key technique for fabricating GaN thin film structures for light-emitting and semiconductor laser diodes. Film uniformity is an important index to measure equipment performance and chip processes. This paper introduces a method to improve the quality of thin films by optimizing the rotation speed of different substrates of a model consisting of a planetary with seven 6-inch wafers for the planetary GaN-MOCVD. A numerical solution to the transient state at low pressure is obtained using computational fluid dynamics. To evaluate the role of the different zone speeds on the growth uniformity, single factor analysis is introduced. The results show that the growth rate and uniformity are strongly related to the rotational speed. Next, a response surface model was constructed by using the variables and the corresponding simulation results. The optimized combination of the matching of different speeds is also proposed as a useful reference for applications in industry, obtained by a response surface model and genetic algorithm with a balance between the growth rate and the growth uniformity. This method can save time, and the optimization can obtain the most uniform and highest thin film quality.

Determining the geotechnical properties of planetary regolith using Low Velocity Penetrometers

NASA Astrophysics Data System (ADS)

Seweryn, K.; Skocki, K.; Banaszkiewicz, M.; Grygorczuk, J.; Kolano, M.; Kuciński, T.; Mazurek, J.; Morawski, M.; Białek, A.; Rickman, H.; Wawrzaszek, R.

2014-09-01

Measurements of mechanical and thermophysical properties of planetary surface allow determining many important parameters useful for planetologists. For example, effective heat conductivity or thermal inertia of the regolith can help to better understand the processes occurring in the bodies interior. Chemical and mineralogical composition gives us a chance to determine the origin and evolution of moons and satellites. Mechanical properties of the surface are one of the key factors needed by civil engineers for developing future bases on space bodies. Space missions to planetary bodies highly restrict the payload concerning its mass and power consumption. Therefore, it is quite impossible to use a standard terrestrial technique like the Load Plate Test or Direct Shear Tests to determine the geotechnical parameters of the planetary regolith. Even the Dynamic Cone Penetration (DCP) method, which is frequently used for field testing, does not fit well with the constraints imposed by a space mission. Nevertheless, its operation principle is very similar to that of at the Low Velocity Penetrators (LVP), several of them being currently on their way to planetary bodies (e.g. the MUPUS instrument) or which were developed in the last couple of years (e.g. the CHOMIK instrument or the KRET device). In this paper we present a comparison between DCP method and LVP operation which was observed during several tests campaigns during mole KRET and CHOMIK instrument development. The tests were performed in different planetary analogues: JSC-1A, Chenobi and AGK-2010, Phobos analogue, cometary analogues F1, F2 and F3 (SRC) and dry quartz sand. In the last part of the paper the concept of results' interpretation is presented.

The topology of non-linear global carbon dynamics: from tipping points to planetary boundaries

NASA Astrophysics Data System (ADS)

Anderies, J. M.; Carpenter, S. R.; Steffen, Will; Rockström, Johan

2013-12-01

We present a minimal model of land use and carbon cycle dynamics and use it to explore the relationship between non-linear dynamics and planetary boundaries. Only the most basic interactions between land cover and terrestrial, atmospheric, and marine carbon stocks are considered in the model. Our goal is not to predict global carbon dynamics as it occurs in the actual Earth System. Rather, we construct a conceptually reasonable heuristic model of a feedback system between different carbon stocks that captures the qualitative features of the actual Earth System and use it to explore the topology of the boundaries of what can be called a ‘safe operating space’ for humans. The model analysis illustrates the existence of dynamic, non-linear tipping points in carbon cycle dynamics and the potential complexity of planetary boundaries. Finally, we use the model to illustrate some challenges associated with navigating planetary boundaries.

Modeling the Surface Temperature of Earth-like Planets

NASA Astrophysics Data System (ADS)

Vladilo, Giovanni; Silva, Laura; Murante, Giuseppe; Filippi, Luca; Provenzale, Antonello

2015-05-01

We introduce a novel Earth-like planet surface temperature model (ESTM) for habitability studies based on the spatial-temporal distribution of planetary surface temperatures. The ESTM adopts a surface energy balance model (EBM) complemented by: radiative-convective atmospheric column calculations, a set of physically based parameterizations of meridional transport, and descriptions of surface and cloud properties more refined than in standard EBMs. The parameterization is valid for rotating terrestrial planets with shallow atmospheres and moderate values of axis obliquity (ɛ ≲ 45{}^\\circ ). Comparison with a 3D model of atmospheric dynamics from the literature shows that the equator-to-pole temperature differences predicted by the two models agree within ≈ 5 K when the rotation rate, insolation, surface pressure and planet radius are varied in the intervals 0.5≲ {Ω }/{{{Ω }}\\oplus }≲ 2, 0.75≲ S/{{S}\\circ }≲ 1.25, 0.3≲ p/(1 bar)≲ 10, and 0.5≲ R/{{R}\\oplus }≲ 2, respectively. The ESTM has an extremely low computational cost and can be used when the planetary parameters are scarcely known (as for most exoplanets) and/or whenever many runs for different parameter configurations are needed. Model simulations of a test-case exoplanet (Kepler-62e) indicate that an uncertainty in surface pressure within the range expected for terrestrial planets may impact the mean temperature by ˜ 60 K. Within the limits of validity of the ESTM, the impact of surface pressure is larger than that predicted by uncertainties in rotation rate, axis obliquity, and ocean fractions. We discuss the possibility of performing a statistical ranking of planetary habitability taking advantage of the flexibility of the ESTM.

Planetary Surface Instruments Workshop

NASA Astrophysics Data System (ADS)

Meyer, Charles; Treiman, Allanh; Kostiuk, Theodor,

1996-01-01

This report on planetary surface investigations an d planetary landers covers: (1) the precise chemic al analysis of solids; (2) isotopes and evolved ga s analyses; (3) planetary interiors; planetary atm ospheres from within as measured by landers; (4) m ineralogical examination of extraterrestrial bodie s; (5) regoliths; and (6) field geology/processes . For individual titles, see N96-34812 through N96-34819. (Derived from text.)

Parallel Study of HEND, RAD, and DAN Instrument Response to Martian Radiation and Surface Conditions

NASA Technical Reports Server (NTRS)

Martiniez Sierra, Luz Maria; Jun, Insoo; Litvak, Maxim; Sanin, Anton; Mitrofanov, Igor; Zeitlin, Cary

2015-01-01

Nuclear detection methods are being used to understand the radiation environment at Mars. JPL (Jet Propulsion Laboratory) assets on Mars include: Orbiter -2001 Mars Odyssey [High Energy Neutron Detector (HEND)]; Mars Science Laboratory Rover -Curiosity [(Radiation Assessment Detector (RAD); Dynamic Albedo Neutron (DAN))]. Spacecraft have instruments able to detect ionizing and non-ionizing radiation. Instrument response on orbit and on the surface of Mars to space weather and local conditions [is discussed] - Data available at NASA-PDS (Planetary Data System).

From Core to Solar Wind: Studying the Space Environment of Planets

NASA Astrophysics Data System (ADS)

Bagenal, F.

2004-05-01

Space physics permeates studies of the planets - from the magnetic field generated in a planetary core, through the charged particle bombardment of surfaces, the heating, excitation and ionization of an atmosphere or corona, to the acceleration of ions and electrons trapped in a planet's magnetosphere. This presentation provides an introductory overview of the space environment of planetary objects - from giant planets to tiny comets. The talk highlights three cases that illustrate the range of issues and applications of planetary space physics. (1) How has the solar wind interaction with Mars' strong, patchy remnant magnetization affected the loss of water? (2) How does the activity of volcanoes on Io trigger dynamics of the vast magnetosphere of Jupiter? (3) How could measurements of particles and fields by the Galileo spacecraft as it flew past Ganymede and Europa tell us that former has a liquid iron core and the latter a layer of liquid water?

A new scheme for the parameterization of the turbulent planetary boundary layer in the GLAS fourth order GCM

NASA Technical Reports Server (NTRS)

Helfand, H. M.

1985-01-01

Methods being used to increase the horizontal and vertical resolution and to implement more sophisticated parameterization schemes for general circulation models (GCM) run on newer, more powerful computers are described. Attention is focused on the NASA-Goddard Laboratory for Atmospherics fourth order GCM. A new planetary boundary layer (PBL) model has been developed which features explicit resolution of two or more layers. Numerical models are presented for parameterizing the turbulent vertical heat, momentum and moisture fluxes at the earth's surface and between the layers in the PBL model. An extended Monin-Obhukov similarity scheme is applied to express the relationships between the lowest levels of the GCM and the surface fluxes. On-line weather prediction experiments are to be run to test the effects of the higher resolution thereby obtained for dynamic atmospheric processes.

Nonlinear dynamics of planetary gears using analytical and finite element models

NASA Astrophysics Data System (ADS)

Ambarisha, Vijaya Kumar; Parker, Robert G.

2007-05-01

Vibration-induced gear noise and dynamic loads remain key concerns in many transmission applications that use planetary gears. Tooth separations at large vibrations introduce nonlinearity in geared systems. The present work examines the complex, nonlinear dynamic behavior of spur planetary gears using two models: (i) a lumped-parameter model, and (ii) a finite element model. The two-dimensional (2D) lumped-parameter model represents the gears as lumped inertias, the gear meshes as nonlinear springs with tooth contact loss and periodically varying stiffness due to changing tooth contact conditions, and the supports as linear springs. The 2D finite element model is developed from a unique finite element-contact analysis solver specialized for gear dynamics. Mesh stiffness variation excitation, corner contact, and gear tooth contact loss are all intrinsically considered in the finite element analysis. The dynamics of planetary gears show a rich spectrum of nonlinear phenomena. Nonlinear jumps, chaotic motions, and period-doubling bifurcations occur when the mesh frequency or any of its higher harmonics are near a natural frequency of the system. Responses from the dynamic analysis using analytical and finite element models are successfully compared qualitatively and quantitatively. These comparisons validate the effectiveness of the lumped-parameter model to simulate the dynamics of planetary gears. Mesh phasing rules to suppress rotational and translational vibrations in planetary gears are valid even when nonlinearity from tooth contact loss occurs. These mesh phasing rules, however, are not valid in the chaotic and period-doubling regions.

Reaction: Chemistry Driven by the Harsh Space Environment

NASA Technical Reports Server (NTRS)

Farrell, William M.

2018-01-01

The studies by Solar System Exploration Research Virtual Institute (SSERVI) teams such as REVEALS and DREAM2 not only connect back to the highest planetary science decadal goals regarding volatiles but also feed forward to understanding the chemical origins of potential resources at the surface useful for human exploration. See https://sservi.nasa.gov for more about SSERVI and its dynamic teams.

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration

NASA Technical Reports Server (NTRS)

1974-01-01

A number of problems related to the design, construction and evaluation of an autonomous roving planetary vehicle and its control and operating systems intended for an unmanned exploration of Mars are studied. Vehicle configuration, dynamics, control, systems and propulsion; systems analysis; terrain sensing and modeling and path selection; and chemical analysis of samples are included.

A unique basaltic micrometeorite expands the inventory of solar system planetary crusts

PubMed Central

Gounelle, Matthieu; Chaussidon, Marc; Morbidelli, Alessandro; Barrat, Jean-Alix; Engrand, Cécile; Zolensky, Michael E.; McKeegan, Kevin D.

2009-01-01

Micrometeorites with diameter ≈100–200 μm dominate the flux of extraterrestrial matter on Earth. The vast majority of micrometeorites are chemically, mineralogically, and isotopically related to carbonaceous chondrites, which amount to only 2.5% of meteorite falls. Here, we report the discovery of the first basaltic micrometeorite (MM40). This micrometeorite is unlike any other basalt known in the solar system as revealed by isotopic data, mineral chemistry, and trace element abundances. The discovery of a new basaltic asteroidal surface expands the solar system inventory of planetary crusts and underlines the importance of micrometeorites for sampling the asteroids' surfaces in a way complementary to meteorites, mainly because they do not suffer dynamical biases as meteorites do. The parent asteroid of MM40 has undergone extensive metamorphism, which ended no earlier than 7.9 Myr after solar system formation. Numerical simulations of dust transport dynamics suggest that MM40 might originate from one of the recently discovered basaltic asteroids that are not members of the Vesta family. The ability to retrieve such a wealth of information from this tiny (a few micrograms) sample is auspicious some years before the launch of a Mars sample return mission. PMID:19366660

Laser Technology in Interplanetary Exploration: The Past and the Future

NASA Technical Reports Server (NTRS)

Smith, David E.

2000-01-01

Laser technology has been used in planetary exploration for many years but it has only been in the last decade that laser altimeters and ranging systems have been selected as flight instruments alongside cameras, spectrometers, magnetometers, etc. Today we have an active laser system operating at Mars and another destined for the asteroid Eros. A few years ago a laser ranging system on the Clementine mission changed much of our thinking about the moon and in a few years laser altimeters will be on their way to Mercury, and also to Europa. Along with the increased capabilities and reliability of laser systems has came the realization that precision ranging to the surface of planetary bodies from orbiting spacecraft enables more scientific problems to be addressed, including many associated with planetary rotation, librations, and tides. In addition, new Earth-based laser ranging systems working with similar systems on other planetary bodies in an asynchronous transponder mode will be able to make interplanetary ranging measurements at the few cm level and will advance our understanding of solar system dynamics and relativistic physics.

Smaller solar system bodies and orbits; Proceedings of Symposium 3, Workshops II, III, and XXVI, and Topical Meetings of the 27th COSPAR Plenary Meeting, Espoo, Finland, July 18-29, 1988

NASA Technical Reports Server (NTRS)

Runcorn, S. K. (Editor); Carr, M. H. (Editor); Moehlmann, D. (Editor); Stiller, H. (Editor); Matson, D. L. (Editor); Ambrosius, B. A. C. (Editor); Kessler, D. J. (Editor)

1990-01-01

Topics discussed in this volume include the reappraisal of the moon and Mars/Phobos/Deimos; the origin and evolution of planetary and satellite systems; asteroids, comets, and dust (a post-IRAS perspective); satellite dynamics; future planetary missions; and orbital debris. Papers are presented on a comparison of the chemistry of moon and Mars, the use of a mobile surface radar to study the atmosphere and ionosphere, and laser-ionization studies with the technical models of the LIMA-D/Phobos. Attention is given to planetogonic scenarios and the evolution of relatively mass-rich preplanetary disks, the kinetic behavior of planetesimals revolving around the sun, the planetary evolution of Mars, and pre- and post-IRAS asteroid taxonomies. Consideration is also given to ocean tides and tectonic plate motions in high-precision orbit determination, the satellite altimeter calibration techniques, a theory of the motion of an artificial satellite in the earth atmosphere, ESA plans for planetary exploration, and the detection of earth orbiting objects by IRAS.

Smaller solar system bodies and orbits; Proceedings of Symposium 3, Workshops II, III, and XXVI, and Topical Meetings of the 27th COSPAR Plenary Meeting, Espoo, Finland, July 18-29, 1988

NASA Astrophysics Data System (ADS)

Runcorn, S. K.; Carr, M. H.; Moehlmann, D.; Stiller, H.; Matson, D. L.; Ambrosius, B. A. C.; Kessler, D. J.

Topics discussed in this volume include the reappraisal of the moon and Mars/Phobos/Deimos; the origin and evolution of planetary and satellite systems; asteroids, comets, and dust (a post-IRAS perspective); satellite dynamics; future planetary missions; and orbital debris. Papers are presented on a comparison of the chemistry of moon and Mars, the use of a mobile surface radar to study the atmosphere and ionosphere, and laser-ionization studies with the technical models of the LIMA-D/Phobos. Attention is given to planetogonic scenarios and the evolution of relatively mass-rich preplanetary disks, the kinetic behavior of planetesimals revolving around the sun, the planetary evolution of Mars, and pre- and post-IRAS asteroid taxonomies. Consideration is also given to ocean tides and tectonic plate motions in high-precision orbit determination, the satellite altimeter calibration techniques, a theory of the motion of an artificial satellite in the earth atmosphere, ESA plans for planetary exploration, and the detection of earth orbiting objects by IRAS.

On evolutionary climate tracks in deep mantle volatile cycle computed from numerical mantle convection simulations and its impact on the habitability of the Earth-like planets

NASA Astrophysics Data System (ADS)

Nakagawa, T.; Tajika, E.; Kadoya, S.

2017-12-01

Discussing an impact of evolution and dynamics in the Earth's deep interior on the surface climate change for the last few decades (see review by Ehlmann et al., 2016), the mantle volatile (particularly carbon) degassing in the mid-oceanic ridges seems to play a key role in understanding the evolutionary climate track for Earth-like planets (e.g. Kadoya and Tajika, 2015). However, since the mantle degassing occurs not only in the mid-oceanic ridges but also in the wedge mantle (island arc volcanism) and hotspots, to incorporate more accurate estimate of mantle degassing flux into the climate evolution framework, we developed a coupled model of surface climate-deep Earth evolution in numerical mantle convection simulations, including more accurate deep water and carbon cycle (e.g. Nakagawa and Spiegelman, 2017) with an energy balance theory of climate change. Modeling results suggest that the evolution of planetary climate computed from a developed model is basically consistent with an evolutionary climate track in simplified mantle degassing model (Kadoya and Tajika, 2015), but an occurrence timing of global (snowball) glaciation is strongly dependent on mantle degassing rate occurred with activities of surface plate motions. With this implication, the surface plate motion driven by deep mantle dynamics would play an important role in the planetary habitability of such as the Earth and Earth-like planets over geologic time-scale.

Globe Browsing: Contextualized Spatio-Temporal Planetary Surface Visualization.

PubMed

Bladin, Karl; Axelsson, Emil; Broberg, Erik; Emmart, Carter; Ljung, Patric; Bock, Alexander; Ynnerman, Anders

2017-08-29

Results of planetary mapping are often shared openly for use in scientific research and mission planning. In its raw format, however, the data is not accessible to non-experts due to the difficulty in grasping the context and the intricate acquisition process. We present work on tailoring and integration of multiple data processing and visualization methods to interactively contextualize geospatial surface data of celestial bodies for use in science communication. As our approach handles dynamic data sources, streamed from online repositories, we are significantly shortening the time between discovery and dissemination of data and results. We describe the image acquisition pipeline, the pre-processing steps to derive a 2.5D terrain, and a chunked level-of-detail, out-of-core rendering approach to enable interactive exploration of global maps and high-resolution digital terrain models. The results are demonstrated for three different celestial bodies. The first case addresses high-resolution map data on the surface of Mars. A second case is showing dynamic processes, such as concurrent weather conditions on Earth that require temporal datasets. As a final example we use data from the New Horizons spacecraft which acquired images during a single flyby of Pluto. We visualize the acquisition process as well as the resulting surface data. Our work has been implemented in the OpenSpace software [8], which enables interactive presentations in a range of environments such as immersive dome theaters, interactive touch tables, and virtual reality headsets.

A comprehensive sensitivity analysis of the WRF model for air quality applications over the Iberian Peninsula

NASA Astrophysics Data System (ADS)

Borge, Rafael; Alexandrov, Vassil; José del Vas, Juan; Lumbreras, Julio; Rodríguez, Encarnacion

Meteorological inputs play a vital role on regional air quality modelling. An extensive sensitivity analysis of the Weather Research and Forecasting (WRF) model was performed, in the framework of the Integrated Assessment Modelling System for the Iberian Peninsula (SIMCA) project. Up to 23 alternative model configurations, including Planetary Boundary Layer schemes, Microphysics, Land-surface models, Radiation schemes, Sea Surface Temperature and Four-Dimensional Data Assimilation were tested in a 3 km spatial resolution domain. Model results for the most significant meteorological variables, were assessed through a series of common statistics. The physics options identified to produce better results (Yonsei University Planetary Boundary Layer, WRF Single-Moment 6-class microphysics, Noah Land-surface model, Eta Geophysical Fluid Dynamics Laboratory longwave radiation and MM5 shortwave radiation schemes) along with other relevant user settings (time-varying Sea Surface Temperature and combined grid-observational nudging) where included in a "best case" configuration. This setup was tested and found to produce more accurate estimation of temperature, wind and humidity fields at surface level than any other configuration for the two episodes simulated. Planetary Boundary Layer height predictions showed a reasonable agreement with estimations derived from routine atmospheric soundings. Although some seasonal and geographical differences were observed, the model showed an acceptable behaviour overall. Despite being useful to define the most appropriate setup of the WRF model for air quality modelling over the Iberian Peninsula, this study provides a general overview of WRF sensitivity and can constitute a reference for future mesoscale meteorological modelling exercises.

Empirical relationships between soil moisture, albedo, and the planetary boundary layer height: a two-layer bucket model approach

NASA Astrophysics Data System (ADS)

Sanchez-Mejia, Z. M.; Papuga, S. A.

2013-12-01

In semiarid regions, where water resources are limited and precipitation dynamics are changing, understanding land surface-atmosphere interactions that regulate the coupled soil moisture-precipitation system is key for resource management and planning. We present a modeling approach to study soil moisture and albedo controls on planetary boundary layer height (PBLh). We used data from the Santa Rita Creosote Ameriflux site and Tucson Airport atmospheric sounding to generate empirical relationships between soil moisture, albedo and PBLh. We developed empirical relationships and show that at least 50% of the variation in PBLh can be explained by soil moisture and albedo. Then, we used a stochastically driven two-layer bucket model of soil moisture dynamics and our empirical relationships to model PBLh. We explored soil moisture dynamics under three different mean annual precipitation regimes: current, increase, and decrease, to evaluate at the influence on soil moisture on land surface-atmospheric processes. While our precipitation regimes are simple, they represent future precipitation regimes that can influence the two soil layers in our conceptual framework. For instance, an increase in annual precipitation, could impact on deep soil moisture and atmospheric processes if precipitation events remain intense. We observed that the response of soil moisture, albedo, and the PBLh will depend not only on changes in annual precipitation, but also on the frequency and intensity of this change. We argue that because albedo and soil moisture data are readily available at multiple temporal and spatial scales, developing empirical relationships that can be used in land surface - atmosphere applications are of great value.

Stability and self-organization of planetary systems.

PubMed

Pakter, Renato; Levin, Yan

2018-04-01

We show that stability of planetary systems is intimately connected with their internal order. An arbitrary initial distribution of planets is susceptible to catastrophic events in which planets either collide or are ejected from the planetary system. These instabilities are a fundamental consequence of chaotic dynamics and of Arnold diffusion characteristic of many body gravitational interactions. To ensure stability over astronomical time scale of a realistic planetary system-in which planets have masses comparable to those of planets in the solar system-the motion must be quasiperiodic. A dynamical mechanism is proposed which naturally evolves a planetary system to a quasiperiodic state from an arbitrary initial condition. A planetary self-organization predicted by the theory is similar to the one found in our solar system.

Stability and self-organization of planetary systems

NASA Astrophysics Data System (ADS)

Pakter, Renato; Levin, Yan

2018-04-01

We show that stability of planetary systems is intimately connected with their internal order. An arbitrary initial distribution of planets is susceptible to catastrophic events in which planets either collide or are ejected from the planetary system. These instabilities are a fundamental consequence of chaotic dynamics and of Arnold diffusion characteristic of many body gravitational interactions. To ensure stability over astronomical time scale of a realistic planetary system—in which planets have masses comparable to those of planets in the solar system—the motion must be quasiperiodic. A dynamical mechanism is proposed which naturally evolves a planetary system to a quasiperiodic state from an arbitrary initial condition. A planetary self-organization predicted by the theory is similar to the one found in our solar system.

Expansion of epicyclic gear dynamic analysis program

NASA Technical Reports Server (NTRS)

Boyd, Linda Smith; Pike, James A.

1987-01-01

The multiple mesh/single stage dynamics program is a gear tooth analysis program which determines detailed geometry, dynamic loads, stresses, and surface damage factors. The program can analyze a variety of both epicyclic and single mesh systems with spur or helical gear teeth including internal, external, and buttress tooth forms. The modifications refine the options for the flexible carrier and flexible ring gear rim and adds three options: a floating Sun gear option; a natural frequency option; and a finite element compliance formulation for helical gear teeth. The option for a floating Sun incorporates two additional degrees of freedom at the Sun center. The natural frequency option evaluates the frequencies of planetary, star, or differential systems as well as the effect of additional springs at the Sun center and those due to a flexible carrier and/or ring gear rim. The helical tooth pair finite element calculated compliance is obtained from an automated element breakup of the helical teeth and then is used with the basic gear dynamic solution and stress postprocessing routines. The flexible carrier or ring gear rim option for planetary and star spur gear systems allows the output torque per carrier and ring gear rim segment to vary based on the dynamic response of the entire system, while the total output torque remains constant.

Analysis of dynamic behavior of multiple-stage planetary gear train used in wind driven generator.

PubMed

Wang, Jungang; Wang, Yong; Huo, Zhipu

2014-01-01

A dynamic model of multiple-stage planetary gear train composed of a two-stage planetary gear train and a one-stage parallel axis gear is proposed to be used in wind driven generator to analyze the influence of revolution speed and mesh error on dynamic load sharing characteristic based on the lumped parameter theory. Dynamic equation of the model is solved using numerical method to analyze the uniform load distribution of the system. It is shown that the load sharing property of the system is significantly affected by mesh error and rotational speed; load sharing coefficient and change rate of internal and external meshing of the system are of obvious difference from each other. The study provides useful theoretical guideline for the design of the multiple-stage planetary gear train of wind driven generator.

Analysis of Dynamic Behavior of Multiple-Stage Planetary Gear Train Used in Wind Driven Generator

PubMed Central

Wang, Jungang; Wang, Yong; Huo, Zhipu

2014-01-01

A dynamic model of multiple-stage planetary gear train composed of a two-stage planetary gear train and a one-stage parallel axis gear is proposed to be used in wind driven generator to analyze the influence of revolution speed and mesh error on dynamic load sharing characteristic based on the lumped parameter theory. Dynamic equation of the model is solved using numerical method to analyze the uniform load distribution of the system. It is shown that the load sharing property of the system is significantly affected by mesh error and rotational speed; load sharing coefficient and change rate of internal and external meshing of the system are of obvious difference from each other. The study provides useful theoretical guideline for the design of the multiple-stage planetary gear train of wind driven generator. PMID:24511295

Isca, v1.0: a framework for the global modelling of the atmospheres of Earth and other planets at varying levels of complexity

NASA Astrophysics Data System (ADS)

Vallis, Geoffrey K.; Colyer, Greg; Geen, Ruth; Gerber, Edwin; Jucker, Martin; Maher, Penelope; Paterson, Alexander; Pietschnig, Marianne; Penn, James; Thomson, Stephen I.

2018-03-01

Isca is a framework for the idealized modelling of the global circulation of planetary atmospheres at varying levels of complexity and realism. The framework is an outgrowth of models from the Geophysical Fluid Dynamics Laboratory in Princeton, USA, designed for Earth's atmosphere, but it may readily be extended into other planetary regimes. Various forcing and radiation options are available, from dry, time invariant, Newtonian thermal relaxation to moist dynamics with radiative transfer. Options are available in the dry thermal relaxation scheme to account for the effects of obliquity and eccentricity (and so seasonality), different atmospheric optical depths and a surface mixed layer. An idealized grey radiation scheme, a two-band scheme, and a multiband scheme are also available, all with simple moist effects and astronomically based solar forcing. At the complex end of the spectrum the framework provides a direct connection to comprehensive atmospheric general circulation models. For Earth modelling, options include an aquaplanet and configurable continental outlines and topography. Continents may be defined by changing albedo, heat capacity, and evaporative parameters and/or by using a simple bucket hydrology model. Oceanic Q fluxes may be added to reproduce specified sea surface temperatures, with arbitrary continental distributions. Planetary atmospheres may be configured by changing planetary size and mass, solar forcing, atmospheric mass, radiation, and other parameters. Examples are given of various Earth configurations as well as a giant planet simulation, a slowly rotating terrestrial planet simulation, and tidally locked and other orbitally resonant exoplanet simulations. The underlying model is written in Fortran and may largely be configured with Python scripts. Python scripts are also used to run the model on different architectures, to archive the output, and for diagnostics, graphics, and post-processing. All of these features are publicly available in a Git-based repository.

A New Framework For The Evolution of Terrestrial Planets: Bi-stability, Stochastic Effects, and the Non-Uniqueness of Tectonic States

NASA Astrophysics Data System (ADS)

Weller, M. B.; Lenardic, A.

2017-12-01

Of all the Solar System bodies, the Earth is the only one for which significant observation and constraints are accessible such that they can be used to discriminate between competing models of Earth's tectonic evolution. Therefore, it is a natural tendency to use these observations to inform more general models of planetary evolution. Yet, our understating of Earth's evolution is far from complete. Geodynamic and geochemical evidence suggests that plate tectonics may not have operated on the early Earth, with both the timing of its onset and the length of its activity far from certain. In recent years, the potential of tectonic bi-stability (multiple stable, energetically allowed solutions) has been shown to be dynamically viable, both from analytical analysis and through numeric experiments in two and three dimensions. The indication is that multiple tectonic modes may operate on a single planetary body at different times within its temporal evolution. Further, there exists the potential that feedback mechanisms between the internal dynamics and surface processes (e.g., surface temperature changes driven by long term climate evolution), acting at different thermal evolution times, can cause terrestrial worlds to alternate between multiple tectonic states over giga-year timescales. Implied here is that terrestrial planets have the potential to migrate through tectonic regimes at similar `thermal evolutionary times' - points were planets have a similar bulk mantle temperature and energies -, but at very different `temporal times' - time since planetary formation. It can then be shown that identical planets at similar stages of their evolution may exhibit different tectonic regimes due to random fluctuations. A new framework of planetary evolution that moves toward probabilistic arguments based on general physical principals, as opposed to particular rheologies, and incorporates the potential of tectonic regime transitions and multiple tectonics states being viable at equivalent physical and chemical conditions, will be discussed.

Impact of northern Eurasian snow cover in autumn on the warm Arctic-cold Eurasia pattern during the following January and its linkage to stationary planetary waves

NASA Astrophysics Data System (ADS)

Xu, Xinping; He, Shengping; Li, Fei; Wang, Huijun

2018-03-01

The connection between Eurasian snow cover (SC) in autumn and Eurasian winter mean surface air temperature (SAT) has been identified by many studies. However, some recent observations indicate that early and late winter climate sometimes shows an out-of-phase relationship, suggesting that the winter mean situation might obscure the important relationships that are relevant for scientific research and applications. This study investigates the relationship between October northern Eurasian SC (NESC; 58°-68°N, 30°-90°E) and Eurasian SAT during the winter months and finds a significant relationship only exists in January. Generally, following reduced October NESC, the East Asian trough and Ural high are intensified in January, and anomalous northeasterly winds prevail in mid-latitudes, causing cold anomalies over Eurasia. Meanwhile, anomalous southwesterly winds along the northern fringe of the Ural high favor warm anomalies in the Arctic. The dynamical mechanism for the connection between NESC in October and the warm Arctic-cold Eurasia (WACE) anomaly in January is further investigated from the perspective of quasi-stationary planetary wave activity. It is found that planetary waves with zonal wavenumber-1 (ZWN1) play a dominant role in this process. Specifically, the ZWN1 pattern of planetary-scale waves concurrent with October NESC anomaly extends from the surface to the upper-stratosphere. It persists in the stratosphere through November-December and propagates downward to the surface by the following January, making the connection between October NESC and January climate possible. Additionally, the influence of October NESC on the January WACE pattern has intensified since the early-2000s.

European Workshop on Planetary Sciences, Rome, Italy, April 23-27, 1979, Proceedings. Part 1

NASA Astrophysics Data System (ADS)

1980-02-01

Papers are presented on the dynamics and evolution of the solar system and its components. Specific topics include the dynamic stability of the solar system, the tidal friction theory of the earth moon system, the stability and irregularity of extrasolar planetary systems, angular momentum and magnetic braking during star formation, the collisional growth of planetesimals, the dynamics, interrelations and evolution of the asteroids and comets, the formation and stability of Saturn's rings, and the importance of nearly tangent orbits in planetary close encounters.

The dynamical behaviour of our planetary system. Proceedings. 4th Alexander von Humboldt Colloquium on Celestial Mechanics, Ramsau (Austria), 17 - 23 Mar 1996.

NASA Astrophysics Data System (ADS)

Dvorak, R.; Henrard, J.

1996-03-01

The following topics were dealt with: celestial mechanics, dynamical astronomy, planetary systems, resonance scattering, Hamiltonian mechanics non-integrability, irregular periodic orbits, escape, dynamical system mapping, fast Fourier method, precession-nutation, Nekhoroshev theorem, asteroid dynamics, the Trojan problem, planet-crossing orbits, Kirkwood gaps, future research, human comprehension limitations.

Exploration of Venus' Deep Atmosphere and Surface Environment

NASA Technical Reports Server (NTRS)

Glaze, L. S.; Amato, M.; Garvin, J. B.; Johnson, N. M.

2017-01-01

Venus formed in the same part of our solar system as Earth, apparently from similar materials. Although both planets are about the same size, their differences are profound. Venus and Earth experienced vastly different evolutionary pathways resulting in unexplained differences in atmospheric composition and dynamics, as well as in geophysical processes of the planetary surfaces and interiors. Understanding when and why the evolutionary pathways of Venus and Earth diverged is key to understanding how terrestrial planets form and how their atmospheres and surfaces evolve. Measurements made in situ, within the near-surface or surface environment, are critical to addressing unanswered questions. We have made substantial progress modernizing and maturing pressure vessel technologies to enable science operations in the high temperature and pressure near-surface/surfaceenvironment of Venus.

Does the planetary dynamo go cycling on? Re-examining the evidence for cycles in magnetic reversal rate

NASA Astrophysics Data System (ADS)

Melott, Adrian L.; Pivarunas, Anthony; Meert, Joseph G.; Lieberman, Bruce S.

2018-01-01

The record of reversals of the geomagnetic field has played an integral role in the development of plate tectonic theory. Statistical analyses of the reversal record are aimed at detailing patterns and linking those patterns to core-mantle processes. The geomagnetic polarity timescale is a dynamic record and new paleomagnetic and geochronologic data provide additional detail. In this paper, we examine the periodicity revealed in the reversal record back to 375 million years ago (Ma) using Fourier analysis. Four significant peaks were found in the reversal power spectra within the 16-40-million-year range (Myr). Plotting the function constructed from the sum of the frequencies of the proximal peaks yield a transient 26 Myr periodicity, suggesting chaotic motion with a periodic attractor. The possible 16 Myr periodicity, a previously recognized result, may be correlated with `pulsation' of mantle plumes and perhaps; more tentatively, with core-mantle dynamics originating near the large low shear velocity layers in the Pacific and Africa. Planetary magnetic fields shield against charged particles, which can give rise to radiation at the surface and ionize the atmosphere, which is a loss mechanism particularly relevant to M stars. Understanding the origin and development of planetary magnetic fields can shed light on the habitable zone.

Contextualising and Analysing Planetary Rover Image Products through the Web-Based PRoGIS

NASA Astrophysics Data System (ADS)

Morley, Jeremy; Sprinks, James; Muller, Jan-Peter; Tao, Yu; Paar, Gerhard; Huber, Ben; Bauer, Arnold; Willner, Konrad; Traxler, Christoph; Garov, Andrey; Karachevtseva, Irina

2014-05-01

The international planetary science community has launched, landed and operated dozens of human and robotic missions to the planets and the Moon. They have collected various surface imagery that has only been partially utilized for further scientific purposes. The FP7 project PRoViDE (Planetary Robotics Vision Data Exploitation) is assembling a major portion of the imaging data gathered so far from planetary surface missions into a unique database, bringing them into a spatial context and providing access to a complete set of 3D vision products. Processing is complemented by a multi-resolution visualization engine that combines various levels of detail for a seamless and immersive real-time access to dynamically rendered 3D scenes. PRoViDE aims to (1) complete relevant 3D vision processing of planetary surface missions, such as Surveyor, Viking, Pathfinder, MER, MSL, Phoenix, Huygens, and Lunar ground-level imagery from Apollo, Russian Lunokhod and selected Luna missions, (2) provide highest resolution & accuracy remote sensing (orbital) vision data processing results for these sites to embed the robotic imagery and its products into spatial planetary context, (3) collect 3D Vision processing and remote sensing products within a single coherent spatial data base, (4) realise seamless fusion between orbital and ground vision data, (5) demonstrate the potential of planetary surface vision data by maximising image quality visualisation in 3D publishing platform, (6) collect and formulate use cases for novel scientific application scenarios exploiting the newly introduced spatial relationships and presentation, (7) demonstrate the concepts for MSL, (9) realize on-line dissemination of key data & its presentation by a web-based GIS and rendering tool named PRoGIS (Planetary Robotics GIS). PRoGIS is designed to give access to rover image archives in geographical context, using projected image view cones, obtained from existing meta-data and updated according to processing results, as a means to interact with and explore the archive. However PRoGIS is more than a source data explorer. It is linked to the PRoVIP (Planetary Robotics Vision Image Processing) system which includes photogrammetric processing tools to extract terrain models, compose panoramas, and explore and exploit multi-view stereo (where features on the surface have been imaged from different rover stops). We have started with the Opportunity MER rover as our test mission but the system is being designed to be multi-mission, taking advantage in particular of UCL MSSL's PDS mirror, and we intend to at least deal with both MER rovers and MSL. For the period of ProViDE until end of 2015 the further intent is to handle lunar and other Martian rover & descent camera data. The presentation discusses the challenges of integrating rover and orbital derived data into a single geographical framework, especially reconstructing view cones; our human-computer interaction intentions in creating an interface to the rover data that is accessible to planetary scientists; how we handle multi-mission data in the database; and a demonstration of the resulting system & its processing capabilities. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 312377 PRoViDE.

A fault diagnosis scheme for planetary gearboxes using modified multi-scale symbolic dynamic entropy and mRMR feature selection

NASA Astrophysics Data System (ADS)

Li, Yongbo; Yang, Yuantao; Li, Guoyan; Xu, Minqiang; Huang, Wenhu

2017-07-01

Health condition identification of planetary gearboxes is crucial to reduce the downtime and maximize productivity. This paper aims to develop a novel fault diagnosis method based on modified multi-scale symbolic dynamic entropy (MMSDE) and minimum redundancy maximum relevance (mRMR) to identify the different health conditions of planetary gearbox. MMSDE is proposed to quantify the regularity of time series, which can assess the dynamical characteristics over a range of scales. MMSDE has obvious advantages in the detection of dynamical changes and computation efficiency. Then, the mRMR approach is introduced to refine the fault features. Lastly, the obtained new features are fed into the least square support vector machine (LSSVM) to complete the fault pattern identification. The proposed method is numerically and experimentally demonstrated to be able to recognize the different fault types of planetary gearboxes.

Developing Science Operations Concepts for the Future of Planetary Surface Exploration

NASA Astrophysics Data System (ADS)

Young, K. E.; Bleacher, J. E.; Rogers, A. D.; McAdam, A.; Evans, C. A.; Graff, T. G.; Garry, W. B.; Whelley, P. L.; Scheidt, S.; Carter, L.; Coan, D.; Reagan, M.; Glotch, T.; Lewis, R.

2017-02-01

Human exploration of other planetary bodies is crucial in answering critical science questions about our solar system. As we seek to put humans on other surfaces by 2050, we must understand the science operations concepts needed for planetary EVA.

Venus atmospheric structure and dynamics from the VEGA lander and balloons: New results and PDS archive

NASA Astrophysics Data System (ADS)

Lorenz, Ralph D.; Crisp, David; Huber, Lyle

2018-05-01

The longest-lived in-situ measurement platforms at Venus have been the Soviet VEGA balloons in 1985 and the only high-quality pressure/temperature profile in the lowest 10 km of the atmosphere is that from the VEGA-2 lander. Here we review the mission and the resultant literature and report the archival of numerical data from these investigations on the NASA Planetary Data System Atmospheres Node to facilitate their access to the community. We additionally report some new results, including the striking absence of a signature of the planetary boundary layer in the near-surface potential temperature profile from the VEGA-2 lander, in contrast to the well-defined boundaries seen in a comparable profile at Titan.

Dynamics of large scale impacts on Venus and Earth

NASA Technical Reports Server (NTRS)

Okeefe, John D.; Ahrens, Thomas J.

1993-01-01

Large scale impacts are a key aspect of the accretion and growth of the planets, the evolution of their atmospheres, and the viability of their life forms. We have performed an extensive series of numerical calculations that examined the mechanics of impacts over a broad range of conditions and are now extending these to account for the effects of the planetary atmosphere. We have examined the effects of large scale impacts in which the trapping and compression of an atmosphere during impact is a significant factor in the transfer of energy to the atmosphere. The various energy transfer regimes and where conventional drag and trapping and subsequent compression of atmosphere between the bolide and planetary surface are significant are shown.

In-Space Propulsion: Where We Stand and What's Next

NASA Technical Reports Server (NTRS)

Sackheim, Robert L.

2003-01-01

The focus of this paper will be on the three stages of in-space transportation propulsion systems, now commonly referred to as in-space propulsion (ISP); i.e., the transfer of payloads from low-Earth orbits into higher orbits or into trajectories for planetary encounters, including planetary landers and sample return launchers, if required. Functions required at the operational location where ISP must provide thrust for orbit include maintenance, position control, stationkeeping, and spacecraft altitude control; i.e., proper pointing and dynamic stability in inertial space; and the third function set to enable operations at various planetary locations, such as atmospheric entry and capture, descent to the surface and ascent, back to rendezvous orbit. The discussion will concentrate on where ISP stands today and some observations of what might be next in line for new ISP technologies and systems for near-term and future flight applications. The architectural choices that are applicable for ISP will also be described and discussed in detail.

A Theoretical and Experimental Study of Emission Spectroscopy of Planetary Surfaces

NASA Astrophysics Data System (ADS)

Henderson, Bradley Gray

1995-01-01

This thesis explores the spectral emissivity of particulate materials on planetary surfaces through theoretical modeling and supporting laboratory and field investigations. In the first part of the thesis, I develop a Monte Carlo ray tracing model to calculate the directional and spectral emissivity and the polarization state of the radiation emitted from a particulate, isothermal surface for emission angles 0^circ-90^ circ and wavelengths 7-16 mu m. The results show that roughness and scattering significantly affect the character of the emitted radiation field and should be taken into account when interpreting the physical properties of a planetary surface from IR spectrophotometry or spectropolarimetry. The remainder of the thesis focuses on understanding near-surface thermal gradients and their effects on emission spectra for different planetary environments. These gradients are formed by radiative cooling in the top few hundred microns of low conductivity particulate materials on planetary surfaces with little or no atmosphere. I model the heat transfer by conduction and radiation in the top few millimeters of a planetary regolith for scattering and non-scattering media. In conjunction with the modeling, I measure emission spectra of fine-grained quartz in an environment chamber designed to simulate the conditions on other planetary surfaces. The results show that significant thermal gradients will form in the near surface of materials on the surface of the Moon and Mercury. Their presence increases spectral contrast and creates emission maxima in the transparent regions of the spectrum. Thermal gradients are shown to be responsible for the observed wavelength shifts of the Christiansen emission peak with variations in thermal conductivity and grain size. The results are also used to analyze recent telescopic spectra of the Moon and Mercury and can explain certain features seen in those data. Thermal gradients are shown to be minor for the surface of Mars and negligible on Earth. I conclude that the spectral effects created by near-surface thermal gradients are predictable and might even provide an extra source of information about the physical nature of a planetary surface, and mid-IR emission spectroscopy should therefore prove to be useful for remote sensing of airless bodies.

Calculational investigation of impact cratering dynamics - Material motions during the crater growth period

NASA Technical Reports Server (NTRS)

Austin, M. G.; Thomsen, J. M.; Ruhl, S. F.; Orphal, D. L.; Schultz, P. H.

1980-01-01

The considered investigation was conducted in connection with studies which are to provide a better understanding of the detailed dynamics of impact cratering processes. Such an understanding is vital for a comprehension of planetary surfaces. The investigation is the continuation of a study of impact dynamics in a uniform, nongeologic material at impact velocities achievable in laboratory-scale experiments conducted by Thomsen et al. (1979). A calculation of a 6 km/sec impact of a 0.3 g spherical 2024 aluminum projectile into low strength (50 kPa) homogeneous plasticene clay has been continued from 18 microseconds to past 600 microseconds. The cratering flow field, defined as the material flow field in the target beyond the transient cavity but well behind the outgoing shock wave, has been analyzed in detail to see how applicable the Maxwell Z-Model, developed from analysis of near-surface explosion cratering calculations, is to impact cratering

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration

NASA Technical Reports Server (NTRS)

Frederick, D. K.; Lashmet, P. K.; Moyer, W. R.; Sandor, G. N.; Shen, C. N.; Smith, E. J.; Yerazunis, S. W.

1973-01-01

The following tasks related to the design, construction, and evaluation of a mobile planetary vehicle for unmanned exploration of Mars are discussed: (1) design and construction of a 0.5 scale dynamic vehicle; (2) mathematical modeling of vehicle dynamics; (3) experimental 0.4 scale vehicle dynamics measurements and interpretation; (4) vehicle electro-mechanical control systems; (5) remote control systems; (6) collapsibility and deployment concepts and hardware; (7) design, construction and evaluation of a wheel with increased lateral stiffness, (8) system design optimization; (9) design of an on-board computer; (10) design and construction of a laser range finder; (11) measurement of reflectivity of terrain surfaces; (12) obstacle perception by edge detection; (13) terrain modeling based on gradients; (14) laser scan systems; (15) path selection system simulation and evaluation; (16) gas chromatograph system concepts; (17) experimental chromatograph separation measurements and chromatograph model improvement and evaluation.

The Twenty-Fifth Lunar and Planetary Science Conference. Part 2: H-O

NASA Technical Reports Server (NTRS)

1994-01-01

Various papers on lunar and planetary science are presented, covering such topics as: planetary geology, lunar geology, meteorites, shock loads, cometary collisions, planetary mapping, planetary atmospheres, chondrites, chondrules, planetary surfaces, impact craters, lava flow, achondrites, geochemistry, stratigraphy, micrometeorites, tectonics, mineralogy, petrology, geomorphology, and volcanology.

Twenty-Second Lunar and Planetary Science Conference

NASA Technical Reports Server (NTRS)

1991-01-01

The papers in this collection were written for general presentation, avoiding jargon and unnecessarily complex terms. Some of the topics covered include: planetary evolution, planetary satellites, planetary composition, planetary surfaces, planetary geology, volcanology, meteorite impacts and composition, and cosmic dust. Particular emphasis is placed on Mars and the Moon.

Structural history of Maxwell Montes, Venus: Implications for Venusian mountain belt formation

NASA Astrophysics Data System (ADS)

Keep, Myra; Hansen, Vicki L.

1994-12-01

Models for Venusian mountain belt formation are important for understanding planetary geodynamic mechanisms. A range of data sets at various scales must be considered in geodynamic modelling. Long wavelength data, such as gravity and geoid to topography ratios, need constraints from smaller-scale observations of the surface. Pre-Magellan images of the Venusian surface were not of high enough resolution to observe details of surface deformation. High-resolution Magellan images of Maxwell Montes and the other deformation belts allow us to determine the nature of surface deformation. With these images we can begin to understand the constraints that surface deformation places on planetary dynamic models. Maxwell Montes and three other deformation belts (Akna, Freyja, and Danu montes) surround the highland plateau Lakshmi Planum in Venus' northern hemisphere. Maxwell, the highest of these belts, stands 11 km above mean planetary radius. We present a detailed structural and kinematic study of Maxwell Montes. Key observations include (1) dominant structure fabrics are broadly distributed and show little change in spacing relative to elevation changes of several kilometers; (2) the spacing, wavelength and inferred amplitude of mapped structures are small; (3) interpreted extensional structures occur only in areas of steep slope, with no extension at the highest topographic levels; and (4) deformation terminates abruptly at the base of steep slopes. One implications of these observations is that topography is independent of thin-skinned, broadly distributed, Maxwell deformation. Maxwell is apparently stable, with no observed extensional collapse. We propose a 'deformation-from-below' model for Maxwell, in which the crust deforms passively over structurally imbricated and thickened lower crust. This model may have implications for the other deformation belts.

Post-main-sequence planetary system evolution.

PubMed

Veras, Dimitri

2016-02-01

The fates of planetary systems provide unassailable insights into their formation and represent rich cross-disciplinary dynamical laboratories. Mounting observations of post-main-sequence planetary systems necessitate a complementary level of theoretical scrutiny. Here, I review the diverse dynamical processes which affect planets, asteroids, comets and pebbles as their parent stars evolve into giant branch, white dwarf and neutron stars. This reference provides a foundation for the interpretation and modelling of currently known systems and upcoming discoveries.

Dynamics and Statistical Mechanics of Rotating and non-Rotating Vortical Flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Chjan

Three projects were analyzed with the overall aim of developing a computational/analytical model for estimating values of the energy, angular momentum, enstrophy and total variation of fluid height at phase transitions between disordered and self-organized flow states in planetary atmospheres. It is believed that these transitions in equilibrium statistical mechanics models play a role in the construction of large-scale, stable structures including super-rotation in the Venusian atmosphere and the formation of the Great Red Spot on Jupiter. Exact solutions of the spherical energy-enstrophy models for rotating planetary atmospheres by Kac's method of steepest descent predicted phase transitions to super-rotating solid-bodymore » flows at high energy to enstrophy ratio for all planetary spins and to sub-rotating modes if the planetary spin is large enough. These canonical statistical ensembles are well-defined for the long-range energy interactions that arise from 2D fluid flows on compact oriented manifolds such as the surface of the sphere and torus. This is because in Fourier space available through Hodge theory, the energy terms are exactly diagonalizable and hence has zero range, leading to well-defined heat baths.« less

Frost grain size metamorphism - Implications for remote sensing of planetary surfaces

NASA Technical Reports Server (NTRS)

Clark, R. N.; Fanale, F. P.; Zent, A. P.

1983-01-01

The effective grain size of a material on a planetary surface affects the strength of absorption features observed in the reflectance of a particulate surface. In the case of a planetary surface containing volatile ices, the absorption characteristics can change in connection with processes leading to a change in the grain size of the material. The present investigation is concerned with an evaluation regarding the occurrence of such processes and the implications for remote sensing applications. It is found that quantitative modeling of the kinetics of grain growth and destruction by thermal and nonthermal processes can provide a means to reconcile apparent optical paths in the volatile portions of planetary surfaces with the physical history of those surfaces. Attention is also given to conditions in the case of the Pluto/Triton system, Uranus and Saturnian satellites, and the Galilean system.

Planetary Rover Robotics Experiments in Education: HUSAR-5, the NXT-Based Rover Model for Measuring the Planetary Surface

NASA Astrophysics Data System (ADS)

Lang, Á.; Bérczi, Sz.; Szalay, K.; Prajczer, P.; Kocsis, Á.

2014-11-01

We report about the work of the HUSAR-5 groups from the Széchenyi István Gimnázium High School Sopron, Hungary. We build and program robot-rovers, that can autonomous move and measure on a planetary surface.

Dynamical Circularization of the Martian Orbit

NASA Astrophysics Data System (ADS)

Bierbaum, Quinn Patrick; Brown, Cole; Williams, Darren M.

2018-06-01

As part of an investigation into the history of the orbital characteristics of the planet Mars, in conjunction with research being performed by Cole Brown and Dr. Darren Williams, I have run dynamical computer simulations of the solar system placing the eccentricity of the Martian orbit between 0.2 and 0.4 in order to discern the viability of eccentricity damping due to long-range planetary interactions as well as interactions with swarms of asteroids placed randomly between 0.5-2.0 AU. This research is one component of a hypothesis intended to explain the geological evidence of flowing water on the primordial Martian surface.

Testing relativity with solar system dynamics

NASA Technical Reports Server (NTRS)

Hellings, R. W.

1984-01-01

A major breakthrough is described in the accuracy of Solar System dynamical tests of relativistic gravity. The breakthrough was achieved by factoring in ranging data from Viking Landers 1 and 2 from the surface of Mars. Other key data sources included optical transit circle observations, lunar laser ranging, planetary radar, and spacecraft (Mariner 9 to Mars and Mariner 10 to Mercury). The Solar System model which is used to fit the data and the process by which such fits are performed are explained and results are discussed. The results are fully consistent with the predictions of General Relativity.

Observations of the Natural Planetary Satellites for Dynamical and Physical Purpose

NASA Astrophysics Data System (ADS)

Arlot, J. E.; Thuillot, W.; Fienga, A.; Bec-Borsenberger, A.; Baron, N.; Berthier, J.; Colas, F.; Descamps, P.

1999-12-01

At the Institut de mecanique celeste-Bureau des longitudes, we started several programs of observation of the natural planetary satellites. First, we took the opportunity of the transit of the Earth and the Sun in the equatorial plane of Jupiter to observe the mutual phenomena of the Galilean satellites. These observations provide astrometric data of high accuracy useful for dynamical studies of the motions of the satellites and photometric data allowing to characterize the surfaces of the satellites. A campaign was organized leading to 400 light curves made throughout the world in about 40 countries. Second, we started astrometric CCD observations of the faint satellites of Jupiter JVI to JXIII and of the satellite of Saturn Phoebe (SIX) for dynamical purpose at Observatoire de Haute Provence using the 120cm-telescope. PPM, Hipparcos and USNO A.2 catalogue were used for calibration in order to get absolute J2000 R.A. and declination of these objects. In August and December, 1998, CCD observations provided 43 absolute positions of JVI, 23 of JVII, 53 of JVIII, 35 of JIX, 29 of JX, 27 of JXI, 18 of JXII, 16 of JXIII and 135 of SIX (Phoebe). A campaign will also take place in 1999.

Winter NH low-frequency variability in a hierarchy of low-order stochastic dynamical models of earth-atmosphere system

NASA Astrophysics Data System (ADS)

Zhao, Nan

2018-02-01

The origin of winter Northern Hemispheric low-frequency variability (hereafter, LFV) is regarded to be related to the coupled earth-atmosphere system characterized by the interaction of the jet stream with mid-latitude mountain ranges. On the other hand, observed LFV usually appears as transitions among multiple planetary-scale flow regimes of Northern Hemisphere like NAO + , AO +, AO - and NAO - . Moreover, the interaction between synoptic-scale eddies and the planetary-scale disturbance is also inevitable in the origin of LFV. These raise a question regarding how to incorporate all these aspects into just one framework to demonstrate (1) a planetary-scale dynamics of interaction of the jet stream with mid-latitude mountain ranges can really produce LFV, (2) such a dynamics can be responsible for the existence of above multiple flow regimes, and (3) the role of interaction with eddy is also clarified. For this purpose, a hierarchy of low-order stochastic dynamical models of the coupled earth-atmosphere system derived empirically from different timescale ranges of indices of Arctic Oscillation (AO), North Atlantic Oscillation (NAO), Pacific/North American (PNA), and length of day (LOD) and related probability density function (PDF) analysis are employed in this study. The results seem to suggest that the origin of LFV cannot be understood completely within the planetary-scale dynamics of the interaction of the jet stream with mid-latitude mountain ranges, because (1) the existence of multiple flow regimes such as NAO+, AO+, AO- and NAO- resulted from processes with timescales much longer than LFV itself, which may have underlying dynamics other than topography-jet stream interaction, and (2) we find LFV seems not necessarily to come directly from the planetary-scale dynamics of the interaction of the jet stream with mid-latitude mountain, although it can produce similar oscillatory behavior. The feedback/forcing of synoptic-scale eddies on the planetary-scale dynamics seems to play a more essential role in its origin.

Post-main-sequence planetary system evolution

PubMed Central

Veras, Dimitri

2016-01-01

The fates of planetary systems provide unassailable insights into their formation and represent rich cross-disciplinary dynamical laboratories. Mounting observations of post-main-sequence planetary systems necessitate a complementary level of theoretical scrutiny. Here, I review the diverse dynamical processes which affect planets, asteroids, comets and pebbles as their parent stars evolve into giant branch, white dwarf and neutron stars. This reference provides a foundation for the interpretation and modelling of currently known systems and upcoming discoveries. PMID:26998326

The importance of planetary rotation period for ocean heat transport.

PubMed

Cullum, J; Stevens, D; Joshi, M

2014-08-01

The climate and, hence, potential habitability of a planet crucially depends on how its atmospheric and ocean circulation transports heat from warmer to cooler regions. However, previous studies of planetary climate have concentrated on modeling the dynamics of atmospheres, while dramatically simplifying the treatment of oceans, which neglects or misrepresents the effect of the ocean in the total heat transport. Even the majority of studies with a dynamic ocean have used a simple so-called aquaplanet that has no continental barriers, which is a configuration that dramatically changes the ocean dynamics. Here, the significance of the response of poleward ocean heat transport to planetary rotation period is shown with a simple meridional barrier--the simplest representation of any continental configuration. The poleward ocean heat transport increases significantly as the planetary rotation period is increased. The peak heat transport more than doubles when the rotation period is increased by a factor of ten. There are also significant changes to ocean temperature at depth, with implications for the carbon cycle. There is strong agreement between the model results and a scale analysis of the governing equations. This result highlights the importance of both planetary rotation period and the ocean circulation when considering planetary habitability.

Current Scientific Issues in Large Scale Atmospheric Dynamics

NASA Technical Reports Server (NTRS)

Miller, T. L. (Compiler)

1986-01-01

Topics in large scale atmospheric dynamics are discussed. Aspects of atmospheric blocking, the influence of transient baroclinic eddies on planetary-scale waves, cyclogenesis, the effects of orography on planetary scale flow, small scale frontal structure, and simulations of gravity waves in frontal zones are discussed.

Analysis of the HASI accelerometers data measured during the impact phase of the Huygens probe on the surface of Titan by means of a simulation with a finite-element model

NASA Astrophysics Data System (ADS)

Bettanini, C.; Zaccariotto, M.; Angrilli, F.

2008-04-01

The Huygens Atmospheric Structure Instrument (HASI) [Fulchignoni, M., Ferri, F., Angrilli, F., Bar-Nun, A., Barucci, M.A., Bianchini, G., Borucki, W., Coradini, M., Coustenis, A., Falkner, P., Flamini, E., Grard, R., Hamelin, M., Harri, A.M., Leppelmaier, G.W., Lopez-Moreno, J.J., McDonnell, J.A.M., McKay, C.P., Neubauer, F.M., Pedersen, A., Piacardi, G., Pirronello, V., Schwingenschuh, K., Seiff, A., Svedhem, H., Vanzani, V., Zarnecki, J.C., 2002. The characterisation of Titan atmosphere physical properties. Space Sci. Rev. 104, 395-431] was a very complete instrument suite installed on board the Huygens probe, the planetary lander of the Cassini Huygens Mission to Saturn system, which successfully completed its mission in January 2005. HASI comprised a set of accelerometers, temperature sensors, pressure transducers and permittivity analysers aimed at the investigation of Titan atmosphere, which were fully operative during a several hour-long parachuted descent from an altitude of 157 km to planetary surface. Accelerometers were the only instruments activated earlier, just after Cassini separation, and recorded data during all the mission phases from atmospheric entry to landing, providing essential information for elaborating probe trajectory as well as Titan atmospheric profiles [G. Colombatti, et al. Reconstruction of the trajectory of the Huygens probe using the Huygens Atmospheric Structure Instrument, this same PSS issue]. Although not specifically designed for monitoring very fast dynamic events, HASI accelerometers have also recorded the trace of probe impact with the planetary surface, building up along with the data from Huygens Surface Science Package (SSP) instrument [ Zarnecki, J.C., Leese, M.R., Garry, J.R.C., Ghafoor, N.A.L., Hathi, B., 2002. Huygens Surface Science Package. Space Sci. Rev. 104, 593-611] the only set of direct measurements of the mechanical properties of the Titan soil. Though not considered secondary with respect to SSP data, HASI data provide peculiar information related to the dynamic response of the whole Huygens probe when impacting the surface, whereas the SSP data were collected mainly by sensors located on a small penetrometer below the main probe dome. Therefore, although having a sensibly lower sampling frequency, HASI Accelerometer Subsystem (ACC) data complete the information of SSP data in the study of impact deceleration profiles, which can provide key information for the estimation of the mechanical parameters of the soil and get an insight of its consistency and composition. In the analysis of Huygens mission data some unexpected features were present in the ACC data sets, so a dedicated study was needed to investigate the presence of dynamic interferences during an acquisition and correct the impact signature. The developed method is based on dynamic analysis of the impact through a three-dimensional finite-element dynamic model of the Huygens probe and the results lead to a corrected interpretation of accelerometer readings and provided an improved description of key aspects of the planetary landing. Although some aspects of probe's state after impact need some further analysis, as for final resting attitude which is to date not completely agreed on, this study disclosed that the probe experienced a vertical decelerating action which is compatible with two possible scenarios: the first one implies the penetration in a soft substrate material followed by a lateral bounce out of the generated hole and the second one suggests the displacement of pebbles from the surface into the soil. Numerical elaboration of impact data calculated a 12 cm penetration into the surface, which may have been experienced either by the lower dome of the probe or from pebbles that were situated under the dome when contacting the planet. In either case after a few seconds of motion the Huygens probe finally rested above Titan's surface with a negligible penetration. Since HASI piezo-accelerometer design was driven by the need of high full-scale values to monitor critical events during entry and descent phase, it was not possible to reconstruct horizontal motion after main deceleration phase without consistent uncertainties due to the poor overall accuracy in a low-acceleration range.

Multifunctional Interface Facility for Receiving and Processing Planetary Surface Materials for Science Investigation and Resource Evaluation at the Deep Space Gateway

NASA Astrophysics Data System (ADS)

Sibille, L.; Mantovani, J. G.; Townsend, I. I.; Mueller, R. P.

2018-02-01

The concepts describe hardware and instrumentation for the study of planetary surface materials at the Deep Space Gateway as a progressive evolution of capabilities for eliminating the need for special handling and Planetary Protection (PP) protocols inside the habitats.

Visualization of Kepler's Laws of Planetary Motion

ERIC Educational Resources Information Center

Lu, Meishu; Su, Jun; Wang, Weiguo; Lu, Jianlong

2017-01-01

For this article, we use a 3D printer to print a surface similar to universal gravitation for demonstrating and investigating Kepler's laws of planetary motion describing the motion of a small ball on the surface. This novel experimental method allows Kepler's laws of planetary motion to be visualized and will contribute to improving the…

Additive Construction with Mobile Emplacement (ACME)

NASA Technical Reports Server (NTRS)

Vickers, John

2015-01-01

The Additive Construction with Mobile Emplacement (ACME) project is developing technology to build structures on planetary surfaces using in-situ resources. The project focuses on the construction of both 2D (landing pads, roads, and structure foundations) and 3D (habitats, garages, radiation shelters, and other structures) infrastructure needs for planetary surface missions. The ACME project seeks to raise the Technology Readiness Level (TRL) of two components needed for planetary surface habitation and exploration: 3D additive construction (e.g., contour crafting), and excavation and handling technologies (to effectively and continuously produce in-situ feedstock). Additionally, the ACME project supports the research and development of new materials for planetary surface construction, with the goal of reducing the amount of material to be launched from Earth.

Exploring the Largest Mass Fraction of the Solar System: the Case for Planetary Interiors

NASA Technical Reports Server (NTRS)

Danielson, L. R.; Draper, D.; Righter, K.; McCubbin, F.; Boyce, J.

2017-01-01

Why explore planetary interiors: The typical image that comes to mind for planetary science is that of a planet surface. And while surface data drive our exploration of evolved geologic processes, it is the interiors of planets that hold the key to planetary origins via accretionary and early differentiation processes. It is that initial setting of the bulk planet composition that sets the stage for all geologic processes that follow. But nearly all of the mass of planets is inaccessible to direct examination, making experimentation an absolute necessity for full planetary exploration.

Structure and Dynamics of Cold Water Super-Earths: The Case of Occluded CH4 and Its Outgassing

NASA Astrophysics Data System (ADS)

Levi, A.; Sasselov, D.; Podolak, M.

2014-09-01

In this work, we study the transport of methane in the external water envelopes surrounding water-rich super-Earths. We investigate the influence of methane on the thermodynamics and mechanics of the water mantle. We find that including methane in the water matrix introduces a new phase (filled ice), resulting in hotter planetary interiors. This effect renders the super-ionic and reticulating phases accessible to the lower ice mantle of relatively low-mass planets (~5 ME ) lacking a H/He atmosphere. We model the thermal and structural profile of the planetary crust and discuss five possible crustal regimes which depend on the surface temperature and heat flux. We demonstrate that the planetary crust can be conductive throughout or partly confined to the dissociation curve of methane clathrate hydrate. The formation of methane clathrate in the subsurface is shown to inhibit the formation of a subterranean ocean. This effect results in increased stresses on the lithosphere, making modes of ice plate tectonics possible. The dynamic character of the tectonic plates is analyzed and the ability of this tectonic mode to cool the planet is estimated. The icy tectonic plates are found to be faster than those on a silicate super-Earth. A mid-layer of low viscosity is found to exist between the lithosphere and the lower mantle. Its existence results in a large difference between ice mantle overturn timescales and resurfacing timescales. Resurfacing timescales are found to be 1 Ma for fast plates and 100 Ma for sluggish plates, depending on the viscosity profile and ice mass fraction. Melting beneath spreading centers is required in order to account for the planetary radiogenic heating. The melt fraction is quantified for the various tectonic solutions explored, ranging from a few percent for the fast and thin plates to total melting of the upwelled material for the thick and sluggish plates. Ice mantle dynamics is found to be important for assessing the composition of the atmosphere. We propose a mechanism for methane release into the atmosphere, where freshly exposed reservoirs of methane clathrate hydrate at the ridge dissociate under surface conditions. We formulate the relation between the outgassing flux and the tectonic mode dynamical characteristics. We give numerical estimates for the global outgassing rate of methane into the atmosphere. We find, for example, that for a 2 ME planet outgassing can release 1027-1029 molecules s-1 of methane to the atmosphere. We suggest a qualitative explanation for how the same outgassing mechanism may result in either a stable or a runaway volatile release, depending on the specifics of a given planet. Finally, we integrate the global outgassing rate for a few cases and quantify how the surface atmospheric pressure of methane evolves over time. We find that methane is likely an important constituent of water planets' atmospheres.

Radiative transfer in a polluted urban planetary boundary layer

NASA Technical Reports Server (NTRS)

Viskanta, R.; Johnson, R. O.; Bergstrom, R. W.

1977-01-01

Radiative transfer in a polluted urban atmosphere is studied using a dynamic model. The diurnal nature of radiative transfer for summer conditions is simulated for an urban area 40 km in extent and the effects of various parameters arising in the problem are investigated. The results of numerical computations show that air pollution has the potential of playing a major role in the radiative regime of the urban area. Absorption of solar energy by aerosols in realistic models of urban atmosphere are of the same order of magnitude as that due to water vapor. The predicted effect of the air pollution aerosol in the city is to warm the earth-atmosphere system, and the net effect of gaseous pollutant is to warm the surface and cool the planetary boundary layer, particularly near the top.

Computational design of the basic dynamical processes of the UCLA general circulation model

NASA Technical Reports Server (NTRS)

Arakawa, A.; Lamb, V. R.

1977-01-01

The 12-layer UCLA general circulation model encompassing troposphere and stratosphere (and superjacent 'sponge layer') is described. Prognostic variables are: surface pressure, horizontal velocity, temperature, water vapor and ozone in each layer, planetary boundary layer (PBL) depth, temperature, moisture and momentum discontinuities at PBL top, ground temperature and water storage, and mass of snow on ground. Selection of space finite-difference schemes for homogeneous incompressible flow, with/without a free surface, nonlinear two-dimensional nondivergent flow, enstrophy conserving schemes, momentum advection schemes, vertical and horizontal difference schemes, and time differencing schemes are discussed.

Video Guidance, Landing, and Imaging system (VGLIS) for space missions

NASA Technical Reports Server (NTRS)

Schappell, R. T.; Knickerbocker, R. L.; Tietz, J. C.; Grant, C.; Flemming, J. C.

1975-01-01

The feasibility of an autonomous video guidance system that is capable of observing a planetary surface during terminal descent and selecting the most acceptable landing site was demonstrated. The system was breadboarded and "flown" on a physical simulator consisting of a control panel and monitor, a dynamic simulator, and a PDP-9 computer. The breadboard VGLIS consisted of an image dissector camera and the appropriate processing logic. Results are reported.

Simulating land-atmosphere feedbacks and response to widespread forest disturbance: The role of lower boundary configuration and dynamic water table in meteorological modeling

NASA Astrophysics Data System (ADS)

Forrester, M.; Maxwell, R. M.; Bearup, L. A.; Gochis, D.

2017-12-01

Numerical meteorological models are frequently used to diagnose land-atmosphere interactions and predict large-scale response to extreme or hazardous events, including widespread land disturbance or perturbations to near-surface moisture. However, few atmospheric modeling platforms consider the impact that dynamic groundwater storage, specifically 3D subsurface flow, has on land-atmosphere interactions. In this study, we use the Weather Research and Forecasting (WRF) mesoscale meteorological model to identify ecohydrologic and land-atmosphere feedbacks to disturbance by the mountain pine beetle (MPB) over the Colorado Headwaters region. Disturbance simulations are applied to WRF with various lower boundary configurations: Including default Noah land surface model soil moisture representation; a version of WRF coupled to ParFlow (PF), an integrated groundwater-surface water model that resolves variably saturated flow in the subsurface; and WRF coupled to PF in a static water table version, simulating only vertical and no lateral subsurface flow. Our results agree with previous literature showing MPB-induced reductions in canopy transpiration in all lower boundary scenarios, as well as energy repartitioning, higher water tables, and higher planetary boundary layer over infested regions. Simulations show that expanding from local to watershed scale results in significant damping of MPB signal as unforested and unimpacted regions are added; and, while deforestation appears to have secondary feedbacks to planetary boundary layer and convection, these slight perturbations to cumulative summer precipitation are insignificant in the context of ensemble methodologies. Notably, the results suggest that groundwater representation in atmospheric modeling affects the response intensity of a land disturbance event. In the WRF-PF case, energy and atmospheric processes are more sensitive to disturbance in regions with higher water tables. Also, when dynamic subsurface hydrology is removed, WRF simulates a greater response to MPB at the land-atmosphere interface, including greater changes to daytime skin temperature, Bowen ratio and near-surface humidity. These findings highlight lower boundary representations in computational meteorology and numerical land-atmosphere modeling.

Natural fracture systems on planetary surfaces: Genetic classification and pattern randomness

NASA Technical Reports Server (NTRS)

Rossbacher, Lisa A.

1987-01-01

One method for classifying natural fracture systems is by fracture genesis. This approach involves the physics of the formation process, and it has been used most frequently in attempts to predict subsurface fractures and petroleum reservoir productivity. This classification system can also be applied to larger fracture systems on any planetary surface. One problem in applying this classification system to planetary surfaces is that it was developed for ralatively small-scale fractures that would influence porosity, particularly as observed in a core sample. Planetary studies also require consideration of large-scale fractures. Nevertheless, this system offers some valuable perspectives on fracture systems of any size.

Neptune and Triton: A Study in Future Exploration

NASA Astrophysics Data System (ADS)

Day, M. D.; Malaska, M. J.; Hosseini, S.; Mcgranaghan, R.; Fernandes, P. A.; Fougere, N.; Clegg, R. N.; Scully, J.; Alibay, F.; Ries, P.; Craig, P. L.; Hutchins, M. L.; Leonard, J.; Uckert, K.; Patthoff, A.; Girazian, Z.

2013-12-01

Neptune provides a unique natural laboratory for studying the dynamics of ice giants. Last visited by Voyager 2 in 1989, Neptune and its moon Triton hold important clues to the evolution of the solar system. The Voyager 2 flyby revealed Neptune to be a dynamic world with large storms, unparalleled wind speeds, and an unusual magnetic field. Triton, Neptune's largest satellite, is believed to be a captured Kuiper Belt Object with a thin atmosphere and possible sub-surface ocean. Further study of the farthest planet in our solar system could offer new insights into the dynamics of ice-giant exoplanets, and help us understand their complex atmospheres. The diverse science questions associated with Neptune and Triton motivate the complex and exciting mission proposed in this study. The proposed mission follows the guidelines of the 2013-2022 Planetary Science Decadal Survey, and optimizes the number of high priority science goals achieved, while still maintaining low mission costs. High priority science goals include understanding the structure, composition, and dynamics of Neptune's atmosphere and magnetosphere, as well as analyzing the surface of Triton. With a budget of $1.5 billion, the mission hosts an atmospheric probe and suite of instruments equipped with technologies significantly more advanced than those carried by Voyager 2. Additionally, the mission offers improved spatial coverage and higher resolution measurements than any previously achieved at Neptune. The proposed spacecraft would complete an orbital tour of Neptune and execute several close flybys of Triton. Further study of Neptune and Triton will provide exciting insights into what lies on the edge of our solar system and beyond. This study was prepared in conjunction with Jet Propulsion Laboratory's 2013 Planetary Science Summer School.

Concept for a research project in early crustal genesis

NASA Technical Reports Server (NTRS)

Phillips, R. J. (Compiler); Ashwal, L. (Compiler)

1983-01-01

Planetary volatiles, physical and chemical planetary evolution, surface processes, planetary formation, metallogenesis, crustal features and their development, tectonics, and paleobiology are discussed.

Structural history of Maxwell Montes, Venus: Implications for Venusian mountain belt formation

NASA Astrophysics Data System (ADS)

Keep, Myra; Hansen, Vicki L.

1994-12-01

Models for Venusian mountain belt formation are important for understanding planetary geodynamic mechanisms. A range of data sets at various scales must be considered in geodynamic modelling. Long wavelength data, such as gravity and geoid to topography ratios, need constraints from smaller-scale observations of the surface. Pre-Magellan images of the Venusian surface were not of high enough resolution to observe details of surface deformation. High-resolution Magellan images of Maxwell Montes and the other deformation belts allow us to determine the nature of surfce deformation. With these images we can begin to understand the constraints that surface deformation places on planetary dynamic models. Maxwell Montes and three other deformation belts (Akna, Freyja, and Danu montes) surround the highland plateau Lakshmi Planum in Venus, northern hemisphere. Maxwell, the highest of these belts, stands 11 km above mean planetary radius. We present a detailed structural and kinematic study of Maxwell Montes. Key observations include (1) dominant structural fabrics are broadly distributed and show little change in spacing relative to elevation changes of several kilometers; (2) the spacing, wavelength, and inferred amplitude of mapped structures are small, (3) interpreted extensional structures occur only in areas of steep slope, with no extension at the highest topographic levels; and (4) deformation terminates abruptly at the base of steep slopes. One implication of these observations is that topography is independent of thin-skinned, broadly distributed, Maxwell deformation. Maxwell is apparently stable, with no observed extensional collapse. We propose a ``deformation-from-below'' model for Maxwell, in which the crust deforms passively over structurally imbricated and thickened lower crust. This model may have implications for the other deformation belts.

TALARIS project update: Overview of flight testing and development of a prototype planetary surface exploration hopper

NASA Astrophysics Data System (ADS)

Rossi, Christopher; Cunio, Phillip M.; Alibay, Farah; Morrow, Joe; Nothnagel, Sarah L.; Steiner, Ted; Han, Christopher J.; Lanford, Ephraim; Hoffman, Jeffrey A.

2012-12-01

The TALARIS (Terrestrial Artificial Lunar And Reduced GravIty Simulator) project is intended to test GNC (Guidance, Navigation, and Control) algorithms on a prototype planetary surface exploration hopper in a dynamic environment with simulated reduced gravity. The vehicle is being developed by the Charles Stark Draper Laboratory and Massachusetts Institute of Technology in support of efforts in the Google Lunar X-Prize contest. This paper presents progress achieved since September 2010 in vehicle development and flight testing. Upgrades to the vehicle are described, including a redesign of the power train for the gravity-offset propulsion system and a redesign of key elements of the spacecraft emulator propulsion system. The integration of flight algorithms into modular flight software is also discussed. Results are reported for restricted degree of freedom (DOF) tests used to tune GNC algorithms on the path to a full 6-DOF hover-hop flight profile. These tests include 3-DOF tests on flat surfaces restricted to horizontal motion, and 2-DOF vertical tests restricted to vertical motion and 1-DOF attitude control. The results of tests leading up to full flight operations are described, as are lessons learned and future test plans.

A New Paradigm for Habitability in Planetary Systems: the Extremophilic Zone

NASA Astrophysics Data System (ADS)

Janot-Pacheco, E., Bernardes, L., Lage, C. A. S.

2014-03-01

More than a thousand exoplanets have been discovered so far. Planetary surface temperature may strongly depends on its albedo and geodynamic conditions. We have fed exoplanets from the Encyclopedia database with a comprehensive model of Earth's atmosphere and plate tectonics. As CO2 is the main agent responsible for the greenhouse effect, its partial pressure has been taken as a free parameter to estimate the surface temperature of some known planets. We also investigated the possible presence of "exomoons" belonging to giant planets in the Habitable Zone capable of harbour dynamic stability, to retain an atmosphere and to keep geodynamic activity for long time spans. Biological data on earthly micro-organisms classified as "extremophiles" indicate that such kind of microbial species could dwell on the surface of many exoplanets and exomoons. We thus propose an extension of the mainly astronomically defined "Habitable Zone" concept into the more astrobiologically one, the "Extremophililic Zone", that takes into account other parameters allowing survival of more robust life forms. This contribution comes from an ongoing project developed by a French-Brazilian colaboration in Astrophysics and Biophysics to search for living fingerprints in astrobiologically promising exoplanets.

Interpretation of surface and planetary directional albedos for vegetated regions

NASA Technical Reports Server (NTRS)

Cess, Robert D.; Vulis, Inna L.

1989-01-01

An atmospheric solar radiation model has been coupled with surface reflectance measurements for two vegetation types, pasture land and savannah, in order to address several issues associated with understanding the directional planetary albedo; i.e., the dependence of planetary albedo upon solar zenith angle. These include an elucidation of processes that influence the variation of planetary albedo with solar zenith angle, as well as emphasizing potential problems associated with converting narrowband planetary albedo measurements to broadband quantities. It is suggested that, for vegetated surfaces, this latter task could be somewhat formidable, since the model simulations indicate that narrowband to broadband conversions strongly depend upon vegetation type. A further aspect of this paper is to illustrate a procedure by which reciprocity inconsistencies within a bidirectional reflectance dataset, if they are not too severe, can be circumvented.

The Anthropocene Generalized: Evolution of Exo-Civilizations and Their Planetary Feedback.

PubMed

Frank, A; Carroll-Nellenback, Jonathan; Alberti, M; Kleidon, A

2018-05-01

We present a framework for studying generic behaviors possible in the interaction between a resource-harvesting technological civilization (an exo-civilization) and the planetary environment in which it evolves. Using methods from dynamical systems theory, we introduce and analyze a suite of simple equations modeling a population which consumes resources for the purpose of running a technological civilization and the feedback those resources drive on the state of the host planet. The feedbacks can drive the planet away from the initial state the civilization originated in and into domains that are detrimental to its sustainability. Our models conceptualize the problem primarily in terms of feedbacks from the resource use onto the coupled planetary systems. In addition, we also model the population growth advantages gained via the harvesting of these resources. We present three models of increasing complexity: (1) Civilization-planetary interaction with a single resource; (2) Civilization-planetary interaction with two resources each of which has a different level of planetary system feedback; (3) Civilization-planetary interaction with two resources and nonlinear planetary feedback (i.e., runaways). All three models show distinct classes of exo-civilization trajectories. We find smooth entries into long-term, "sustainable" steady states. We also find population booms followed by various levels of "die-off." Finally, we also observe rapid "collapse" trajectories for which the population approaches n = 0. Our results are part of a program for developing an "Astrobiology of the Anthropocene" in which questions of sustainability, centered on the coupled Earth-system, can be seen in their proper astronomical/planetary context. We conclude by discussing the implications of our results for both the coupled Earth system and for the consideration of exo-civilizations across cosmic history. Key Words: Anthropocene-Astrobiology-Civilization-Dynamical system theory-Exoplanets-Population dynamics. Astrobiology 18, 503-518.

Lunar soil and surface processes studies

NASA Technical Reports Server (NTRS)

Glass, B. P.

1975-01-01

Glass particles in lunar soil were characterized and compared to terrestrial analogues. In addition, useful information was obtained concerning the nature of lunar surface processes (e.g. volcanism and impact), maturity of soils and chemistry and heterogeneity of lunar surface material. It is felt, however, that the most important result of the study was that it demonstrated that the investigation of glass particles from the regolith of planetary bodies with little or no atmospheres can be a powerful method for learning about the surface processes and chemistry of planetary surfaces. Thus, the return of samples from other planetary bodies (especially the terrestrial planets and asteroids) using unmanned spacecraft is urged.

DYNAMICS OF SELF-GRAVITY WAKES IN DENSE PLANETARY RINGS. I. PITCH ANGLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michikoshi, Shugo; Kokubo, Eiichiro; Fujii, Akihiko

2015-10-20

We investigate the dynamics of self-gravity wakes in dense planetary rings. In particular, we examine how the pitch angles of self-gravity wakes depend on ring parameters using N-body simulations. We calculate the pitch angles using the two-dimensional autocorrelation function of the ring surface density. We obtain the pitch angles for the inner and outer parts of the autocorrelation function separately. We confirm that the pitch angles are 15°–30° for reasonable ring parameters, which are consistent with previous studies. We find that the inner pitch angle increases with the Saturnicentric distance, while it barely depends on the optical depth and themore » restitution coefficient of ring particles. The increase of the inner pitch angle with the Saturnicentric distance is consistent with the observations of the A ring. The outer pitch angle does not have a clear dependence on any ring parameters and is about 10°–15°. This value is consistent with the pitch angle of spiral arms in collisionless systems.« less

Dynamical Coupling Between the Stratosphere and the Troposphere: The Influence of External Forcings

NASA Astrophysics Data System (ADS)

Hansen, Felicitas; Matthes, Katja

2013-04-01

The dynamical coupling between the stratosphere and the troposphere is dominated by planetary waves that are generated in the troposphere by orography and land-sea contrasts. These waves travel upward into the stratosphere where they either dissipate or are reflected downward to impact the troposphere again. Through the interaction with the zonal mean flow planetary waves can induce stratospheric sudden warmings (SSWs), i.e., conditions during NH winter where the stratospheric polar vortex is disturbed so that the zonal mean zonal wind in the NH stratospheric jet becomes easterly and the polar cap meridional temperature gradient reverses. Since strong major SSWs can propagate down into the troposphere and even affect surface weather, SSWs present a strong and clear manifestation of the dynamical coupling in the stratosphere-troposphere system. We will investigate the influence of some external forcings, namely sea surface temperatures (SSTs), anthropogenic greenhouse gases and the quasi-biennial oscillation (QBO), on these coupling processes. Thereby we are interested in how the distribution of SSWs in the winter months changes due to the different forcings, whether the events evolve differently, and whether they show differences in their preconditioning, e.g. a different wave geometry. We will also investigate whether and how vertical reflective surfaces in the stratosphere, which can reflect upward propagating planetary waves, influence the evolution of SSWs. To address these questions, we performed a set of model simulations with NCAR's Community Earth System Model (CESM), a coupled model system including an interactive ocean (POP2), land (CLM4), sea ice (CICE) and atmosphere (NCAR's Whole Atmosphere Community Climate Model (WACCM)) component. Our control experiment is a 140-year simulation with the fully coupled atmosphere-ocean version of CESM. A second experiment is a 55-year simulation with only CESM's atmospheric component WACCM, a fully interactive chemistry-climate model extending from the Earth's surface through the thermosphere (about 140 km), with underlying climatological SSTs obtained from the coupled CESM control run. A third 55-year simulation is performed without the nudging of the equatorial QBO. All three simulations develop under conditions where greenhouse gases are held constant at the 1960 level. In a fourth simulations, the greenhouse gases follow the RCP8.5 scenario. From the differences of the individual simulations to the control experiment we can estimate the respective roles of SSTs, the QBO and anthropogenic greenhouse gases for the stratosphere-troposphere coupling. The model results will be compared to the Modern Era Retrospective-Analysis for Research and Applications (MERRA) dataset.

Simulating dynamics of δ13C of CO2 in the planetary boundary layer over a boreal forest region: covariation between surface fluxes and atmospheric mixing

NASA Astrophysics Data System (ADS)

Chen, Baozhang; Chen, Jing M.; Tans, Pieter P.; Huang, Lin

2006-11-01

Stable isotopes of CO2 contain unique information on the biological and physical processes that exchange CO2 between terrestrial ecosystems and the atmosphere. Ecosystem exchange of carbon isotopes with the atmosphere is correlated diurnally and seasonally with the planetary boundary layer (PBL) dynamics. The strength of this kind of covariation affects the vertical gradient of δ13C and thus the global δ13C distribution pattern. We need to understand the various processes involved in transport/diffusion of carbon isotope ratio in the PBL and between the PBL and the biosphere and the troposphere. In this study, we employ a one-dimensional vertical diffusion/transport atmospheric model (VDS), coupled to an ecosystem isotope model (BEPS-EASS) to simulate dynamics of 13CO2 in the PBL over a boreal forest region in the vicinity of the Fraserdale (FRD) tower (49°52'29.9''N, 81°34'12.3''W) in northern Ontario, Canada. The data from intensive campaigns during the growing season in 1999 at this site are used for model validation in the surface layer. The model performance, overall, is satisfactory in simulating the measured data over the whole course of the growing season. We examine the interaction of the biosphere and the atmosphere through the PBL with respect to δ13C on diurnal and seasonal scales. The simulated annual mean vertical gradient of δ13C in the PBL in the vicinity of the FRD tower was about 0.25‰ in 1999. The δ13C vertical gradient exhibited strong diurnal (29%) and seasonal (71%) variations that do not exactly mimic those of CO2. Most of the vertical gradient (96.5% +/-) resulted from covariation between ecosystem exchange of carbon isotopes and the PBL dynamics, while the rest (3.5%+/-) was contributed by isotopic disequilibrium between respiration and photosynthesis. This disequilibrium effect on δ13C of CO2 dynamics in PBL, moreover, was confined to the near surface layers (less than 350 m).

Study of the Effects of Photometric Geometry on Spectral Reflectance Measurements

NASA Technical Reports Server (NTRS)

Helfenstein, Paul

1998-01-01

The objective of this research is to investigate how the spectrophotometric properties of planetary surface materials depend on photometric geometry by refining and applying radiative transfer theory to data obtained from spacecraft and telescope observations of planetary surfaces, studies of laboratory analogs, and computer simulations. The goal is to perfect the physical interpretation of photometric parameters in the context of planetary surface geological properties and processes. The purpose of this report is to document the research achievements associated with this study.

NEWTON - NEW portable multi-sensor scienTific instrument for non-invasive ON-site characterization of rock from planetary surface and sub-surfaces

NASA Astrophysics Data System (ADS)

Díaz-Michelena, M.; de Frutos, J.; Ordóñez, A. A.; Rivero, M. A.; Mesa, J. L.; González, L.; Lavín, C.; Aroca, C.; Sanz, M.; Maicas, M.; Prieto, J. L.; Cobos, P.; Pérez, M.; Kilian, R.; Baeza, O.; Langlais, B.; Thébault, E.; Grösser, J.; Pappusch, M.

2017-09-01

In space instrumentation, there is currently no instrument dedicated to susceptibly or complete magnetization measurements of rocks. Magnetic field instrument suites are generally vector (or scalar) magnetometers, which locally measure the magnetic field. When mounted on board rovers, the electromagnetic perturbations associated with motors and other elements make it difficult to reap the benefits from the inclusion of such instruments. However, magnetic characterization is essential to understand key aspects of the present and past history of planetary objects. The work presented here overcomes the limitations currently existing in space instrumentation by developing a new portable and compact multi-sensor instrument for ground breaking high-resolution magnetic characterization of planetary surfaces and sub-surfaces. This new technology introduces for the first time magnetic susceptometry (real and imaginary parts) as a complement to existing compact vector magnetometers for planetary exploration. This work aims to solve the limitations currently existing in space instrumentation by means of providing a new portable and compact multi-sensor instrument for use in space, science and planetary exploration to solve some of the open questions on the crustal and more generally planetary evolution within the Solar System.

The Importance of Planetary Rotation Period for Ocean Heat Transport

PubMed Central

Stevens, D.; Joshi, M.

2014-01-01

Abstract The climate and, hence, potential habitability of a planet crucially depends on how its atmospheric and ocean circulation transports heat from warmer to cooler regions. However, previous studies of planetary climate have concentrated on modeling the dynamics of atmospheres, while dramatically simplifying the treatment of oceans, which neglects or misrepresents the effect of the ocean in the total heat transport. Even the majority of studies with a dynamic ocean have used a simple so-called aquaplanet that has no continental barriers, which is a configuration that dramatically changes the ocean dynamics. Here, the significance of the response of poleward ocean heat transport to planetary rotation period is shown with a simple meridional barrier—the simplest representation of any continental configuration. The poleward ocean heat transport increases significantly as the planetary rotation period is increased. The peak heat transport more than doubles when the rotation period is increased by a factor of ten. There are also significant changes to ocean temperature at depth, with implications for the carbon cycle. There is strong agreement between the model results and a scale analysis of the governing equations. This result highlights the importance of both planetary rotation period and the ocean circulation when considering planetary habitability. Key Words: Exoplanet—Oceans—Rotation—Climate—Habitability. Astrobiology 14, 645–650. PMID:25041658

Intelligent robots for planetary exploration and construction

NASA Technical Reports Server (NTRS)

Albus, James S.

1992-01-01

Robots capable of practical applications in planetary exploration and construction will require realtime sensory-interactive goal-directed control systems. A reference model architecture based on the NIST Real-time Control System (RCS) for real-time intelligent control systems is suggested. RCS partitions the control problem into four basic elements: behavior generation (or task decomposition), world modeling, sensory processing, and value judgment. It clusters these elements into computational nodes that have responsibility for specific subsystems, and arranges these nodes in hierarchical layers such that each layer has characteristic functionality and timing. Planetary exploration robots should have mobility systems that can safely maneuver over rough surfaces at high speeds. Walking machines and wheeled vehicles with dynamic suspensions are candidates. The technology of sensing and sensory processing has progressed to the point where real-time autonomous path planning and obstacle avoidance behavior is feasible. Map-based navigation systems will support long-range mobility goals and plans. Planetary construction robots must have high strength-to-weight ratios for lifting and positioning tools and materials in six degrees-of-freedom over large working volumes. A new generation of cable-suspended Stewart platform devices and inflatable structures are suggested for lifting and positioning materials and structures, as well as for excavation, grading, and manipulating a variety of tools and construction machinery.

Insights into the dynamics of planetary interiors obtained through the study of global distribution of volcanoes I: Empirical calibration on Earth

NASA Astrophysics Data System (ADS)

Cañon-Tapia, Edgardo; Mendoza-Borunda, Ramón

2014-06-01

The distribution of volcanic features is ultimately controlled by processes taking place beneath the surface of a planet. For this reason, characterization of volcano distribution at a global scale can be used to obtain insights concerning dynamic aspects of planetary interiors. Until present, studies of this type have focused on volcanic features of a specific type, or have concentrated on relatively small regions. In this paper, (the first of a series of three papers) we describe the distribution of volcanic features observed over the entire surface of the Earth, combining an extensive database of submarine and subaerial volcanoes. The analysis is based on spatial density contours obtained with the Fisher kernel. Based on an empirical approach that makes no a priori assumptions concerning the number of modes that should characterize the density distribution of volcanism we identified the most significant modes. Using those modes as a base, the relevant distance for the formation of clusters of volcanoes is constrained to be on the order of 100 to 200 km. In addition, it is noted that the most significant modes lead to the identification of clusters that outline the most important tectonic margins on Earth without the need of making any ad hoc assumptions. Consequently, we suggest that this method has the potential of yielding insights about the probable occurrence of tectonic features within other planets.

Surface Telerobotics: Development and Testing of a Crew Controlled Planetary Rover System

NASA Technical Reports Server (NTRS)

Bualat, Maria G.; Fong, Terrence; Allan, Mark; Bouyssounouse, Xavier; Cohen, Tamar; Kobayashi, Linda

2013-01-01

In planning for future exploration missions, architecture and study teams have made numerous assumptions about how crew can be telepresent on a planetary surface by remotely operating surface robots from space (i.e. from a flight vehicle or deep space habitat). These assumptions include estimates of technology maturity, existing technology gaps, and operational risks. These assumptions, however, have not been grounded by experimental data. Moreover, to date, no crew-controlled surface telerobot has been fully tested in a high-fidelity manner. To address these issues, we developed the "Surface Telerobotics" tests to do three things: 1) Demonstrate interactive crew control of a mobile surface telerobot in the presence of short communications delay. 2) Characterize a concept of operations for a single astronaut remotely operating a planetary rover with limited support from ground control. 3) Characterize system utilization and operator work-load for a single astronaut remotely operating a planetary rover with limited support from ground control.

Lunar Science Conference, 8th, Houston, Tex., March 14-18, 1977, Proceedings. Volume 1 - The moon and the inner solar system. Volume 2 - Petrogenetic studies of mare and highland rocks. Volume 3 - Planetary and lunar surfaces

NASA Technical Reports Server (NTRS)

Merril, R. B.

1977-01-01

Solar system processes are considered along with the origin and evolution of the moon, planetary geophysics, lunar basins and crustal layering, lunar magnetism, the lunar surface as a planetary probe, remote observations of lunar and planetary surfaces, earth-based measurements, integrated studies, physical properties of lunar materials, and asteroids, meteorites, and the early solar system. Attention is also given to studies of mare basalts, the kinetics of basalt crystallization, topical studies of mare basalts, highland rocks, experimental studies of highland rocks, geochemical studies of highland rocks, studies of materials of KREEP composition, a consortium study of lunar breccia 73215, topical studies on highland rocks, Venus, and regional studies of the moon. Studies of surface processes, are reported, taking into account cratering mechanics and fresh crater morphology, crater statistics and surface dating, effects of exposure and gardening, and the chemistry of surfaces.

Special Software for Planetary Image Processing and Research

NASA Astrophysics Data System (ADS)

Zubarev, A. E.; Nadezhdina, I. E.; Kozlova, N. A.; Brusnikin, E. S.; Karachevtseva, I. P.

2016-06-01

The special modules of photogrammetric processing of remote sensing data that provide the opportunity to effectively organize and optimize the planetary studies were developed. As basic application the commercial software package PHOTOMOD™ is used. Special modules were created to perform various types of data processing: calculation of preliminary navigation parameters, calculation of shape parameters of celestial body, global view image orthorectification, estimation of Sun illumination and Earth visibilities from planetary surface. For photogrammetric processing the different types of data have been used, including images of the Moon, Mars, Mercury, Phobos, Galilean satellites and Enceladus obtained by frame or push-broom cameras. We used modern planetary data and images that were taken over the years, shooting from orbit flight path with various illumination and resolution as well as obtained by planetary rovers from surface. Planetary data image processing is a complex task, and as usual it can take from few months to years. We present our efficient pipeline procedure that provides the possibilities to obtain different data products and supports a long way from planetary images to celestial body maps. The obtained data - new three-dimensional control point networks, elevation models, orthomosaics - provided accurate maps production: a new Phobos atlas (Karachevtseva et al., 2015) and various thematic maps that derived from studies of planetary surface (Karachevtseva et al., 2016a).

On Star-Planet Interaction: Magnetospheric Dynamics and Atmospheric Evolution

NASA Astrophysics Data System (ADS)

Tilley, Matthew Tilley

With the explosion of exoplanetary discoveries, the question of planetary habitability is at the forefront, and generates many interesting and complex questions. One of those questions: Are planetary global magnetic fields necessary for the development of complex surface organics and the development of life? Does a global field protect planetary atmospheres? What detection signatures can be gleaned from a planet or moon with a global field as opposed to one without? We have a wealth of in situ magnetospheric data from Earth, as well as solar system planets and their moons from several vital satellite missions, such as the Voyager missions, the Pioneer missions, Galileo, Cassini, Messenger, MAVEN, and New Horizons. Due to the distances involved, it is not tenable to send satellites to obtain data at exoplanetary bodies, so we rely on simulations and using solar system data as analog environments to help set ground truth validation for the numerical work. In this dissertation, I use a multifluid plasma model for gas giant magnetospheres to predict the potential dynamical consequences and detection signatures for giant exoplanets in a warm orbit (˜0.2 AU). I discuss the dynamics of plasma loss from an exomoon injected torus, and how the total mass flux out of the system is altered by increased stellar wind forcing as a function of orbital semi-major axis. Detection signatures for such a planet, including transit depth modifications due to plasma densities and radio emissions, show promise for further detecting and characterizing future systems. I also improve the multifluid model by implementing a full treatment of pressure anisotropy at Saturn, with a focus on the dynamics and structure of the magnetosphere. The improvements to the physics of the model generate more accurate system when compared to Cassini data; the anisotropic simulations show stronger current confinement of the Enceladus torus, consistent and well-structure flux interchange events, and global corotational convection that match more closely with the Cassini data than the isotropic model. Turning from giant planets to terrestrial, I use a coupled one-dimensional photochemical and radiative-convective climate model to investigate the effects of M dwarf stellar flare activity on an Earth-like atmosphere for an unmagnetized planet in the nominal habitable zone. I find that EM-only activity - even to the level of some of the most active stars yet observed - is insufficient at the age of the universe to reduce the ozone column to the point that UV-C radiation can reach the surface. However, repeated proton events from frequent daily flare activity, which has been observed on several M dwarfs, can erode the ozone column by several orders of magnitude, allowing the surface of the planet to be bathed in UV-C, which is sterilizing and detrimental to the development of complex organic structures. The ability of a strong planetary magnetic field to deflect incoming stellar wind and flare-energized protons seems to be of import to maintain surface habitability. I also use scaling laws to predict a potential atomic oxygen auroral signal from Proxima Centauri b, the detection of which would constrain the presence of an atmosphere and point to the presence of a magnetic field. The increased forcing from Proxima Centauri's stellar wind is expected to drive powerful emissions, orders of magnitude stronger than at Earth, and within easy reach of the next generation of observational telescopic instruments. Magnetic fields do seem to be important for both detection and potential shielding of the atmosphere of exoplanets, but much work remains to be performed. Future observations combined with simulations validated against solar system star-planet interactions will likely provide answers to these questions, and perhaps lead to a focus on specific planetary targets for extensive investigation of astrobiological interest.

Measuring and interpreting X-ray fluorescence from planetary surfaces.

PubMed

Owens, Alan; Beckhoff, Burkhard; Fraser, George; Kolbe, Michael; Krumrey, Michael; Mantero, Alfonso; Mantler, Michael; Peacock, Anthony; Pia, Maria-Grazia; Pullan, Derek; Schneider, Uwe G; Ulm, Gerhard

2008-11-15

As part of a comprehensive study of X-ray emission from planetary surfaces and in particular the planet Mercury, we have measured fluorescent radiation from a number of planetary analog rock samples using monochromatized synchrotron radiation provided by the BESSY II electron storage ring. The experiments were carried out using a purpose built X-ray fluorescence (XRF) spectrometer chamber developed by the Physikalisch-Technische Bundesanstalt, Germany's national metrology institute. The XRF instrumentation is absolutely calibrated and allows for reference-free quantitation of rock sample composition, taking into account secondary photon- and electron-induced enhancement effects. The fluorescence data, in turn, have been used to validate a planetary fluorescence simulation tool based on the GEANT4 transport code. This simulation can be used as a mission analysis tool to predict the time-dependent orbital XRF spectral distributions from planetary surfaces throughout the mapping phase.

Precise Chemical Analyses of Planetary Surfaces

NASA Technical Reports Server (NTRS)

Kring, David; Schweitzer, Jeffrey; Meyer, Charles; Trombka, Jacob; Freund, Friedemann; Economou, Thanasis; Yen, Albert; Kim, Soon Sam; Treiman, Allan H.; Blake, David;

FITS and PDS4: Planetary Surface Data Interoperability Made Easier

NASA Astrophysics Data System (ADS)

Marmo, C.; Hare, T. M.; Erard, S.; Cecconi, B.; Minin, M.; Rossi, A. P.; Costard, F.; Schmidt, F.

2018-04-01

This abstract describes how Flexible Image Transport System (FITS) can be used in planetary surface investigations, and how its metadata can easily be inserted in the PDS4 metadata distribution model.

Science Drivers for Polarimetric Exploration of the Solar System and Beyond

NASA Astrophysics Data System (ADS)

Yanamandra-Fisher, P. A.

2012-12-01

Remote sensing and robotic exploration of our solar system and exoplanetary systems can be enhanced with the inclusion of spectrophotopolarimetry as a complementary approach to standard techniques of imaging and spectroscopy. Since all objects have unique polarimetric signatures, like fingerprints, much can be learned about the scattering object. I highlight some of the science drivers that will benefit from polarimteric exploration. In our own dynamic solar system, the study of linear polarization of reflected light by solar system objects (planetary atmospheres, satellites, rings systems, comets, asteroids, dust, etc.) provides insight into the scattering characteristics of aerosols and hazes in atmospheres and surficial properties of atmosphereless objects. Well-known examples are the identification of spherical droplets of sulphuric acid in the atmosphere of Venus, and dust storms and ice clouds on Mars. In the case of outer planets, although the phase angles available from earth to observe are limited to a very narrow range, measurements of linear limb polarization characterizes the variation of aerosol properties across the planetary disk. Since methane is present in all giant planets' atmospheres, limb measurements of linear polarization in various methane bands allow a direct measurement of the vertical distribution of aerosol and haze particles, complementary to direct imaging and spectroscopy. Linear polarization of atmosphereless objects (the Moon, planetary satellites and asteroids) are diagnostic of surface texture, and demonstrate that most of them have their surfaces covered with a regolith of fine material, function of particle size and packing density. The recent discovery of multi-planetary systems (or multis) by Kepler mission, illustrate that a variety of planetary systems exist beyond our solar system. Current indirect techniques such as radial velocity, pulsar timing, and transits identify exoplanetary candidates and identification of atmospheric species. Direct detection and characterization of exoplanets can be achieved by measurement of linear polarization of reflected starlight by exoplanets. Our solar system, therefore, provides a dynamic laboratory and template to detect and characterize exoplanetary systems. Search for habitability elsewhere in the solar and exoplanetary systems is another important science driver. Chirality or handedness is a property of molecules that exhibit mirror-image symmetry (similar to right and left hands). Right- or left-chirality is characterized by circularly polarized light. All known biological activity and all life forms on earth are chiral and pre-dominantly left-handed. This property can be investigated by measuring the circular polarization of various species on planetary bodies. The search for the emergence of habitability in the solar system and exoplanetary systems can be aided by the measurement of circular polarization of comets; planetary and satellites' atmospheres and asteroids. Therefore, inclusion of polarimetric remote sensing and development of spectropolarimeters for ground-based facilities and instruments on space missions is needed, with similar maturation of vector radiative transfer models and related laboratory measurements.

SERENA: A suite of four instruments (ELENA, STROFIO, PICAM and MIPA) on board BepiColombo-MPO for particle detection in the Hermean environment

NASA Astrophysics Data System (ADS)

Orsini, S.; Livi, S.; Torkar, K.; Barabash, S.; Milillo, A.; Wurz, P.; di Lellis, A. M.; Kallio, E.; The Serena Team

2010-01-01

'Search for Exospheric Refilling and Emitted Natural Abundances' (SERENA) is an instrument package that will fly on board the BepiColombo/Mercury Planetary Orbiter (MPO). It will investigate Mercury's complex particle environment that is composed of thermal and directional neutral atoms (exosphere) caused by surface release and charge-exchange processes, and of ionized particles caused by photo-ionization of neutrals as well by charge exchange and surface release processes. In order to investigate the structure and dynamics of the environment, an in-situ analysis of the key neutral and charged components is necessary, and for this purpose the SERENA instrument shall include four units: two neutral particle analyzers (Emitted Low Energy Neutral Atoms (ELENA) sensor and Start from a Rotating FIeld mass spectrometer (STROFIO)) and two ion spectrometers (Miniature Ion Precipitation Analyzer (MIPA) and Planetary Ion Camera (PICAM)). The scientific merits of SERENA are presented, and the basic characteristics of the four units are described, with a focus on novel technological aspects.

Ammonia clathrate hydrates as new solid phases for Titan, Enceladus, and other planetary systems.

PubMed

Shin, Kyuchul; Kumar, Rajnish; Udachin, Konstantin A; Alavi, Saman; Ripmeester, John A

2012-09-11

There is interest in the role of ammonia on Saturn's moons Titan and Enceladus as the presence of water, methane, and ammonia under temperature and pressure conditions of the surface and interior make these moons rich environments for the study of phases formed by these materials. Ammonia is known to form solid hemi-, mono-, and dihydrate crystal phases under conditions consistent with the surface of Titan and Enceladus, but has also been assigned a role as water-ice antifreeze and methane hydrate inhibitor which is thought to contribute to the outgassing of methane clathrate hydrates into these moons' atmospheres. Here we show, through direct synthesis from solution and vapor deposition experiments under conditions consistent with extraterrestrial planetary atmospheres, that ammonia forms clathrate hydrates and participates synergistically in clathrate hydrate formation in the presence of methane gas at low temperatures. The binary structure II tetrahydrofuran + ammonia, structure I ammonia, and binary structure I ammonia + methane clathrate hydrate phases synthesized have been characterized by X-ray diffraction, molecular dynamics simulation, and Raman spectroscopy methods.

Ammonia clathrate hydrates as new solid phases for Titan, Enceladus, and other planetary systems

PubMed Central

Shin, Kyuchul; Kumar, Rajnish; Udachin, Konstantin A.; Alavi, Saman; Ripmeester, John A.

2012-01-01

There is interest in the role of ammonia on Saturn’s moons Titan and Enceladus as the presence of water, methane, and ammonia under temperature and pressure conditions of the surface and interior make these moons rich environments for the study of phases formed by these materials. Ammonia is known to form solid hemi-, mono-, and dihydrate crystal phases under conditions consistent with the surface of Titan and Enceladus, but has also been assigned a role as water-ice antifreeze and methane hydrate inhibitor which is thought to contribute to the outgassing of methane clathrate hydrates into these moons’ atmospheres. Here we show, through direct synthesis from solution and vapor deposition experiments under conditions consistent with extraterrestrial planetary atmospheres, that ammonia forms clathrate hydrates and participates synergistically in clathrate hydrate formation in the presence of methane gas at low temperatures. The binary structure II tetrahydrofuran + ammonia, structure I ammonia, and binary structure I ammonia + methane clathrate hydrate phases synthesized have been characterized by X-ray diffraction, molecular dynamics simulation, and Raman spectroscopy methods. PMID:22908239

Electrostatic Phenomena on Planetary Surfaces

NASA Astrophysics Data System (ADS)

Calle, Carlos I.

2017-02-01

The diverse planetary environments in the solar system react in somewhat different ways to the encompassing influence of the Sun. These different interactions define the electrostatic phenomena that take place on and near planetary surfaces. The desire to understand the electrostatic environments of planetary surfaces goes beyond scientific inquiry. These environments have enormous implications for both human and robotic exploration of the solar system. This book describes in some detail what is known about the electrostatic environment of the solar system from early and current experiments on Earth as well as what is being learned from the instrumentation on the space exploration missions (NASA, European Space Agency, and the Japanese Space Agency) of the last few decades. It begins with a brief review of the basic principles of electrostatics.

Near Mbar-Level Dynamic Loading of Materials by Direct Laser-Irradiation

NASA Astrophysics Data System (ADS)

Tierney, T. E.; Swift, D. C.; Gammel, J. T.; Luo, S.; Johnson, R. P.

2003-12-01

We are developing techniques to perform direct-laser-illumination-driven, dynamic materials experiments at up to Mbar pressures with use of the Trident Laser Laboratory at Los Alamos. By temporally controlling the laser-irradiance, we are able to shape our loading for studies of fast-rise shocks, precursors, or isentropic compression. Laser-driven shock experiments are advantageous when considering the efficiency (fast turnaround), relative ease of sample recovery, taylorable dynamic loading, and in-situ structure diagnostics. Frequently, these experiments last 1-5 nanoseconds, and thus, permit investigation of rate-dependent processes and high strain rate environments. Laser-driven dynamic experiments are an important complement to traditional dynamic (e.g., light-gas gun) and static (e.g., diamond-anvil cell) experiments with certain advantages in studying equation of state, phase transitions and mechanical-chemical properties of Earth and planetary materials. Understanding high-pressure behavior in this regime is critical to phase boundaries for planetary interiors and dynamic properties of impact processes. Although we have studied silicates, oxides, metals, alloys and organic materials, this paper will focus on shocked and isentropically-compressed results obtained for iron in the range of 10-70 GPa (0.1-0.7 Mbar). Free surface velocities are measured using a Velocity Interferometer System for Any Reflector (VISAR). Nanosecond-scale laser experiments were interpreted with careful attention to exaggerated elastic-plastic effects and using accurate new equations of state for the phases of iron. This poster will present our technique, experimental results, and interpretation. *Work performed under the auspices of the US DOE under contract No. W-7405-ENG-36.

Dark Matter Halos with VIRUS-P

NASA Astrophysics Data System (ADS)

Murphy, Jeremy; Gebhardt, K.

2010-05-01

We present new, two-dimensional stellar kinematic data on several of the most massive galaxies in the local universe. These data were taken with the integral field spectrograph, VIRUS-P, and extend to unprecedented radial distances. Once robust stellar kinematics are in hand, we run orbit-based axisymmetric dynamical models in order to constrain the stellar mass-to-light ratio and dark matter halo parameters. We have run a large set of dynamical models on the second rank galaxy in the Virgo cluster, M87, and find clear evidence for a massive dark matter halo. The two-dimensional stellar kinematics for several of our other targets, all first and second rank galaxies, are also presented. Dark matter halos are known to dominate the mass profile of elliptical galaxies somewhere between one to two effective radii, yet due to the low surface brightness at these radial distances, determining stellar dynamics is technologically challenging. To overcome this, constraints on the dark matter halo are often made with planetary nebulae or globular clusters at large radii. However, as results from different groups have returned contradictory results, it remains unclear whether different dynamical tracers always follow the stellar kinematics. Due to VIRUS-P's large field of view and on-sky fiber diameter, we are able to determine stellar kinematics at radial distances that overlap with other dynamical tracers. Understanding what the dynamics of stars, planetary nebula and globular clusters tell us about both the extent of the dark matter halo profile and the formation histories of the largest elliptical galaxies is a primary science driver for this work.

Evolution of Autonomous Self-Righting Behaviors for Articulated Nanorovers

NASA Technical Reports Server (NTRS)

Tunstel, Edward

1999-01-01

Miniature rovers with articulated mobility mechanisms are being developed for planetary surface exploration on Mars and small solar system bodies. These vehicles are designed to be capable of autonomous recovery from overturning during surface operations. This paper describes a computational means of developing motion behaviors that achieve the autonomous recovery function. It proposes a control software design approach aimed at reducing the effort involved in developing self-righting behaviors. The approach is based on the integration of evolutionary computing with a dynamics simulation environment for evolving and evaluating motion behaviors. The automated behavior design approach is outlined and its underlying genetic programming infrastructure is described.

Balance models for equatorial planetary-scale dynamics

NASA Astrophysics Data System (ADS)

Chan, Ian Hiu-Fung

This thesis aims at advancing our understanding of large-scale dynamics in the tropics, specifically the characterization of slow planetary-scale motions through a balance theory; current balance theories in the tropics are unsatisfactory as they filter out Kelvin waves, which are an important component of variability, along with fast inertia-gravity (IG) waves. (Abstract shortened by UMI.).

Planetary Geology: A Teacher's Guide with Activities in Physical and Earth Sciences.

ERIC Educational Resources Information Center

National Aeronautics and Space Administration, Washington, DC.

This educator's guide discusses planetary geology. Exercises are grouped into five units: (1) introduction to geologic processes; (2) impact cratering activities; (3) planetary atmospheres; (4) planetary surfaces; and (5) geologic mapping. Suggested introductory exercises are noted at the beginning of each exercise. Each activity includes an…

The Twenty-Fifth Lunar and Planetary Science Conference. Part 3: P-Z

NASA Technical Reports Server (NTRS)

1994-01-01

Various papers on lunar and planetary science are presented, covering such topics as: impact craters, tektites, lunar geology, lava flow, geodynamics, chondrites, planetary geology, planetary surfaces, volcanology, tectonics, topography, regolith, metamorphic rock, geomorphology, lunar soil, geochemistry, petrology, cometary collisions, geochronology, weathering, and meteoritic composition.

Technological support of tool wear resistant qualities and cost saving of process of planetary grinding of flat parts

NASA Astrophysics Data System (ADS)

Ivanova, T. N.; Lyupa, D. C.; Revenko, N. F.; Berkutova, T. A.; Silivanova, O. A.

2018-03-01

A lot of factors varied in time lead to instability of the grinding process. Besides, the method of grinding influences significantly the productivity and quality of processing. In this regard a creation of processes of intensive defect-free grinding on the basis of new constructive and technology solutions represents the scientific problem which is of great importance. One of such solutions is application of planetary face grinding which allows simultaneously changing the kinematics of movement, implementing discontinuous grinding. The distinctive features of such grinding are decreasing the heat release rate in a contact zone; ensuring intermittence of the process with a solid grinding wheel; reverse grinding; cutting by different edges of an abrasive grain; stabilization of working parameters of a grinding wheel; ensuring work of a grinding wheel in a self-sharpening mode. The design of the planetary grinding tool was developed for plane surface processing for implementation of the specified distinctive features of planetary grinding. The kinematics of shaping a surface by flat face diamond grinding has been investigated; manufacturing capabilities of planetary face grinding have been revealed, and ways of improvement of quality and productivity have been offered. The algorithm and the program to define the motion path of a grain depending on the given set of grinding factors were received. Optimization of the process of face diamond grinding using the planetary grinding device has been confirmed with the developed program and techniques to choose cutting conditions of planetary grinding and characteristics of grinding wheels for processing different materials. While studying the process of planetary grinding, special attention was paid to the research how processing conditions influence microgeometry of the processed surface made of steel 4X5M (Russian State Standard (GOST)). As a result of the executed research, it was established that surface roughness parameter Ra during the processing using the planetary grinding device is 35 - 40% less than when using the tool with the solid cutting surface. This phenomenon can be accounted for more uniform work of the cutting grains of the planetary grinding tool as the number of meetings of diamond grains with the surface being processed increases. At the same time, it should be noted that during the planetary grinding more intensive smoothing of tops of microroughnesses is observed that provides the creation of steadier cutting shape. The given method of calculation of cost value of grinding operation allows solving various manufacturing problems: to compare cost value of grinding different materials, grinding wheels of different parameters; to define the optimum grinding conditions.

Visualization of Kepler’s laws of planetary motion

NASA Astrophysics Data System (ADS)

Lu, Meishu; Su, Jun; Wang, Weiguo; Lu, Jianlong

2017-03-01

For this article, we use a 3D printer to print a surface similar to universal gravitation for demonstrating and investigating Kepler’s laws of planetary motion describing the motion of a small ball on the surface. This novel experimental method allows Kepler’s laws of planetary motion to be visualized and will contribute to improving the manipulative ability of middle school students and the accessibility of classroom education.

An abstract model for radiative transfer in an atmosphere with reflection by the planetary surface

NASA Astrophysics Data System (ADS)

Greenberg, W.; van der Mee, C. V. M.

1985-07-01

A Hilbert-space model is developed that applies to radiative transfer in a homogeneous, plane-parallel planetary atmosphere. Reflection and absorption by the planetary surface are taken into account by imposing a reflective boundary condition. The existence and uniqueness of the solution of this boundary value problem are established by proving the invertibility of a scattering operator using the Fredholm alternative.

Comparative Climates of the Trappist-1 Planetary System: Results from a Simple Climate-vegetation Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alberti, Tommaso; Carbone, Vincenzo; Lepreti, Fabio

The recent discovery of the planetary system hosted by the ultracool dwarf star TRAPPIST-1 could open new paths for investigations of the planetary climates of Earth-sized exoplanets, their atmospheres, and their possible habitability. In this paper, we use a simple climate-vegetation energy-balance model to study the climate of the seven TRAPPIST-1 planets and the climate dependence on various factors: the global albedo, the fraction of vegetation that could cover their surfaces, and the different greenhouse conditions. The model allows us to investigate whether liquid water could be maintained on the planetary surfaces (i.e., by defining a “surface water zone (SWZ)”)more » in different planetary conditions, with or without the presence of a greenhouse effect. It is shown that planet TRAPPIST-1d seems to be the most stable from an Earth-like perspective, since it resides in the SWZ for a wide range of reasonable values of the model parameters. Moreover, according to the model, outer planets (f, g, and h) cannot host liquid water on their surfaces, even with Earth-like conditions, entering a snowball state. Although very simple, the model allows us to extract the main features of the TRAPPIST-1 planetary climates.« less

Development of a Catalytic Coating for a Shuttle Flight Experiment

NASA Technical Reports Server (NTRS)

Stewart, David A.; Goekcen, Tahir; Sepka, Steven E.; Leiser, Daniel B.; Rezin, Marc D.

2010-01-01

A spray-on coating was developed for use on the shuttle wing tiles to obtain data that could be correlated with computational fluid dynamics (CFD) solutions to better understand the effect of chemical heating on a fore-body heat shield having a turbulent boundary layer during planetary entry at hypersonic speed. The selection of a spray-on coating was conducted in two Phases 1) screening tests to select the catalytic coating formulation and 2) surface property determination using both arc-jet and side-arm facilities at NASA Ames Research Center. Comparison of the predicted surface temperature profile over a flat-plate with measured values obtained during arc-jet exposure (Phase I study) was used to validate the surface properties obtained during Phase II.

The Minimum-Mass Surface Density of the Solar Nebula using the Disk Evolution Equation

NASA Technical Reports Server (NTRS)

Davis, Sanford S.

2005-01-01

The Hayashi minimum-mass power law representation of the pre-solar nebula (Hayashi 1981, Prog. Theo. Phys.70,35) is revisited using analytic solutions of the disk evolution equation. A new cumulative-planetary-mass-model (an integrated form of the surface density) is shown to predict a smoother surface density compared with methods based on direct estimates of surface density from planetary data. First, a best-fit transcendental function is applied directly to the cumulative planetary mass data with the surface density obtained by direct differentiation. Next a solution to the time-dependent disk evolution equation is parametrically adapted to the planetary data. The latter model indicates a decay rate of r -1/2 in the inner disk followed by a rapid decay which results in a sharper outer boundary than predicted by the minimum mass model. The model is shown to be a good approximation to the finite-size early Solar Nebula and by extension to extra solar protoplanetary disks.

Goldstone solar system radar

NASA Technical Reports Server (NTRS)

Jurgens, R. F.; Clark, P. E.; Goldstein, R. M.; Ostro, S. J.; Slade, M. A.; Thompson, T. W.; Saunders, R. S.

1986-01-01

Information is provided about physical nature planetary surfaces and their topography as well as dynamical properties such as orbits and spin states using ground based radar as a remote sensing tool. Accessible targets are the terrestrial planets: the Earth's Moon, Mercury, Venus and Mars, the outer planets rings and major moons, and many transient objects such as asteroids and comets. Data acquisition utilizes the unique facilities of the Goldstone Deep Space Network, occasionally the Arecibo radar, and proposed use of the VLA (very large array).

Twenty-fourth Lunar and Planetary Science Conference. Part 1: A-F

NASA Technical Reports Server (NTRS)

1993-01-01

The topics covered include the following: petrology, petrography, meteoritic composition, planetary geology, atmospheric composition, astronomical spectroscopy, lunar geology, Mars (planet), Mars composition, Mars surface, volcanology, Mars volcanoes, Mars craters, lunar craters, mineralogy, mineral deposits, lithology, asteroids, impact melts, planetary composition, planetary atmospheres, planetary mapping, cosmic dust, photogeology, stratigraphy, lunar craters, lunar exploration, space exploration, geochronology, tectonics, atmospheric chemistry, astronomical models, and geochemistry.

Global Particle-in-Cell Simulations of Mercury's Magnetosphere

NASA Astrophysics Data System (ADS)

Schriver, D.; Travnicek, P. M.; Lapenta, G.; Amaya, J.; Gonzalez, D.; Richard, R. L.; Berchem, J.; Hellinger, P.

2017-12-01

Spacecraft observations of Mercury's magnetosphere have shown that kinetic ion and electron particle effects play a major role in the transport, acceleration, and loss of plasma within the magnetospheric system. Kinetic processes include reconnection, the breakdown of particle adiabaticity and wave-particle interactions. Because of the vast range in spatial scales involved in magnetospheric dynamics, from local electron Debye length scales ( meters) to solar wind/planetary magnetic scale lengths (tens to hundreds of planetary radii), fully self-consistent kinetic simulations of a global planetary magnetosphere remain challenging. Most global simulations of Earth's and other planet's magnetosphere are carried out using MHD, enhanced MHD (e.g., Hall MHD), hybrid, or a combination of MHD and particle in cell (PIC) simulations. Here, 3D kinetic self-consistent hybrid (ion particle, electron fluid) and full PIC (ion and electron particle) simulations of the solar wind interaction with Mercury's magnetosphere are carried out. Using the implicit PIC and hybrid simulations, Mercury's relatively small, but highly kinetic magnetosphere will be examined to determine how the self-consistent inclusion of electrons affects magnetic reconnection, particle transport and acceleration of plasma at Mercury. Also the spatial and energy profiles of precipitating magnetospheric ions and electrons onto Mercury's surface, which can strongly affect the regolith in terms of space weathering and particle outflow, will be examined with the PIC and hybrid codes. MESSENGER spacecraft observations are used both to initiate and validate the global kinetic simulations to achieve a deeper understanding of the role kinetic physics play in magnetospheric dynamics.

Dynamics of early planetary gear trains

NASA Technical Reports Server (NTRS)

August, R.; Kasuba, R.; Frater, J. L.; Pintz, A.

1984-01-01

A method to analyze the static and dynamic loads in a planetary gear train was developed. A variable-variable mesh stiffness (VVMS) model was used to simulate the external and internal spur gear mesh behavior, and an equivalent conventional gear train concept was adapted for the dynamic studies. The analysis can be applied either involute or noninvolute spur gearing. By utilizing the equivalent gear train concept, the developed method may be extended for use for all types of epicyclic gearing. The method is incorporated into a computer program so that the static and dynamic behavior of individual components can be examined. Items considered in the analysis are: (1) static and dynamic load sharing among the planets; (2) floating or fixed Sun gear; (3) actual tooth geometry, including errors and modifications; (4) positioning errors of the planet gears; (5) torque variations due to noninvolute gear action. A mathematical model comprised of power source, load, and planetary transmission is used to determine the instantaneous loads to which the components are subjected. It considers fluctuating output torque, elastic behavior in the system, and loss of contact between gear teeth. The dynamic model has nine degrees of freedom resulting in a set of simultaneous second order differential equations with time varying coefficients, which are solved numerically. The computer program was used to determine the effect of manufacturing errors, damping and component stiffness, and transmitted load on dynamic behavior. It is indicated that this methodology offers the designer/analyst a comprehensive tool with which planetary drives may be quickly and effectively evaluated.

Exploration Consequences of Particle Radiation Environments at Airless Planetary Surfaces: Lessons Learned at the Moon by LRO/CRaTER and Scaling to Other Solar System Objects

NASA Astrophysics Data System (ADS)

Spence, H. E.

2017-12-01

We examine and compare the energetic particle ionizing radiation environments at airless planetary surfaces throughout the solar system. Energetic charged particles fill interplanetary space and bathe the environments of planetary objects with a ceaseless source of sometimes powerful yet ever-present ionizing radiation. In turn, these charged particles interact with planetary bodies in various ways, depending upon the properties of the body as well as upon the nature of the charged particles themselves. The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaisance Orbiter (LRO), launched in 2009, continues to provide new insights into the ways by which the lunar surface is influenced by these energetic particles. In this presentation, we briefly review some of these mechanisms and how they operate at the Moon, and then compare and contrast the radiation environments at other atmospherereless planetary objects within our solar system that are potential future human exploration targets. In particular, we explore two primary sources of ionizing radiation, galactic cosmic rays (GCR) and solar energetic particles (SEP), in the environments of planetary objects that have weak or absent atmospheres and intrinsic magnetic fields. We motivate the use of simplified scaling relationships with heliocentric distance to estimate their intensity, which then serves as a basis for estimating the relative importance of various energetic particle and planetary surface physical interactions, in the context of humankind's expanding explorations beyond low-Earth orbit.

Past and future of radio occultation studies of planetary atmospheres

NASA Technical Reports Server (NTRS)

Eshleman, Von R.; Hinson, David P.; Tyler, G. Leonard; Lindal, Gunnar F.

1987-01-01

Measurements of radio waves that have propagated through planetary atmospheres have provided exploratory results on atmospheric constituents, structure, dynamics, and ionization for Venus, Mars, Titan, Jupiter, Saturn, and Uranus. Highlights of past results are reviewed in order to define and illustrate the potential of occultation and related radio studies in future planetary missions.

The Variation of Planetary Surfaces' Structure and Size Distribution with Depth

NASA Astrophysics Data System (ADS)

Charalambous, C. A.; Pike, W. T.

2014-12-01

The particle, rock and boulder size distribution of a planetary surface bring important implications not only to crucial aspects of future missions but also to the better understanding of planetary and earth sciences. By exploiting a novel statistical model, the evolution of particle fragmentation phenomena can be understood in terms of a descriptive maturity index, a measure of the number of fragmentation events that have produced the soil. This statistical model, which is mathematically constructed via fundamental physical principles, has been validated by terrestrial mineral grinding data and impact experiments. Applying the model to planetary surfaces, the number of fragmentation events is determined by production function curves that quantify the degree of impact cratering. The model quantifies the variation of the maturity index of the regolith with depth, with a high maturity index at the surface decreasing to a low index corresponding to the megaregolith of a blocky population and fractured bedrock. The measured lunar and martian particle size distributions at the surface is well matched by the model over several orders of magnitude. The continuous transition invoked by the model can be furthermore synthesised to provide temporal and spatial visualisations of the internal architecture of the Martian and Lunar regolith. Finally, the model is applied to the risk assessment and success criteria of future mission landings as well as drilling on planetary surfaces. The solutions to a variety of planetary fragmentation related problems can be found via exact mathematical foundations or through simulations using the particle population provided by the model's maturation.

DYNAMICAL ACCRETION OF PRIMORDIAL ATMOSPHERES AROUND PLANETS WITH MASSES BETWEEN 0.1 AND 5 M {sub ⊕} IN THE HABITABLE ZONE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stökl, Alexander; Dorfi, Ernst A.; Johnstone, Colin P.

2016-07-10

In the early, disk-embedded phase of evolution of terrestrial planets, a protoplanetary core can accumulate gas from the circumstellar disk into a planetary envelope. In order to relate the accumulation and structure of this primordial atmosphere to the thermal evolution of the planetary core, we calculated atmosphere models characterized by the surface temperature of the core. We considered cores with masses between 0.1 and 5 M {sub ⊕} situated in the habitable zone around a solar-like star. The time-dependent simulations in 1D-spherical symmetry include the hydrodynamics equations, gray radiative transport, and convective energy transport. Using an implicit time integration scheme,more » we can use large time steps and and thus efficiently cover evolutionary timescales. Our results show that planetary atmospheres, when considered with reference to a fixed core temperature, are not necessarily stable, and multiple solutions may exist for one core temperature. As the structure and properties of nebula-embedded planetary atmospheres are an inherently time-dependent problem, we calculated estimates for the amount of primordial atmosphere by simulating the accretion process of disk gas onto planetary cores and the subsequent evolution of the embedded atmospheres. The temperature of the planetary core is thereby determined from the computation of the internal energy budget of the core. For cores more massive than about one Earth mass, we obtain that a comparatively short duration of the disk-embedded phase (∼10{sup 5} years) is sufficient for the accumulation of significant amounts of hydrogen atmosphere that are unlikely to be removed by later atmospheric escape processes.« less

Rover mounted ground penetrating radar as a tool for investigating the near-surface of Mars and beyong

NASA Technical Reports Server (NTRS)

Grant, J. A.; Schultz, P. H.

1993-01-01

In spite of the highly successful nature of recent planetary missions to the terrestrial planets and outer satellites a number of questions concerning the evolution of their surfaces remain unresolved. For example, knowledge of many characteristics of the stratigraphy and soils comprising the near-surface on Mars remains largely unknown, but is crucial in order to accurately define the history of surface processes and near-surface sedimentary record. Similar statements can be made regarding our understanding of near-surface stratigraphy and processes on other extraterrestrial planetary bodies. Ground penetrating radar (GPR) is a proven and standard instrument capable of imaging the subsurface at high resolution to 10's of meters depth in a variety of terrestrial environments. Moreover, GPR is portable and easily modified for rover deployment. Data collected with a rover mounted GPR could resolve a number of issues related to planetary surface evolution by defining shallow stratigraphic records and would provide context for interpreting results of other surface analyses (e.g. elemental or mineralogical). A discussion of existing GPR capabilities is followed first by examples of how GPR might be used to better define surface evolution on Mars and then by a brief description of possible GPR applications to the Moon and other planetary surfaces.

Dynamic Response of a Planetary Gear System Using a Finite Element/Contact Mechanics Model

NASA Technical Reports Server (NTRS)

Parker, Robert G.; Agashe, Vinayak; Vijayakar, Sandeep M.

2000-01-01

The dynamic response of a helicopter planetary gear system is examined over a wide range of operating speeds and torques. The analysis tool is a unique, semianalytical finite element formulation that admits precise representation of the tooth geometry and contact forces that are crucial in gear dynamics. Importantly, no a priori specification of static transmission error excitation or mesh frequency variation is required; the dynamic contact forces are evaluated internally at each time step. The calculated response shows classical resonances when a harmonic of mesh frequency coincides with a natural frequency. However, peculiar behavior occurs where resonances expected to be excited at a given speed are absent. This absence of particular modes is explained by analytical relationships that depend on the planetary configuration and mesh frequency harmonic. The torque sensitivity of the dynamic response is examined and compared to static analyses. Rotation mode response is shown to be more sensitive to input torque than translational mode response.

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration

NASA Technical Reports Server (NTRS)

Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Smith, E. V.; Yerazunis, S. W.

1973-01-01

Problems related to the design and control of a mobile planetary vehicle to implement a systematic plan for the exploration of Mars are reported. Problem areas include: vehicle configuration, control, dynamics, systems and propulsion; systems analysis, terrain modeling and path selection; and chemical analysis of specimens. These tasks are summarized: vehicle model design, mathematical model of vehicle dynamics, experimental vehicle dynamics, obstacle negotiation, electrochemical controls, remote control, collapsibility and deployment, construction of a wheel tester, wheel analysis, payload design, system design optimization, effect of design assumptions, accessory optimal design, on-board computer subsystem, laser range measurement, discrete obstacle detection, obstacle detection systems, terrain modeling, path selection system simulation and evaluation, gas chromatograph/mass spectrometer system concepts, and chromatograph model evaluation and improvement.

Planetary Science from NASA's WB-57 Canberra High Altitude Research Aircraft During the Great American Eclipse of 2017

NASA Astrophysics Data System (ADS)

Tsang, C.; Caspi, A.; DeForest, C. E.; Durda, D. D.; Steffl, A.; Lewis, J.; Wiseman, J.; Collier, J.; Mallini, C.; Propp, T.; Warner, J.

2017-12-01

The Great American Eclipse of 2017 provided an excellent opportunity for heliophysics research on the solar corona and dynamics that encompassed a large number of research groups and projects, including projects flown in the air and in space. Two NASA WB-57F Canberra high altitude research aircraft were launched from NASA's Johnson Space Center, Ellington Field into the eclipse path. At an altitude of 50,000ft, and outfitted with visible and near-infrared cameras, these aircraft provided increased duration of observations during eclipse totality, and much sharper images than possible on the ground. Although the primary mission goal was to study heliophysics, planetary science was also conducted to observe the planet Mercury and to search for Vulcanoids. Mercury is extremely challenging to study from Earth. The 2017 eclipse provided a rare opportunity to observe Mercury under ideal astronomical conditions. Only a handful of near-IR thermal images of Mercury exist, but IR images provide critical surface property (composition, albedo, porosity) information, essential to interpreting lower resolution IR spectra. Critically, no thermal image of Mercury currently exists. By observing the nightside surface during the 2017 Great American Eclipse, we aimed to measure the diurnal temperature as a function of local time (longitude) and attempted to deduce the surface thermal inertia integrated down to a few-cm depth below the surface. Vulcanoids are a hypothesized family of asteroids left over from the formation of the solar system, in the dynamically stable orbits between the Sun and Mercury at 15-45 Rs (4-12° solar elongation). Close proximity to the Sun, plus their small theoretical sizes, make Vulcanoid searches rare and difficult. The 2017 eclipse was a rare opportunity to search for Vulcanoids. If discovered these unique, highly refractory and primordial bodies would have a significant impact on our understanding of solar system formation. Only a handful of deep searches have been conducted. Our observations will only be the second time ever a search for Vulcanoids will have been conducted in the NIR. In this presentation, I will review our NASA flight program, and focus on the planetary science observations that came from the Great American Eclipse of 2017.

An Approach for the Dynamic Measurement of Ring Gear Strains of Planetary Gearboxes Using Fiber Bragg Gratings

PubMed Central

Zhang, Xiaodong; Hou, Chenggang

2017-01-01

The strain of the ring gear can reflect the dynamic characteristics of planetary gearboxes directly, which makes it an ideal signal to monitor the health condition of the gearbox. To overcome the disadvantages of traditional methods, a new approach for the dynamic measurement of ring gear strains using fiber Bragg gratings (FBGs) is proposed in this paper. Firstly, the installation of FBGs is determined according to the analysis for the strain distribution of the ring gear. Secondly, the parameters of the FBG are determined in consideration of the accuracy and sensitivity of the measurement as well as the size of the ring gear. The strain measured by the FBG is then simulated under non-uniform strain field conditions. Thirdly, a dynamic measurement system is built and tested. Finally, the strains of the ring gear are measured in a planetary gearbox under normal and faulty conditions. The experimental results showed good agreement with the theoretical results in values, trends, and the fault features can be seen from the time domain of the measured strain signal, which proves that the proposed method is feasible for the measurement of the ring gear strains of planetary gearboxes. PMID:29258164

An Approach for the Dynamic Measurement of Ring Gear Strains of Planetary Gearboxes Using Fiber Bragg Gratings.

PubMed

Niu, Hang; Zhang, Xiaodong; Hou, Chenggang

2017-12-16

The strain of the ring gear can reflect the dynamic characteristics of planetary gearboxes directly, which makes it an ideal signal to monitor the health condition of the gearbox. To overcome the disadvantages of traditional methods, a new approach for the dynamic measurement of ring gear strains using fiber Bragg gratings (FBGs) is proposed in this paper. Firstly, the installation of FBGs is determined according to the analysis for the strain distribution of the ring gear. Secondly, the parameters of the FBG are determined in consideration of the accuracy and sensitivity of the measurement as well as the size of the ring gear. The strain measured by the FBG is then simulated under non-uniform strain field conditions. Thirdly, a dynamic measurement system is built and tested. Finally, the strains of the ring gear are measured in a planetary gearbox under normal and faulty conditions. The experimental results showed good agreement with the theoretical results in values, trends, and the fault features can be seen from the time domain of the measured strain signal, which proves that the proposed method is feasible for the measurement of the ring gear strains of planetary gearboxes.

A mineralogical instrument for planetary applications

NASA Technical Reports Server (NTRS)

Blake, David F.; Vaniman, David T.; Bish, David L.

1994-01-01

The mineralogy of a planetary surface can be used to identify the provenance of soil or sediment and reveal the volcanic, metamorphic and/or sedimentological history of a particular region. We have discussed elsewhere the applications and the instrument design of possible X-ray diffraction and X-ray fluorescence (XRD/XRF) devices for the mineralogical characterization of planetary surfaces. In this abstract we evaluate some aspects of sample-detector geometry and sample collection strategies.

Planetary Atmosphere and Surfaces Chamber (PASC): A Platform to Address Various Challenges in Astrobiology

NASA Astrophysics Data System (ADS)

Mateo-Marti, Eva

2014-08-01

The study of planetary environments of astrobiological interest has become a major challenge. Because of the obvious technical and economical limitations on in situ planetary exploration, laboratory simulations are one of the most feasible research options to make advances both in planetary science and in developing a consistent description of the origin of life. With this objective in mind, we applied vacuum technology to the design of versatile vacuum chambers devoted to the simulation of planetary atmospheres' conditions. These vacuum chambers are able to simulate atmospheres and surface temperatures representative of the majority of planetary objects, and they are especially appropriate for studying the physical, chemical and biological changes induced in a particular sample by in situ irradiation or physical parameters in a controlled environment. Vacuum chambers are a promising potential tool in several scientific and technological fields, such as engineering, chemistry, geology and biology. They also offer the possibility of discriminating between the effects of individual physical parameters and selected combinations thereof. The implementation of our vacuum chambers in combination with analytical techniques was specifically developed to make feasible the in situ physico-chemical characterization of samples. Many wide-ranging applications in astrobiology are detailed herein to provide an understanding of the potential and flexibility of these experimental systems. Instruments and engineering technology for space applications could take advantage of our environment-simulation chambers for sensor calibration. Our systems also provide the opportunity to gain a greater understanding of the chemical reactivity of molecules on surfaces under different environments, thereby leading to a greater understanding of interface processes in prebiotic chemical reactions and facilitating studies of UV photostability and photochemistry on surfaces. Furthermore, the stability and presence of certain minerals on planetary surfaces and the potential habitability of microorganisms under various planetary environmental conditions can be studied using our apparatus. Therefore, these simulation chambers can address multiple different challenging and multidisciplinary astrobiological studies.

Activities at the Lunar and Planetary Institute

NASA Technical Reports Server (NTRS)

Burke, K.

1984-01-01

The scientific and administrative activities of the Lunar and Planetary Institute are summarized. Recent research relating to geophysics, planetary geology, the origin of the Earth and Moon, the lunar surface, Mars, meteorites, and image processing techniques is discussed.

Dynamics of planetary rings

NASA Technical Reports Server (NTRS)

Araki, Suguru

1991-01-01

The modeling of the dynamics of particle collisions within planetary rings is discussed. Particles in the rings collide with one another because they have small random motions in addition to their orbital velocity. The orbital speed is roughly 10 km/s, while the random motions have an average speed of about a tenth of a millimeter per second. As a result, the particle collisions are very gentle. Numerical analysis and simulation of the ring dynamics, performed with the aid of a supercomputer, is outlined.

Ultra-Compact Raman Spectrometer for Planetary Explorations

NASA Technical Reports Server (NTRS)

Davis, Derek; Hornef, James; Lucas, John; Elsayed-Ali, Hani; Abedin, M. Nurul

2016-01-01

To develop a compact Raman spectroscopy system with features that will make it suitable for future space missions which require surface landing. Specifically, this system will be appropriate for any mission in which planetary surface samples need to be measured and analyzed.

Reports of planetary geology program, 1979 - 1980. [bibliographies

NASA Technical Reports Server (NTRS)

Wirth, P.; Greeley, R.; Dalli, R.

1980-01-01

Abstracts of 145 reports are compiled addressing the morphology, geochemistry, and stratigraphy of planetary surfaces with some specific examinations of volcanic, aeolian, fluvial, and periglacial processes and landforms. In addition, reports on cartography and remote sensing of planet surfaces are included.

Lessons Learned in Science Operations for Planetary Surface Exploration

NASA Technical Reports Server (NTRS)

Young, K. E.; Graff, T. G.; Reagan, M.; Coan, D.; Evans, C. A.; Bleacher, J. E.; Glotch, T. D.

2017-01-01

The six Apollo lunar surface missions represent the only occasions where we have conducted scientific operations on another planetary surface. While these six missions were successful in bringing back valuable geologic samples, technology advances in the subsequent forty years have enabled much higher resolution scientific activity in situ. Regardless of where astronauts next visit (whether it be back to the Moon or to Mars or a Near Earth Object), the science operations procedures completed during this mission will need to be refined and updated to reflect these advances. We have undertaken a series of operational tests in relevant field environments to understand how best to develop the new generation of science operations procedures for planetary surface exploration.

Lithospheric Thickness on Venus from Magellan Gravity and Topography

NASA Technical Reports Server (NTRS)

Johnson, C. L.

2005-01-01

This final report summarizes work carried out during my PGG funding for the period 3/1/02-2/28/05. Research under this award has focused on the areas described below and is represented in the publications list, invited departmental lectures and presentations at professional meetings. The grant has provided partial support for 1 graduate student, Renee Bulow, and provided 1 month per year of my summer salary. The linking theme of the research performed under this award is the manifestation of the thermal history of terrestrial planetary bodies through the existence and evolution of internally-generated magnetic fields (martian magnetism research, and beginnings of lunar magnetism research), mantle dynamical processes and their resulting surface expression (studies of Venusian coronae task) and the crust and upper mantle structure of a planetary body (lunar seismic structure task). The investigations build upon and extend my previous work supported by the PGG program.

Large-Scale Experimental Planetary Science Meets Planetary Defense: Deorbiting an Asteroidal Satellite

NASA Technical Reports Server (NTRS)

Cintala, M. J.; Durda, D. D.; Housen, K. R.

2005-01-01

Other than remote-sensing and spacecraft-derived data, the only information that exists regarding the physical and chemical properties of asteroids is that inferred through calculations, numerical simulations, extrapolation of experiments, and meteorite studies. Our understanding of the dynamics of accretion of planetesimals, collisional disruption of asteroids, and the macroscopic, shock-induced modification of the surfaces of such small objects is also, for the most part, founded on similar inferences. While considerable strides have been made in improving the state of asteroid science, too many unknowns remain to assert that we understand the parameters necessary for the more practical problem of deflecting an asteroid or asteroid pair on an Earth-intersecting trajectory. Many of these deficiencies could be reduced or eliminated by intentionally deorbiting an asteroidal satellite and monitoring the resulting collision between it and the primary asteroid, a capability that is well within the limitations of current technology.

Differentiating biotic from abiotic methane genesis in hydrothermally active planetary surfaces

PubMed Central

Oze, Christopher; Jones, L. Camille; Goldsmith, Jonas I.; Rosenbauer, Robert J.

2012-01-01

Molecular hydrogen (H2) is derived from the hydrothermal alteration of olivine-rich planetary crust. Abiotic and biotic processes consume H2 to produce methane (CH4); however, the extent of either process is unknown. Here, we assess the temporal dependence and limit of abiotic CH4 related to the presence and formation of mineral catalysts during olivine hydrolysis (i.e., serpentinization) at 200 °C and 0.03 gigapascal. Results indicate that the rate of CH4 production increases to a maximum value related to magnetite catalyzation. By identifying the dynamics of CH4 production, we kinetically model how the H2 to CH4 ratio may be used to assess the origin of CH4 in deep subsurface serpentinization systems on Earth and Mars. Based on our model and available field data, low H2/CH4 ratios (less than approximately 40) indicate that life is likely present and active. PMID:22679287

Differentiating biotic from abiotic methane genesis in hydrothermally active planetary surfaces.

PubMed

Oze, Christopher; Jones, L Camille; Goldsmith, Jonas I; Rosenbauer, Robert J

2012-06-19

Molecular hydrogen (H(2)) is derived from the hydrothermal alteration of olivine-rich planetary crust. Abiotic and biotic processes consume H(2) to produce methane (CH(4)); however, the extent of either process is unknown. Here, we assess the temporal dependence and limit of abiotic CH(4) related to the presence and formation of mineral catalysts during olivine hydrolysis (i.e., serpentinization) at 200 °C and 0.03 gigapascal. Results indicate that the rate of CH(4) production increases to a maximum value related to magnetite catalyzation. By identifying the dynamics of CH(4) production, we kinetically model how the H(2) to CH(4) ratio may be used to assess the origin of CH(4) in deep subsurface serpentinization systems on Earth and Mars. Based on our model and available field data, low H(2)/CH(4) ratios (less than approximately 40) indicate that life is likely present and active.

Multi-Beam Surface Lidar for Lunar and Planetary Mapping

NASA Technical Reports Server (NTRS)

Bufton, Jack L.; Garvin, James B.

1998-01-01

Surface lidar techniques are now being demonstrated in low Earth orbit with a single beam of pulsed laser radiation at 1064 nm that profiles the vertical structure of Earth surface landforms along the nadir track of a spacecraft. In addition, a profiling laser altimeter, called MOLA, is operating in elliptical Martian orbit and returning surface topography data. These instruments form the basis for suggesting an improved lidar instrument that employs multiple beams for extension of sensor capabilities toward the goal of true, 3-dimensional mapping of the Moon or other similar planetary surfaces. In general the lidar waveform acquired with digitization of a laser echo can be used for laser distance measurement (i.e. range-to-the-surface) by time-of-flight measurement and for surface slope and shape measurements by examining the detailed lidar waveform. This is particularly effective when the intended target is the lunar surface or another planetary body free of any atmosphere. The width of the distorted return pulse is a first order measure of the surface incidence angle, a combination of surface slope and laser beam pointing. Assuming an independent and absolute (with respect to inertial space) measurement of laser beam pointing on the spacecraft, it is possible to derive a surface slope with-respect-to the mean planetary surface or its equipotential gravity surface. Higher-order laser pulse distortions can be interpreted in terms of the vertical relief of the surface or reflectivity variations within the area of the laser beam footprint on the surface.

Solar System atlas series on the Eötvös University, Budapest, Hungary: textbooks for space and planetary science education

NASA Astrophysics Data System (ADS)

Berczi, Sz.; Hargitai, H.; Horvath, A.; Illes, E.; Kereszturi, A.; Mortl, M.; Sik, A.; Weidinger, T.; Hegyi, S.; Hudoba, Gy.

Planetary science education needs new forms of teaching. Our group have various initiatives of which a new atlas series about the studies of the Solar System materials, planetary surfaces and atmospheres, instrumental field works with robots (landers, rovers) and other beautiful field work analog studies. Such analog studies are both used in comparative planetology as scientific method and it also plays a key role in planetary science education. With such initiatives the whole system of the knowledge of terrestrial geology can be transformed to the conditions of other planetary worlds. We prepared both courses and their textbooks in Eötvös University in space science education and edited the following educational materials worked out by the members of our space science education and research group: (1): Planetary and Material Maps on: Lunar Rocks, Meteorites (2000); (2): Investigating Planetary Surfaces with the Experimental Space Probe Hunveyor Constructed on the Basis of Surveyor (2001); (3): Atlas of Planetary Bodies (2001); (4): Atlas of Planetary Atmospheres (2002); (5): Space Research and Geometry (2002); (6): Atlas of Micro Environments of Planetary Surfaces (2003); (7): Atlas of Rovers and Activities on Planetary Surfaces (2004); (8): Space Research and Chemistry (2005); (9): Planetary Analog Studies and Simulations: Materials, Terrains, Morphologies, Processes. (2005); References: [1] Bérczi Sz., Hegyi S., Kovács Zs., Fabriczy A., Földi T., Keresztesi M., Cech V., Drommer B., Gránicz K., Hevesi L., Borbola T., Tóth Sz., Németh I., Horváth Cs., Diósy T., Kovács B., Bordás F., Köll˝ Z., Roskó F., Balogh Zs., Koris A., o 1 Imrek Gy. (Bérczi Sz., Kabai S. Eds.) (2002): Concise Atlas of the Solar System (2): From Surveyor to Hunveyor. How we constructed an experimental educational planetary lander model. UNICONSTANT. Budapest-Pécs-Szombathely-Püspökladány. [2] Bérczi Sz., Hargitai H., Illés E., Kereszturi Á., Sik A., Földi T., Hegyi S., Kovács Zs., Mörtl M., Weidinger T. (2004): Concise Atlas of the Solar System (6): Atlas of Microenvironments of Planetary surfaces. ELTE TTK Kozmikus Anyagokat Vizsgáló Ûrkutató Csoport, UNICONSTANT, Budapest-Püspökladány; [3] Szaniszló Bérczi, Henrik Hargitai, Ákos Kereszturi, András Sik (2005): Concise Atlas on the Solar System (3): Atlas of Planetary Bodies. ELTE TTK Kozmikus Anyagokat Vizsgáló Ûrkutató Csoport. Budapest, [4] Szaniszló Bérczi, Tivadar Földi, Péter Gadányi, Arnold Gucsik, Henrik Hargitai, Sándor Hegyi, György Hudoba, Sándor Józsa, Ákos Kereszturi, János Rakonczai, András Sik, György Szakmány, Kálmán Török (2005): Concise Atlas on the Solar System (9): Planetary Analog Studies and Simulations: Materials, Terrains, Morphologies, Processes. (Szaniszló Bérczi, editor) ELTE TTK Kozmikus Anyagokat Vizsgáló Ûrkutató Csoport, UNICONSTANT, Budapest-Püspökladány. 2

An Impact Cratering Interactive Website Used for Outreach and in Professional Development Workshops for Middle School Science Teachers

NASA Astrophysics Data System (ADS)

Croft, S. K.; Pierazzo, E.; Canizo, T.; Lebofsky, L. A.

2009-12-01

Impact cratering is one of the fundamental geologic processes affecting all planetary and asteroidal bodies in the Solar System. With few exceptions, all bodies with solid surfaces explored so far show the presence of impact craters - from the less than 200 known craters on Earth to the many thousands seen on the Moon, Mercury, and other bodies. Indeed, the study of crater populations is one of the principal tools for understanding the geologic history of planetary surfaces. In recent years, impact cratering has gained public notoriety through its portrayal in several Hollywood movies. Questions that are raised after watching these movies include: “How often do impacts occur?” “How do scientists learn about impact cratering?” and “What information do impact craters provide in understanding the evolution planetary surfaces?” On our website: “Explorer’s Guide to Impact Craters,” we answer those questions in a fun, informative and interactive way. The website provides the interested public with an opportunity to: 1) experience how scientists explore known terrestrial craters through a virtual fieldtrips; 2) learn more about the dynamics of impact cratering using numerical simulations of various impacts; and 3) investigate how impact cratering affects rocks via images and descriptions of field samples of impact rocks. This learning tool has been a popular outreach endeavor (recently reaching 100,000 hits), and it has recently been incorporated in the Impact Cratering Workshop developed by scientists and EPO specialists at the Planetary Science Institute. The workshop provides middle school science teachers with an inquiry-based understanding of the process of impact cratering and how it affects the solar system. Participants are instructed via standards-based multimedia presentations, analysis of planetary images, hands-on experience with geologic samples from terrestrial impact craters, and first-hand experience forming impact craters. Through the “Explorer’s Guide to Impact Craters,” participants are able to virtually explore three terrestrial impact craters, while examining, first-hand, samples of rocks collected at the three impact sites by real field geologists. The rock samples are included in our Impact Rock Kits that are available for check-out by teachers desiring to involve their students in the study of impact craters.

Structure of Multi-component Basaltic Glasses under Static and Dynamic Compression: Implications for Mantle Melting and Impact Processes on Planetary Surfaces

NASA Astrophysics Data System (ADS)

Lee, S.; Mosenfelder, J. L.; Tschauner, O. D.; Asimow, P. D.; Park, S.; Kim, H.

2012-12-01

The structures of basaltic melts under both static and dynamic compression are essential to understand the changes in the corresponding melt properties and to provide atomistic insights into impact-induced events in Earth's crust and planetary surfaces. Despite the importance, structural changes in basaltic glasses due both to dynamic and static compression have not been well understood. The advances in multi-nuclear NMR and multi-edge inelastic x-ray scattering allow us to obtain details of the pressure-induced changes in the degree of melt polymerization and cation coordination number in multi-component melts under static and dynamic compression (e.g. Lee, Proc. Nat. Aca. Sci. 2011, 108, 6847; Sol. St. NMR. 2010, 38, 45; Lee et al. Geophys. Res. Letts. 39 5306; Proc. Nat. Aca. Sci. 2008, 105, 7925). Here, we explore the structures of shock compressed silicate glass with a diopside-anorthite eutectic composition (Di64An36), a common Fe-free model basaltic composition, using oxygen K-edge X-ray Raman scattering and high- resolution Al-27 solid-state NMR spectroscopy and report details of shock-induced changes in the atomic configurations. A topologically driven densification of the Di64An36 glass is indicated by the increase in oxygen K-edge energy for the glass upon shock compression with peak pressure up to 20 GPa. The first experimental evidence of the increase in the fraction of highly coordinated Al in shock compressed glass is found in the Al-27 NMR spectra. This result provides atomistic insights into shock compression in basaltic glasses and allows us to microscopically constrain the magnitude of impact events or relevant processes involving natural basalts on Earth and planetary surfaces. We also report the first high pressure multi-nuclear NMR spectrum for basaltic glass up to 5 GPa. While [4]Al species is dominant at 1atm, the significant fraction of [5,6]Al in the glass is apparent, leading to changes in oxygen connectivity in the multi-component. The prevalence of highly coordinated Al and high energy oxygen cluster in the basaltic melts at 5 GPa implies that thermodynamic properties (e.g. element portioning coefficient between melts and crystal) of primary mantle melts formed at mid-ocean ridge (~150 km in depth) should be largely different from what can be predicted for silicate melts at 1 atm. The structural transitions in model basaltic glass at high pressure provide atomistic origins of anomalous mantle composition based on MORB at 1atm that is different from the prediction from chondritic meteorite (e.g. missing Si content in the primitive mantle).

Small reactor power systems for manned planetary surface bases

NASA Technical Reports Server (NTRS)

Bloomfield, Harvey S.

1987-01-01

A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a variety of human-rated modular reactor power system configurations selected for a range of power levels from 25 kWe to hundreds of kilowatts is described. Trade-off analyses for reactor power systems utilizing both man-made and indigenous shielding materials are provided to examine performance, installation and operational safety feasibility issues. The results of this study have confirmed the preliminary feasibility of a wide variety of small reactor power plant configurations for growth oriented manned planetary surface exploration missions. The capability for power level growth with increasing manned presence, while maintaining safe radiation levels, was favorably assessed for nominal 25 to 100 kWe modular configurations. No feasibility limitations or technical barriers were identified and the use of both distance and indigenous planetary soil material for human rated radiation shielding were shown to be viable and attractive options.

Derivation of planetary topography using multi-image shape-from-shading

USGS Publications Warehouse

Lohse, V.; Heipke, C.; Kirk, R.L.

2006-01-01

In many cases, the derivation of high-resolution digital terrain models (DTMs) from planetary surfaces using conventional digital image matching is a problem. The matching methods need at least one stereo pair of images with sufficient texture. However, many space missions provide only a few stereo images and planetary surfaces often possess insufficient texture. This paper describes a method for the generation of high-resolution DTMs from planetary surfaces, which has the potential to overcome the described problem. The suggested method, developed by our group, is based on shape-from-shading using an arbitrary number of digital optical images, and is termed "multi-image shape-from-shading" (MI-SFS). The paper contains an explanation of the theory of MI-SFS, followed by a presentation of current results, which were obtained using images from NASA's lunar mission Clementine, and constitute the first practical application with our method using extraterrestrial imagery. The lunar surface is reconstructed under the assumption of different kinds of reflectance models (e.g. Lommel-Seeliger and Lambert). The represented results show that the derivation of a high-resolution DTM of real digital planetary images by means of MI-SFS is feasible. ?? 2006 Elsevier Ltd. All rights reserved.

Long-Period Planets in Open Clusters and the Evolution of Planetary Systems

NASA Astrophysics Data System (ADS)

Quinn, Samuel N.; White, Russel; Latham, David W.; Stefanik, Robert

2018-01-01

Recent discoveries of giant planets in open clusters confirm that they do form and migrate in relatively dense stellar groups, though overall occurrence rates are not yet well constrained because the small sample of giant planets discovered thus far predominantly have short periods. Moreover, planet formation rates and the architectures of planetary systems in clusters may vary significantly -- e.g., due to intercluster differences in the chemical properties that regulate the growth of planetary embryos or in the stellar space density and binary populations, which can influence the dynamical evolution of planetary systems. Constraints on the population of long-period Jovian planets -- those representing the reservoir from which many hot Jupiters likely form, and which are most vulnerable to intracluster dynamical interactions -- can help quantify how the birth environment affects formation and evolution, particularly through comparison of populations possessing a range of ages and chemical and dynamical properties. From our ongoing RV survey of open clusters, we present the discovery of several long-period planets and candidate substellar companions in the Praesepe, Coma Berenices, and Hyades open clusters. From these discoveries, we improve estimates of giant planet occurrence rates in clusters, and we note that high eccentricities in several of these systems support the prediction that the birth environment helps shape planetary system architectures.

Monsoon dependent ecosystems: Implications of the vertical distribution of soil moisture on land surface-atmosphere interactions

NASA Astrophysics Data System (ADS)

Sanchez-Mejia, Zulia M.

Uncertainty of predicted change in precipitation frequency and intensity motivates the scientific community to better understand, quantify, and model the possible outcome of dryland ecosystems. In pulse dependent ecosystems (i.e. monsoon driven) soil moisture is tightly linked to atmospheric processes. Here, I analyze three overarching questions; Q1) How does soil moisture presence or absence in a shallow or deep layer influence the surface energy budget and planetary boundary layer characteristics?, Q2) What is the role of vegetation on ecosystem albedo in the presence or absence of deep soil moisture?, Q3) Can we develop empirical relationships between soil moisture and the planetary boundary layer height to help evaluate the role of future precipitation changes in land surface atmosphere interactions? . To address these questions I use a conceptual framework based on the presence or absence of soil moisture in a shallow or deep layer. I define these layers by using root profiles and establish soil moisture thresholds for each layer using four years of observations from the Santa Rita Creosote Ameriflux site. Soil moisture drydown curves were used to establish the shallow layer threshold in the shallow layer, while NEE (Net Ecosystem Exchange of carbon dioxide) was used to define the deep soil moisture threshold. Four cases were generated using these thresholds: Case 1, dry shallow layer and dry deep layer; Case 2, wet shallow layer and dry deep layer; Case 3, wet shallow layer and wet deep layer, and Case 4 dry shallow and wet deep layer. Using this framework, I related data from the Ameriflux site SRC (Santa Rita Creosote) from 2008 to 2012 and from atmospheric soundings from the nearby Tucson Airport; conducted field campaigns during 2011 and 2012 to measure albedo from individual bare and canopy patches that were then evaluated in a grid to estimate the influence of deep moisture on albedo via vegetation cover change; and evaluated the potential of using a two-layer bucket model and empirical relationships to evaluate the link between deep soil moisture and the planetary boundary layer height under changing precipitation regime. My results indicate that (1) the presence or absence of water in two layers plays a role in surface energy dynamics, (2) soil moisture presence in the deep layer is linked with decreased ecosystem albedo and planetary boundary layer height, (3) deep moisture sustains vegetation greenness and decreases albedo, and (4) empirical relationships are useful in modeling planetary boundary layer height from dryland ecosystems. Based on these results we argue that deep soil moisture plays an important role in land surface-atmosphere interactions.

Planetary Surface-Atmosphere Interactions

NASA Astrophysics Data System (ADS)

Merrison, J. P.; Bak, E.; Finster, K.; Gunnlaugsson, H. P.; Holstein-Rathlou, C.; Knak Jensen, S.; Nørnberg, P.

2013-09-01

Planetary bodies having an accessible solid surface and significant atmosphere, such as Earth, Mars, Venus, Titan, share common phenomenology. Specifically wind induced transport of surface materials, subsequent erosion, the generation and transport of solid aerosols which leads both to chemical and electrostatic interaction with the atmosphere. How these processes affect the evolution of the atmosphere and surface will be discussed in the context of general planetology and the latest laboratory studies will be presented.

Anelastic and Compressible Simulation of Moist Dynamics at Planetary Scales

NASA Astrophysics Data System (ADS)

Kurowski, M.; Smolarkiewicz, P. K.; Grabowski, W.

2015-12-01

Moist anelastic and compressible numerical solutions to the planetary baroclinic instability and climate benchmarks are compared. The solutions are obtained applying a consistent numerical framework for dis- crete integrations of the various nonhydrostatic flow equations. Moist extension of the baroclinic instability benchmark is formulated as an analog of the dry case. Flow patterns, surface vertical vorticity and pressure, total kinetic energy, power spectra, and total amount of condensed water are analyzed. The climate bench- mark extends the baroclinic instability study by addressing long-term statistics of an idealized planetary equilibrium and associated meridional transports. Short-term deterministic anelastic and compressible so- lutions differ significantly. In particular, anelastic baroclinic eddies propagate faster and develop slower owing to, respectively, modified dispersion relation and abbreviated baroclinic vorticity production. These eddies also carry less kinetic energy, and the onset of their rapid growth occurs later than for the compressible solutions. The observed differences between the two solutions are sensitive to initial conditions as they di- minish for large-amplitude excitations of the instability. In particular, on the climatic time scales, the anelastic and compressible solutions evince similar zonally averaged flow patterns with the matching meridional transports of entropy, momentum, and moisture.

Phenomenology of summer ozone episodes over the Madrid Metropolitan Area, central Spain

NASA Astrophysics Data System (ADS)

Querol, Xavier; Alastuey, Andrés; Gangoiti, Gotzon; Perez, Noemí; Lee, Hong K.; Eun, Heeram R.; Park, Yonghee; Mantilla, Enrique; Escudero, Miguel; Titos, Gloria; Alonso, Lucio; Temime-Roussel, Brice; Marchand, Nicolas; Moreta, Juan R.; Arantxa Revuelta, M.; Salvador, Pedro; Artíñano, Begoña; García dos Santos, Saúl; Anguas, Mónica; Notario, Alberto; Saiz-Lopez, Alfonso; Harrison, Roy M.; Millán, Millán; Ahn, Kang-Ho

2018-05-01

Various studies have reported that the photochemical nucleation of new ultrafine particles (UFPs) in urban environments within high insolation regions occurs simultaneously with high ground ozone (O3) levels. In this work, we evaluate the atmospheric dynamics leading to summer O3 episodes in the Madrid air basin (central Iberia) by means of measuring a 3-D distribution of concentrations for both pollutants. To this end, we obtained vertical profiles (up to 1200 m above ground level) using tethered balloons and miniaturised instrumentation at a suburban site located to the SW of the Madrid Metropolitan Area (MMA), the Majadahonda site (MJDH), in July 2016. Simultaneously, measurements of an extensive number of air quality and meteorological parameters were carried out at three supersites across the MMA. Furthermore, data from O3 soundings and daily radio soundings were also used to interpret atmospheric dynamics.The results demonstrate the concatenation of venting and accumulation episodes, with relative lows (venting) and peaks (accumulation) in O3 surface levels. Regardless of the episode type, the fumigation of high-altitude O3 (arising from a variety of origins) contributes the major proportion of surface O3 concentrations. Accumulation episodes are characterised by a relatively thinner planetary boundary layer (< 1500 m at midday, lower in altitude than the orographic features), light synoptic winds, and the development of mountain breezes along the slopes of the Guadarrama Mountain Range (located W and NW of the MMA, with a maximum elevation of > 2400 m a.s.l.). This orographic-meteorological setting causes the vertical recirculation of air masses and enrichment of O3 in the lower tropospheric layers. When the highly polluted urban plume from Madrid is affected by these dynamics, the highest Ox (O3+ NO2) concentrations are recorded in the MMA.Vertical O3 profiles during venting episodes, with strong synoptic winds and a deepening of the planetary boundary layer reaching > 2000 m a.s.l., were characterised by an upward gradient in O3 levels, whereas a reverse situation with O3 concentration maxima at lower levels was found during the accumulation episodes due to local and/or regional production. The two contributions to O3 surface levels (fumigation from high-altitude strata, a high O3 background, and/or regional production) require very different approaches for policy actions. In contrast to O3 vertical top-down transfer, UFPs are formed in the planetary boundary layer (PBL) and are transferred upwards progressively with the increase in PBL growth.

Transforming Roving-Rolling Explorer (TRREx) for Planetary Exploration

NASA Astrophysics Data System (ADS)

Edwin, Lionel Ernest

All planetary surface exploration missions thus far have employed traditional rovers with a rocker-bogie suspension. These rovers can navigate moderately rough and flat terrain, but are not designed to traverse rugged terrain with steep slopes. The fact is, however, that many scientifically interesting missions require exploration platforms with capabilities for navigating such types of chaotic terrain. This issue motivates the development of new kinds of rovers that take advantage of the latest advances in robotic technologies to traverse rugged terrain efficiently. This dissertation proposes and analyses one such rover concept called the Transforming Roving-Rolling Explorer (TRREx) that is principally aimed at addressing the above issue. Biologically inspired by the way the armadillo curls up into a ball when threatened, and the way the golden wheel spider uses the dynamic advantages of a sphere to roll down hills when escaping danger, the novel TRREx rover can traverse like a traditional 6-wheeled rover over conventional terrain, but can also transform itself into a sphere, when necessary, to travel down steep inclines, or navigate rough terrain. This work presents the proposed design architecture and capabilities followed by the development of mathematical models and experiments that facilitate the mobility analysis of the TRREx in the rolling mode. The ability of the rover to self-propel in the rolling mode in the absence of a negative gradient increases its versatility and concept value. Therefore, a dynamic model of a planar version of the problem is first used to investigate the feasibility and value of such self-propelled locomotion - 'actuated rolling'. Construction and testing of a prototype Planar/Cylindrical TRREx that is capable of demonstrating actuated rolling is presented, and the results from the planar dynamic model are experimentally validated. This planar model is then built upon to develop a mathematical model of the spherical TRREx in the rolling mode, i.e. when the rover is a sphere and can steer itself through actuations that shift its center of mass to achieve the desired direction of roll. Case studies that demonstrate the capabilities of the rover in rolling mode and parametric analyses that investigate the dependence of the rover's mobility on its design are presented. This work highlights the contribution of the spherical rolling mode to the enhanced mobility of the TRREx rover and how it could enable challenging surface exploration missions in the future. It represents an important step toward developing a rover capable of traversing a variety of terrains that are impassible by the current fleet of rover designs, and thus has the potential to revolutionize planetary surface exploration.

Europlanet Research Infrastructure: Planetary Simulation Facilities

NASA Astrophysics Data System (ADS)

Davies, G. R.; Mason, N. J.; Green, S.; Gómez, F.; Prieto, O.; Helbert, J.; Colangeli, L.; Srama, R.; Grande, M.; Merrison, J.

2008-09-01

EuroPlanet The Europlanet Research Infrastructure consortium funded under FP7 aims to provide the EU Planetary Science community greater access for to research infrastructure. A series of networking and outreach initiatives will be complimented by joint research activities and the formation of three Trans National Access distributed service laboratories (TNA's) to provide a unique and comprehensive set of analogue field sites, laboratory simulation facilities, and extraterrestrial sample analysis tools. Here we report on the infrastructure that comprises the second TNA; Planetary Simulation Facilities. 11 laboratory based facilities are able to recreate the conditions found in the atmospheres and on the surfaces of planetary systems with specific emphasis on Martian, Titan and Europa analogues. The strategy has been to offer some overlap in capabilities to ensure access to the highest number of users and to allow for progressive and efficient development strategies. For example initial testing of mobility capability prior to the step wise development within planetary atmospheres that can be made progressively more hostile through the introduction of extreme temperatures, radiation, wind and dust. Europlanet Research Infrastructure Facilties: Mars atmosphere simulation chambers at VUA and OU These relatively large chambers (up to 1 x 0.5 x 0.5 m) simulate Martian atmospheric conditions and the dual cooling options at VUA allows stabilised instrument temperatures while the remainder of the sample chamber can be varied between 220K and 350K. Researchers can therefore assess analytical protocols for instruments operating on Mars; e.g. effect of pCO2, temperature and material (e.g., ± ice) on spectroscopic and laser ablation techniques while monitoring the performance of detection technologies such as CCD at low T & variable p H2O & pCO2. Titan atmosphere and surface simulation chamber at OU The chamber simulates Titan's atmospheric composition under a range of pressures and temperatures and through provision of external UV light and or electrical discharge can be used to form the well known Titan Aerosol species, which can subsequently be analysed using one of several analytical techniques (UV-Vis, FTIR and mass spectrometry). Simulated surfaces can be produced (icy surfaces down to 15K) and subjected to a variety of light and particles (electron and ion) sources. Chemical and physical changes in the surface may be explored using remote spectroscopy. Planetary Simulation chamber for low density atmospheres INTA-CAB The planetary simulation chamber-ultra-high vacuum equipment (PSC-UHV) has been designed to study planetary surfaces and low dense atmospheres, space environments or any other hypothetic environment at UHV. Total pressure ranges from 7 mbar (Martian conditions) to 5x10-9 mbar. A residual gas analyzer regulates gas compositions to ppm precision. Temperature ranges from 4K to 325K and most operations are computer controlled. Radiation levels are simulated using a deuterium UV lamp, and ionization sources. 5 KV electron and noble-gas discharge UV allows measurement of IR and UV spectra and chemical compositions are determined by mass spectroscopy. Planetary Simulation chamber for high density planetary atmospheres at INTA-CAB The facility allows experimental study of planetary environments under high pressure, and was designed to include underground, seafloor and dense atmosphere environments. Analytical capabilities include Raman spectra, physicochemical properties of materials, e.a. thermal conductivity. P-T can be controlled as independent variables to allow monitoring of the tolerance of microorganisms and the stability of materials and their phase changes. Planetary Simulation chamber for icy surfaces at INTA-CAB This chamber is being developed to the growth of ice samples to simulate the chemical and physical properties of ices found on both planetary bodies and their moons. The goal is to allow measurement of the physical properties of ice samples formed under planetary conditions to assess how rheology varies with pressure and temperature and grain size to gain a far better understanding of how tectonics may operate on icy moons. Hot planetary surfaces simulation chamber at DLR The planetary simulation chamber is to study the behaviour of planetary analogue materials on the surface of hot (airless) bodies in the solar system. Samples can be heated up to temperatures of 500°C simulating conditions found on the surface of Mercury and Venus. This enables highly accurate thermal emission measurements using the integrated infrared spectrometer and calibrated sources. Thermal gradients can be applied to samples to simulate diurnal thermal cycles and examine thermal stresses in materials. The chamber can be placed under vacuum or purged with gas. In addition, to the high temperature chamber a number of further planetary simulation chambers are available equipped with LIBS and Raman-spectroscopy equipment. Dust analogue simulation chamber at INAF/OACN This facility produces and characterises dust analogues (arc discharge, laser ablation, grinding of minerals, ices) in a variety of simulation chambers under variable pressure (10-6 - 10-3 mbar), temperature (80 - 330 K) and gas composition. Dust and analogues are characterised by a variety of Spectroscopic (absorption, transmission, diffuse-specular reflectance) and imaging techniques (SEM) and can be subjected to thermal annealing, ion bombardment and UV irradiation. Dust accelerator facility at Max Planck Institüt Nuclear Physics, Heidelberg. This facility allows the investigation of hypervelocity dust impacts onto various materials. Dust grain materials from nano to micron sizes are accelerated using a 2 MV Vande- Graaff to velocities between 1 and 60 km/s comparable to the planetary rings of the giant gas planets and impact ejecta processes on the surface of small bodies (asteroids, comets) as well as moons and planetary surfaces. Potential phenomena for study include dust charging, dust magentosphere interactions, dust impact flashes and the possibility of obtaining compositional measurements of impact plasma plumes. Mars surface simulation Laboratory, Aberystwyth University. A Planetary Analogue Terrain Laboratory facilitates comprehensive mission operations emulation experiments designed to interpret and maximise scientific data return from robotic instruments. This facility includes Mars Soil Simulant and `science target' rocks that have been fully characterised. The terrain also has an area for sub-surface sampling. An Access Grid Node allows simulation of remote control operation and diminishes the need for direct onsite attendance. PAT Lab has a large selection of software tools for rover, robot arm and instrument modelling and simulation, and for the processing and visualisation of captured instrument data. Instrument motion is measured using a Vicon motion capture system with a resolution < 0.1 mm. Dusty wind tunnel at Aarhus University, Denmark The Aarhus wind tunnel simulates wind driven dust exposure on Mars. This allows study into analogue materials, dust/surface processes, meteorological condition and microbiological survival under Martian conditions. The multipurpose facility is used to quantify dust deposition (i.e. on optical surfaces, electrical or mechanical components) and examine the operation of instrumentation in dusty/windy environment under Martian conditions (pressure, gas composition & temperature). This includes calibration of wind flow instrumentation and dust sensors.

Planetary science: A lunar perspective

NASA Technical Reports Server (NTRS)

Taylor, S. R.

1982-01-01

An interpretative synthesis of current knowledge on the moon and the terrestrial planets is presented, emphasizing the impact of recent lunar research (using Apollo data and samples) on theories of planetary morphology and evolution. Chapters are included on the exploration of the solar system; geology and stratigraphy; meteorite impacts, craters, and multiring basins; planetary surfaces; planetary crusts; basaltic volcanism; planetary interiors; the chemical composition of the planets; the origin and evolution of the moon and planets; and the significance of lunar and planetary exploration. Photographs, drawings, graphs, tables of quantitative data, and a glossary are provided.

The interactive role of subsynoptic scale jet streak and planetary boundary layer processes in organizing an isolated convective complex

NASA Technical Reports Server (NTRS)

Kaplan, M. L.; Zack, J. W.; Wong, V. C.; Coats, G. D.

1984-01-01

Surface analyses and numerical simulation sensitivity studies are compared in order to determine the role played by deep, well-mixed, and well-heated boundary layers in perturbing a weak jet streak in proximity to the development of an isolated but intense convective complex associated with the Grand Island, Nebraska tornado outbreak of June 3-4, 1980. A brief description of the case is first presented, emphasizing three-hourly surface analyses, radar, and satellite data. The results of numerical experiments comparing differences in the runs with and without diurnal surface sensible heating are discussed and related to observations. The dynamical processes responsible for these simulation differences are discussed, and the significance of these differences are considered in terms of their effect on the preconvective environment.

Spectral Feature Analysis of Minerals and Planetary Surfaces in an Introductory Planetary Science Course

ERIC Educational Resources Information Center

Urban, Michael J.

2013-01-01

Using an ALTA II reflectance spectrometer, the USGS digital spectral library, graphs of planetary spectra, and a few mineral hand samples, one can teach how light can be used to study planets and moons. The author created the hands-on, inquiry-based activity for an undergraduate planetary science course consisting of freshman to senior level…

Automatic detection of surface changes on Mars - a status report

NASA Astrophysics Data System (ADS)

Sidiropoulos, Panagiotis; Muller, Jan-Peter

2016-10-01

Orbiter missions have acquired approximately 500,000 high-resolution visible images of the Martian surface, covering an area approximately 6 times larger than the overall area of Mars. This data abundance allows the scientific community to examine the Martian surface thoroughly and potentially make exciting new discoveries. However, the increased data volume, as well as its complexity, generate problems at the data processing stages, which are mainly related to a number of unresolved issues that batch-mode planetary data processing presents. As a matter of fact, the scientific community is currently struggling to scale the common ("one-at-a-time" processing of incoming products by expert scientists) paradigm to tackle the large volumes of input data. Moreover, expert scientists are more or less forced to use complex software in order to extract input information for their research from raw data, even though they are not data scientists themselves.Our work within the STFC and EU FP7 i-Mars projects aims at developing automated software that will process all of the acquired data, leaving domain expert planetary scientists to focus on their final analysis and interpretation. Moreover, after completing the development of a fully automated pipeline that processes automatically the co-registration of high-resolution NASA images to ESA/DLR HRSC baseline, our main goal has shifted to the automated detection of surface changes on Mars. In particular, we are developing a pipeline that uses as an input multi-instrument image pairs, which are processed by an automated pipeline, in order to identify changes that are correlated with Mars surface dynamic phenomena. The pipeline has currently been tested in anger on 8,000 co-registered images and by the time of DPS/EPSC we expect to have processed many tens of thousands of image pairs, producing a set of change detection results, a subset of which will be shown in the presentation.The research leading to these results has received funding from the STFC "MSSL Consolidated Grant under "Planetary Surface Data Mining" ST/K000977/1 and partial support from the European Union's Seventh Framework Programme (FP7/2007-2013) under iMars grant agreement number 607379

The chemical composition and mineralogy of meteorites measured with very high spatial resolution by a laser mass spectrometer for in situ planetary research

NASA Astrophysics Data System (ADS)

Brigitte Neuland, Maike; Mezger, Klaus; Tulej, Marek; Frey, Samira; Riedo, Andreas; Wurz, Peter; Wiesendanger, Reto

2017-04-01

The knowledge of the chemical composition of moons, comets, asteroids or other planetary bodies is of particular importance for the investigation of the origin and evolution of the Solar System. High resolution in situ studies on planetary surfaces can yield important information on surface heterogeneity, basic grain mineralogy and chemical composition of surface and subsurface. In turn, these data are the basis for our understanding of the physical and chemical processes which led to the formation and alteration of planetary material [1]. We investigated samples of Allende and Sayh al Uhaymir with a highly miniaturised laser mass spectrometer (LMS), which has been designed and built for in situ space research [2,3]. Both meteorite samples were investigated with a spatial resolution of about 10μm in lateral direction. The high sensitivity and high dynamic range of the LMS allow for quantitative measurements of the abundances of the rock-forming and minor and trace elements with high accuracy [4]. From the data, the modal mineralogy of micrometre-sized chondrules can be inferred [5], conclusions about the condensation sequence of the material are possible and the sensitivity for radiogenic elements allows for dating analyses of the investigated material. We measured the composition of various chondrules in Allende, offering valuable clues about the condensation sequence of the different components of the meteorite. We explicitly investigated the chemical composition and heterogeneity of the Allende matrix with an accuracy that cannot be reached by the mechanical analysis methods that were and are widely used in meteoritic research. We demonstrate the capabilities for dating analyses with the LMS. By applying the U-Th-dating method, the age of the SaU169 sample could be determined. Our analyses show that the LMS would be a suitable instrument for high-quality quantitative chemical composition measurements on the surface of a celestial body like a planet, moon or asteroid. [1] Wurz, P., Whitby, J., Managadze, G. , "Laser Mass Spectrometry in Planetary Science", AIP Conf.Proc. CP1144(2009): 70-75. [2] Rohner, U., Whitby, J.A. and Wurz, P. "A miniature laser ablation time-of-flight mass spectrometer for in situ planetary exploration", Measurement Science and Technology 14 (2003): 2159-2164. [3] Riedo, A., Bieler, A., Neuland, M., Tulej, M. and Wurz, P., "Performance evaluation of a miniature laser ablation time-of-flight mass spectrometer designed for in situ investigations in planetary space research", Journal of Mass Spectrometry 48 (2013): 1 -15 [4] Neuland, M.B., Grimaudo, V., Mezger, K., Moreno-García, P., Riedo, A., Tulej, M. and Wurz, P., "Quantitative measurement of the chemical composition of geological standards with a miniature laser ablation/ionisation mass spectrometer designed for in situ application in space research", Meas. Sci. Technol. 27(2016), article ID:035904, 1 - 13. [5] Tulej, M., Neubeck, A., Ivarsson, M., Riedo, A., Neuland, M.B., Meyer, S. and Wurz, P., "Chemical composition of micrometer-sized filaments in an aragonite host by a miniature laser ablation/ionization mass spectrometer", Astrobiol., 15 (2015): 669 - 682.

Planetary Gearbox Fault Diagnosis Using a Single Piezoelectric Strain Sensor

DTIC Science & Technology

2014-12-23

However, the fault detection of planetary gearbox is very complicate since the c omplex nature of dynamic rolling structure of p lanetary gearbox...vibration transfer paths due to the unique dynamic structure of rotating planet gears. Therefore, it is difficult to diagnose PGB faults via vibration...al. 2014). To overcome the above mentioned challenges in developing effective PGB fau lt diagnosis capability , a research investigation on

Structure and dynamics of cold water super-Earths: the case of occluded CH{sub 4} and its outgassing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levi, A.; Podolak, M.; Sasselov, D., E-mail: amitlevi.planetphys@gmail.com

2014-09-10

In this work, we study the transport of methane in the external water envelopes surrounding water-rich super-Earths. We investigate the influence of methane on the thermodynamics and mechanics of the water mantle. We find that including methane in the water matrix introduces a new phase (filled ice), resulting in hotter planetary interiors. This effect renders the super-ionic and reticulating phases accessible to the lower ice mantle of relatively low-mass planets (∼5 M{sub E} ) lacking a H/He atmosphere. We model the thermal and structural profile of the planetary crust and discuss five possible crustal regimes which depend on the surfacemore » temperature and heat flux. We demonstrate that the planetary crust can be conductive throughout or partly confined to the dissociation curve of methane clathrate hydrate. The formation of methane clathrate in the subsurface is shown to inhibit the formation of a subterranean ocean. This effect results in increased stresses on the lithosphere, making modes of ice plate tectonics possible. The dynamic character of the tectonic plates is analyzed and the ability of this tectonic mode to cool the planet is estimated. The icy tectonic plates are found to be faster than those on a silicate super-Earth. A mid-layer of low viscosity is found to exist between the lithosphere and the lower mantle. Its existence results in a large difference between ice mantle overturn timescales and resurfacing timescales. Resurfacing timescales are found to be 1 Ma for fast plates and 100 Ma for sluggish plates, depending on the viscosity profile and ice mass fraction. Melting beneath spreading centers is required in order to account for the planetary radiogenic heating. The melt fraction is quantified for the various tectonic solutions explored, ranging from a few percent for the fast and thin plates to total melting of the upwelled material for the thick and sluggish plates. Ice mantle dynamics is found to be important for assessing the composition of the atmosphere. We propose a mechanism for methane release into the atmosphere, where freshly exposed reservoirs of methane clathrate hydrate at the ridge dissociate under surface conditions. We formulate the relation between the outgassing flux and the tectonic mode dynamical characteristics. We give numerical estimates for the global outgassing rate of methane into the atmosphere. We find, for example, that for a 2 M{sub E} planet outgassing can release 10{sup 27}-10{sup 29} molecules s{sup –1} of methane to the atmosphere. We suggest a qualitative explanation for how the same outgassing mechanism may result in either a stable or a runaway volatile release, depending on the specifics of a given planet. Finally, we integrate the global outgassing rate for a few cases and quantify how the surface atmospheric pressure of methane evolves over time. We find that methane is likely an important constituent of water planets' atmospheres.« less

Planetary benchmarks. [structural design criteria for radar reference devices on planetary surfaces

NASA Technical Reports Server (NTRS)

Uphoff, C.; Staehle, R.; Kobrick, M.; Jurgens, R.; Price, H.; Slade, M.; Sonnabend, D.

1978-01-01

Design criteria and technology requirements for a system of radar reference devices to be fixed to the surfaces of the inner planets are discussed. Offshoot applications include the use of radar corner reflectors as landing beacons on the planetary surfaces and some deep space applications that may yield a greatly enhanced knowledge of the gravitational and electromagnetic structure of the solar system. Passive retroreflectors with dimensions of about 4 meters and weighing about 10 kg are feasible for use with orbiting radar at Venus and Mars. Earth-based observation of passive reflectors, however, would require very large and complex structures to be delivered to the surfaces. For Earth-based measurements, surface transponders offer a distinct advantage in accuracy over passive reflectors. A conceptual design for a high temperature transponder is presented. The design appears feasible for the Venus surface using existing electronics and power components.

Traverse Planning Experiments for Future Planetary Surface Exploration

NASA Technical Reports Server (NTRS)

Hoffman, Stephen J.; Voels, Stephen A.; Mueller, Robert P.; Lee, Pascal C.

2012-01-01

The purpose of the investigation is to evaluate methodology and data requirements for remotely-assisted robotic traverse of extraterrestrial planetary surface to support human exploration program, assess opportunities for in-transit science operations, and validate landing site survey and selection techniques during planetary surface exploration mission analog demonstration at Haughton Crater on Devon Island, Nunavut, Canada. Additionally, 1) identify quality of remote observation data sets (i.e., surface imagery from orbit) required for effective pre-traverse route planning and determine if surface level data (i.e., onboard robotic imagery or other sensor data) is required for a successful traverse, and if additional surface level data can improve traverse efficiency or probability of success (TRPF Experiment). 2) Evaluate feasibility and techniques for conducting opportunistic science investigations during this type of traverse. (OSP Experiment). 3) Assess utility of remotely-assisted robotic vehicle for landing site validation survey. (LSV Experiment).

Analysis and design of a capsule landing system and surface vehicle control system for Mars exporation

NASA Technical Reports Server (NTRS)

Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Smith, E. J.; Yerazunis, S. W.

1972-01-01

The problems related to the design and control of a mobile planetary vehicle to implement a systematic plan for the exploration of Mars were investigated. Problem areas receiving attention include: vehicle configuration, control, dynamics, systems and propulsion; systems analysis; navigation, terrain modeling and path selection; and chemical analysis of specimens. The following specific tasks were studied: vehicle model design, mathematical modeling of dynamic vehicle, experimental vehicle dynamics, obstacle negotiation, electromechanical controls, collapsibility and deployment, construction of a wheel tester, wheel analysis, payload design, system design optimization, effect of design assumptions, accessory optimal design, on-board computer subsystem, laser range measurement, discrete obstacle detection, obstacle detection systems, terrain modeling, path selection system simulation and evaluation, gas chromatograph/mass spectrometer system concepts, chromatograph model evaluation and improvement and transport parameter evaluation.

(abstract) TOPEX/Poseidon: Four Years of Synoptic Oceanography

NASA Technical Reports Server (NTRS)

Fu, Lee-Lueng

1996-01-01

Exceeding all expectations of measurement precision and accuracy, the US/France TOPEX/Poseidon satellite mission is now in its 5th year. Returning more than 98 percent of the altimetric data, the measured global geocentric height of the sea surface has provided unprecedented opportunities to address a host of scientific problems ranging from the dynamics of ocean circulation to the distribution of internal tidal energy. Scientific highlights of this longest-running altimetric satellite mission include improvements in our understanding of the dynamics and thermodynamics of the large-scale ocean variability, such as, the properties of planetary waves; the energetics of basin-wide gyres; the heat budget of the ocean; and the ocean's response to wind forcing. For the first time, oceanographers have quantitative descriptions of a dynamic variable of the physical state of the global oceans available in near-real-time.

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration

NASA Technical Reports Server (NTRS)

Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Smith, E. J.; Yerazunis, S. W.

1972-01-01

Investigation of problems related to the design and control of a mobile planetary vehicle to implement a systematic plan for the exploration of Mars has been undertaken. Problem areas receiving attention include: vehicle configuration, control, dynamics, systems and propulsion; systems analysis; terrain modeling and path selection; and chemical analysis of specimens. The following specific tasks have been under study: vehicle model design, mathematical modeling of a dynamic vehicle, experimental vehicle dynamics, obstacle negotiation, electromechanical controls, collapsibility and deployment, construction of a wheel tester, wheel analysis, payload design, system design optimization, effect of design assumptions, accessory optimal design, on-board computer sybsystem, laser range measurement, discrete obstacle detection, obstacle detection systems, terrain modeling, path selection system simulation and evaluation, gas chromatograph/mass spectrometer system concepts, chromatograph model evaluation and improvement.

Dust Dynamics Near Planetary Surfaces

NASA Astrophysics Data System (ADS)

Colwell, Joshua; Hughes, Anna; Grund, Chris

Observations of a lunar "horizon glow" by several Surveyor spacecraft in the 1960s opened the study of the dynamics of charged dust particles near planetary surfaces. The surfaces of the Moon and other airless planetary bodies in the solar system (asteroids, and other moons) are directly exposed to the solar wind and ionizing solar ultraviolet radiation, resulting in a time-dependent electric surface potential. Because these same objects are also exposed to bombardment by micrometeoroids, the surfaces are usually characterized by a power-law size distribution of dust that extends to sub-micron-sized particles. Individual particles can acquire a charge different from their surroundings leading to electrostatic levitation. Once levitated, particles may simply return to the surface on nearly ballistic trajectories, escape entirely from the moon or asteroid if the initial velocity is large, or in some cases be stably levitated for extended periods of time. All three outcomes have observable consequences. Furthermore, the behavior of charged dust near the surface has practical implications for planned future manned and unmanned activities on the lunar surface. Charged dust particles also act as sensitive probes of the near-surface plasma environment. Recent numerical modeling of dust levitation and transport show that charged micron-sized dust is likely to accumulate in topographic lows such as craters, providing a mechanism for the creation of dust "ponds" observed on the asteroid 433 Eros. Such deposition can occur when particles are supported by the photoelectron sheath above the dayside and drift over shadowed regions of craters where the surface potential is much smaller. Earlier studies of the lunar horizon glow are consistent with those particles being on simple ballistic trajectories following electrostatic launching from the surface. Smaller particles may be accelerated from the lunar surface to high altitudes consistent with observations of high altitude streams observed by Apollo astronauts and potentially also by the Clementine spacecraft. In addition to the Surveyor images of lunar horizon glow and the high altitude streamer measurements, the Apollo 17 Lunar Ejecta and Meteorite surface package detected signals consistent with the impact of relatively slow-moving dust particles that may have been charged dust electrostatically levitated from the surface. There is renewed interest in this near-surface dust environment with plans to return robotic landers and astronauts to the lunar surface. No Apollo-era instruments were specifically designed to detect or measure dust levitated off the lunar surface. One new experiment under study is the Autonomous Lunar Dust Observer (ALDO). ALDO is a high-sensitivity scanning lidar (laser radar) that autonomously maps and records its 3-D dust environment. Flexibility of programmable scan pattern enables ALDO to characterize the dust context in and around experiment sites. Repeated shallow angle scans in a vertical plane enable high vertical resolution studies of dust levitation near the ground. Single elevation angle sector or full azimuth scans enable large-area statistical surveys of the frequency and size of ejecta plumes from micrometeoroid impacts, and vertical or fixed-angle stares enable very high sensitivity dust profiles to extended ranges. It is estimated that backscatter from dust concentrations as low as 1/cm3 can be measured. The concept is equally applicable to surface and atmospheric studies of other airless bodies.

Data catalog series for space science and applications flight missions. Volume 1A: Brief descriptions of planetary and heliocentric spacecraft and investigations

NASA Technical Reports Server (NTRS)

Cameron, W. S. (Editor); Vostreys, R. W. (Editor)

1982-01-01

Planetary and heliocentric spacecraft, including planetary flybys and probes, are described. Imaging, particles and fields, ultraviolet, infrared, radio science and celestial mechanics, atmospheres, surface chemistry, biology, and polarization are discussed.

Integrated optimization of planetary rover layout and exploration routes

NASA Astrophysics Data System (ADS)

Lee, Dongoo; Ahn, Jaemyung

2018-01-01

This article introduces an optimization framework for the integrated design of a planetary surface rover and its exploration route that is applicable to the initial phase of a planetary exploration campaign composed of multiple surface missions. The scientific capability and the mobility of a rover are modelled as functions of the science weight fraction, a key parameter characterizing the rover. The proposed problem is formulated as a mixed-integer nonlinear program that maximizes the sum of profits obtained through a planetary surface exploration mission by simultaneously determining the science weight fraction of the rover, the sites to visit and their visiting sequences under resource consumption constraints imposed on each route and collectively on a mission. A solution procedure for the proposed problem composed of two loops (the outer loop and the inner loop) is developed. The results of test cases demonstrating the effectiveness of the proposed framework are presented.

Stratospheric Impact of Varying Sea Surface Temperatures

NASA Technical Reports Server (NTRS)

Newman, Paul A.; Nash, Eric R.; Nielsen, Jon E.; Waugh, Darryn; Pawson, Steven

2004-01-01

The Finite-Volume General Circulation Model (FVGCM) has been run in 50 year simulations with the: 1) 1949-1999 Hadley Centre sea surface temperatures (SST), and 2) a fixed annual cycle of SSTs. In this presentation we first show that the 1949-1999 FVGCM simulation produces a very credible stratosphere in comparison to an NCEP/NCAR reanalysis climatology. In particular, the northern hemisphere has numerous major and minor stratospheric warming, while the southern hemisphere has only a few over the 50-year simulation. During the northern hemisphere winter, temperatures are both warmer in the lower stratosphere and the polar vortex is weaker than is found in the mid-winter southern hemisphere. Mean temperature differences in the lower stratosphere are shown to be small (less than 2 K), and planetary wave forcing is found to be very consistent with the climatology. We then will show the differences between our varying SST simulation and the fixed SST simulation in both the dynamics and in two parameterized trace gases (ozone and methane). In general, differences are found to be small, with subtle changes in planetary wave forcing that lead to reduced temperatures in the SH and increased temperatures in the NH.

Planetary Wind Determination by Doppler Tracking of a Small Entry Probe Network

NASA Astrophysics Data System (ADS)

Atkinson, D. H.; Asmar, S.; Lazio, J.; Preston, R. A.

2017-12-01

To understand the origin and chemical/dynamical evolution of planetary atmospheres, measurements of atmospheric chemistries and processes including dynamics are needed. In situ measurements of planetary winds have been demonstrated on multiple occasions, including the Pioneer multiprobe and Venera missions to Venus, and the Galileo/Jupiter and Huygens/Titan probes. However, with the exception of Pioneer Venus, the retrieval of the zonal (east-west) wind profile has been limited to a single atmospheric slice. significantly improved understanding of the global dynamics requires sampling of multiple latitudes, times of day, and seasons. Simultaneous tracking of a small network of probes would enable measurements of spatially distributed winds providing a substantially improved characterization of a planet's global atmospheric circulation. Careful selection of descent locations would provide wind measurements at latitudes receiving different solar insolations, longitudes reflecting different times of day, and different seasons if both hemispheres are targeted. Doppler wind retrievals are limited by the stability of the probe and carrier spacecraft clocks, and must be equipped with an ultrastable oscillator, accelerometers for reconstructing the probe entry trajectory, and pressure / temperature sensors for determination of descent speed. A probe were equipped with both absolute and dynamic pressure sensors can measure planet center-relative and atmosphere-relative descent speeds, enabling the measurement of vertical winds from convection or atmospheric waves. Possible ambiguities arising from the assumption of no north-south winds could be removed if the probe were simultaneously tracked from the carrier spacecraft as well as from the Earth or a second spacecraft. The global circulation of an atmosphere comprising waves and flows that vary with location and depth is inherently tied to the thermal, chemical, and energy structure of the atmosphere. Wind measurements along a single vertical atmospheric slice cannot adequately represent the overall dynamical properties of the atmosphere. To more completely characterize the dynamical structure of a planetary atmosphere, it is proposed that future in situ planetary missions include a network of small probes dedicated to wind measurements.

Fluvial geomorphology on Earth-like planetary surfaces: A review.

PubMed

Baker, Victor R; Hamilton, Christopher W; Burr, Devon M; Gulick, Virginia C; Komatsu, Goro; Luo, Wei; Rice, James W; Rodriguez, J A P

2015-09-15

Morphological evidence for ancient channelized flows (fluvial and fluvial-like landforms) exists on the surfaces of all of the inner planets and on some of the satellites of the Solar System. In some cases, the relevant fluid flows are related to a planetary evolution that involves the global cycling of a volatile component (water for Earth and Mars; methane for Saturn's moon Titan). In other cases, as on Mercury, Venus, Earth's moon, and Jupiter's moon Io, the flows were of highly fluid lava. The discovery, in 1972, of what are now known to be fluvial channels and valleys on Mars sparked a major controversy over the role of water in shaping the surface of that planet. The recognition of the fluvial character of these features has opened unresolved fundamental questions about the geological history of water on Mars, including the presence of an ancient ocean and the operation of a hydrological cycle during the earliest phases of planetary history. Other fundamental questions posed by fluvial and fluvial-like features on planetary bodies include the possible erosive action of large-scale outpourings of very fluid lavas, such as those that may have produced the remarkable canali forms on Venus; the ability of exotic fluids, such as methane, to create fluvial-like landforms, as observed on Saturn's moon, Titan; and the nature of sedimentation and erosion under different conditions of planetary surface gravity. Planetary fluvial geomorphology also illustrates fundamental epistemological and methodological issues, including the role of analogy in geomorphological/geological inquiry.

High-autonomy control of space resource processing plants

NASA Technical Reports Server (NTRS)

Schooley, Larry C.; Zeigler, Bernard P.; Cellier, Francois E.; Wang, Fei-Yue

1993-01-01

A highly autonomous intelligent command/control architecture has been developed for planetary surface base industrial process plants and Space Station Freedom experimental facilities. The architecture makes use of a high-level task-oriented mode with supervisory control from one or several remote sites, and integrates advanced network communications concepts and state-of-the-art man/machine interfaces with the most advanced autonomous intelligent control. Attention is given to the full-dynamics model of a Martian oxygen-production plant, event-based/fuzzy-logic process control, and fault management practices.

The Onset of the Cataclysm: In Situ Dating of the Nectaris Basin Impact Melt Sheet

NASA Technical Reports Server (NTRS)

Cohen, B. A.

2017-01-01

The impact history of the Moon has significant implications beyond simply excavating the surface of our nearest neighbor. The age distribution of lunar impact breccias inspired the idea of a catastrophic influx of asteroids and comets about 4 billion years ago and motivated new models of planetary dynamics. An epoch of heavy bombardment after planets had atmospheres and continents would have influenced the course of biologic evolution. The story of a cataclysmic bombardment, written in the rocks of the Moon, has far-reaching consequences.

Intercomparison of 7 Planetary Boundary-Layer/Surface-Layer Physics Schemes over Complex Terrain for Battlefield Situational Awareness

DTIC Science & Technology

This study considers the performance of 7 of the Weather Research and Forecast model boundary-layer (BL) parameterization schemes in a complex...schemes performed best. The surface parameters, planetary BL structure, and vertical profiles are important for US Army Research Laboratory

New Design and Improvement of Planetary Gear Trains

NASA Technical Reports Server (NTRS)

Handschuh, Robert (Technical Monitor); Litvin, Faydor L.; Fuentes, Alfonso; Vecchiato, Daniele; Gonzalez-Perez, Ignacio

2004-01-01

The development of new types of planetary and planetary face-gear drives is proposed. The new designs are based on regulating backlash between the gears and modifying the tooth surfaces to improve the design. The goal of this work is to obtain a nearly uniform distribution of load between the planet gears. In addition, a new type of planetary face-gear drive was developed in this project.

Planetary-scale surface water detection from space

NASA Astrophysics Data System (ADS)

Donchyts, G.; Baart, F.; Winsemius, H.; Gorelick, N.

2017-12-01

Accurate, efficient and high-resolution methods of surface water detection are needed for a better water management. Datasets on surface water extent and dynamics are crucial for a better understanding of natural and human-made processes, and as an input data for hydrological and hydraulic models. In spite of considerable progress in the harmonization of freely available satellite data, producing accurate and efficient higher-level surface water data products remains very challenging. This presentation will provide an overview of existing methods for surface water extent and change detection from multitemporal and multi-sensor satellite imagery. An algorithm to detect surface water changes from multi-temporal satellite imagery will be demonstrated as well as its open-source implementation (http://aqua-monitor.deltares.nl). This algorithm was used to estimate global surface water changes at high spatial resolution. These changes include climate change, land reclamation, reservoir construction/decommissioning, erosion/accretion, and many other. This presentation will demonstrate how open satellite data and open platforms such as Google Earth Engine have helped with this research.

Thermal Modeling on Planetary Regoliths

NASA Technical Reports Server (NTRS)

Hale, A. S.; Hapke, B.W.

2002-01-01

The thermal region of the spectrum is one of special interest in planetary science as it is the only region where planetary emission is significant. Studying how planetary surfaces emit in the thermal infrared can tell us about their physical makeup and chemical composition, as well as their temperature profile with depth. This abstract will discuss a model of thermal energy transfer in planetary regoliths on airless bodies which includes both conductive and radiative processes while including the time dependence of the solar input function.

The Effect of Rotation Rate on Seasonally Migrating Tropical Precipitation Zones on Terrestrial Planets

NASA Astrophysics Data System (ADS)

Faulk, Sean P.; Mitchell, Jonathan L.; Bordoni, Simona

2014-11-01

In the Earth’s atmosphere, tropical precipitation zones migrate seasonally but never extend beyond 30N, even in regions of large-scale monsoons. On Titan, however, seasonal, monsoon-like weather patterns regularly pump liquid methane to the poles. In this study, we argue that rotation rate is the main control on the seasonal extent of planetary monsoons, while surface thermal inertia plays a secondary role: i.e. the control is primarily dynamic rather than thermodynamic. Factors controlling the position and the sensitivity to energetic perturbations of the intertropical convergence zone (ITCZ) on Earth, a narrow latitudinal band where tropical precipitation is concentrated, have been widely investigated in the literature. Interestingly, while on Earth the ITCZ is limited to low latitudes, on Mars and Titan the ITCZ can migrate significantly off the equator into the summer hemisphere. Previous explanations for the ITCZ’s larger migration on Mars and Titan compared to Earth emphasize the lower surface thermal inertias of those planets. Here, we study a wide range of atmospheric circulations with an idealized General Circulation Model (GCM), in which an atmospheric model with idealized physics is coupled to an aquaplanet slab ocean of fixed depth and the top-of-atmosphere insolation is varied seasonally. A broad range of circulation regimes is studied by changing the thermal inertia of the slab ocean and the planetary rotation, while keeping the seasonal cycle of insolation fixed and all other parameters Earth-like. We find that for rotation rates 1/8 that of Earth's and slower, essentially Titan-like rotation rates, Earth’s ITCZ reaches the summer pole. At odds with previous explanations, we also find that decreasing the surface thermal inertia, to Titan’s surface thermal inertia and smaller, does little to extend the ITCZ’s summer migration off the equator. These results suggest that the ITCZ may be more controlled by dynamical mechanisms than previously thought. We explore such mechanisms within the framework of the momentum budget.

Quantitative measurement of the chemical composition of geological standards with a miniature laser ablation/ionization mass spectrometer designed for in situ application in space research

NASA Astrophysics Data System (ADS)

Neuland, M. B.; Grimaudo, V.; Mezger, K.; Moreno-García, P.; Riedo, A.; Tulej, M.; Wurz, P.

2016-03-01

A key interest of planetary space missions is the quantitative determination of the chemical composition of the planetary surface material. The chemical composition of surface material (minerals, rocks, soils) yields fundamental information that can be used to answer key scientific questions about the formation and evolution of the planetary body in particular and the Solar System in general. We present a miniature time-of-flight type laser ablation/ionization mass spectrometer (LMS) and demonstrate its capability in measuring the elemental and mineralogical composition of planetary surface samples quantitatively by using a femtosecond laser for ablation/ionization. The small size and weight of the LMS make it a remarkable tool for in situ chemical composition measurements in space research, convenient for operation on a lander or rover exploring a planetary surface. In the laboratory, we measured the chemical composition of four geological standard reference samples USGS AGV-2 Andesite, USGS SCo-l Cody Shale, NIST 97b Flint Clay and USGS QLO-1 Quartz Latite with LMS. These standard samples are used to determine the sensitivity factors of the instrument. One important result is that all sensitivity factors are close to 1. Additionally, it is observed that the sensitivity factor of an element depends on its electron configuration, hence on the electron work function and the elemental group in agreement with existing theory. Furthermore, the conformity of the sensitivity factors is supported by mineralogical analyses of the USGS SCo-l and the NIST 97b samples. With the four different reference samples, the consistency of the calibration factors can be demonstrated, which constitutes the fundamental basis for a standard-less measurement-technique for in situ quantitative chemical composition measurements on planetary surface.

NASA Desert RATS 2010: Preliminary Results for Science Operations Conducted in the San Francisco Volcanic Field, Arizona

NASA Technical Reports Server (NTRS)

Gruener, J. E.; Lofgren, G. E.; Bluethmann, W. J.; Bell, E. R.

2011-01-01

The National Aeronautics and Space Administration (NASA) is working with international partners to develop the space architectures and mission plans necessary for human spaceflight beyond earth orbit. These mission plans include the exploration of planetary surfaces with significant gravity fields. The Apollo missions to the Moon demonstrated conclusively that surface mobility is a key asset that improves the efficiency of human explorers on a planetary surface. NASA's Desert Research and Technology Studies (Desert RATS) is a multi-year series tests of hardware and operations carried out annually in the high desert of Arizona. Conducted since 1998, these activities are designed to exercise planetary surface hardware and operations in relatively harsh climatic conditions where long-distance, multi-day roving is achievable

Lightweight Modular Instrumentation for Planetary Applications

NASA Technical Reports Server (NTRS)

Joshi, P. B.

1993-01-01

An instrumentation, called Space Active Modular Materials ExperimentS (SAMMES), is developed for monitoring the spacecraft environment and for accurately measuring the degradation of space materials in low earth orbit (LEO). The SAMMES architecture concept can be extended to instrumentation for planetary exploration, both on spacecraft and in situ. The operating environment for planetary application will be substantially different, with temperature extremes and harsh solar wind and cosmic ray flux on lunar surfaces and temperature extremes and high winds on venusian and Martian surfaces. Moreover, instruments for surface deployment, which will be packaged in a small lander/rover (as in MESUR, for example), must be extremely compact with ultralow power and weight. With these requirements in mind, the SAMMES concept was extended to a sensor/instrumentation scheme for the lunar and Martian surface environment.

Planetary Regolith Delivery Systems for ISRU

NASA Technical Reports Server (NTRS)

Mantovani, James G.; Townsend, Ivan I., III

2012-01-01

The challenges associated with collecting regolith on a planetary surface and delivering it to an in-situ resource utilization system differ significantly from similar activities conducted on Earth. Since system maintenance on a planetary body can be difficult or impossible to do, high reliability and service life are expected of a regolith delivery system. Mission costs impose upper limits on power and mass. The regolith delivery system must provide a leak-tight interface between the near-vacuum planetary surface and the pressurized ISRU system. Regolith delivery in amounts ranging from a few grams to tens of kilograms may be required. Finally, the spent regolith must be removed from the ISRU chamber and returned to the planetary environment via dust tolerant valves capable of operating and sealing over a large temperature range. This paper will describe pneumatic and auger regolith transfer systems that have already been field tested for ISRU, and discuss other systems that await future field testing.

Multi-Spoked Wheel Assembly

NASA Technical Reports Server (NTRS)

Greer, Lawrence (Inventor); Krasowski, Michael (Inventor)

2017-01-01

A robust ground traction (drive) assembly for remotely controlled vehicles, which not only operates smoothly on surfaces that are flat, but also upon surfaces that include rugged terrain, snow, mud, and sand, is provided. The assembly includes a sun gear and a braking gear. The sun gear is configured to cause rotational force to be applied to second planetary gears through a coupling of first planetary gears. The braking gear is configured to cause the assembly (or the second planetary gears) to rotate around the braking gear when an obstacle or braking force is applied.

Monitoring Earth's reservoir and lake dynamics from space

NASA Astrophysics Data System (ADS)

Donchyts, G.; Eilander, D.; Schellekens, J.; Winsemius, H.; Gorelick, N.; Erickson, T.; Van De Giesen, N.

2016-12-01

Reservoirs and lakes constitute about 90% of the Earth's fresh surface water. They play a major role in the water cycle and are critical for the ever increasing demands of the world's growing population. Water from reservoirs is used for agricultural, industrial, domestic, and other purposes. Current digital databases of lakes and reservoirs are scarce, mainly providing only descriptive and static properties of the reservoirs. The Global Reservoir and Dam (GRanD) database contains almost 7000 entries while OpenStreetMap counts more than 500 000 entries tagged as a reservoir. In the last decade several research efforts already focused on accurate estimates of surface water dynamics, mainly using satellite altimetry, However, currently they are limited only to less than 1000 (mostly large) water bodies. Our approach is based on three main components. Firstly, a novel method, allowing automated and accurate estimation of surface area from (partially) cloud-free optical multispectral or radar satellite imagery. The algorithm uses satellite imagery measured by Landsat, Sentinel and MODIS missions. Secondly, a database to store reservoir static and dynamic parameters. Thirdly, a web-based tool, built on top of Google Earth Engine infrastructure. The tool allows estimation of surface area for lakes and reservoirs at planetary-scale at high spatial and temporal resolution. A prototype version of the method, database, and tool will be presented as well as validation using in-situ measurements.

Mathematical Modeling of Electrodynamics Near the Surface of Earth and Planetary Water Worlds

NASA Technical Reports Server (NTRS)

Tyler, Robert H.

2017-01-01

An interesting feature of planetary bodies with hydrospheres is the presence of an electrically conducting shell near the global surface. This conducting shell may typically lie between relatively insulating rock, ice, or atmosphere, creating a strong constraint on the flow of large-scale electric currents. All or parts of the shell may be in fluid motion relative to main components of the rotating planetary magnetic field (as well as the magnetic fields due to external bodies), creating motionally-induced electric currents that would not otherwise be present. As such, one may expect distinguishing features in the types of electrodynamic processes that occur, as well as an opportunity for imposing specialized mathematical methods that efficiently address this class of application. The purpose of this paper is to present and discuss such specialized methods. Specifically, thin-shell approximations for both the electrodynamics and fluid dynamics are combined to derive simplified mathematical formulations describing the behavior of these electric currents as well as their associated electric and magnetic fields. These simplified formulae allow analytical solutions featuring distinct aspects of the thin-shell electrodynamics in idealized cases. A highly efficient numerical method is also presented that is useful for calculations under inhomogeneous parameter distributions. Finally, the advantages as well as limitations in using this mathematical approach are evaluated. This evaluation is presented primarily for the generic case of bodies with water worlds or other thin spherical conducting shells. More specific discussion is given for the case of Earth, but also Europa and other satellites with suspected oceans.

CIRS-lite, a Fourier Transform Spectrometer for Low-Cost Planetary Missions

NASA Technical Reports Server (NTRS)

Brasunas, J.; Bly, V.; Edgerton, M.; Gong, Q.; Hagopian, J.; Mamakos, W.; Morelli, A.; Pasquale, B.; Strojny, C.

2011-01-01

Passive spectroscopic remote sensing of planetary atmospheres and surfaces in the thermal infrared is a powerful tool for obtaining information about surface and atmospheric temperatures, composition, and dynamics (via the thermal wind equation). Due to its broad spectral coverage, the Fourier transform spectrometer (FTS) is particularly suited to the exploration and discovery of molecular species. NASA's Goddard Space Flight Center (GSFC) developed the CIRS (Composite Infrared Spectrometer) FTS for the NASA/ESA Cassini mission to the Saturnian system. CIRS observes Saturn, Titan, icy moons such as Enceladus, and the rings in thermal self-emission over the spectral range of 7 to 1000 ell11. CIRS has given us important new insights into stratospheric composition and jets on Jupiter and Saturn, the cryo-geyser and thermal stripes on Enceladus, and the winter polar vortex on Titan. CIRS has a mass of 43 kg, contrasted with the earlier GSFC FTS, pre-Voyager IRIS (14 kg). Future low-cost planetary missions will have very tight constraints on science payload mass, thus we must endeavor to return to IRIS-level mass while maintaining CIRS-level science capabilities ("do more with less"). CIRS-lite achieves this by pursuing: a) more sensitive infrared detectors (high Tc superconductor) to enable smaller optics. b) changed long wavelength limit from 1000 to 300 microns to reduce diffraction by smaller optics. c) CVD (chemical vapor deposition) diamond beam-splitter for broad spectral coverage. d) single FTS architecture instead of a dual FTS architecture. e) novel materials, such as single crystal silicon for the input telescope primary.

Vibration characteristics of two-stage planetary transmission system with thin-walled ring gear on elastic supports

NASA Astrophysics Data System (ADS)

Li, JianYing; Hu, QingChun; Zong, ChangFu; Zhu, TianJun; Zhang, ZeXing

2018-03-01

A dual-clutch and dual-speed planetary gears mechanism of a hybrid car coupled-system is taken as research subject, in which the ring gear of planet set II is a thin-walled structure and the clutch friction plates of planet set II are used as its elastic supports. Based on the lumped parameter-rigid elastic coupled dynamic model of two-stage planetary transmission system with thin-walled ring gear on elastic supports, the motion differential equations are established and the dynamic responses are solved by the Runge-Kutta method considering each stage internal and external time-varying mesh stiffness. The vibration displacements of each stage ring gear have been affected differently in time-domain, the translational vibration displacement of the ring gear of planet set I are obviously more than the torsional vibration displacement, but it is opposite for the ring gear of planet set II; The translational and torsional vibration responses of each stage ring gear arrive the peak in low-frequency. The analysis results of this paper can enrich the theoretical research of multistage planetary transmission and provide guidance for dynamic design.

ATMOSPHERIC DYNAMICS OF TERRESTRIAL EXOPLANETS OVER A WIDE RANGE OF ORBITAL AND ATMOSPHERIC PARAMETERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaspi, Yohai; Showman, Adam P., E-mail: yohai.kaspi@weizmann.ac.il

The recent discoveries of terrestrial exoplanets and super-Earths extending over a broad range of orbital and physical parameters suggest that these planets will span a wide range of climatic regimes. Characterization of the atmospheres of warm super-Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone—including transitions to Snowball-like states and runaway-greenhouse feedbacks—depend on the equator-to-pole temperature differences, patterns of relativemore » humidity, and other aspects of the dynamics. Here, using an idealized moist atmospheric general circulation model including a hydrological cycle, we study the dynamical principles governing the atmospheric dynamics on such planets. We show how the planetary rotation rate, stellar flux, atmospheric mass, surface gravity, optical thickness, and planetary radius affect the atmospheric circulation and temperature distribution on such planets. Our simulations demonstrate that equator-to-pole temperature differences, meridional heat transport rates, structure and strength of the winds, and the hydrological cycle vary strongly with these parameters, implying that the sensitivity of the planet to global climate feedbacks will depend significantly on the atmospheric circulation. We elucidate the possible climatic regimes and diagnose the mechanisms controlling the formation of atmospheric jet streams, Hadley and Ferrel cells, and latitudinal temperature differences. Finally, we discuss the implications for understanding how the atmospheric circulation influences the global climate.« less

Definition and Development of Habitation Readiness Levels (HRLs) for Planetary Surface Habitats

NASA Technical Reports Server (NTRS)

Connolly, Janis H.; Toups, Larry

2007-01-01

One could argue that NASA has never developed a true habitat for a planetary surface, with only the Lunar Module from the 1960's-era Apollo Program providing for a sparse 2 person, 3 day capability. An integral part of NASA's current National Vision for Space Exploration is missions back to the moon and eventually to Mars. One of the largest leaps i11 lunar surface exploration beyond the Apollo lunar missions will be the conduct of these extended duration human missions. These missions could range from 30 to 90 days in length initially and may eventually range up to 500 days in length. To enable these extended duration human missions, probably the single-most important lunar surface element is the Surface Habitat. The requirements that must be met by the Surface Habitat will go far beyond the safety, performance and operational requirements of the Lunar Module, and NASA needs to develop a basis for making intelligent, technically correct habitat design decisions. This paper will discuss the possibilities of the definition and development of a Habitation Readiness Level (HRL) scale that might be mapped to current Technology Readiness Levels (TRLs) for technology development. HRLs could help measure how well a particular technology thrust is advanced by a proposed planetary habitat concept. The readiness level would have to be measured differently than TRLs, and may include such milestones as habitat design performance under simulated mission operations and constraints (including relevant field testing), functional allocation demonstrations, crew interface evaluation and post-occupancy evaluation. With many concepts for planetary habitats proposed over the past 20 years, there are many strategic technical challenges facing designers of planetary habitats that will support NASA's exploration of the moon and Mars. The systematic assessment of a variety of planetary habitat options will be an important approach and will influence the associated requirements for human design, volumetrics, functionality, systems hardware and operations.

Planetary Radar

NASA Technical Reports Server (NTRS)

Neish, Catherine D.; Carter, Lynn M.

2015-01-01

This chapter describes the principles of planetary radar, and the primary scientific discoveries that have been made using this technique. The chapter starts by describing the different types of radar systems and how they are used to acquire images and accurate topography of planetary surfaces and probe their subsurface structure. It then explains how these products can be used to understand the properties of the target being investigated. Several examples of discoveries made with planetary radar are then summarized, covering solar system objects from Mercury to Saturn. Finally, opportunities for future discoveries in planetary radar are outlined and discussed.

Empirical Modeling of Planetary Boundary Layer Dynamics Under Multiple Precipitation Scenarios Using a Two-Layer Soil Moisture Approach: An Example From a Semiarid Shrubland

NASA Astrophysics Data System (ADS)

Sanchez-Mejia, Zulia Mayari; Papuga, Shirley A.

2017-11-01

In semiarid regions, where water resources are limited and precipitation dynamics are changing, understanding land surface-atmosphere interactions that regulate the coupled soil moisture-precipitation system is key for resource management and planning. We present a modeling approach to study soil moisture and albedo controls on planetary boundary layer height (PBLh). We used Santa Rita Creosote Ameriflux and Tucson Airport atmospheric sounding data to generate empirical relationships between soil moisture, albedo, and PBLh. Empirical relationships showed that ˜50% of the variation in PBLh can be explained by soil moisture and albedo with additional knowledge gained by dividing the soil profile into two layers. Therefore, we coupled these empirical relationships with soil moisture estimated using a two-layer bucket approach to model PBLh under six precipitation scenarios. Overall we observed that decreases in precipitation tend to limit the recovery of the PBL at the end of the wet season. However, increases in winter precipitation despite decreases in summer precipitation may provide opportunities for positive feedbacks that may further generate more winter precipitation. Our results highlight that the response of soil moisture, albedo, and the PBLh will depend not only on changes in annual precipitation, but also on the frequency and intensity of this change. We argue that because albedo and soil moisture data are readily available at multiple temporal and spatial scales, developing empirical relationships that can be used in land surface-atmosphere applications have great potential for exploring the consequences of climate change.

Fluvial geomorphology on Earth-like planetary surfaces: A review

PubMed Central

Baker, Victor R.; Hamilton, Christopher W.; Burr, Devon M.; Gulick, Virginia C.; Komatsu, Goro; Luo, Wei; Rice, James W.; Rodriguez, J.A.P.

2017-01-01

Morphological evidence for ancient channelized flows (fluvial and fluvial-like landforms) exists on the surfaces of all of the inner planets and on some of the satellites of the Solar System. In some cases, the relevant fluid flows are related to a planetary evolution that involves the global cycling of a volatile component (water for Earth and Mars; methane for Saturn’s moon Titan). In other cases, as on Mercury, Venus, Earth’s moon, and Jupiter’s moon Io, the flows were of highly fluid lava. The discovery, in 1972, of what are now known to be fluvial channels and valleys on Mars sparked a major controversy over the role of water in shaping the surface of that planet. The recognition of the fluvial character of these features has opened unresolved fundamental questions about the geological history of water on Mars, including the presence of an ancient ocean and the operation of a hydrological cycle during the earliest phases of planetary history. Other fundamental questions posed by fluvial and fluvial-like features on planetary bodies include the possible erosive action of large-scale outpourings of very fluid lavas, such as those that may have produced the remarkable canali forms on Venus; the ability of exotic fluids, such as methane, to create fluvial-like landforms, as observed on Saturn’s moon, Titan; and the nature of sedimentation and erosion under different conditions of planetary surface gravity. Planetary fluvial geomorphology also illustrates fundamental epistemological and methodological issues, including the role of analogy in geomorphological/geological inquiry. PMID:29176917

The Role of Remote Sensing Displays in Earth Climate and Planetary Atmospheric Research

NASA Technical Reports Server (NTRS)

DelGenio, Anthony D.; Hansen, James E. (Technical Monitor)

2001-01-01

The communities of scientists who study the Earth's climate and the atmospheres of the other planets barely overlap, but the types of questions they pose and the resulting implications for the use and interpretation of remote sensing data sets have much in common. Both seek to determine the characteristic behavior of three-dimensional fluids that also evolve in time. Climate researchers want to know how and why the general patterns that define our climate today might be different in the next century. Planetary scientists try to understand why circulation patterns and clouds on Mars, Venus, or Jupiter are different from those on Earth. Both disciplines must aggregate large amounts of data covering long time periods and several altitudes to have a representative picture of the rapidly changing atmosphere they are studying. This emphasis separates climate scientists from weather forecasters, who focus at any one time on a limited number of images. Likewise, it separates planetary atmosphere researchers from planetary geologists, who rely primarily on single images (or mosaics of images covering the globe) to study two-dimensional planetary surfaces that are mostly static over the duration of a spacecraft mission yet reveal dynamic processes acting over thousands to millions of years. Remote sensing displays are usually two-dimensional projections that capture an atmosphere at an instant in time. How scientists manipulate and display such data, how they interpret what they see, and how they thereby understand the physical processes that cause what they see, are the challenges I discuss in this chapter. I begin by discussing differences in how novices and experts in the field relate displays of data to the real world. This leads to a discussion of the use and abuse of image enhancement and color in remote sensing displays. I then show some examples of techniques used by scientists in climate and planetary research to both convey information and design research strategies using remote sensing displays.

Significant achievements in the Planetary Geology Program. [geologic processes, comparative planetology, and solar system evolution

NASA Technical Reports Server (NTRS)

Head, J. W. (Editor)

1978-01-01

Developments reported at a meeting of principal investigators for NASA's planetology geology program are summarized. Topics covered include: constraints on solar system formation; asteriods, comets, and satellites; constraints on planetary interiors; volatiles and regoliths; instrument development techniques; planetary cartography; geological and geochemical constraints on planetary evolution; fluvial processes and channel formation; volcanic processes; Eolian processes; radar studies of planetary surfaces; cratering as a process, landform, and dating method; and the Tharsis region of Mars. Activities at a planetary geology field conference on Eolian processes are reported and techniques recommended for the presentation and analysis of crater size-frequency data are included.

Planetary rings - Theory

NASA Technical Reports Server (NTRS)

Borderies, Nicole

1989-01-01

Theoretical models of planetary-ring dynamics are examined in a brief analytical review. The mathematical description of streamlines and streamline interactions is outlined; the redistribution of angular momentum due to collisions between particles is explained; and problems in the modeling of broad, narrow, and arc rings are discussed.

Biogeophysical consequences of a tropical deforestation scenario: A GCM simulation study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sud, Y.C.; Lau, W.K.M.; Walker, G.K.

1996-12-01

Two 3-year (1979-1982) integrations were carried out with a version of the GLA GCM that contains the Simple Biosphere Model (SiB) for simulating land-atmosphere interactions. The control case used the usual SiB vegetation cover (comprising 12 vegetation types), while its twin, the deforestation case, imposed a scenario in which all tropical rainforests were entirely replaced by grassland. Except for this difference, all other initial and prescribed boundary conditions were kept identical in both integrations. An intercomparison of the integrations shows that tropical: deforestation decreases evapotranspiration and increases land surface outgoing longwave radiation and sensible heat flux, thereby warming and dryingmore » the planetary boundary layer. This happens despite the reduced absorption of solar radiation due to higher surface albedo of the deforested land. Produces significant and robust local as well as global climate changes. The local effect includes significant changes (mostly reductions) in precipitation and diabatic heating, while the large-scale effect is to weaken the Hadley circulation but invigorate the southern Ferrel cell, drawing larger air mass from the indirect polar cells. Decreases the surface stress (drag force) owing to reduced surface roughness of deforested land, which in turn intensifies winds in the planetary boundary layer, thereby affecting the dynamic structure of moisture convergence. The simulated surface winds are about 70% stronger and are accompanied by significant changes in the power spectrum of the annual cycle of surface and PBL winds and precipitation. Our results broadly confirm several findings of recent tropical deforestation simulation experiments. In addition, some global-scale climatic influences of deforestation not identified in earlier studies are delineated. 57 refs., 10 figs., 3 tabs.« less

Characterizing the Physical and Thermal Properties of Planetary Regolith at Low Temperatures

NASA Technical Reports Server (NTRS)

Mantovani, James G.; Swanger, Adam; Townsend, Ivan I., III; Sibille, Laurent; Galloway, Gregory

2014-01-01

The success or failure of in-situ resource utilization for planetary surface exploration-whether for science, colonization, or commercialization-relies heavily on the design and implementation of systems that can effectively process planetary regolith and exploit its potential benefits. In most cases, this challenge necessarily includes the characterization of regolith properties at low temperatures (cryogenic). None of the nearby solar system destinations of interest, such as the moon, Mars and asteroids, possess a sufficient atmosphere to sustain the consistently "high" surface temperatures found on Earth. Therefore, they can experience permanent cryogenic temperatures or dramatic cyclical changes in surface temperature. Characterization of physical properties (e.g., specific heat, thermal and electrical conductivity) over the entire temperature profile is important when planning a mission to a planetary surface; however, the impact on mechanical properties due to the introduction of icy deposits must also be explored in order to devise effective and robust excavation technologies. The Granular Mechanics and Regolith Operations Laboratory and the Cryogenics Test Laboratory at NASA Kennedy Space Center are developing technologies and experimental methods to address these challenges and to aid in the characterization of the physical and mechanical properties of regolith at cryogenic temperatures. This paper will review the current state of knowledge concerning planetary regolith at low temperature, including that of icy regolith, and describe efforts to manipulate icy regolith through novel penetration and excavation techniques.

Planetary Accretion in the Inner Solar System: Dependence on Nebula Surface Density Profile and Giant Planet Eccentricities

NASA Technical Reports Server (NTRS)

Chambers, J. E.; Cassen, P.

2002-01-01

We present 32 N-body simulations of planetary accretion in the inner Solar System, examining the effect of nebula surface density profile and initial eccentricities of Jupiter and Saturn on the compositions and orbits of the inner planets. Additional information is contained in the original extended abstract.

Modeling, Modal Properties, and Mesh Stiffness Variation Instabilities of Planetary Gears

NASA Technical Reports Server (NTRS)

Parker, Robert G.; Lin, Jian; Krantz, Timothy L. (Technical Monitor)

2001-01-01

Planetary gear noise and vibration are primary concerns in their applications in helicopters, automobiles, aircraft engines, heavy machinery and marine vehicles. Dynamic analysis is essential to the noise and vibration reduction. This work analytically investigates some critical issues and advances the understanding of planetary gear dynamics. A lumped-parameter model is built for the dynamic analysis of general planetary gears. The unique properties of the natural frequency spectra and vibration modes are rigorously characterized. These special structures apply for general planetary gears with cyclic symmetry and, in practically important case, systems with diametrically opposed planets. The special vibration properties are useful for subsequent research. Taking advantage of the derived modal properties, the natural frequency and vibration mode sensitivities to design parameters are investigated. The key parameters include mesh stiffnesses, support/bearing stiffnesses, component masses, moments of inertia, and operating speed. The eigen-sensitivities are expressed in simple, closed-form formulae associated with modal strain and kinetic energies. As disorders (e.g., mesh stiffness variation. manufacturing and assembling errors) disturb the cyclic symmetry of planetary gears, their effects on the free vibration properties are quantitatively examined. Well-defined veering rules are derived to identify dramatic changes of natural frequencies and vibration modes under parameter variations. The knowledge of free vibration properties, eigen-sensitivities, and veering rules provide important information to effectively tune the natural frequencies and optimize structural design to minimize noise and vibration. Parametric instabilities excited by mesh stiffness variations are analytically studied for multi-mesh gear systems. The discrepancies of previous studies on parametric instability of two-stage gear chains are clarified using perturbation and numerical methods. The operating conditions causing parametric instabilities are expressed in closed-form suitable for design guidance. Using the well-defined modal properties of planetary gears, the effects of mesh parameters on parametric instability are analytically identified. Simple formulae are obtained to suppress particular instabilities by adjusting contact ratios and mesh phasing.

Honors

NASA Astrophysics Data System (ADS)

2011-05-01

Among the new members elected to the U.S. National Academy of Sciences in May are five AGU members: Richard Edwards, George and Orpha Gibson Chair of Earth Systems Sciences and Distinguished McKnight University Professor, Department of Geology and Geophysics, University of Minnesota, Minneapolis; T. Mark Harrison, director, Institute of Geophysics and Planetary Physics, and professor of geology, Department of Earth and Space Sciences, University of California, Los Angeles; David Sandwell, professor of geophysics, Institute for Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla (president of the AGU Geodesy section); Benjamin Santer, physicist and atmospheric scientist, Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory, Livermore, Calif.; and Steven Wofsy, Abbott Lawrence Rotch Professor of Atmospheric and Environmental Science, Department of Earth and Planetary Sciences, Harvard University, Cambridge, Mass. Four AGU members are among the 2011 prizewinners announced by the Division for Planetary Sciences (DPS) of the American Astronomical Society on 19 May. The prizes will be presented at the joint meeting of DPS and the European Planetary Science Congress in October. William Ward of the Southwest Research Institute, San Antonio, Tex., is the recipient of the Gerard P. Kuiper Prize for outstanding contributions to the field of planetary science. DPS indicated that Ward originally proposed and evaluated “many dynamical processes that are now cornerstones of current theories of how planets form and evolve” and that his “visionary ideas form the foundation for a significant portion of current work in planetary formation and dynamics.”

Factors Affecting the Habitability of Earth-like Planets

NASA Astrophysics Data System (ADS)

Meadows, Victoria; NAI-Virtual Planetary Laboratory Team

2014-03-01

Habitability is a measure of an environment's potential to support life. For exoplanets, the concept of habitability can be used broadly - to inform our calculations of the possibility and distribution of life elsewhere - or as a practical tool to inform mission designs and to prioritize specific targets in the search for extrasolar life. Although a planet's habitability does depend critically on the effect of stellar type and planetary semi-major axis on climate balance, work in the interdisciplinary field of astrobiology has identified many additional factors that can affect a planet's environment and its potential ability to support life. Life requires material for metabolism and structures, a liquid medium for chemical transport, and an energy source to drive metabolism and other life processes. Whether a planet's surface or sub-surface can provide these requirements is the result of numerous planetary and astrophysical processes that affect the planet's formation and evolution. Many of these factors are interdependent, and fall into three main categories: stellar effects, planetary effects and planetary system effects. Key abiotic processes affecting the resultant planetary environment include photochemistry (e.g. Segura et al., 2003; 2005), stellar effects on climate balance (e.g. Joshii et al., 2012; Shields et al., 2013), atmospheric loss (e.g. Lopez and Fortney, 2013), and gravitational interactions with the star (e.g. Barnes et al., 2013). In many cases, the effect of these processes is strongly dependent on a specific planet's existing environmental properties. Examples include the resultant UV flux at a planetary surface as a product of stellar activity and the strength of a planet's atmospheric UV shield (Segura et al., 2010); and the amount of tidal energy available to a planet to drive plate tectonics and heat the surface (Barnes et al., 2009), which is in turn due to a combination of stellar mass, planetary mass and composition, planetary orbital parameters and the gravitational influence of other planets in the system. A thorough assessment of a planet's environment and its potential habitability is a necessary first step in the search for biosignatures. Targeted environmental characteristics include surface temperature and pressure (e.g. Misra et al., 2013), a census of bulk and trace atmospheric gases, and whether there are signs of liquid water on the planetary surface (e.g. Robinson et al., 2010). The robustness of a planetary biosignature is dependent on being able to characterize the environment sufficiently well, and to understand likely star-planet interactions, to preclude formation of a biosignature gas via abiotic processes such as photochemistry (e.g. Segura et al., 2007; Domagal-Goldman et al., 2011; Grenfell et al., 2012). Here we also discuss potential false positives for O2 and O3, which, in large quantities, are often considered robust biosignatures for oxygenic photosynthesis. There is clearly significant future work required to better identify and understand the key environmental processes and interactions that allow a planet to support life, and to distinguish life's global impact on an environment from the environment itself.

Lunar and Planetary Science XXXV: Mars: Wind, Dust Sand, and Debris

NASA Technical Reports Server (NTRS)

2004-01-01

The session "Mars: Wind, Dust Sand, and Debris" included: Mars Exploration Rovers: Laboratory Simulations of Aeolian Interactions; Thermal and Spectral Analysis of an Intracrater Dune Field in Amazonis Planitia; How High is that Dune? A Comparison of Methods Used to Constrain the Morphometry of Aeolian Bedforms on Mars; Dust Devils on Mars: Scaling of Dust Flux Based on Laboratory Simulations; A Close Encounter with a Terrestrial Dust Devil; Interpretation of Wind Direction from Eolian Features: Herschel Crater, Mars Erosion Rates at the Viking 2 Landing Site; Mars Dust: Characterization of Particle Size and Electrostatic Charge Distributions; Simple Non-fluvial Models of Planetary Surface Modification, with Application to Mars; Comparison of Geomorphically Determined Winds with a General Circulation Model: Herschel Crater, Mars; Analysis of Martian Debris Aprons in Eastern Hellas Using THEMIS; Origin of Martian Northern Hemisphere Mid-Latitude Lobate Debris Aprons; Debris Aprons in the Tempe/Mareotis Region of Mars;and Constraining Flow Dynamics of Mass Movements on Earth and Mars.

Lunar and Planetary Surface Dynamics and Early History

NASA Technical Reports Server (NTRS)

2003-01-01

This document, submitted as part of this proposal renewal represents the Final Report required by NASA for Grant NAGS-9442. It should be emphasized that, while this work statement in the original proposal outlined anticipated directions of our research, the specific activities we carried out during this period differed slightly from those proposed, capitalizing on new unexpected results and new advances in analytical capability. The thrust of all the work we completed were completely within the stated research goals of the proposal and significantly advanced our knowledge of planetary processes and our understanding of the early solar system. The following summary outlines our achievements in the different areas of research. These include: A) Early solar system processes and time scales using I-Xe chronometry; B) The Active Capture of Volatiles: A new mechanism for the capture of heavy noble gases, possible implications for phase Q and planetary heavy noble gases; C) Separation of Xe-L from Xe-H: Physically selective experiments; D) Abundances of Presolar grains; E) Studies of Neon and Helium from single interstellar SiC and graphite grains; F) Pre-compaction exposure of meteoritic grains and chondrules; G) Geochemically Measured Half-Lives: Double beta-decay of Te and Ba isotopes; H) Noble gases in stratospheric interplanetary dust particles; I) New Analytical Instrument.

Rise of planetary bodies.

NASA Astrophysics Data System (ADS)

Czechowski, Z.; Leliwa-Kopystyński, J.; Teisseyre, R.

Contents: 1. On the probability of the formation of planetary systems. 2. Condensation triggered by supernova explosion and tidal capture theory. 3. Foundations of accretion theory. 4. The structure and evolution of the protoplanetary disk. 5. Coagulation of orbiting bodies. 6. Collision phenomena related to planetology: accretion, fragmentation, cratering. 7. Dynamics of planetesimals: Introduction, Safronov's approach, elements of the kinetic theory of gases, Nakagawa's approach, approaches considering inelastic collisions and gravitational encounters of planetesimals, Hämeen-Anttila approach, planetesimals with different masses. 8. Growth of the planetary embryo: Basic equations, model of growth of planetary embryos. 9. Origin of the Moon and the satellites.

Effects of Planetary Thermal Structure on the Ascent and Cooling of Magma on Venus

NASA Technical Reports Server (NTRS)

Sakimoto, Susan E. H.; Zuber, Maria T.

1995-01-01

Magellan radar images of the surface of Venus show a spatially broad distribution of volcanic features. Models of magmatic ascent processes to planetary surfaces indicate that the thermal structure of the interior significantly influences the rate of magmatic cooling and thus the amount of magma that can be transported to the surface before solidification. In order to understand which aspects of planetary thermal structure have the greatest influence on the cooling of buoyantly ascending magma, we have constructed magma cooling profiles for a plutonic ascent mechanism, and evaluated the profiles for variations in the surface and mantle temperature, surface temperature gradient, and thermal gradient curvature. Results show that, for a wide variety of thermal conditions, smaller and slower magma bodies are capable of reaching the surface on Venus compared to Earth, primarily due to the higher surface temperature of Venus. Little to no effect on the cooling and transport of magma are found to result from elevated mantle temperatures, elevation-dependent surface temperature variations, or details of the thermal gradient curvature. The enhanced tendency of magma to reach the surface on Venus may provide at least a partial explanation for the extensive spatial distribution of observed volcanism on the surface.

Data mining and visualization from planetary missions: the VESPA-Europlanet2020 activity

NASA Astrophysics Data System (ADS)

Longobardo, Andrea; Capria, Maria Teresa; Zinzi, Angelo; Ivanovski, Stavro; Giardino, Marco; di Persio, Giuseppe; Fonte, Sergio; Palomba, Ernesto; Antonelli, Lucio Angelo; Fonte, Sergio; Giommi, Paolo; Europlanet VESPA 2020 Team

2017-06-01

This paper presents the VESPA (Virtual European Solar and Planetary Access) activity, developed in the context of the Europlanet 2020 Horizon project, aimed at providing tools for analysis and visualization of planetary data provided by space missions. In particular, the activity is focused on minor bodies of the Solar System.The structure of the computation node, the algorithms developed for analysis of planetary surfaces and cometary comae and the tools for data visualization are presented.

Arecibo Radar Investigations of Planetary and Small-Body Surfaces

NASA Astrophysics Data System (ADS)

Taylor, P. A.

2016-12-01

The 305-m William E. Gordon telescope at Arecibo Observatory in Puerto Rico is the most sensitive, most powerful, and most active planetary radar facility in the world. Over the last 50-plus years, the S-band (12.6 cm, 2380 MHz) and P-band (70 cm, 430 MHz) radars at Arecibo have studied solid bodies in the solar system from Mercury to Saturn's rings. Radar provides fine spatial resolution of these bodies surpassed only by dedicated spacecraft while adding the extra dimensions of near-surface, wavelength-scale roughness and penetration to several wavelengths below the surface. For asteroids and comets, this spatial resolution is akin to a spacecraft flyby revealing spin, size, and shape information and geologic features such as ridges, crater-like depressions, and boulders. For planetary bodies, radar can reveal geologic features on the surface such as ancient lava flows or features buried beneath the regolith including lava tubes and water-ice deposits. We will present an overview of how the Arecibo radar systems are utilized in the study of planetary and small-body surfaces and what can be learned without ever leaving the comfort of Earth's surface. The Arecibo Observatory is operated by SRI International under a cooperative agreement with the National Science Foundation (AST-1100968) and in alliance with Ana G. Mendez-Universidad Metropolitana (UMET) and the Universities Space Research Association (USRA). The Arecibo Planetary Radar Program is supported by the National Aeronautics and Space Administration under Grant Nos. NNX12AF24G and NNX13AQ46G issued through the Near-Earth Object Observations program and operated by USRA in alliance with SRI International and UMET.

Planetary Migration and Kuiper Belt Dynamics

NASA Astrophysics Data System (ADS)

Malhotra, Renu

The Kuiper belt holds memory of the dynamical processes that shaped the architecture of the solar system, including the orbital migration history of the giant planets. We propose studies of the orbital dynamics of the Kuiper Belt in order to understand the origin of its complex dynamical structure and its link to the orbital migration history of the giant planets. By means of numerical simulations, statistical tests, as well as analytical calculations we will (1) investigate the origin of resonant Kuiper belt objects to test alternative scenarios of Neptune's migration history, (2) investigate the long term dynamical evolution of the Haumea family of Kuiper Belt objects in order to improve the age estimate of this family, and (3) investigate resonance-sticking behavior and the Kozai-Lidov mechanism and its role in the origin of the extended scattered disk. These studies directly support the goals of the NASA-OSS program by improving our understanding of the origin of the solar system's architecture. Our results will provide constraints on the nature and timing of the dynamical excitation event that is thought to have occurred in early solar system history and to have determined the architecture of the present-day solar system; our results will also provide deeper theoretical understanding of sticky mean motion resonances which contribute greatly to the longevity of many small bodies, improve our understanding of dynamical transport of planetesimals in planetary systems, and help interpret observations of other planetary systems.

The Thermal Phase Curve Offset on Tidally and Nontidally Locked Exoplanets: A Shallow Water Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Penn, James; Vallis, Geoffrey K, E-mail: jp492@exeter.ac.uk, E-mail: g.vallis@exeter.ac.uk

2017-06-20

Using a shallow water model with time-dependent forcing, we show that the peak of an exoplanet thermal phase curve is, in general, offset from the secondary eclipse when the planet is rotating. That is, the planetary hot spot is offset from the point of maximal heating (the substellar point) and may lead or lag the forcing; the extent and sign of the offset are functions of both the rotation rate and orbital period of the planet. We also find that the system reaches a steady state in the reference frame of the moving forcing. The model is an extension ofmore » the well-studied Matsuno–Gill model into a full spherical geometry and with a planetary-scale translating forcing representing the insolation received on an exoplanet from a host star. The speed of the gravity waves in the model is shown to be a key metric in evaluating the phase curve offset. If the velocity of the substellar point (relative to the planet’s surface) exceeds that of the gravity waves, then the hot spot will lag the substellar point, as might be expected by consideration of forced gravity wave dynamics. However, when the substellar point is moving slower than the internal wave speed of the system, the hottest point may lead the passage of the forcing. We provide an interpretation of this result by consideration of the Rossby and Kelvin wave dynamics, as well as, in the very slowly rotating case, a one-dimensional model that yields an analytic solution. Finally, we consider the inverse problem of constraining planetary rotation rate from an observed phase curve.« less

Climatic Evolution and Habitability of Terrestrial Planets: Perspectives from Coupled Atmosphere-Mantle Systems

NASA Astrophysics Data System (ADS)

Basu Sarkar, D.; Moore, W. B.

2016-12-01

A multitude of factors including the distance from the host star and the stage of planetary evolution affect planetary climate and habitability. The complex interactions between the atmosphere and dynamics of the deep interior of the planets along with stellar fluxes present a formidable challenge. This work employs simplified approaches to address these complex issues in a systematic way. To be specific, we are investigating the coupled evolution of atmosphere and mantle dynamics. The overarching goal here is to simulate the evolutionary history of the terrestrial planets, for example Venus, Earth and Mars. This research also aims at deciphering the history of Venus-like runaway greenhouse and thus explore the possibility of cataclysmic shifts in climate of Earth-like planets. We focus on volatile cycling within the solid planets to understand the role of carbon/water in climatic and tectonic outcomes of such planets. In doing so, we are considering the feedbacks in the coupled mantle-atmosphere system. The primary feedback between the atmosphere and mantle is the surface temperature established by the greenhouse effect, which regulates the temperature gradient that drives the mantle convection and controls the rate at which volatiles are exchanged through weathering. We start our models with different initial assumptions to determine the final climate outcomes within a reasonable parameter space. Currently, there are very few planetary examples, to sample the climate outcomes, however this will soon change as exoplanets are discovered and examined. Therefore, we will be able to work with a significant number of potential candidates to answer questions like this one: For every Earth is there one Venus? ten? a thousand?

Visible Wavelength Exoplanet Phase Curves from Global Albedo Maps

NASA Astrophysics Data System (ADS)

Webber, Matthew; Cahoy, Kerri Lynn

2015-01-01

To investigate the effect of three-dimensional global albedo maps we use an albedo model that: calculates albedo spectra for each points across grid in longitude and latitude on the planetary disk, uses the appropriate angles for the source-observer geometry for each location, and then weights and sums these spectra using the Tschebychev-Gauss integration method. This structure permits detailed 3D modeling of an illuminated planetary disk and computes disk-integrated phase curves. Different pressure-temperature profiles are used for each location based on geometry and dynamics. We directly couple high-density pressure maps from global dynamic radiative-transfer models to compute global cloud maps. Cloud formation is determined from the correlation of the species condensation curves with the temperature-pressure profiles. We use the detailed cloud patterns, of spatial-varying composition and temperature, to determine the observable albedo spectra and phase curves for exoplanets Kepler-7b and HD189733b. These albedo spectra are used to compute planet-star flux ratios using PHOENIX stellar models, exoplanet orbital parameters, and telescope transmission functions. Insight from the Earthshine spectrum and solid surface albedo functions (e.g. water, ice, snow, rocks) are used with our planetary grid to determine the phase curve and flux ratios of non-uniform Earth and Super Earth-like exoplanets with various rotation rates and stellar types. Predictions can be tailored to the visible and Near-InfraRed (NIR) spectral windows for the Kepler space telescope, Hubble space telescope, and future observatories (e.g. WFIRST, JWST, Exo-C, Exo-S). Additionally, we constrain the effect of exoplanet urban-light on the shape of the night-side phase curve for Earths and Super-Earths.

Laboratory investigation of surface processes on airless bodies due to electrostatic dust mobilization

NASA Astrophysics Data System (ADS)

Wang, X.; Hood, N.; Schwan, J.; Hsu, H. W.; Horanyi, M.

2017-12-01

Electrostatic dust mobilization on the surfaces of airless bodies due to direct exposure to solar wind and solar ultraviolet (UV) radiation has been suggested from a number of unusual planetary observations and supported by our recent laboratory experiments. This electrostatic process may have a significant contribution in the evolution of these surfaces in addition to other surface processes, e.g., thermal fragmentation. The critical questions are how this process changes the surface physical characteristics and how efficient this process can be. We report new laboratory experiments that record dust activities as function of the incoming fluxes of photons or energetic electrons over a long exposure time under Earth gravity. Dust is observed to hop and move on the surface, causing the significant change in surface morphology and becoming smoother over time. Our results indicate that the dynamics of dust mobilization may be complicated by temporal charging effect as dust moves. Various sizes and types of dust are examined, showing large effects on dust mobilization. These laboratory data will help us to predict the electrostatic surface processes and estimate their timescales in space conditions.

Post Viking planetary protection requirements study

NASA Technical Reports Server (NTRS)

Wolfson, R. P.

1977-01-01

Past planetary quarantine requirements were reviewed in the light of present Viking data to determine the steps necessary to prevent contamination of the Martian surface on future missions. The currently used term planetary protection reflects a broader scope of understanding of the problems involved. Various methods of preventing contamination are discussed in relation to proposed projects, specifically the 1984 Rover Mission.

Mass Tracking with a MEMS-based Gravity Sensor

NASA Astrophysics Data System (ADS)

Pike, W. T.; Mukherjee, A.; Warren, T.; Charalambous, C.; Calcutt, S. B.; Standley, I.

2017-12-01

We achieve the first demonstration of the dynamic location of a moving mass using a MEMS sensor to detect gravity. The sensor is based on a microseismometer developed for planetary geophysics. In an updated version of the original Cavendish experiment the noise floor of the sensor, at 0.25 µgal/rtHz, allows the determination of the dynamic gravitational field from the motion of the mass of an oscillating pendulum. Using the determined noise floor we show that this performance should be sufficient for practical subsurface gravity surveying, in particular detection of 50-cm diameter pipes up to 10 m below the surface. Beyond this specific application, this sensor with a mass of less than 250 g per axis represents a new technology that opens up the possibility of drone deloyments for gravity mapping.

OAST Space Theme Workshop. Volume 3: Working group summary. 9: Aerothermodynamics (M-3). A: Statement. B: Technology needs (form 1). C. Priority assessment (form 2). D. Additional assessments

NASA Technical Reports Server (NTRS)

1976-01-01

Twelve aerothermodynamic space technology needs were identified to reduce the design uncertainties in aerodynamic heating and forces experienced by heavy lift launch vehicles, orbit transfer vehicles, and advanced single stage to orbit vehicles for the space transportation system, and for probes, planetary surface landers, and sample return vehicles for solar system exploration vehicles. Research and technology needs identified include: (1) increasing the fluid dynamics capability by at least two orders of magnitude by developing an advanced computer processor for the solution of fluid dynamic problems with improved software; (2) predicting multi-engine base flow fields for launch vehicles; and (3) developing methods to conserve energy in aerothermodynamic ground test facilities.

On the State of Stress and Failure Prediction Near Planetary Surface Loads

NASA Astrophysics Data System (ADS)

Schultz, R. A.

1996-03-01

The state of stress surrounding planetary surface loads has been used extensively to predict failure of surface rocks and to invert this information for effective elastic thickness. As demonstrated previously, however, several factors can be important including an explicit comparison between model stresses and rock strength as well as the magnitude of calculated stress. As re-emphasized below, failure to take stress magnitudes into account can lead to erroneous predictions of near-surface faulting. This abstract results from discussions on graben formation at Fall 1995 AGU.

Investigation of the small-scale structure and dynamics of Uranus' atmosphere

NASA Technical Reports Server (NTRS)

Eshleman, Von R.; Hinson, David P.

1991-01-01

This document constitutes the final technical report of the Uranus Analysis Program. Papers and/or abstracts resulting from this research are presented. The following topics are covered: (1) past and future of radio occultation studies of planetary atmospheres; (2) equatorial waves in the stratosphere of Uranus; (3) the atmosphere of Uranus- results of radio occultation measurements with Voyager 2; (4) Uranus' atmospheric dynamics and circulation; (5) small-scale structure and dynamics in the atmosphere of Uranus; (6) evidence for inertia-gravity waves in the stratosphere of Uranus derived from Voyager 2 radio occultation data; and (7) planetary waves in the equatorial stratosphere of Uranus.

A New Global Geomorphology?

NASA Technical Reports Server (NTRS)

Baker, V. R.

1985-01-01

Geomorphology is entering a new era of discovery and scientific excitement centered on expanding scales of concern in both time and space. The catalysts for this development include technological advances in global remote sensing systems, mathematical modeling, and the dating of geomorphic surfaces and processes. Even more important are new scientific questions centered on comparative planetary geomorphology, the interaction of tectonism with landscapes, the dynamics of late Cenozoic climatic changes, the influence of cataclysmic processes, the recognition of extremely ancient landforms, and the history of the world's hydrologic systems. These questions all involve feedback relationships with allied sciences that have recently yielded profound developments.

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration

NASA Technical Reports Server (NTRS)

Gisser, D. G.; Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Yerazunis, S. Y.

1975-01-01

Problems related to an unmanned exploration of the planet Mars by means of an autonomous roving planetary vehicle are investigated. These problems include: design, construction and evaluation of the vehicle itself and its control and operating systems. More specifically, vehicle configuration, dynamics, control, propulsion, hazard detection systems, terrain sensing and modelling, obstacle detection concepts, path selection, decision-making systems, and chemical analyses of samples are studied. Emphasis is placed on development of a vehicle capable of gathering specimens and data for an Augmented Viking Mission or to provide the basis for a Sample Return Mission.

Application of the Regional Atmospheric Modeling System to the Martian Atmosphere

NASA Technical Reports Server (NTRS)

Rafkin, Scot C. R.

1998-01-01

The core dynamics of the Regional Atmospheric Modeling System (RAMS), a widely used and powerful mesoscale Earth model, is adapted to the Martian Atmosphere and applied in the study of aeolian surface features. In particular, research efforts focused on the substitution of Martian planetary and atmospheric properties such as rotation rate, and thermodynamic constants in place of hard-wired Earth properties. Application of the model was restricted to three-dimensional flow impinging upon impact craters, and the search for plausible wind patterns that could produce the so-called light and dark streaks downwind of topographic barriers.

Laboratory Impact Experiments

NASA Astrophysics Data System (ADS)

Horanyi, M.; Munsat, T.

2017-12-01

The experimental and theoretical programs at the SSERVI Institute for Modeling Plasmas, Atmospheres, and Cosmic Dust (IMPACT) address the effects of hypervelocity dust impacts and the nature of the space environment of granular surfaces interacting with solar wind plasma and ultraviolet radiation. These are recognized as fundamental planetary processes due their role in shaping the surfaces of airless planetary objects, their plasma environments, maintaining dust haloes, and sustaining surface bound exospheres. Dust impacts are critically important for all airless bodies considered for possible human missions in the next decade: the Moon, Near Earth Asteroids (NEAs), Phobos, and Deimos, with direct relevance to crew and mission safety and our ability to explore these objects. This talk will describe our newly developed laboratory capabilities to assess the effects of hypervelocity dust impacts on: 1) the gardening and redistribution of dust particles; and 2) the generation of ionized and neutral gasses on the surfaces of airless planetary bodies.

Space environment and lunar surface processes

NASA Technical Reports Server (NTRS)

Comstock, G. M.

1979-01-01

The development of a general rock/soil model capable of simulating in a self consistent manner the mechanical and exposure history of an assemblage of solid and loose material from submicron to planetary size scales, applicable to lunar and other space exposed planetary surfaces is discussed. The model was incorporated into a computer code called MESS.2 (model for the evolution of space exposed surfaces). MESS.2, which represents a considerable increase in sophistication and scope over previous soil and rock surface models, is described. The capabilities of previous models for near surface soil and rock surfaces are compared with the rock/soil model, MESS.2.

Applying Multiagent Simulation to Planetary Surface Operations

NASA Technical Reports Server (NTRS)

Sierhuis, Maarten; Sims, Michael H.; Clancey, William J.; Lee, Pascal; Swanson, Keith (Technical Monitor)

2000-01-01

This paper describes a multiagent modeling and simulation approach for designing cooperative systems. Issues addressed include the use of multiagent modeling and simulation for the design of human and robotic operations, as a theory for human/robot cooperation on planetary surface missions. We describe a design process for cooperative systems centered around the Brahms modeling and simulation environment being developed at NASA Ames.

The Explorer's Guide to Impact Craters

NASA Technical Reports Server (NTRS)

Chuang, F.; Pierazzo, E.; Osinski, G.

2005-01-01

Impact cratering is a fundamental geologic process of our solar system. It competes with other processes, such as plate tectonics, volcanism, fluvial, glacial and eolian activity, in shaping the surfaces of planetary bodies. In some cases, like the Moon and Mercury, impact craters are the dominant landform. On other planetary bodies impact craters are being continuously erased by the action of other geological processes, like volcanism on Io, erosion and plate tectonics on the Earth, tectonic and volcanic resurfacing on Venus, or ancient erosion periods on Mars. The study of crater populations is one of the principal tools for understanding the geologic history of a planetary surface. Among the general public, impact cratering has drawn wide attention through its portrayal in several Hollywood movies. Questions that are raised after watching these movies include: How do scientists learn about impact cratering? , and What information do impact craters provide in understanding the evolution of a planetary surface? Fundamental approaches used by scientists to learn about impact cratering include field work at known terrestrial craters, remote sensing studies of craters on various solid surfaces of solar system bodies, and theoretical and laboratory studies using the known physics of impact cratering.

Remote X-Ray Diffraction and X-Ray Fluorescence Analysis on Planetary Surfaces

NASA Technical Reports Server (NTRS)

Blake, David F.; DeVincenzi, D. (Technical Monitor)

1999-01-01

The legacy of planetary X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) began in 1960 when W. Parish proposed an XRD instrument for deployment on the moon. The instrument was built and flight qualified, but the Lunar XRD program was cancelled shortly before the first human landing in 1969. XRF chemical data have been collected in situ by surface landers on Mars (Viking 1 & 2, Pathfinder) and Venus (Venera 13 & 14). These highly successful experiments provide critical constraints on our current understanding of surface processes and planetary evolution. However, the mineralogy, which is more critical to planetary surface science than simple chemical analysis, will remain unknown or will at best be imprecisely constrained until X-ray diffraction (XRD) data are collected. Recent progress in X-ray detector technology allows the consideration of simultaneous XRD (mineralogic analysis) and high-precision XRF (elemental analysis) in systems miniaturized to the point where they can be mounted on fixed landers or small robotic rovers. There is a variety of potential targets for XRD/XRF equipped landers within the solar system, the most compelling of which are the poles of the moon, the southern highlands of Mars and Europa.

Asteroid, Lunar and Planetary Regolith Management A Layered Engineering Defense

NASA Technical Reports Server (NTRS)

Wagner, Sandra

2014-01-01

During missions on asteroid and lunar and planetary surfaces, space systems and crew health may be degraded by exposure to dust and dirt. Furthermore, for missions outside the Earth-Moon system, planetary protection must be considered in efforts to minimize forward and backward contamination. This paper presents an end-to-end approach to ensure system reliability, crew health, and planetary protection in regolith environments. It also recommends technology investments that would be required to implement this layered engineering defense.

Ongoing Mars Missions: Extended Mission Plans

NASA Astrophysics Data System (ADS)

Zurek, Richard; Diniega, Serina; Crisp, Joy; Fraeman, Abigail; Golombek, Matt; Jakosky, Bruce; Plaut, Jeff; Senske, David A.; Tamppari, Leslie; Thompson, Thomas W.; Vasavada, Ashwin R.

2016-10-01

Many key scientific discoveries in planetary science have been made during extended missions. This is certainly true for the Mars missions both in orbit and on the planet's surface. Every two years, ongoing NASA planetary missions propose investigations for the next two years. This year, as part of the 2016 Planetary Sciences Division (PSD) Mission Senior Review, the Mars Odyssey (ODY) orbiter project submitted a proposal for its 7th extended mission, the Mars Exploration Rover (MER-B) Opportunity submitted for its 10th, the Mars Reconnaissance Orbiter (MRO) for its 4th, and the Mars Science Laboratory (MSL) Curiosity rover and the Mars Atmosphere and Volatile Evolution (MVN) orbiter for their 2nd extended missions, respectively. Continued US participation in the ongoing Mars Express Mission (MEX) was also proposed. These missions arrived at Mars in 2001, 2004, 2006, 2012, 2014, and 2003, respectively. Highlights of proposed activities include systematic observations of the surface and atmosphere in twilight (early morning and late evening), building on a 13-year record of global mapping (ODY); exploration of a crater rim gully and interior of Endeavour Crater, while continuing to test what can and cannot be seen from orbit (MER-B); refocused observations of ancient aqueous deposits and polar cap interiors, while adding a 6th Mars year of change detection in the atmosphere and the surface (MRO); exploration and sampling by a rover of mineralogically diverse strata of Mt. Sharp and of atmospheric methane in Gale Crater (MSL); and further characterization of atmospheric escape under different solar conditions (MVN). As proposed, these activities follow up on previous discoveries (e.g., recurring slope lineae, habitable environments), while expanding spatial and temporal coverage to guide new detailed observations. An independent review panel evaluated these proposals, met with project representatives in May, and made recommendations to NASA in June 2016. In this presentation, we will highlight the planned activities of these NASA Mars missions, as they start new chapters in their historic exploration of the dynamic and complex planet that is Mars.

Permo-Carboniferous sedimentary basins related to the distribution of planetary cryptoblemes

USGS Publications Warehouse

Windolph, J.F.

1997-01-01

Massive/high velocity solar, galactic, and cosmic debris impacting the Earths surface may account for the enormous energy required for the formation of Permo-Carboniferous sedimentary basins and related mountain building orogenies. Analysis of satellite immagry, sea floor sonar, geophysical data, and geotectonic fabrics show a strong correlation throughout geologic time between sedimentary basin origin and planetary cryptoblemes. Cryptoblemes are subtile, multi-ringed, radial centric impact shock signatures covering the entire terrestrial surface and ocean floors, having a geometry and distribution strikingly similar to the surfaces of the lunar planetary bodies in the solar system. Investigations of Permo-Carboniferous basins show an intensely overprinted pattern of cryptoblemes coinciding with partial obliteration and elliptical compression of pre-existing basins and accompanying shock patterns. Large distorted cryptoblemes may incorporate thin skin deformation, localized sediment diagenesis, regional metamorphism, and juxtaposed exotic terrains. These data, related to basin morphogenic symmetry, suggest that large episodic impact events are the primary cause of tectonogenic features, geologic boundary formation and mass extinction episodes on the planet Earth. Plate tectonics may be only a slow moving, low energy secondary effect defined and set in motion by megacosmic accretion events. Permo-Carboniferous sediments of note are preserved or accumulated in relatively small rectangular to arcuate rift valleys and synclinal down warps, such as the Narraganset basin of Massachusetts, USA, and Paganzo basin in Argentina, S.A. These deposits and depocenters may originate from dynamic reinforcement/cancellation impact effects, as can be seen in the Basin Range of Nevada and Utah, USA. Large circular to oval sedimentary basins commonly include internal ring structures indicating post depositional subsidence and rebound adjustments with growth faulting, notable in the Illinois basin USA and Ordos basin in China. Recent impact events on the planet Jupiter, July 1994, lend increasing support towards an impact orogenic geologic paradigm on the planet Earth.

Earth as an Exoplanet: Lessons in Recognizing Planetary Habitability

NASA Astrophysics Data System (ADS)

Meadows, Victoria; Robinson, Tyler; Misra, Amit; Ennico, Kimberly; Sparks, William B.; Claire, Mark; Crisp, David; Schwieterman, Edward; Bussey, D. Ben J.; Breiner, Jonathan

2015-01-01

Earth will always be our best-studied example of a habitable world. While extrasolar planets are unlikely to look exactly like Earth, they may share key characteristics, such as oceans, clouds and surface inhomogeneity. Earth's globally-averaged characteristics can therefore help us to recognize planetary habitability in data-limited exoplanet observations. One of the most straightforward ways to detect habitability will be via detection of 'glint', specular reflectance from an ocean (Robinson et al., 2010). Other methods include undertaking a census of atmospheric greenhouse gases, or attempting to measure planetary surface temperature and pressure, to determine if liquid water would be feasible on the planetary surface. Here we present recent research on detecting planetary habitability, led by the NASA Astrobiology Institute's Virtual Planetary Laboratory Team. This work includes a collaboration with the NASA Lunar Science Institute on the detection of ocean glint and ozone absorption using Lunar Crater Observation and Sensing Satellite (LCROSS) Earth observations (Robinson et al., 2014). This data/model comparison provides the first observational test of a technique that could be used to determine exoplanet habitability from disk-integrated observations at visible and near-infrared wavelengths. We find that the VPL spectral Earth model is in excellent agreement with the LCROSS Earth data, and can be used to reliably predict Earth's appearance at a range of phases relevant to exoplanet observations. Determining atmospheric surface pressure and temperature directly for a potentially habitable planet will be challenging due to the lack of spatial-resolution, presence of clouds, and difficulty in spectrally detecting many bulk constituents of terrestrial atmospheres. Additionally, Rayleigh scattering can be masked by absorbing gases and absorption from the underlying surface. However, new techniques using molecular dimers of oxygen (Misra et al., 2014) and nitrogen (Schwieterman et al., 2014) may provide an alternative means to determine terrestrial atmospheric pressure for both transit transmission and direct imaging observations.

Planetary Taxonomy: Label Round Bodies "Worlds"

NASA Astrophysics Data System (ADS)

Margot, Jean-Luc; Levison, H. F.

2009-05-01

The classification of planetary bodies is as important to Astronomy as taxonomy is to other sciences. The etymological, historical, and IAU definitions of planet rely on a dynamical criterion, but some authors prefer a geophysical criterion based on "roundness". Although the former criterion is superior when it comes to classifying newly discovered objects, the conflict need not exist if we agree to identify the subset of "round" planetary objects as "worlds". This addition to the taxonomy would conveniently recognize that "round" objects such as Earth, Europa, Titan, Triton, and Pluto share some common planetary-type processes regardless of their distance from the host star. Some of these worlds are planets, others are not. Defining how round is round and handling the inevitable transition objects are non-trivial tasks. Because images at sufficient resolution are not available for the overwhelming majority of newly discovered objects, the degree of roundness is not a directly observable property and is inherently problematic as a basis for classification. We can tolerate some uncertainty in establishing the "world" status of a newly discovered object, and still establish its planet or satellite status with existing dynamical criteria. Because orbital parameters are directly observable, and because mass can often be measured either from orbital perturbations or from the presence of companions, the dynamics provide a robust and practical planet classification scheme. It may also be possible to determine which bodies are dynamically dominant from observations of the population magnitude/size distribution.

Planetary Surface Visualization and Analytics

NASA Astrophysics Data System (ADS)

Law, E. S.; Solar System Treks Team

2018-04-01

An introduction and update of the Solar System Treks Project which provides a suite of interactive visualization and analysis tools to enable users (engineers, scientists, public) to access large amounts of mapped planetary data products.

A Compact Instrument for Remote Raman and Fluorescence Measurements to a Radial Distance of 100 m

NASA Technical Reports Server (NTRS)

Sharma, S. K.; Misra, A. K.; Lucey, P. g.; McKay, C. P.

2005-01-01

Compact remote spectroscopic instruments that could provide detailed information about mineralogy, organic and biomaterials on a planetary surface over a relatively large area are desirable for NASA s planetary exploration program. Ability to explore a large area on the planetary surfaces as well as in impact craters from a fixed location of a rover or lander will enhance the probability of selecting target rocks of high scientific contents as well as desirable sites in search of organic compounds and biomarkers on Mars and other planetary bodies. We have developed a combined remote inelastic scattering (Raman) and laser-induced fluorescence emission (LIFE) compact instrument capable of providing accurate information about minerals, organic and biogenic materials to a radial distance of 100 m. Here we present the Raman and LIFE (R-LIFE) data set.

New Indivisible Planetary Science Paradigm: Consequence of Questioning Popular Paradigms

NASA Astrophysics Data System (ADS)

Marvin Herndon, J.

2014-05-01

Progress in science involves replacing less precise understanding with more precise understanding. In science and in science education one should always question popular ideas; ask "What's wrong with this picture?" Finding limitations, conflicts or circumstances that require special ad hoc consideration sometimes is the key to making important discoveries. For example, from thermodynamic considerations, I found that the 'standard model of solar system formation' leads to insufficiently massive planetary cores. That understanding led me to discover a new indivisible planetary science paradigm. Massive-core planets formed by condensing and raining-out from within giant gaseous protoplanets at high pressures and high temperatures, accumulating heterogeneously on the basis of volatility with liquid core-formation preceding mantle-formation; the interior states of oxidation resemble that of the Abee enstatite chondrite. Core-composition was established during condensation based upon the relative solubilities of elements, including uranium, in liquid iron in equilibrium with an atmosphere of solar composition at high pressures and high temperatures. Uranium settled to the central region and formed planetary nuclear fission reactors, producing heat and planetary magnetic fields. Earth's complete condensation included a ~300 Earth-mass gigantic gas/ice shell that compressed the rocky kernel to about 66% of Earth's present diameter. T-Tauri eruptions, associated with the thermonuclear ignition of the Sun, stripped the gases away from the Earth and the inner planets. The T-Tauri outbursts stripped a portion of Mercury's incompletely condensed protoplanet and transported it to the region between Mars and Jupiter where it fused with in-falling oxidized condensate from the outer regions of the Solar System, forming the parent matter of ordinary chondrite meteorites, the main-Belt asteroids, and veneer for the inner planets, especially Mars. With its massive gas/ice shell removed, pressure began to build in the compressed rocky kernel of Earth and eventually the rigid crust began to crack. The major energy source for planetary decompression and for heat emplacement at the base of the crust is the stored energy of protoplanetary compression. In response to decompression-driven volume increases, cracks form to increase surface area and fold-mountain ranges form to accommodate changes in curvature. One of the most profound mysteries of modern planetary science is this: As the terrestrial planets are more-or-less of common chondritic composition, how does one account for the marked differences in their surface dynamics? Differences among the inner planets are principally due to the degree of compression experienced. Planetocentric georeactor nuclear fission, responsible for magnetic field generation and concomitant heat production, is applicable to compressed and non-compressed planets and large moons. The internal composition of Mercury is calculated based upon an analogy with the deep-Earth mass ratio relationships. The origin and implication of Mercurian hydrogen geysers is described. Besides Earth, only Venus appears to have sustained protoplanetary compression; the degree of which might eventually be estimated from understanding Venetian surface geology. A basis is provided for understanding that Mars essentially lacks a 'geothermal gradient' which implies potentially greater subsurface water reservoir capacity than previously expected. Resources at NuclearPlanet.com .

Towards Camera-LIDAR Fusion-Based Terrain Modelling for Planetary Surfaces: Review and Analysis

PubMed Central

Shaukat, Affan; Blacker, Peter C.; Spiteri, Conrad; Gao, Yang

2016-01-01

In recent decades, terrain modelling and reconstruction techniques have increased research interest in precise short and long distance autonomous navigation, localisation and mapping within field robotics. One of the most challenging applications is in relation to autonomous planetary exploration using mobile robots. Rovers deployed to explore extraterrestrial surfaces are required to perceive and model the environment with little or no intervention from the ground station. Up to date, stereopsis represents the state-of-the art method and can achieve short-distance planetary surface modelling. However, future space missions will require scene reconstruction at greater distance, fidelity and feature complexity, potentially using other sensors like Light Detection And Ranging (LIDAR). LIDAR has been extensively exploited for target detection, identification, and depth estimation in terrestrial robotics, but is still under development to become a viable technology for space robotics. This paper will first review current methods for scene reconstruction and terrain modelling using cameras in planetary robotics and LIDARs in terrestrial robotics; then we will propose camera-LIDAR fusion as a feasible technique to overcome the limitations of either of these individual sensors for planetary exploration. A comprehensive analysis will be presented to demonstrate the advantages of camera-LIDAR fusion in terms of range, fidelity, accuracy and computation. PMID:27879625

The Stellar Imager (SI) Project: Resolving Stellar Surfaces, Interiors, and Magnetic Activity

NASA Technical Reports Server (NTRS)

Carpenter, Kenneth G.; Schrijver, K.; Karovska, M.

2007-01-01

The Stellar Imager (SI) is a UV/Optical. Space-Based Interferometer designed to enable 0.1 milli-arcsec (mas) spectral imaging of stellar surfaces and, via asteroseismology, stellar interiors and of the Universe in general. The ultra-sharp images of SI will revolutionize our view of many dynamic astrophysical processes by transforming point sources into extended sources, and snapshots into evolving views. The science of SI focuses on the role of magnetism in the Universe, particularly on magnetic activity on the surfaces of stars like the Sun. Its prime goal is to enable long-term forecasting of solar activity and the space weather that it drives. SI will also revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. In this paper we discuss the science goals, technology needs, and baseline design of the SI mission.

Impacts of raindrop evaporative cooling on tropical cyclone secondary eyewall formation

NASA Astrophysics Data System (ADS)

Ge, Xuyang; Guan, Liang; Yan, Ziyu

2018-06-01

The impacts of raindrop evaporative cooling on secondary eyewall formation (SEF) of simulated tropical cyclones are investigated using idealized numerical experiments. The results suggest that the raindrop evaporative cooling effect is beneficial to the development of secondary eyewall through the planetary boundary layer (PBL) cold pool process. The evaporative cooling-driven downdrafts bring about the surface cold pool beneath a precipitation cloud. This cold pool dynamics act as a lifting mechanism to trigger the outer convection. The radially outward propagation of spiral rainbands broadens the TC size, by which modifies the surface heat fluxes and thus outer convection. Furthermore, the unbalanced PBL process contributes to the SEF. The radially outward surface outflows forces convection at outer region and thus favors a larger TC size. A larger TC implies an enhanced inertial stability at the outer region, which favors a higher conversion efficiency of diabatic heating to kinetic energy.

Life near the Roche limit - Behavior of ejecta from satellites close to planets

NASA Technical Reports Server (NTRS)

Dobrovolskis, A. R.; Burns, J. A.

1980-01-01

A study of the dynamics of nearby debris from impact craters was made to explain the distinctive features seen on Phobos, Deimis, and Amalthea. The planetary tides and satellite rotation were considered, and the usual pseudo-energy (Jacobi) integral was numerically calculated in the framework of a restricted body problem where satellites are modelled as triaxial ellipsoids rather than point masses. Iso-contours of this integral show that Deimos and Amalthea are entirely closed by Roche lobes, and the surfaces of their model ellipsoids lie nearly along equipotentials. Presently, the surface of Phobos overflows its Roche lobe, except for regions within a few km of the sub-Mars and anti-Mars points. The behavior of crater ejecta from the satellites of Mars were also examined by numerical integration of trajectories for particles leaving their surfaces in the equatorial plane.

Planetary surface reactor shielding using indigenous materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houts, Michael G.; Poston, David I.; Trellue, Holly R.

The exploration and development of Mars will require abundant surface power. Nuclear reactors are a low-cost, low-mass means of providing that power. A significant fraction of the nuclear power system mass is radiation shielding necessary for protecting humans and/or equipment from radiation emitted by the reactor. For planetary surface missions, it may be desirable to provide some or all of the required shielding from indigenous materials. This paper examines shielding options that utilize either purely indigenous materials or a combination of indigenous and nonindigenous materials.

Remote Thermal IR Spectroscopy of our Solar System

NASA Technical Reports Server (NTRS)

Kostiuk, Theodor; Hewagama, Tilak; Goldstein, Jeffrey; Livengood, Timothy; Fast, Kelly

1999-01-01

Indirect methods to detect extrasolar planets have been successful in identifying a number of stars with companion planets. No direct detection of an extrasolar planet has yet been reported. Spectroscopy in the thermal infrared region provides a potentially powerful approach to detection and characterization of planets and planetary systems. We can use knowledge of our own solar system, its planets and their atmospheres to model spectral characteristics of planets around other stars. Spectra derived from modeling our own solar system seen from an extrasolar perspective can be used to constrain detection strategies, identification of planetary class (terrestrial vs. gaseous) and retrieval of chemical, thermal and dynamical information. Emission from planets in our solar system peaks in the thermal infrared region, approximately 10 - 30 microns, substantially displaced from the maximum of the much brighter solar emission in the visible near 0.5 microns. This fact provides a relatively good contrast ratio to discriminate between stellar (solar) and planetary emission and optimize the delectability of planetary spectra. Important molecular constituents in planetary atmospheres have rotational-vibrational spectra in the thermal infrared region. Spectra from these molecules have been well characterized in the laboratory and studied in the atmospheres of solar system planets from ground-based and space platforms. The best example of such measurements are the studies with Fourier transform spectrometers, the Infrared Interferometer Spectrometers (IRIS), from spacecraft: Earth observed from NIMBUS 8, Mars observed from Mariner 9, and the outer planets observed from Voyager spacecraft. An Earth-like planet is characterized by atmospheric spectra of ozone, carbon dioxide, and water. Terrestrial planets have oxidizing atmospheres which are easily distinguished from reducing atmospheres of gaseous giant planets which lack oxygen-bearing species and are characterized by spectra containing hydrocarbons such as methane and ethane. Spectroscopic information on extrasolar planets thus can permit their classification. Spectra and spectral lines contain information on the temperature structure of the atmosphere. Line and band spectra can be used to identify the molecular constituents and retrieve species abundances, thereby classifying and characterizing the planet. At high enough spectral resolution characteristic planetary atmospheric dynamics and unique phenomena such as failure of local thermodynamic equilibrium can be identified. Dynamically induced effects such as planetary rotation and orbital velocity shift and change the shape of spectral features and must be modeled in detailed spectral studies. We will use our knowledge of the compositional, thermal and dynamical characteristics of planetary atmospheres in our own solar system to model spectra observed remotely on similar planets in extrasolar planetary systems. We will use a detailed radiative transfer and beam integration program developed for the modeling and interpretation of thermal infrared spectra measured from nearby planet planets to generate models of an extra-solar "Earth" and "Jupiter". From these models we will show how key spectral features distinguish between terrestrial and gaseous planets, what information can be obtained with different spectral resolution, what spectral features can be used to search for conditions for biogenic activity, and how dynamics and distance modify the observed spectra. We also will look at unique planetary phenomena such as atmospheric lasing and discuss their utility as probes for detection and identification of planets. Results of such studies will provide information to constrain design for instrumentation needed to directly detect extrasolar planets.

Mars ecopoiesis test bed: on earth and on the red planet

NASA Astrophysics Data System (ADS)

Todd, Paul; Kurk, Michael Andy; Boland, Eugene; Thomas, David; Scherzer, Christopher

2016-07-01

The concept of autotrophic organisms serving as planetary pioneers as a precursor to terraforming has been under consideration for several decades, and the term Ecopoiesis was introduced by the ecopoiets C. Sagan, M. Avener, R. Haynes and C. McKay to call attention to this possibility. There is a continuing need for experimental evidence to support this concept, one of them being the need to evaluate the survivability of terrestrial autotrophic microbes in a planetary environment. For this and other purposes a planetary simulation facility was constructed and operated at Techshot, Inc. in Indiana, USA. This facility has an accumulated record of more than one year's worth of experimentation under simulated Mars conditions. In a recent study this facility was operated for five weeks in a mode that simulated 35 sols on and just below the surface of Mars at low latitude. The diurnal lighting period was 12 hours:12 hours using xenon arc light filtered to simulate the solar intensity and spectrum on the Martian surface. A daily temperature profile followed that recorded at low latitudes with night-time minima at -80 C and noontime maxima at +26 C. Atmosphere was CO _{2} at <11 mbar. Moisture was monitored to confirm that no water could exist in the liquid phase. Test organisms included the cyanobacteria Anabena, sp., Chroococcidiopsis CCMEE171 and Plectonema boryanum and Eukaryota: Chlorella ellipsoidia maintained in the simulator under the above-described conditions. The exposed specimens were tested for intracellular esterase activity, chlorophyll content and reproductive survival. All tests yielded low-level positive survival results for these organisms. No definitive data relating to function and/or growth during exposure were sought. In parallel to these terrestrial studies a planned design study was undertaken for a proposed test bed to be operated on the surface of Mars. Design requirements include compact assembly for transport and installation on the planetary surface (multiple units per mission would be expected), protective internal package for the release of organisms, a means of atmosphere exchange, access to sunlight, a means of penetrating the planetary surface, and most importantly a means of acquiring regolith while meeting requirements of planetary protection. An enlarged-scale mock-up of this design was fabricated by additive manufacturing with moving parts that simulate the components of the design. This mock-up assembly marks a starting point for a planetary surface probe for safe implantation on the surface of the Red Planet some decades in the future. This research was supported by NASA NIAC Phase I Grant "Mars Ecopoiesis Testbed" NNX14AM97G.

Influence of deep vortices on the ocean surface

NASA Astrophysics Data System (ADS)

Ciani, Daniele; Carton, Xavier; Bashmachnikov, Igor; Chapron, Bertrand

2015-04-01

The oceanic motion at mesoscale (20-200 km) and submesoscale (0.5-20 km) is highly populated by vortices. These recirculating structures are more energetic than the mean flow, they trap water masses from their origination areas and advect them across the ocean, with consequent impact on the 3D distribution of heat and tracers. Mesoscale and submesoscale structures characterize the ocean dynamics both at the sea-surface and at intrathermocline depths (0-1500 m), and are presently investigated by means of model outputs and satellite (surface) data, the latest being the only way to get high resolution and synoptic observations at planetary scale (e.g., thermal-band observations, future altimetric observations given by the SWOT mission). The scientific question arising from this context is related to the role of the ocean surface for inferring informations on mesoscale and submesoscale vortices at depth. This study has also been motivated by the recent detection of subsurface eddies east of the Arabian Peninsula (PHYSINDIEN experiment - 2011). Using analytical models in the frame of the quasi-geostrophic (QG) theory, we could describe the theoretical altimetric signature of non-drifting and of drifting subsurface eddies. Numerical experiments, using both QG and primitive equations models, allowed us to investigate the surface expression of intrathermocline eddies interacting with baroclinic currents or evolving under planetary beta-effect. The eddies' characteristics (radius, depth, thickness, velocity) were varied in order to represent various oceanic examples (Meddies, Swoddies, Reddies, Peddies, Leddies). Idealized simulations with the ROMS model, confirming theoretical estimates, showed that drifting subsurface-intensified vortices can induce dipolar sea level anomalies, up to 3 cm. This result, compatibly with future SWOT measurement accuracies (about 2 cm), represents a contribution for systematic and synoptic detection of subsurface vortices.

Comments on the Synergism Between the Analytic Planetary Boundary-Layer Model and Remote Sensing Data

NASA Astrophysics Data System (ADS)

Brown, R. A.

2005-08-01

This paper is adapted from a presentation at the session of the European Geophysical Society meeting in 2002 honouring Joost Businger. It documents the interaction of the non-linear planetary boundary-layer (PBL) model (UW-PBL) and satellite remote sensing of marine surface winds from verification and calibration studies for the sensor model function to the current state of verification of the model by satellite data. It is also a personal history where Joost Businger had seminal input to this research at several critical junctures. The first scatterometer in space was on SeaSat in 1978, while currently in orbit there are the QuikSCAT and ERS-2 scatterometers and the WindSat radiometer. The volume and detail of data from the scatterometers during the past decade are unprecedented, though the value of these data depends on a careful interpretation of the PBL dynamics. The model functions (algorithms) that relate surface wind to sensor signal have evolved from straight empirical correlation with simple surface-layer 10-m winds to satellite sensor model functions for surface pressure fields. A surface stress model function is also available. The validation data for the satellite model functions depended crucially on the PBL solution. The non-linear solution for the flow of fluid in the boundary layer of a rotating coordinate system was completed in 1969. The implications for traditional ways of measuring and modelling the PBL were huge and continue to this day. Unfortunately, this solution replaced an elegant one by Ekman with a stability/finite perturbation equilibrium solution. Consequently, there has been great reluctance to accept this solution. The verification of model predictions has been obtained from the satellite data.

Planetary heat flow measurements.

PubMed

Hagermann, Axel

2005-12-15

The year 2005 marks the 35th anniversary of the Apollo 13 mission, probably the most successful failure in the history of manned spaceflight. Naturally, Apollo 13's scientific payload is far less known than the spectacular accident and subsequent rescue of its crew. Among other instruments, it carried the first instrument designed to measure the flux of heat on a planetary body other than Earth. The year 2005 also should have marked the launch of the Japanese LUNAR-A mission, and ESA's Rosetta mission is slowly approaching comet Churyumov-Gerasimenko. Both missions carry penetrators to study the heat flow from their target bodies. What is so interesting about planetary heat flow? What can we learn from it and how do we measure it?Not only the Sun, but all planets in the Solar System are essentially heat engines. Various heat sources or heat reservoirs drive intrinsic and surface processes, causing 'dead balls of rock, ice or gas' to evolve dynamically over time, driving convection that powers tectonic processes and spawns magnetic fields. The heat flow constrains models of the thermal evolution of a planet and also its composition because it provides an upper limit for the bulk abundance of radioactive elements. On Earth, the global variation of heat flow also reflects the tectonic activity: heat flow increases towards the young ocean ridges, whereas it is rather low on the old continental shields. It is not surprising that surface heat flow measurements, or even estimates, where performed, contributed greatly to our understanding of what happens inside the planets. In this article, I will review the results and the methods used in past heat flow measurements and speculate on the targets and design of future experiments.

Vibrational-Rotational Spectroscopy For Planetary Atmospheres, volume 1

NASA Technical Reports Server (NTRS)

Mumma, M. J. (Editor); Fox, K. (Editor); Hornstein, J. (Editor)

1982-01-01

Comprehensive information on the composition and dynamics of the varied planetary atmospheres is summarized. New observations resulted in new demands for supporting laboratory studies. Spectra observed from spacecraft used to interpret planetary atmospheric structure measurements, to aid in greenhouse and cloud physics calculations, and to plan future experiments are discussed. Current findings and new ideas of physicists, chemists, and planetry astronomers relating to the knowledge of the structure of things large and small, of planets and of molecules are summarized.

Robotic Access to Planetary Surfaces Capability Roadmap

NASA Technical Reports Server (NTRS)

2005-01-01

A set of robotic access to planetary surfaces capability developments and supporting infrastructure have been identified. Reference mission pulls derived from ongoing strategic planning. Capability pushes to enable broader mission considerations. Facility and flight test capability needs. Those developments have been described to the level of detail needed for high-level planning. Content and approach. Readiness and metrics. Rough schedule and cost. Connectivity to mission concepts.

Planetary Research Center. [astronomical photography of planetary surfaces and atmospheres

NASA Technical Reports Server (NTRS)

Baum, W. A.; Millis, R. L.; Bowell, E. L. G.

1974-01-01

Extensive Earth-based photography of Mars, Jupiter, and Venus is presented which monitors the atmospheric and/or surface changes that take place day to day. Color pictures are included of the 1973 dust storm on Mars, showing the daily cycle of the storm's regeneration. Martian topography, and the progress of the storm is examined. Areas most affected by the storm are summarized.

Effects of leaf area index on the coupling between water table, land surface energy fluxes, and planetary boundary layer at the regional scale

NASA Astrophysics Data System (ADS)

Lu, Y.; Rihani, J.; Langensiepen, M.; Simmer, C.

2013-12-01

Vegetation plays an important role in the exchange of moisture and energy at the land surface. Previous studies indicate that vegetation increases the complexity of the feedbacks between the atmosphere and subsurface through processes such as interception, root water uptake, leaf surface evaporation, and transpiration. Vegetation cover can affect not only the interaction between water table depth and energy fluxes, but also the development of the planetary boundary layer. Leaf Area Index (LAI) is shown to be a major factor influencing these interactions. In this work, we investigate the sensitivity of water table, surface energy fluxes, and atmospheric boundary layer interactions to LAI as a model input. We particularly focus on the role LAI plays on the location and extent of transition zones of strongest coupling and how this role changes over seasonal timescales for a real catchment. The Terrestrial System Modelling Platform (TerrSysMP), developed within the Transregional Collaborative Research Centre 32 (TR32), is used in this study. TerrSysMP consists of the variably saturated groundwater model ParFlow, the land surface model Community Land Model (CLM), and the regional climate and weather forecast model COSMO (COnsortium for Small-scale Modeling). The sensitivity analysis is performed over a range of LAI values for different vegetation types as extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS) dataset for the Rur catchment in Germany. In the first part of this work, effects of vegetation structure on land surface energy fluxes and their connection to water table dynamics are studied using the stand-alone CLM and the coupled subsurface-surface components of TerrSysMP (ParFlow-CLM), respectively. The interconnection between LAI and transition zones of strongest coupling are investigated and analyzed through a subsequent set of subsurface-surface-atmosphere coupled simulations implementing the full TerrSysMP model system.

Galactic cosmic ray-induced radiation dose on terrestrial exoplanets.

PubMed

Atri, Dimitra; Hariharan, B; Grießmeier, Jean-Mathias

2013-10-01

This past decade has seen tremendous advancements in the study of extrasolar planets. Observations are now made with increasing sophistication from both ground- and space-based instruments, and exoplanets are characterized with increasing precision. There is a class of particularly interesting exoplanets that reside in the habitable zone, which is defined as the area around a star where the planet is capable of supporting liquid water on its surface. Planetary systems around M dwarfs are considered to be prime candidates to search for life beyond the Solar System. Such planets are likely to be tidally locked and have close-in habitable zones. Theoretical calculations also suggest that close-in exoplanets are more likely to have weaker planetary magnetic fields, especially in the case of super-Earths. Such exoplanets are subjected to a high flux of galactic cosmic rays (GCRs) due to their weak magnetic moments. GCRs are energetic particles of astrophysical origin that strike the planetary atmosphere and produce secondary particles, including muons, which are highly penetrating. Some of these particles reach the planetary surface and contribute to the radiation dose. Along with the magnetic field, another factor governing the radiation dose is the depth of the planetary atmosphere. The higher the depth of the planetary atmosphere, the lower the flux of secondary particles will be on the surface. If the secondary particles are energetic enough, and their flux is sufficiently high, the radiation from muons can also impact the subsurface regions, such as in the case of Mars. If the radiation dose is too high, the chances of sustaining a long-term biosphere on the planet are very low. We have examined the dependence of the GCR-induced radiation dose on the strength of the planetary magnetic field and its atmospheric depth, and found that the latter is the decisive factor for the protection of a planetary biosphere.

The Stellar Activity of TRAPPIST-1 and Consequences for the Planetary Atmospheres

NASA Astrophysics Data System (ADS)

Roettenbacher, Rachael M.; Kane, Stephen R.

2017-12-01

The signatures of planets hosted by M dwarfs are more readily detected with transit photometry and radial velocity methods than those of planets around larger stars. Recently, transit photometry was used to discover seven planets orbiting the late-M dwarf TRAPPIST-1. Three of TRAPPIST-1's planets fall in the Habitable Zone, a region where liquid water could exist on the planetary surface given appropriate planetary conditions. We aim to investigate the habitability of the TRAPPIST-1 planets by studying the star’s activity and its effect on the planets. We analyze previously published space- and ground-based light curves and show the photometrically determined rotation period of TRAPPIST-1 appears to vary over time due to complicated, evolving surface activity. The dramatic changes of the surface of TRAPPIST-1 suggest that rotation periods determined photometrically may not be reliable for this and similarly active stars. While the activity of the star is low, we use the premise of the “cosmic shoreline” to provide evidence that the TRAPPIST-1 environment has potentially led to the erosion of possible planetary atmospheres by extreme ultraviolet stellar emission.

Planetary surface roughness derived from ice penetrating radar data: Method and concept validation in Antarctica

NASA Astrophysics Data System (ADS)

Grima, C.; Schroeder, D. M.; Blankenship, D. D.; Young, D. A.

2013-12-01

Geological and climatic processes shaping the landscape of planetary bodies imprint the surface with particular textures, i.e. continuous topographic entities at meters to decameters scales where the surface elevation is dominated by a stochastic behavior. The so-called roughness is a proxy to get insights into the type of surface terrain and its ongoing evolution. It is also an important descriptor involved in landing site selection processes to ensure the safe delivery of a lander/rover over a stable work zone. Planetary surface roughnesses are usually derived from point-to-point elevation models acquired by laser altimetry or stereo-imagery. However, in the last decade, nadir-looking penetrating radars have become another remote-sensing technology commonly used for planetary surface and sub-surface characterization (e.g. MARSIS/SHARAD on Mars, LRS on the Moon, and Ice Penetrating Radars for future missions to Europa). Here, we present a statistical method to extract the reflected and scattered components embedded in the surface echoes of HF (3-30 MHz) and VHF (30-300 MHz) penetrating radars in order to derive significant roughness information. We demonstrate the reliability of the method with an application to a radar dataset acquired during the 2004-05 austral summer campaign of the Airborne Geophysical Survey of the Amundsen Sea Embayment, Antarctica, (AGASEA) project with the High-Capability Radar Sounder (HiCARS, 60 MHz) system operated by the University of Texas Institute for Geophysics (UTIG). Results are thoroughly compared with simultaneously acquired laser altimetry and nadir imagery of the surface. We emphasize the possibilities and advantages of the method in light of the future exploration of the Europa and Ganymede icy moons by multi-frequency ice penetrating radars.

Planetary Geology: Goals, Future Directions, and Recommendations

NASA Technical Reports Server (NTRS)

1988-01-01

Planetary exploration has provided a torrent of discoveries and a recognition that planets are not inert objects. This expanded view has led to the notion of comparative planetology, in which the differences and similarities among planetary objects are assessed. Solar system exploration is undergoing a change from an era of reconnaissance to one of intensive exploration and focused study. Analyses of planetary surfaces are playing a key role in this transition, especially as attention is focused on such exploration goals as returned samples from Mars. To assess how the science of planetary geology can best contribute to the goals of solar system exploration, a workshop was held at Arizona State University in January 1987. The participants discussed previous accomplishments of the planetary geology program, assessed the current studies in planetary geology, and considered the requirements to meet near-term and long-term exploration goals.

Feasibility of Dynamic Stability Measurements of Planetary Entry Capsules Using MSBS

NASA Technical Reports Server (NTRS)

Britcher, Colin; Schoenenberger, Mark

2015-01-01

The feasibility of conducting dynamic stability testing of planetary entry capsules at low supersonic Mach numbers using a Magnetic Suspension and Balance System (MSBS) is reviewed. The proposed approach would employ a spherical magnetic core, exert control in three degrees-of-freedom (i.e. x, y, z translations) and allow the model to freely rotate in pitch, yaw, and roll. A proof-of-concept system using an existing MSBS electromagnet array in a subsonic wind tunnel is described, with future potential for development of a new system for a supersonic wind tunnel.

Compositional mapping of planetary moons by mass spectrometry of dust ejecta

NASA Astrophysics Data System (ADS)

Postberg, Frank; Grün, Eberhard; Horanyi, Mihaly; Kempf, Sascha; Krüger, Harald; Schmidt, Jürgen; Spahn, Frank; Srama, Ralf; Sternovsky, Zoltan; Trieloff, Mario

2011-11-01

Classical methods to analyze the surface composition of atmosphereless planetary objects from an orbiter are IR and gamma ray spectroscopy and neutron backscatter measurements. The idea to analyze surface properties with an in-situ instrument has been proposed by Johnson et al. (1998). There, it was suggested to analyze Europa's thin atmosphere with an ion and neutral gas spectrometer. Since the atmospheric components are released by sputtering of the moon's surface, they provide a link to surface composition. Here we present an improved, complementary method to analyze rocky or icy dust particles as samples of planetary objects from which they were ejected. Such particles, generated by the ambient meteoroid bombardment that erodes the surface, are naturally present on all atmosphereless moons and planets. The planetary bodies are enshrouded in clouds of ballistic dust particles, which are characteristic samples of their surfaces. In situ mass spectroscopic analysis of these dust particles impacting onto a detector of an orbiting spacecraft reveals their composition. Recent instrumental developments and tests allow the chemical characterization of ice and dust particles encountered at speeds as low as 1 km/s and an accurate reconstruction of their trajectories. Depending on the sampling altitude, a dust trajectory sensor can trace back the origin of each analyzed grain with about 10 km accuracy at the surface. Since the detection rates are of the order of thousand per orbit, a spatially resolved mapping of the surface composition can be achieved. Certain bodies (e.g., Europa) with particularly dense dust clouds, could provide impact statistics that allow for compositional mapping even on single flybys. Dust impact velocities are in general sufficiently high at orbiters about planetary objects with a radius >1000 km and with only a thin or no atmosphere. In this work we focus on the scientific benefit of a dust spectrometer on a spacecraft orbiting Earth's Moon as well as Jupiter's Galilean satellites. This 'dust spectrometer' approach provides key chemical and isotopic constraints for varying provinces or geological formations on the surfaces, leading to better understanding of the body's geological evolution.

Considerations in the Design of Future Planetary Laser Altimeters

NASA Astrophysics Data System (ADS)

Smith, D. E.; Neumann, G. A.; Mazarico, E.; Zuber, M. T.; Sun, X.

2017-12-01

Planetary laser altimeters have generally been designed to provide high accuracy measurements of the nadir range to an uncooperative surface for deriving the shape of the target body, and sometimes specifically for identifying and characterizing potential landing sites. However, experience has shown that in addition to the range measurement, other valuable observations can be acquired, including surface reflectance and surface roughness, despite not being given high priority in the original altimeter design or even anticipated. After nearly 2 decades of planetary laser altimeter design, the requirements are evolving and additional capabilities are becoming equally important. The target bodies, once the terrestrial planets, are now equally asteroids and moons that in many cases do not permit simple orbital operations due to their small mass, radiation issues, or spacecraft fuel limitations. In addition, for a number of reasons, it has become necessary to perform shape determination from a much greater range, even thousands of kilometers, and thus ranging is becoming as important as nadir altimetry. Reflectance measurements have also proved important for assessing the presence of ice, water or CO2, and laser pulse spreading informed knowledge of surface roughness; all indicating a need for improved instrument capability. Recently, the need to obtain accurate range measurement to laser reflectors on landers or on a planetary surface is presenting new science opportunities but for which current designs are far from optimal. These changes to classic laser altimetry have consequences for many instrument functions and capabilities, including beam divergence, laser power, number of beams and detectors, pixelation, energy measurements, pointing stability, polarization, laser wavelengths, and laser pulse rate dependent range. We will discuss how a new consideration of these trades will help make lidars key instruments to execute innovative science in future planetary missions.

Suited for Space

NASA Technical Reports Server (NTRS)

Kosmo, Joseph J.

2006-01-01

This viewgraph presentation describes the basic functions of space suits for EVA astronauts. Space suits are also described from the past, present and future space missions. The contents include: 1) Why Do You Need A Space Suit?; 2) Generic EVA System Requirements; 3) Apollo Lunar Surface Cycling Certification; 4) EVA Operating Cycles for Mars Surface Missions; 5) Mars Surface EVA Mission Cycle Requirements; 6) Robustness Durability Requirements Comparison; 7) Carry-Weight Capabilities; 8) EVA System Challenges (Mars); 9) Human Planetary Surface Exploration Experience; 10) NASA Johnson Space Center Planetary Analog Activities; 11) Why Perform Remote Field Tests; and 12) Other Reasons Why We Perform Remote Field Tests.

Low-Thrust Many-Revolution Trajectory Optimization via Differential Dynamic Programming and a Sundman Transformation

NASA Astrophysics Data System (ADS)

Aziz, Jonathan D.; Parker, Jeffrey S.; Scheeres, Daniel J.; Englander, Jacob A.

2018-01-01

Low-thrust trajectories about planetary bodies characteristically span a high count of orbital revolutions. Directing the thrust vector over many revolutions presents a challenging optimization problem for any conventional strategy. This paper demonstrates the tractability of low-thrust trajectory optimization about planetary bodies by applying a Sundman transformation to change the independent variable of the spacecraft equations of motion to an orbit angle and performing the optimization with differential dynamic programming. Fuel-optimal geocentric transfers are computed with the transfer duration extended up to 2000 revolutions. The flexibility of the approach to higher fidelity dynamics is shown with Earth's J 2 perturbation and lunar gravity included for a 500 revolution transfer.

Low-Thrust Many-Revolution Trajectory Optimization via Differential Dynamic Programming and a Sundman Transformation

NASA Astrophysics Data System (ADS)

Aziz, Jonathan D.; Parker, Jeffrey S.; Scheeres, Daniel J.; Englander, Jacob A.

2018-06-01

Low-thrust trajectories about planetary bodies characteristically span a high count of orbital revolutions. Directing the thrust vector over many revolutions presents a challenging optimization problem for any conventional strategy. This paper demonstrates the tractability of low-thrust trajectory optimization about planetary bodies by applying a Sundman transformation to change the independent variable of the spacecraft equations of motion to an orbit angle and performing the optimization with differential dynamic programming. Fuel-optimal geocentric transfers are computed with the transfer duration extended up to 2000 revolutions. The flexibility of the approach to higher fidelity dynamics is shown with Earth's J 2 perturbation and lunar gravity included for a 500 revolution transfer.

Planetary Systems Dynamics Eccentric patterns in debris disks & Planetary migration in binary systems

NASA Astrophysics Data System (ADS)

Faramaz, V.; Beust, H.; Augereau, J.-C.; Bonsor, A.; Thébault, P.; Wu, Y.; Marshall, J. P.; del Burgo, C.; Ertel, S.; Eiroa, C.; Montesinos, B.; Mora, A.

2014-01-01

We present some highlights of two ongoing investigations that deal with the dynamics of planetary systems. Firstly, until recently, observed eccentric patterns in debris disks were found in young systems. However recent observations of Gyr-old eccentric debris disks leads to question the survival timescale of this type of asymmetry. One such disk was recently observed in the far-IR by the Herschel Space Observatory around ζ2 Reticuli. Secondly, as a binary companion orbits a circumprimary disk, it creates regions where planet formation is strongly handicapped. However, some planets were detected in this zone in tight binary systems (γ Cep, HD 196885). We aim to determine whether a binary companion can affect migration such that planets are brought in these regions and focus in particular on the planetesimal-driven migration mechanism.

Concept study for a Venus Lander Mission to Analyze Atmospheric and Surface Composition

NASA Astrophysics Data System (ADS)

Kumar, K.; Banks, M. E.; Benecchi, S. D.; Bradley, B. K.; Budney, C. J.; Clark, G. B.; Corbin, B. A.; James, P. B.; O'Brien, R. C.; Rivera-Valentin, E. G.; Saltman, A.; Schmerr, N. C.; Seubert, C. R.; Siles, J. V.; Stickle, A. M.; Stockton, A. M.; Taylor, C.; Zanetti, M.; JPL Team X

2011-12-01

We present a concept-level study of a New Frontiers class, Venus lander mission that was developed during Session 1 of NASA's 2011 Planetary Science Summer School, hosted by Team X at JPL. Venus is often termed Earth's sister planet, yet they have evolved in strikingly different ways. Venus' surface and atmosphere dynamics, and their complex interaction are poorly constrained. A lander mission to Venus would enable us to address a multitude of outstanding questions regarding the geological evolution of the Venusian atmosphere and crust. Our proposed mission concept, VenUs Lander for Composition ANalysis (VULCAN), is a two-component mission, consisting of a lander and a carrier spacecraft functioning as relay to transmit data to Earth. The total mission duration is 150 days, with primary science obtained during a 1-hour descent through the atmosphere and a 2-hour residence on the Venusian surface. In the atmosphere, the lander will provide new data on atmospheric evolution by measuring dominant and trace gas abundances, light stable isotopes, and noble gas isotopes with a neutral mass spectrometer. It will make important meteorological observations of mid-lower atmospheric dynamics with pressure and temperature sensors and obtain unprecedented, detailed imagery of surface geomorphology and properties with a descent Near-IR/VIS camera. A nepholometer will provide new constraints on the sizes of suspended particulate matter within the lower atmosphere. On the surface, the lander will quantitatively investigate the chemical and mineralogical evolution of the Venusian crust with a LIBS-Raman spectrometer. Planetary differentiation processes recorded in heavy elements will be evaluated using a gamma-ray spectrometer. The lander will also provide the first stereo images for evaluating the geomorphologic/volcanic evolution of the Venusian surface, as well as panoramic views of the sample site using multiple filters, and detailed images of unconsolidated material and rock textures from a microscopic imager. Our mission proposal will enable the construction of a unique Venus test facility that will attract a new generation of scientists to Venus science. With emphasis on flight heritage, we demonstrate our cost basis and risk mitigation strategies to ensure that the VULCAN mission can be conducted within the requirements and constraints of the New Frontiers Program.

The Geology of the Terrestrial Planets

NASA Technical Reports Server (NTRS)

Carr, M. H. (Editor); Saunders, R. S.; Strom, R. G.; Wilhelms, D. E.

1984-01-01

The geologic history of the terrestrial planets is outlined in light of recent exploration and the revolution in geologic thinking. Among the topics considered are planet formation; planetary craters, basins, and general surface characteristics; tectonics; planetary atmospheres; and volcanism.

Rovers for intelligent, agile traverse of challenging terrain

NASA Technical Reports Server (NTRS)

Schenker, P.; Huntsberger, T.; Pirjanian, P.; Dubowsky, S.; Iagnemma, K.; Sujan, V.

2003-01-01

Planetary surface mobility has to date been limited to benign locations. If rover systems could be developed for more challenging terrain, e.g., sloped and irregularly feathered areas, then planetary science opportunities would be greatly expanded.

Planetary Geochemistry Techniques: Probing In-Situ with Neutron and Gamma Rays (PING) Instrument

NASA Technical Reports Server (NTRS)

Parsons, A.; Bodnarik, J.; Burger, D.; Evans, L.; Floyd, S.; Lin, L.; McClanahan, T.; Nankung, M.; Nowicki, S.; Schweitzer, J.;

A Team Approach to the Development of Gamma Ray and x Ray Remote Sensing and in Situ Spectroscopy for Planetary Exploration Missions

NASA Technical Reports Server (NTRS)

Trombka, J. I.; Floyd, S.; Ruitberg, A.; Evans, L.; Starr, R.; Metzger, A.; Reedy, R.; Drake, D.; Moss, C.; Edwards, B.

1993-01-01

An important part of the investigation of planetary origin and evolution is the determination of the surface composition of planets, comets, and asteroids. Measurements of discrete line X-ray and gamma ray emissions from condensed bodies in space can be used to obtain both qualitative and quantitative elemental composition information. The Planetary Instrumentation Definition and Development Program (PIDDP) X-Ray/Gamma Ray Team has been established to develop remote sensing and in situ technologies for future planetary exploration missions.

Spatial Query for Planetary Data

NASA Technical Reports Server (NTRS)

Shams, Khawaja S.; Crockett, Thomas M.; Powell, Mark W.; Joswig, Joseph C.; Fox, Jason M.

2011-01-01

Science investigators need to quickly and effectively assess past observations of specific locations on a planetary surface. This innovation involves a location-based search technology that was adapted and applied to planetary science data to support a spatial query capability for mission operations software. High-performance location-based searching requires the use of spatial data structures for database organization. Spatial data structures are designed to organize datasets based on their coordinates in a way that is optimized for location-based retrieval. The particular spatial data structure that was adapted for planetary data search is the R+ tree.

Workshop on Early Crustal Genesis: Implications from Earth

NASA Technical Reports Server (NTRS)

Phinney, W. C. (Compiler)

1981-01-01

Ways to foster increased study of the early evolution of the Earth, considering the planet as a whole, were explored and recommendations were made to NASA with the intent of exploring optimal ways for integrating Archean studies with problems of planetary evolution. Major themes addressed include: (1) Archean contribution to constraints for modeling planetary evolution; (2) Archean surface conditions and processes as clues to early planetary history; and (3) Archean evidence for physical, chemical and isotopic transfer processes in early planetary crusts. Ten early crustal evolution problems are outlined.

Reports of Planetary Geology and Geophysics Program, 1984

NASA Technical Reports Server (NTRS)

Holt, H. E. (Compiler); Watters, T. R. (Compiler)

1985-01-01

Topics include outer planets and satellites; asteroids and comets; Venus; lunar origin and solar dynamics; cratering process; planetary interiors, petrology, and geochemistry; volcanic processes; aeolian processes and landforms; fluvial processes; geomorphology; periglacial and permafrost processes; remote sensing and regolith studies; structure, tectonics, and stratigraphy; geological mapping, cartography, and geodesy; and radar applications.

Investigations of planetary ring phenomena

NASA Technical Reports Server (NTRS)

Burns, Joseph A.

1987-01-01

Faint planetary rings, their dynamical behavior and physical properties, were the main focus of the research efforts. The motion of weakly-charged dust through the gravitational and magnetic fields of Jupiter were examined. Several topics concerning features of Saturn's rings were addressed. The origin and fate of the Uranian ring dust is presently being studied.

Predicting Mercury's precession using simple relativistic Newtonian dynamics

NASA Astrophysics Data System (ADS)

Friedman, Y.; Steiner, J. M.

2016-03-01

We present a new simple relativistic model for planetary motion describing accurately the anomalous precession of the perihelion of Mercury and its origin. The model is based on transforming Newton's classical equation for planetary motion from absolute to real spacetime influenced by the gravitational potential and introducing the concept of influenced direction.

A Comparative Examination of Plasmoid Structure and Dynamics at Mercury, Earth, Jupiter, and Saturn

NASA Technical Reports Server (NTRS)

Slavin, James A.

2010-01-01

The circulation of plasma and magnetic flux within planetary magnetospheres is governed by the solar wind-driven Dungey and planetary rotation-driven cycles. The Dungey cycle is responsible for all circulation at Mercury and Earth. Jupiter and Saturn's magnetospheres are dominated by the Vasyliunas cycle, but there is evidence for a small Dungey cycle contribution driven by the solar wind. Despite these fundamental differences, all well-observed magnetospheres eject relatively large parcels of the hot plasma, termed plasmoids, down their tails at high speeds. Plasmoids escape from the restraining force of the planetary magnetic field through reconnection in the equatorial current sheet separating the northern and southern hemispheres of the magnetosphere. The reconnection process gives the magnetic field threading plasmoids a helical or flux rope-type topology. In the Dungey cycle reconnection also provides the primary tailward force that accelerates plasmoids to high speeds as they move down the tail. We compare the available observations of plasmoids at Mercury, Earth, Jupiter, and Saturn for the purpose of determining the relative role of plasmoids and the reconnection process in the dynamics these planetary magnetic tails.

Planetary System Physics

NASA Technical Reports Server (NTRS)

Peale, S. J.

2002-01-01

Contents include a summary of publications followed by their abstracts titeled: 1. On microlensing rates and optical depth toward the Galactic center. 2. Newly discovered brown dwarfs not seen in microlensing timescale frequency distribution? 3. Origin and evolution of the natural satellites. 4. Probing the structure of the galaxy with microlensing. 5. Tides, Encyclopedia of Astronomy and Astrophysics. 6. The Puzzle of the Titan-Hyperion 4:3 Orbital Resonance. 7. On the Validity of the Coagulation Equation and the Nature of Runaway Growth. 8. Making Hyperion. 9. The MESSENGER mission to Mercury: Scientific objectives and implementation. 10. A Survey of Numerical Solutions to the Coagulation. 11. Probability of detecting a planetary companion during a microlensing event. 12. Dynamics and origin of the 2:l orbital resonances of the GJ876 planets. 13. Planetary Interior Structure Revealed by Spin Dynamics. 14. A primordial origin of the Laplace relation among the Galilean Satellites. 15. A procedure for determining the nature of Mercury's core. 16. Secular evolution of hierarchical planetary systems. 17. Tidally induced volcanism. 18. Extrasolar planets and mean motion resonances. 19. Comparison of a ground-based microlensing search for planets with a search from space.

The correlation of VLF propagation variations with atmospheric planetary-scale waves

NASA Technical Reports Server (NTRS)

Cavalieri, D. J.; Deland, R. J.; Potemra, T. A.; Gavin, R. F.

1973-01-01

Variations in the received daytime phase of long distance, cesium-controlled, VLF transmission were compared to the height variations of the 10-mb isobaric surface during the first three months of 1965 and 1969. The VLF phase values are also compared to height variations of constant electron densities in the E-region and to variations of f-min which have been shown to be well correlated with planetary-scale variations in the stratosphere by Deland and Cavalieri (1973). The VLF phase variations show good correlation with these previous ionospheric measurements and with the 10-mb surfaces. The planetary scale waves in the stratosphere are shown to be travelling on the average eastward in 1965 and westward in 1969. These correlations are interpreted as due to the propagation of travelling planetary scale waves with westward tilted wave fronts. Upward energy transport due to the vertical structure of those waves is also discussed. These correlations provide further evidence for the coupling between the lower ionosphere at about 70 km altitude (the daytime VLF reflection height and the stratosphere, and they demonstrate the importance of planetary wave phenomena to VLF propagation.

The Moon: Keystone to Understanding Planetary Geological Processes and History

NASA Technical Reports Server (NTRS)

2002-01-01

Extensive and intensive exploration of the Earth's Moon by astronauts and an international array of automated spacecraft has provided an unequaled data set that has provided deep insight into geology, geochemistry, mineralogy, petrology, chronology, geophysics and internal structure. This level of insight is unequaled except for Earth. Analysis of these data sets over the last 35 years has proven fundamental to understanding planetary surface processes and evolution, and is essential to linking surface processes with internal and thermal evolution. Much of the understanding that we presently have of other terrestrial planets and outer planet satellites derives from the foundation of these data. On the basis of these data, the Moon is a laboratory for understanding of planetary processes and a keystone for providing evolutionary perspective. Important comparative planetology issues being addressed by lunar studies include impact cratering, magmatic activity and tectonism. Future planetary exploration plans should keep in mind the importance of further lunar exploration in continuing to build solid underpinnings in this keystone to planetary evolution. Examples of these insights and applications to other planets are cited.

Planetary Magnetic Fields: Planetary Interiors and Habitability W. M. Keck Institute for Space Studies Report

NASA Astrophysics Data System (ADS)

Lazio, T. Joseph; Shkolnik, Evgenya; Hallinan, Gregg

2017-05-01

The W. M. Keck Institute for Space Studies (KISS) sponsored the "Planetary Magnetic Fields: Planetary Interiors and Habitability" study to review the state of knowledge of extrasolar planetary magnetic fields and the prospects for their detection.There were multiple motivations for this Study. Planetary-scale magnetic fields are a window to a planet's interior and provide shielding of the planet's atmosphere. The Earth, Mercury, Ganymede, and the giant planets of the solar system all contain internal dynamo currents that generate planetary-scale magnetic fields. In turn, these internal dynamo currents arise from differential rotation, convection, compositional dynamics, or a combination of these in objects' interiors. If coupled to an energy source, such as the incident kinetic or magnetic energy from the solar wind or an orbiting satellite, a planet's magnetic field can produce intense electron cyclotron masers in its magnetic polar regions. The most well known example of this process in the solar system is the Jovian decametric emission, but all of the giant planets and the Earth contain similar electron cyclotron masers within their magnetospheres. Extrapolated to extrasolar planets, the remote detection of the magnetic field of an extrasolar planet would provide a means of obtaining constraints on the thermal state, composition, and dynamics of its interior--all of which will be difficult to determine by other means--as well as improved understanding of the basic planetary dynamo process.We review the findings from the Study, including potential mission concepts that emerged and recent developments toward one of the mission concepts, a space-based radio wavelength array. There was an identification of that radio wavelength observations would likely be key to making significant progress in this field.We acknowledge ideas and advice from the participants in the "Planetary Magnetic Fields: Planetary Interiors and Habitability" study organized by the W. M. Keck Institute for Space Studies. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Validating early stellar encounters as the cause of dynamically hot planetary systems

NASA Astrophysics Data System (ADS)

Kalas, Paul

2017-08-01

One of the key questions concerning exoplanetary systems is why some are dynamically cold, such as TRAPPIST-1, whereas others are dynamically hot, with highly eccentric planets and/or perturbed debris disks. Dynamical theory describes a variety of plausible mechanisms, but few can be empirically tested since the critical dynamical evolution that sets the final planetary architecture is short-lived. One rare system available for testing dynamical upheaval scenarios is the 400 Myr-old Fomalhaut system. In Cycle 22 we coronagraphically studied Fomalhaut C, which is a wide M-dwarf companion to Fomalhaut A, in order to test our prediction that the unresolved, Herschel-detected debris disk around Fomalhaut C may be highly perturbed because of a recent close interaction with Fomalhaut A. Using HST/STIS we discovered a highly asymmetric feature extending northward of Fomalhaut C by 3 that resembles our model of a dynamically hot disk. However, it may be a background galaxy and the definitive test of its physical relationship to Fomalhaut C is to demonstrate common proper motion. Using Keck adaptive optics follow-up observations in J band, we did not detect the feature, and hence follow-up HST observations are the only way to test for common proper motion. Here we request a very small program to revisit Fomalhaut C with STIS in order to validate the initial discovery as a debris disk (1 proper motion between HST epochs). The astrophysical significance is demonstrating that the Fomalhaut system is a valuable case for studying dynamical upheavals via stellar encounters that are inferred to occur in the evolution of many other planetary systems.

The Arctic Vortex in March 2011: A Dynamical Perspective

NASA Technical Reports Server (NTRS)

Hurwitz, Margaret M.; Newman, Paul A.; Garfinkel,Chaim I.

2011-01-01

Despite the record ozone loss observed in March 2011, dynamical conditions in the Arctic stratosphere were unusual but not unprecedented. Weak planetary wave driving in February preceded cold anomalies in t he polar lower stratosphere in March and a relatively late breakup of the Arctic vortex in April. La Nina conditions and the westerly phas e of the quasi-biennial oscillation (QBO) were observed in March 201 1. Though these conditions are generally associated with a stronger vortex in mid-winter, the respective cold anomalies do not persist t hrough March. Therefore, the La Nina and QBO-westerly conditions cannot explain the observed cold anomalies in March 2011. In contrast, po sitive sea surface temperature anomalies in the North Pacific may ha ve contributed to the unusually weak tropospheric wave driving and s trong Arctic vortex in late winter 2011.

Low-latency teleoperations, planetary protection, and astrobiology

NASA Astrophysics Data System (ADS)

Lupisella, Mark L.

2018-07-01

The remote operation of an asset with time-delays short enough to allow for `real-time' or near real-time control - often referred to as low-latency teleoperations (LLT) - has important potential to address planetary protection concerns and to enhance astrobiology exploration. Not only can LLT assist with the search for extraterrestrial life and help mitigate planetary protection concerns as required by international treaty, but it can also aid in the real-time exploration of hazardous areas, robotically manipulate samples in real-time, and engage in precise measurements and experiments without the presence of crew in the immediate area. Furthermore, LLT can be particularly effective for studying `Special Regions' - areas of astrobiological interest that might be adversely affected by forward contamination from humans or spacecraft contaminants during activities on Mars. LLT can also aid human exploration by addressing concerns about backward contamination that could impact mission details for returning Martian samples and crew back to Earth.This paper provides an overview of LLT operational considerations and findings from recent NASA analyses and workshops related to planetary protection and human missions beyond Earth orbit. The paper focuses primarily on three interrelated areas of Mars operations that are particularly relevant to the planetary protection and the search for life: Mars orbit-to-surface LLT activities; Crew-on-surface and drilling LLT; and Mars surface science laboratory LLT. The paper also discusses several additional mission implementation considerations and closes with information on key knowledge gaps identified as necessary for the advance of LLT for planetary protection and astrobiology purposes on future human missions to Mars.

Path planning for planetary rover using extended elevation map

NASA Technical Reports Server (NTRS)

Nakatani, Ichiro; Kubota, Takashi; Yoshimitsu, Tetsuo

1994-01-01

This paper describes a path planning method for planetary rovers to search for paths on planetary surfaces. The planetary rover is required to travel safely over a long distance for many days over unfamiliar terrain. Hence it is very important how planetary rovers process sensory information in order to understand the planetary environment and to make decisions based on that information. As a new data structure for informational mapping, an extended elevation map (EEM) has been introduced, which includes the effect of the size of the rover. The proposed path planning can be conducted in such a way as if the rover were a point while the size of the rover is automatically taken into account. The validity of the proposed methods is verified by computer simulations.

Requirements for maintaining cryogenic propellants during planetary surface stays

NASA Technical Reports Server (NTRS)

Riccio, Joseph R.; Schoenberg, Richard J.

1991-01-01

Potential impacts on the planetary surface system infrastructure resulting from the use of liquid hydrogen and oxygen propellants for a stage and half lander are discussed. Particular attention is given to techniques which can be incorporated into the surface infrastructure and/or the vehicle to minimize the impact resulting from the use of these cryogens. Methods offered for reducing cryogenic propellant boiloff include modification of the lander to accommodate boiloff, incorporation of passive thermal control devices to the lander, addition of active propellant management, and use of alternative propellants.

Planetary surface reactor shielding using indigenous materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houts, Michael G.; Poston, David I.; Trellue, Holly R.

The exploration and development of Mars will require abundant surface power. Nuclear reactors are a low-cost, low-mass means of providing that power. A significant fraction of the nuclear power system mass is radiation shielding necessary for protecting humans and/or equipment from radiation emitted by the reactor. For planetary surface missions, it may be desirable to provide some or all of the required shielding from indigenous materials. This paper examines shielding options that utilize either purely indigenous materials or a combination of indigenous and nonindigenous materials. {copyright} {ital 1999 American Institute of Physics.}

On-Orbit Planetary Science Laboratories for Simulating Surface Conditions of Planets and Small Bodies

NASA Astrophysics Data System (ADS)

Thangavelautham, J.; Asphaug, E.; Schwartz, S.

2017-02-01

Our work has identified the use of on-orbit centrifuge science laboratories as a key enabler towards low-cost, fast-track physical simulation of off-world environments for future planetary science missions.

Physical studies of the planetary rings

NASA Technical Reports Server (NTRS)

Ip, W.-H.

1980-01-01

In this review paper, the physical properties of the Saturnian and Uranian rings as derived from ground-based observations are first discussed. Focus is then shifted to the study of the orbital dynamics of the ring particles. Numerical simulations of the evolutionary history of a system of colliding particles in differential rotation together with theoretical modeling of the inelastic collision processes are surveyed. In anticipation of the information returned from in situ measurements by space probes, interactions of the planetary rings with the interplanetary meteoroids and planetary magnetospheres are briefly considered. Finally, models of planetary ring origin are examined. In this connection, some recent work on the satellite resonant perturbation effects on the ring structure are also touched upon.

My chaotic trajectory: A brief (personalized) history of solar-system dynamics.

NASA Astrophysics Data System (ADS)

Burns, Joseph A.

2014-05-01

I will use this opportunity to recall my professional career. Like many, I was drawn into the space program during the mid-60s and early 70s when the solar system’s true nature was being revealed. Previously, dynamical astronomy discussed the short-term, predictable motions of point masses; simultaneously, small objects (e.g., satellites, asteroids, dust) were thought boring rather than dynamically rich. Many of today’s most active research subjects were unknown: TNOs, planetary rings, exoplanets and debris disks. The continuing stream of startling findings by spacecraft, ground-based surveys and numerical simulations forced a renaissance in celestial mechanics, incorporating new dynamical paradigms and additional physics (e.g., energy loss, catastrophic events, radiation forces). My interests evolved as the space program expanded outward: dust, asteroids, natural satellites, rings; rotations, orbital evolution, origins. Fortunately for me, in the early days, elementary models with simple solutions were often adequate to gain a first-order explanation of many puzzles. One could be a generalist, always learning new things.My choice of research subjects was influenced greatly by: i) Cornell colleagues involved in space missions who shared results: the surprising diversity of planetary satellites, the unanticipated orbital and rotational dynamics of asteroids, the chaotic histories of solar system bodies, the non-intuitive behavior of dust and planetary rings, irregular satellites. ii) Teaching introductory courses in applied math, dynamics and planetary science encouraged understandable models. iii) The stimulation of new ideas owing to service at Icarus and on space policy forums. iv) Most importantly, excellent students and colleagues who pushed me into new research directions, and who then stimulated and educated me about those topics.If time allows, I will describe some of today’s puzzles for me and point out similarities between the past development in our understanding of the solar system’s operation and the contemporary quest to figure out exoplanet systems.

Intelligence for Human-Assistant Planetary Surface Robots

NASA Technical Reports Server (NTRS)

Hirsh, Robert; Graham, Jeffrey; Tyree, Kimberly; Sierhuis, Maarten; Clancey, William J.

2006-01-01

The central premise in developing effective human-assistant planetary surface robots is that robotic intelligence is needed. The exact type, method, forms and/or quantity of intelligence is an open issue being explored on the ERA project, as well as others. In addition to field testing, theoretical research into this area can help provide answers on how to design future planetary robots. Many fundamental intelligence issues are discussed by Murphy [2], including (a) learning, (b) planning, (c) reasoning, (d) problem solving, (e) knowledge representation, and (f) computer vision (stereo tracking, gestures). The new "social interaction/emotional" form of intelligence that some consider critical to Human Robot Interaction (HRI) can also be addressed by human assistant planetary surface robots, as human operators feel more comfortable working with a robot when the robot is verbally (or even physically) interacting with them. Arkin [3] and Murphy are both proponents of the hybrid deliberative-reasoning/reactive-execution architecture as the best general architecture for fully realizing robot potential, and the robots discussed herein implement a design continuously progressing toward this hybrid philosophy. The remainder of this chapter will describe the challenges associated with robotic assistance to astronauts, our general research approach, the intelligence incorporated into our robots, and the results and lessons learned from over six years of testing human-assistant mobile robots in field settings relevant to planetary exploration. The chapter concludes with some key considerations for future work in this area.

SPEX: the Spectropolarimeter for Planetary Exploration

NASA Astrophysics Data System (ADS)

Rietjens, J. H. H.; Snik, F.; Stam, D. M.; Smit, J. M.; van Harten, G.; Keller, C. U.; Verlaan, A. L.; Laan, E. C.; ter Horst, R.; Navarro, R.; Wielinga, K.; Moon, S. G.; Voors, R.

2017-11-01

We present SPEX, the Spectropolarimeter for Planetary Exploration, which is a compact, robust and low-mass spectropolarimeter designed to operate from an orbiting or in situ platform. Its purpose is to simultaneously measure the radiance and the state (degree and angle) of linear polarization of sunlight that has been scattered in a planetary atmosphere and/or reflected by a planetary surface with high accuracy. The degree of linear polarization is extremely sensitive to the microphysical properties of atmospheric or surface particles (such as size, shape, and composition), and to the vertical distribution of atmospheric particles, such as cloud top altitudes. Measurements as those performed by SPEX are therefore crucial and often the only tool for disentangling the many parameters that describe planetary atmospheres and surfaces. SPEX uses a novel, passive method for its radiance and polarization observations that is based on a carefully selected combination of polarization optics. This method, called spectral modulation, is the modulation of the radiance spectrum in both amplitude and phase by the degree and angle of linear polarization, respectively. The polarization optics consists of an achromatic quarter-wave retarder, an athermal multiple-order retarder, and a polarizing beam splitter. We will show first results obtained with the recently developed prototype of the SPEX instrument, and present a performance analysis based on a dedicated vector radiative transport model together with a recently developed SPEX instrument simulator.

Reflection spectra of solids of planetary interest

NASA Technical Reports Server (NTRS)

Sill, G. T.

1973-01-01

The spectra of solids are reproduced which might be found on the surfaces of planetary bodies or as solid condensates in the upper planetary atmosphere. Among these are spectra of various iron compounds of interest in the study of the clouds of Venus. Other spectra are included of various sulfides, some at low temperature, relevant to the planet Jupiter. Meteorite and coal abstracts are also included, to illustrate dark carbon compounds.

Reflection spectra of solids of planetary interest

NASA Technical Reports Server (NTRS)

Sill, G. T.; Carm, O.

1973-01-01

This paper reproduces the spectra of solids which might be found on the surfaces of planetary bodies or as solid condensates in the upper planetary atmosphere. Among these are spectra of various iron compounds of interest in the study of the clouds of Venus. Other spectra (some at low temperature) are included for various sulfides relevant to the planet Jupiter. Meteorite and coal spectra are also included to illustrate dark carbon compounds.

Surface Telerobotics: Development and Testing of a Crew Controlled Planetary Rover System

NASA Technical Reports Server (NTRS)

Fong, Terry; Bualat, Maria; Allan, Mark B; Bouyssounouse, Xavier; Cohen, Tamar

2013-01-01

During Summer 2013, we conducted a series of tests to examine how astronauts in the In- ternational Space Station (ISS) can remotely operate a planetary rover. The tests simulated portions of a proposed mission, in which an astronaut in lunar orbit remotely operates a planetary rover to deploy a radio telescope on the lunar farside. In this paper, we present the design, implementation, and preliminary test results.

Inventory of File nam.t00z.smartpr00.tm00.grib2

Science.gov Websites

layer WDIR analysis Wind Direction (from which blowing) [degtrue] 016 planetary boundary layer WIND analysis Wind Speed [m/s] 017 planetary boundary layer RH analysis Relative Humidity [%] 018 planetary boundary layer DIST analysis Geometric Height [m] 019 surface 4LFTX analysis Best (4 layer) Lifted Index [K

Inventory of File nam.t00z.smartak00.tm00.grib2

Science.gov Websites

layer WDIR analysis Wind Direction (from which blowing) [degtrue] 016 planetary boundary layer WIND analysis Wind Speed [m/s] 017 planetary boundary layer RH analysis Relative Humidity [%] 018 planetary boundary layer DIST analysis Geometric Height [m] 019 surface 4LFTX analysis Best (4 layer) Lifted Index [K

Inventory of File gfs.t06z.smartguam00.tm00.grib2

Science.gov Websites

boundary layer WDIR analysis Wind Direction (from which blowing) [degtrue] 013 planetary boundary layer WIND analysis Wind Speed [m/s] 014 planetary boundary layer RH analysis Relative Humidity [%] 015 planetary boundary layer DIST analysis Geometric Height [m] 016 surface 4LFTX analysis Best (4 layer) Lifted

Inventory of File nam.t00z.smarthi00.tm00.grib2

Science.gov Websites

layer WDIR analysis Wind Direction (from which blowing) [degtrue] 016 planetary boundary layer WIND analysis Wind Speed [m/s] 017 planetary boundary layer RH analysis Relative Humidity [%] 018 planetary boundary layer DIST analysis Geometric Height [m] 019 surface 4LFTX analysis Best (4 layer) Lifted Index [K

In Situ Chemical Composition Measurements of Planetary Surfaces with a Laser Ablation Mass Spectrometer

NASA Astrophysics Data System (ADS)

Brigitte Neuland, Maike; Riedo, Andreas; Meyer, Stefan; Mezger, Klaus; Tulej, Marek; Wurz, Peter

2013-04-01

The knowledge of the chemical composition of moons, comets, asteroids or other planetary bodies is of particular importance for the investigation of the origin and evolution of the Solar System. For cosmochemistry, the elemental and isotopic composition of the surface material is essential information to investigate origin, differentiation and evolution processes of the body and therefore the history of our Solar System [1]. We show that the use of laser-based mass spectrometers is essential in such research because of their high sensitivity in the ppm range and their capability for quantitative elemental and isotopic analysis. A miniaturised Laser Ablation Time-of-Flight Mass Spectrometer (LMS) was developed in our group to study the elemental composition of solid samples [2]. The instrument's small size and light weight make it suitable for an application on a space mission to determine the elemental composition of a planetary surface for example [3]. Meteorites offer the excellent possibility to study extraterrestrial material in the laboratory. To demonstrate the sensitivity and functionality of the LMS instrument, a sample of the Allende meteorite has been investigated with a high spatial resolution. The LMS measurements allowed investigations of the elemental abundances in the Allende meteorite and detailed studies of the mineralogy and volatility [4]. These approaches can be of considerable interest for in situ investigation of grains and inhomogeneous materials with high sensitivity on a planetary surface. [1] Wurz, P., Whitby, J., Managadze, G., 2009, Laser Mass Spectrometry in Planetary Science, AIP Conf. Proc. CP1144, 70-75. [2] Tulej, M., Riedo, A., Iakovleva, M., Wurz, P., 2012, Int. J. Spec., On Applicability of a Miniaturized Laser Ablation Time of Flight Mass Spectrometer for Trace Element Measurements, article ID 234949. [3] Riedo, A., Bieler, A., Neuland, M., Tulej, M., Wurz, P., 2012, Performance evaluation of a miniature laser ablation time-of-flight mass spectrometer designed for in-situ investigations in planetary space research, J. Mass Spectrom., in press. [4] Neuland, M.B., Meyer, S., Mezger, K., Riedo, A., Tulej, M., Wurz, P., Probing the Allende meteorite with a miniature Laser-Ablation Mass Analyser for space application, Planetary and Space Science, Special Issue: Terrestrial Planets II, submitted

Unravelling thermal emissivity spectra of the main minerals on Mercury's surface by comparison with ab initio calculated IR-HT vibrational frequencies

NASA Astrophysics Data System (ADS)

Stangarone, C.; Helbert, J.; Tribaudino, M.; Maturilli, A.; D'Amore, M.; Ferrari, S.; Prencipe, M.

2015-12-01

Spectral signatures of minerals are intimately related to the crystal structure; therefore they may represent a remote sensing model to determine surface composition of planetary bodies, by analysing their spectral reflectance and emission. However, one of the most critical point is data interpretation considering planetary surfaces, as Mercury, where the changes in spectral characteristics are induced by the high temperatures conditions (Helbert et al., 2013). The aim of this work is to interpret the experimental thermal emissivity spectra with an innovative approach: simulating IR spectra of the main mineral families that compose the surface of Mercury, focusing on pyroxenes (Sprague et al., 2002), both at room and high temperature, exploiting the accuracy of ab initio quantum mechanical calculations, by means of CRYSTAL14 code (Dovesi et al., 2014). The simulations will be compared with experimental emissivity measurements of planetary analogue samples at temperature up to 1000K, performed at Planetary Emissivity Laboratory (PEL) by Institute of Planetary Research (DLR, Berlin). Results will be useful to create a theoretical background to interpret HT-IR emissivity spectra that will be collected by the Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS), a spectrometer developed by DLR that will be on board of the ESA BepiColombo Mercury Planetary Orbiter (MPO) scheduled for 2017. The goal is to point out the most interesting spectral features for a geological mapping of Mercury and other rocky bodies, simulating the environmental conditions of the inner planets of Solar System. Dovesi R., Saunders V. R., Roetti C., Orlando R., Zicovich-Wilson C. M., Pascale F., Civalleri B., Doll K., Harrison N. M., Bush I. J., D'Arco P., Llunell M., Causà M. & Noël Y. 2014. CRYSTAL14 User's Manual, University of Torino. Sprague, A. L., Emery, J. P., Donaldson, K. L., Russell, R. W., Lynch, D. K., & Mazuk, A. L. (2002). Mercury: Mid-infrared (3-13.5 μm) observations show heterogeneous composition, presence of intermediate and basic soil types, and pyroxene. Meteoritics & Planetary Science, 37(9), 1255-1268.

Intelligent excavator control system for lunar mining system

NASA Astrophysics Data System (ADS)

Lever, Paul J. A.; Wang, Fei-Yue

1995-01-01

A major benefit of utilizing local planetary resources is that it reduces the need and cost of lifting materials from the Earth's surface into Earth orbit. The location of the moon makes it an ideal site for harvesting the materials needed to assist space activities. Here, lunar excavation will take place in the dynamic unstructured lunar environment, in which conditions are highly variable and unpredictable. Autonomous mining (excavation) machines are necessary to remove human operators from this hazardous environment. This machine must use a control system structure that can identify, plan, sense, and control real-time dynamic machine movements in the lunar environment. The solution is a vision-based hierarchical control structure. However, excavation tasks require force/torque sensor feedback to control the excavation tool after it has penetrated the surface. A fuzzy logic controller (FLC) is used to interpret the forces and torques gathered from a bucket mounted force/torque sensor during excavation. Experimental results from several excavation tests using the FLC are presented here. These results represent the first step toward an integrated sensing and control system for a lunar mining system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coulter, R.L.; Klazura, J.; Lesht, B.M.

The Argonne Boundary Layer Experiments (ABLE) facility, located in south central Kansas, east of Wichita, is devoted primarily to investigations of and within the planetary boundary layer (PBL), including the dynamics of the mixed layer during both day and night; effects of varying land use and landform; the interactive role of precipitation, runoff, and soil moisture; storm development; and energy budgets on scales of 10 to 100 km. With an expected lifetime of 10--15 years, the facility is well situated to observe the effects of gradual urbanization on PBL dynamics and structure as the Wichita urban area expands to themore » east and several small municipalities located within the study area expand. Combining the continuous measurements of ABLE with (1) ancillary continuous measurements of, for example, the Atmospheric Radiation Measurement (ARM) program and the Global Energy Water Cycle Experiment (GEWEX) programs and with (2) shorter, more intensive studies within ABLE, such as the Cooperative Atmosphere Surface Exchange Studies (CASES) Program, allows hypothesized features of urbanization, including heat island effects, precipitation enhancement, and modification of the surface energy budget partitioning, to be studied.« less

Camera Image Transformation and Registration for Safe Spacecraft Landing and Hazard Avoidance

NASA Technical Reports Server (NTRS)

Jones, Brandon M.

2005-01-01

Inherent geographical hazards of Martian terrain may impede a safe landing for science exploration spacecraft. Surface visualization software for hazard detection and avoidance may accordingly be applied in vehicles such as the Mars Exploration Rover (MER) to induce an autonomous and intelligent descent upon entering the planetary atmosphere. The focus of this project is to develop an image transformation algorithm for coordinate system matching between consecutive frames of terrain imagery taken throughout descent. The methodology involves integrating computer vision and graphics techniques, including affine transformation and projective geometry of an object, with the intrinsic parameters governing spacecraft dynamic motion and camera calibration.

Theory of Tumbling Bodies Entering Planetary Atmospheres with Application to Probe Vehicles and the Australian Tektites

NASA Technical Reports Server (NTRS)

Tobak, Murray; Peterson, Victor L.

1964-01-01

The tumbling motion of aerodynamically stable bodies entering planetary atmospheres is analyzed considering that the tumbling, its arrest, and the subsequent oscillatory motion are governed by the equation for the fifth Painleve' transcendent. Results based on the asymptotic behavior of the transcendent are applied to study (1) the oscillatory behavior of planetary probe vehicles in relation to aerodynamic heating and loads and (2) the dynamic behavior of the Australian tektites on entering the Earth's atmosphere, under the hypothesis that their origin was the Moon.

Conceptual design of a multiple cable crane for planetary surface operations

NASA Technical Reports Server (NTRS)

Mikulas, Martin M., Jr.; Yang, Li-Farn

1991-01-01

A preliminary design study is presented of a mobile crane suitable for conducting remote, automated construction operations on planetary surfaces. A cursory study was made of earth based mobile cranes and the needs for major improvements were identified. Current earth based cranes have a single cable supporting the payload, and precision positioning is accomplished by the use of construction workers controlling the payload by the use of tethers. For remote, autonomous operations on planetary surfaces it will be necessary to perform the precision operations without the use of humans. To accomplish this the payload must be stabilized relative to the crane. One approach for accomplishing this is to suspend the payload on multiple cable. A 3-cable suspension system crane concept is discussed. An analysis of the natural frequency of the system is presented which verifies the legitimacy of the concept.

High temperature crystal field spectra of transition metal-bearing minerals - Relevance to remote-sensed spectra of planetary surfaces

NASA Technical Reports Server (NTRS)

Parkin, K. M.; Burns, R. G.

1980-01-01

It is pointed out that transition metal ions in silicate minerals, glasses, and crystalline and amorphous oxyhydroxides and salts contribute to the visible-near infrared spectral profiles of planetary surfaces. Investigations are conducted to obtain spectral information which might be helpful in the interpretation of the remote-sensed spectra of planetary surfaces. A description is presented of the results of high temperature crystal field spectral measurements of a variety of heated minerals containing Cr(3+), Fe(3+), Fe(++), and Mn(++) ions in different coordination symmetries, taking into account a correlation of the temperature-induced variations with those previously observed for octahedrally coordinated Fe(++)-bearing silicates. The employed experimental methods are also discussed, giving attention to the preparation of the samples, the determination of the absorption spectra, electron microprobe analyses, and the curve fitting procedure.

Planetary gear profile modification design based on load sharing modelling

NASA Astrophysics Data System (ADS)

Iglesias, Miguel; Fernández Del Rincón, Alfonso; De-Juan, Ana Magdalena; Garcia, Pablo; Diez, Alberto; Viadero, Fernando

2015-07-01

In order to satisfy the increasing demand on high performance planetary transmissions, an important line of research is focused on the understanding of some of the underlying phenomena involved in this mechanical system. Through the development of models capable of reproduce the system behavior, research in this area contributes to improve gear transmission insight, helping developing better maintenance practices and more efficient design processes. A planetary gear model used for the design of profile modifications ratio based on the levelling of the load sharing ratio is presented. The gear profile geometry definition, following a vectorial approach that mimics the real cutting process of gears, is thoroughly described. Teeth undercutting and hypotrochoid definition are implicitly considered, and a procedure for the incorporation of a rounding arc at the tooth tip in order to deal with corner contacts is described. A procedure for the modeling of profile deviations is presented, which can be used for the introduction of both manufacturing errors and designed profile modifications. An easy and flexible implementation of the profile deviation within the planetary model is accomplished based on the geometric overlapping. The contact force calculation and dynamic implementation used in the model are also introduced, and parameters from a real transmission for agricultural applications are presented for the application example. A set of reliefs is designed based on the levelling of the load sharing ratio for the example transmission, and finally some other important dynamic factors of the transmission are analyzed to assess the changes in the dynamic behavior with respect to the non-modified case. Thus, the main innovative aspect of the proposed planetary transmission model is the capacity of providing a simulated load sharing ratio which serves as design variable for the calculation of the tooth profile modifications.

A Detailed Analysis of the HD 73526 2:1 Resonant Planetary System

NASA Astrophysics Data System (ADS)

Wittenmyer, Robert A.; Tan, Xianyu; Lee, Man Hoi; Horner, Jonathan; Tinney, C. G.; Butler, R. P.; Salter, G. S.; Carter, B. D.; Jones, H. R. A.; O'Toole, S. J.; Bailey, J.; Wright, D.; Crane, J. D.; Schectman, S. A.; Arriagada, P.; Thompson, I.; Minniti, D.; Diaz, M.

2014-01-01

We present six years of new radial velocity data from the Anglo-Australian and Magellan Telescopes on the HD 73526 2:1 resonant planetary system. We investigate both Keplerian and dynamical (interacting) fits to these data, yielding four possible configurations for the system. The new data now show that both resonance angles are librating, with amplitudes of 40° and 60°, respectively. We then perform long-term dynamical stability tests to differentiate these solutions, which only differ significantly in the masses of the planets. We show that while there is no clearly preferred system inclination, the dynamical fit with i = 90° provides the best combination of goodness-of-fit and long-term dynamical stability. This paper includes data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile.

Using Sandia's Z Machine and Density Functional Theory Simulations to Understand Planetary Materials

NASA Astrophysics Data System (ADS)

Root, Seth

2017-06-01

The use of Z, NIF, and Omega have produced many breakthrough results in high pressure physics. One area that has greatly benefited from these facilities is the planetary sciences. The high pressure behavior of planetary materials has implications for numerous geophysical and planetary processes. The continuing discovery of exosolar super-Earths demonstrates the need for accurate equation of state data to better inform our models of their interior structures. Planetary collision processes, such as the moon-forming giant impact, require understanding planetary materials over a wide-range of pressures and temperatures. Using Z, we examined the shock compression response of some common planetary materials: MgO, Mg2SiO4, and Fe2O3 (hematite). We compare the experimental shock compression measurements with density functional theory (DFT) based quantum molecular dynamics (QMD) simulations. The combination of experiment and theory provides clearer understanding of planetary materials properties at extreme conditions. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Simulation of large scale motions and small scale structures in planetary atmospheres and oceans: From laboratory to space experiments on ISS

NASA Astrophysics Data System (ADS)

Egbers, Christoph; Futterer, Birgit; Zaussinger, Florian; Harlander, Uwe

2014-05-01

Baroclinic waves are responsible for the transport of heat and momentum in the oceans, in the Earth's atmosphere as well as in other planetary atmospheres. The talk will give an overview on possibilities to simulate such large scale as well as co-existing small scale structures with the help of well defined laboratory experiments like the baroclinic wave tank (annulus experiment). The analogy between the Earth's atmosphere and the rotating cylindrical annulus experiment only driven by rotation and differential heating between polar and equatorial regions is obvious. From the Gulf stream single vortices seperate from time to time. The same dynamics and the co-existence of small and large scale structures and their separation can be also observed in laboratory experiments as in the rotating cylindrical annulus experiment. This experiment represents the mid latitude dynamics quite well and is part as a central reference experiment in the German-wide DFG priority research programme ("METSTRÖM", SPP 1276) yielding as a benchmark for lot of different numerical methods. On the other hand, those laboratory experiments in cylindrical geometry are limited due to the fact, that the surface and real interaction between polar and equatorial region and their different dynamics can not be really studied. Therefore, I demonstrate how to use the very successful Geoflow I and Geoflow II space experiment hardware on ISS with future modifications for simulations of small and large scale planetary atmospheric motion in spherical geometry with differential heating between inner and outer spheres as well as between the polar and equatorial regions. References: Harlander, U., Wenzel, J., Wang, Y., Alexandrov, K. & Egbers, Ch., 2012, Simultaneous PIV- and thermography measurements of partially blocked flow in a heated rotating annulus, Exp. in Fluids, 52 (4), 1077-1087 Futterer, B., Krebs, A., Plesa, A.-C., Zaussinger, F., Hollerbach, R., Breuer, D. & Egbers, Ch., 2013, Sheet-like and plume-like thermal flow in a spherical convection experiment performed under microgravity, J. Fluid Mech., vol. 75, p 647-683

Middle Atmosphere Dynamics with Gravity Wave Interactions in the Numerical Spectral Model: Tides and Planetary Waves

NASA Technical Reports Server (NTRS)

Mayr, Hans G.; Mengel, J. G.; Chan, K. L.; Huang, F. T.

2010-01-01

As Lindzen (1981) had shown, small-scale gravity waves (GW) produce the observed reversals of the zonal-mean circulation and temperature variations in the upper mesosphere. The waves also play a major role in modulating and amplifying the diurnal tides (DT) (e.g., Waltersheid, 1981; Fritts and Vincent, 1987; Fritts, 1995a). We summarize here the modeling studies with the mechanistic numerical spectral model (NSM) with Doppler spread parameterization for GW (Hines, 1997a, b), which describes in the middle atmosphere: (a) migrating and non-migrating DT, (b) planetary waves (PW), and (c) global-scale inertio gravity waves. Numerical experiments are discussed that illuminate the influence of GW filtering and nonlinear interactions between DT, PW, and zonal mean variations. Keywords: Theoretical modeling, Middle atmosphere dynamics, Gravity wave interactions, Migrating and non-migrating tides, Planetary waves, Global-scale inertio gravity waves.

The Influence of Planetary Mass on the Dynamical Lifetime of Planetary Systems

NASA Technical Reports Server (NTRS)

Lissauer, J. J.; Duncan, M. J.; Young, Richard E. (Technical Monitor)

1997-01-01

Recent numerical and analytic studies of planetary orbits have demonstrated the importance of resonances and chaos in destabilizing planetary systems. Newton's "clockwork" description of regular, predictable planetary orbits has been replaced by a view in which many systems can have long but finite lifetimes. This new knowledge has altered our perceptions of the later stages of planetary growth and of the stability of planetary systems. Stability criteria are inexact and time dependent. Most previous studies have focused on the effects in initial planetary orbits on the stability of the system. We are conducting an investigation which focuses on the dependence of stability criteria on planetary mass. Synthetic systems are created by increasing the masses of the planets in our Solar System or of the moons of a particular planet; these systems are then integrated until orbit crossing occurs. We have found that over some ranges, the time until orbit crossing varies to a good approximation as a power clothe factor by which the masses of the secondaries arc increased; some scatter occurs as a consequence of vie chaotic nature of orbital evolution. The slope of this power law varies substantially from system to system, and for moons it is mildly dependent on the inclusion of the planet's quadrupole moment in the gravitational potential.

Dynamic behavior of the mechanical systems from the structure of a hybrid automobile

NASA Astrophysics Data System (ADS)

Dinel, Popa; Irina, Tudor; Nicolae-Doru, Stănescu

2017-10-01

In introduction are presented solutions of planetary mechanisms that can be used in the construction of the hybrid automobiles where the thermal and electrical sources must be coupled. The systems have in their composition a planetary mechanism with two degrees of mobility at which are coupled a thermal engine, two revertible electrical machines, a gear transmission with four gears and a differential mechanism which transmits the motion at the driving wheels. For the study of the dynamical behavior, with numerical results, one designs such mechanisms, models the elements with solids in AutoCAD, and obtains the mechanical properties of the elements. Further on, we present and solve the equations of motion of a hybrid automotive for which one knows the dynamical parameters.

New test of general relativity - Measurement of de Sitter geodetic precession rate for lunar perigee

NASA Technical Reports Server (NTRS)

Bertotti, Bruno; Ciufolini, Ignazio; Bender, Peter L.

1987-01-01

According to general relativity, the calculated rate of motion of lunar perigee should include a contribution of 19.2 msec/yr from geodetic precession. It is shown that existing analyses of lunar-laser-ranging data confirm the general-relativistic rate for geodetic precession with respect to the planetary dynamical frame. In addition, the comparison of earth-rotation results from lunar laser ranging and from VLBI shows that the relative drift of the planetary dynamical frame and the extragalactic VLBI reference frame is small. The estimated accuracy is about 10 percent.

Low-Thrust Many-Revolution Trajectory Optimization via Differential Dynamic Programming and a Sundman Transformation

NASA Technical Reports Server (NTRS)

Aziz, Jonathan D.; Parker, Jeffrey S.; Scheeres, Daniel J.; Englander, Jacob A.

2017-01-01

Low-thrust trajectories about planetary bodies characteristically span a high count of orbital revolutions. Directing the thrust vector over many revolutions presents a challenging optimization problem for any conventional strategy. This paper demonstrates the tractability of low-thrust trajectory optimization about planetary bodies by applying a Sundman transformation to change the independent variable of the spacecraft equations of motion to the eccentric anomaly and performing the optimization with differential dynamic programming. Fuel-optimal geocentric transfers are shown in excess of 1000 revolutions while subject to Earths J2 perturbation and lunar gravity.

Sodium Ion Dynamics in the Magnetospheric Flanks of Mercury

NASA Astrophysics Data System (ADS)

Aizawa, Sae; Delcourt, Dominique; Terada, Naoki

2018-01-01

We investigate the transport of planetary ions in the magnetospheric flanks of Mercury. In situ measurements from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft show evidences of Kelvin-Helmholtz instability development in this region of space, due to the velocity shear between the downtail streaming flow of solar wind originating protons in the magnetosheath and the magnetospheric populations. Ions that originate from the planet exosphere and that gain access to this region of space may be transported across the magnetopause along meandering orbits. We examine this transport using single-particle trajectory calculations in model Magnetohydrodynamics simulations of the Kelvin-Helmholtz instability. We show that heavy ions of planetary origin such as Na+ may experience prominent nonadiabatic energization as they E × B drift across large-scale rolled up vortices. This energization is controlled by the characteristics of the electric field burst encountered along the particle path, the net energy change realized corresponding to the maximum E × B drift energy. This nonadiabatic energization also is responsible for prominent scattering of the particles toward the direction perpendicular to the magnetic field.

A numerical analysis of transient planetary waves and the vertical structure in a meso-strato-troposphere model, part 1.4A

NASA Technical Reports Server (NTRS)

Zhang, K. S.; Sasamori, T.

1984-01-01

The structure of unstable planetary waves is computed by a quasi-geostrophic model extending from the surface up to 80 km by means of eigenvalue-eigenfunction techniques in spherical coordinates. Three kinds of unstable modes of distinct phase speeds and vertical structures are identified in the winter climate state: (1) the deep Green mode with its maximum amplitude in the stratosphere; (2) the deep Charney mode with its maximum amplitude in the troposphere: and (3) the shallow Charney mode which is largely confined to the troposphere. Both the Green mode and the deep Charney mode are characterized by very slow phase speeds. They are mainly supported by upward wave energy fluxes, but the local baroclinic energy conversion within the stratosphere also contributes in supporting these deep modes. The mesosphere and the troposphere are dynamically independent in the summer season decoupled by the deep stratospheric easterly. The summer mesosphere supports the easterly unstable waves 1-4. Waves 3 and 4 are identified with the observed mesospheric 2-day wave and 1.7-day wave, respectively.

The planetary waves dynamics and interannual course of meteorological parameters of the high latitude stratosphere and mesosphere of the Northern and Southern Hemispheres during the 20th and 21st solar cycles and different phases of QBO

NASA Technical Reports Server (NTRS)

Kidiyarova, V. G.; Fomina, N. N.

1989-01-01

The part of energy of the planetary waves which enters the stratosphere depends on conditions of planetary wave generation and propagation through the tropopause, and the part of planetary wave energy which enters the mesosphere depends on conditions of planetary wave propagation through the stratopause. An attempt is made to estimate connections between extratropical middle atmosphere temperature long term variations and portions of energy of planetary waves which enter the mesosphere and stratosphere during winter seasons in Northern and Southern Hemispheres. Interannual variations of temperatures at the 30 km and 70 km levels are investigated for the central winter months of the period 1970 to 1986. This period includes the descending branch of the 20th solar cycle and the whole 21st cycle. Calculations are made on the basis of measurements at Heiss Island and Molodezhnaya.

The effects of Venus' thermal structure on buoyant magma ascent

NASA Technical Reports Server (NTRS)

Sakimoto, S. E. H.; Zuber, M. T.

1992-01-01

The recent Magellan images have revealed a broad spatial distribution of surface volcanism on Venus. Previous work in modeling the ascent of magma on both Venus and Earth has indicated that the planetary thermal structure significantly influences the magmatic cooling rates and thus the amount of magma that can be transported to the surface before solidification. In order to understand which aspects of the thermal structure have the greatest influence on the cooling of ascending magma, we have constructed magma cooling curves for both plutonic and crack buoyant ascent mechanisms, and evaluated the curves for variations in the planetary mantle temperature, thermal gradient curvature with depth, surface temperature gradient, and surface temperature. The planetary thermal structure is modeled as T/T(sub 0) = 1-tau(1-Z/Z(sub 0)(exp n), where T is the temperature, T(sub 0) is the source depth temperature, tau = 1-(T(sub s)/T(sub 0)) where T(sub s) is the planetary surface temperature, Z is the depth, Z(sub 0) is the source depth, and n is a constant that controls thermal gradient curvature with depth. The equation is used both for mathematical convenience and flexibility, as well as its fit to the thermal gradients predicted by the cooling half-space models. We assume a constant velocity buoyant ascent, body-averaged magma temperatures and properties, an initially crystal-free magma, and the same liquidus and solidus for both Venus and Earth.

Elpasolite Planetary Ice and Composition Spectrometer (EPICS): A Low-Resource Combined Gamma-Ray and Neutron Spectrometer for Planetary Science

NASA Astrophysics Data System (ADS)

Stonehill, L. C.; Coupland, D. D. S.; Dallmann, N. A.; Feldman, W. C.; Mesick, K.; Nowicki, S.; Storms, S.

2017-12-01

The Elpasolite Planetary Ice and Composition Spectrometer (EPICS) is an innovative, low-resource gamma-ray and neutron spectrometer for planetary science missions, enabled by new scintillator and photodetector technologies. Neutrons and gamma rays are produced by cosmic ray interactions with planetary bodies and their subsequent interactions with the near-surface materials produce distinctive energy spectra. Measuring these spectra reveals details of the planetary near-surface composition that are not accessible through any other phenomenology. EPICS will be the first planetary science instrument to fully integrate the neutron and gamma-ray spectrometers. This integration is enabled by the elpasolite family of scintillators that offer gamma-ray spectroscopy energy resolutions as good as 3% FWHM at 662 keV, thermal neutron sensitivity, and the ability to distinguish gamma-ray and neutron signals via pulse shape differences. This new detection technology will significantly reduce size, weight, and power (SWaP) while providing similar neutron performance and improved gamma energy resolution compared to previous scintillator instruments, and the ability to monitor the cosmic-ray source term. EPICS will detect scintillation light with silicon photomultipliers rather than traditional photomultiplier tubes, offering dramatic additional SWaP reduction. EPICS is under development with Los Alamos National Laboratory internal research and development funding. Here we report on the EPICS design, provide an update on the current status of the EPICS development, and discuss the expected sensitivity and performance of EPICS in several potential missions to airless bodies.

Sputtering from a Porous Material by Penetrating Ions

NASA Technical Reports Server (NTRS)

Rodriguez-Nieva, J. F.; Bringa, E. M.; Cassidy, T. A.; Johnson, R. E.; Caro, A.; Fama, M.; Loeffler, M.; Baragiola, R. A.; Farkas, D.

2012-01-01

Porous materials are ubiquitous in the universe and weathering of porous surfaces plays an important role in the evolution of planetary and interstellar materials. Sputtering of porous solids in particular can influence atmosphere formation, surface reflectivity, and the production of the ambient gas around materials in space, Several previous studies and models have shown a large reduction in the sputtering of a porous solid compared to the sputtering of the non-porous solid. Using molecular dynamics simulations we study the sputtering of a nanoporous solid with 55% of the solid density. We calculate the electronic sputtering induced by a fast, penetrating ion, using a thermal spike representation of the deposited energy. We find that sputtering for this porous solid is, surprisingly, the same as that for a full-density solid, even though the sticking coefficient is high.

Oort spike comets with large perihelion distances

NASA Astrophysics Data System (ADS)

Królikowska, Małgorzata; Dybczyński, Piotr A.

2017-12-01

The complete sample of large-perihelion nearly-parabolic comets discovered during the period 1901-2010 is studied, starting with their orbit determination. Next, an orbital evolution that includes three perihelion passages (previous-observed-next) is investigated in which a full model of Galactic perturbations and perturbations from passing stars is incorporated. We show that the distribution of planetary perturbations suffered by actual large-perihelion comets during their passage through the Solar system has a deep, unexpected minimum around zero, which indicates a lack of 'almost unperturbed' comets. Using a series of simulations we show that this deep well is moderately resistant to some diffusion of the orbital elements of the analysed comets. It seems reasonable to assert that the observed stream of these large-perihelion comets experienced a series of specific planetary configurations when passing through the planetary zone. An analysis of the past dynamics of these comets clearly shows that dynamically new comets can appear only when their original semimajor axes are greater than 20 000 au. On the other hand, dynamically old comets are completely absent for semimajor axes longer than 40 000 au. We demonstrate that the observed 1/aori-distribution exhibits a local minimum separating dynamically new from dynamically old comets. Long-term dynamical studies reveal a wide variety of orbital behaviour. Several interesting examples of the action of passing stars are also described, in particular the impact of Gliese 710, which will pass close to the Sun in the future. However, none of the obtained stellar perturbations is sufficient to change the dynamical status of the analysed comets.

Problems encountered in the use of neutron methods for elemental analysis on planetary surfaces

USGS Publications Warehouse

Senftle, F.; Philbin, P.; Moxham, R.; Boynton, G.; Trombka, J.

1974-01-01

From experimental studies of gamma rays from fast and thermal neutron reactions in hydrogeneous and non-hydrogeneous, semi-infinite samples and from Monte Carlo calculations on soil of a composition which might typically be encountered on planetary surfaces, it is found that gamma rays from fast or inelastic scattering reactions would dominate the observed spectra. With the exception of gamma rays formed by inelastically scattered neutrons on oxygen, useful spectra would be limited to energies below 3 MeV. Other experiments were performed which show that if a gamma-ray detector were placed within 6 m of an isotopic neutron source in a spacecraft, it would be rendered useless for gamma-ray spectrometry below 3 MeV because of internal activation produced by neutron exposure during space travel. Adequate shielding is not practicable because of the size and weight constraints for planetary missions. Thus, it is required that the source be turned off or removed to a safe distance during non-measurement periods. In view of these results an accelerator or an off-on isotopic source would be desirable for practical gamma-ray spectral analysis on planetary surfaces containing but minor amounts of hydrogen. ?? 1974.

An online planetary exploration tool: ;Country Movers;

NASA Astrophysics Data System (ADS)

Gede, Mátyás; Hargitai, Henrik

2017-08-01

Results in astrogeologic investigations are rarely communicated towards the general public by maps despite the new advances in planetary spatial informatics and new spatial datasets in high resolution and more complete coverage. Planetary maps are typically produced by astrogeologists for other professionals, and not by cartographers for the general public. We report on an application designed for students, which uses cartography as framework to aid the virtual exploration of other planets and moons, using the concepts of size comparison and travel time calculation. We also describe educational activities that build on geographic knowledge and expand it to planetary surfaces.

Planetary Boundary Layer Dynamics over Reno, Nevada in Summer

NASA Astrophysics Data System (ADS)

Liming, A.; Sumlin, B.; Loria Salazar, S. M.; Holmes, H.; Arnott, W. P.

2014-12-01

Quantifying the height of the planetary boundary layer (PBL) is important to understand the transport behavior, mixing, and surface concentrations of air pollutants. In Reno, NV, located in complex, mountainous terrain with high desert climate, the daytime boundary layer can rise to an estimated 3km or more on a summer day due to surface heating and convection. The nocturnal boundary layer, conversely, tends to be much lower and highly stable due to radiative cooling from the surface at night and downslope flow of cool air from nearby mountains. With limited availability of radiosonde data, current estimates of the PBL height at any given time or location are potentially over or underestimated. To better quantify the height and characterize the PBL physics, we developed portable, lightweight sensors that measure CO2 concentrations, temperature, pressure, and humidity every 5 seconds. Four of these sensors are used on a tethered balloon system to monitor CO2 concentrations from the surface up to 300m. We will combine this data with Radio Acoustic Sounding System (RASS) data that measures vertical profiles of wind speed, temperature, and humidity from 40m to 400m. This experiment will characterize the diurnal evolution of CO2 concentrations at multiple heights in the PBL, provide insight into PBL physics during stability transition periods at sunrise and sunset, and estimate the nighttime PBL depth during August in Reno. Further, we expect to gain a better understanding of the impact of mixing volume changes (i.e., PBL height) on air quality and pollution concentrations in Reno. The custom portable sensor design will also be presented. It is expected that these instruments can be used for indoor or outdoor air quality studies, where lightness, small size, and battery operation can be of benefit.

Origin and evolution of planetary atmospheres

NASA Technical Reports Server (NTRS)

Lewis, John S.

1992-01-01

This report concerns several research tasks related to the origin and evolution of planetary atmospheres and the large-scale distribution of volatile elements in the Solar System. These tasks and their present status are as follows: (1) we have conducted an analysis of the volatility and condensation behavior of compounds of iron, aluminum, and phosphorus in the atmosphere of Venus in response to publish interpretations of the Soviet Venera probe XRF experiment data, to investigate the chemistry of volcanic gases, injection of volatiles by cometary and asteroidal impactors, and reactions in the troposphere; (2) we have completed and are now writing up our research on condensation-accretion modeling of the terrestrial planets; (3) we have laid the groundwork for a detailed study of the effects of water transport in the solar nebula on the bulk composition, oxidation state, and volatile content of preplanetary solids; (4) we have completed an extensive laboratory study of cryovolcanic materials in the outer solar system; (5) we have begun to study the impact erosion and shock alteration of the atmosphere of Mars resulting from cometary and asteroidal bombardment; and (6) we have developed a new Monte Carlo model of the cometary and asteroidal bombardment flux on the terrestrial planets, including all relevant chemical and physical processes associated with atmospheric entry and impact, to assess both the hazards posed by this bombardment to life on Earth and the degree of cross-correlation between the various phenomena (NO(x) production, explosive yield, crater production, iridium signature, etc.) that characterize this bombardment. The purpose of these investigations has been to contribute to the developing understanding of both the dynamics of long-term planetary atmosphere evolution and the short-term stability of planetary surface environments.

Regolith-Derived Heat Shield for Planetary Body Entry and Descent System with In-Situ Fabrication

NASA Technical Reports Server (NTRS)

Hogue, Michael D.; Mueller, Robert P.; Sibille, Laurent; Hintze, Paul E.; Rasky, Daniel J.

2012-01-01

High-mass planetary surface access is one of NASA's Grand Challenges involving entry, descent, and landing (EDL). Heat shields fabricated in-situ can provide a thermal protection system for spacecraft that routinely enter a planetary atmosphere. Fabricating the heat shield from extraterrestrial regolith will avoid the costs of launching the heat shield mass from Earth. This project will investigate three methods to fabricate heat shield using extraterrestrial regolith.

Inventory of File gfs.t06z.smartguam24.tm00.grib2

Science.gov Websites

boundary layer WDIR 24 hour fcst Wind Direction (from which blowing) [degtrue] 016 planetary boundary layer WIND 24 hour fcst Wind Speed [m/s] 017 planetary boundary layer RH 24 hour fcst Relative Humidity [%] 018 planetary boundary layer DIST 24 hour fcst Geometric Height [m] 019 surface 4LFTX 24 hour fcst

Astrobiology Science and Technology: A Path to Future Discovery

NASA Technical Reports Server (NTRS)

Meyer, M. A.; Lavaery, D. B.

2001-01-01

The Astrobiology Program is described. However, science-driven robotic exploration of extreme environments is needed for a new era of planetary exploration requiring biologically relevant instrumentation and extensive, autonomous operations on planetary surfaces. Additional information is contained in the original extended abstract.

TOWARD A DETERMINISTIC MODEL OF PLANETARY FORMATION. VII. ECCENTRICITY DISTRIBUTION OF GAS GIANTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ida, S.; Lin, D. N. C.; Nagasawa, M., E-mail: ida@geo.titech.ac.jp, E-mail: lin@ucolick.org, E-mail: nagasawa.m.ad@m.titech.ac.jp

2013-09-20

The ubiquity of planets and diversity of planetary systems reveal that planet formation encompasses many complex and competing processes. In this series of papers, we develop and upgrade a population synthesis model as a tool to identify the dominant physical effects and to calibrate the range of physical conditions. Recent planet searches have led to the discovery of many multiple-planet systems. Any theoretical models of their origins must take into account dynamical interactions between emerging protoplanets. Here, we introduce a prescription to approximate the close encounters between multiple planets. We apply this method to simulate the growth, migration, and dynamicalmore » interaction of planetary systems. Our models show that in relatively massive disks, several gas giants and rocky/icy planets emerge, migrate, and undergo dynamical instability. Secular perturbation between planets leads to orbital crossings, eccentricity excitation, and planetary ejection. In disks with modest masses, two or less gas giants form with multiple super-Earths. Orbital stability in these systems is generally maintained and they retain the kinematic structure after gas in their natal disks is depleted. These results reproduce the observed planetary mass-eccentricity and semimajor axis-eccentricity correlations. They also suggest that emerging gas giants can scatter residual cores to the outer disk regions. Subsequent in situ gas accretion onto these cores can lead to the formation of distant (∼> 30 AU) gas giants with nearly circular orbits.« less

Exploring Venus: the Venus Exploration Analysis Group (VEXAG)

NASA Astrophysics Data System (ADS)

Ocampo, A.; Atreya, S.; Thompson, T.; Luhmann, J.; Mackwell, S.; Baines, K.; Cutts, J.; Robinson, J.; Saunders, S.

In July 2005 NASA s Planetary Division established the Venus Exploration Analysis Group VEXAG http www lpi usra edu vexag in order to engage the scientific community at large in identifying scientific priorities and strategies for the exploration of Venus VEXAG is a community-based forum open to all interested in the exploration of Venus VEXAG was designed to provide scientific input and technology development plans for planning and prioritizing the study of Venus over the next several decades including a Venus surface sample return VEXAG regularly evaluates NASA s Venus exploration goals scientific objectives investigations and critical measurement requirements including the recommendations in the National Research Council Decadal Survey and NASA s Solar System Exploration Strategic Roadmap VEXAG will take into consideration the latest scientific results from ESA s Venus Express mission and the MESSENGER flybys as well as the results anticipated from JAXA s Venus Climate Orbiter together with science community inputs from venues such as the February 13-16 2006 AGU Chapman Conference to identify the scientific priorities and strategies for future NASA Venus exploration VEXAG is composed of two co-chairs Sushil Atreya University of Michigan Ann Arbor and Janet Luhmann University of California Berkeley VEXAG has formed three focus groups in the areas of 1 Planetary Formation and Evolution Surface and Interior Volcanism Geodynamics etc Focus Group Lead Steve Mackwell LPI 2 Atmospheric Evolution Dynamics Meteorology

Simulations of GCR interactions within planetary bodies using GEANT4

NASA Astrophysics Data System (ADS)

Mesick, K.; Feldman, W. C.; Stonehill, L. C.; Coupland, D. D. S.

2017-12-01

On planetary bodies with little to no atmosphere, Galactic Cosmic Rays (GCRs) can hit the body and produce neutrons primarily through nuclear spallation within the top few meters of the surfaces. These neutrons undergo further nuclear interactions with elements near the planetary surface and some will escape the surface and can be detected by landed or orbiting neutron radiation detector instruments. The neutron leakage signal at fast neutron energies provides a measure of average atomic mass of the near-surface material and in the epithermal and thermal energy ranges is highly sensitive to the presence of hydrogen. Gamma-rays can also escape the surface, produced at characteristic energies depending on surface composition, and can be detected by gamma-ray instruments. The intra-nuclear cascade (INC) that occurs when high-energy GCRs interact with elements within a planetary surface to produce the leakage neutron and gamma-ray signals is highly complex, and therefore Monte Carlo based radiation transport simulations are commonly used for predicting and interpreting measurements from planetary neutron and gamma-ray spectroscopy instruments. In the past, the simulation code that has been widely used for this type of analysis is MCNPX [1], which was benchmarked against data from the Lunar Neutron Probe Experiment (LPNE) on Apollo 17 [2]. In this work, we consider the validity of the radiation transport code GEANT4 [3], another widely used but open-source code, by benchmarking simulated predictions of the LPNE experiment to the Apollo 17 data. We consider the impact of different physics model options on the results, and show which models best describe the INC based on agreement with the Apollo 17 data. The success of this validation then gives us confidence in using GEANT4 to simulate GCR-induced neutron leakage signals on Mars in relevance to a re-analysis of Mars Odyssey Neutron Spectrometer data. References [1] D.B. Pelowitz, Los Alamos National Laboratory, LA-CP-05-0369, 2005. [2] G.W. McKinney et al, Journal of Geophysics Research, 111, E06004, 2006. [3] S. Agostinelli et al, Nuclear Instrumentation and Methods A, 506, 2003.

An investigation of current and future satellite and in-situ data for the remote sensing of the land surface energy balance

NASA Technical Reports Server (NTRS)

Diak, George R.

1994-01-01

This final report from the University of Wisconsin-Madison Cooperative Institute for Meteorological Satellite Studies (CIMSS) summarizes a research program designed to improve our knowledge of the water and energy balance of the land surface through the application of remote sensing and in-situ data sources. The remote sensing data source investigations to be detailed involve surface radiometric ('skin') temperatures and also high-spectral-resolution infrared radiance data from atmospheric sounding instruments projected to be available at the end of the decade, which have shown promising results for evaluating the land-surface water and energy budget. The in-situ data types to be discussed are measurements of the temporal changes of the height of the planetary boundary layer and measurements of air temperature within the planetary boundary layer. Physical models of the land surface, planetary boundary layer and free atmosphere have been used as important tools to interpret the in-situ and remote sensing signals of the surface energy balance. A prototype 'optimal' system for combining multiple data sources into a three-dimensional estimate of the surface energy balance was developed and first results from this system will be detailed. Potential new sources of data for this system and suggested continuation research will also be discussed.

Conceptual Design and Dynamics Testing and Modeling of a Mars Tumbleweed Rover

NASA Technical Reports Server (NTRS)

Calhoun Philip C.; Harris, Steven B.; Raiszadeh, Behzad; Zaleski, Kristina D.

2005-01-01

The NASA Langley Research Center has been developing a novel concept for a Mars planetary rover called the Mars Tumbleweed. This concept utilizes the wind to propel the rover along the Mars surface, bringing it the potential to cover vast distances not possible with current Mars rover technology. This vehicle, in its deployed configuration, must be large and lightweight to provide the ratio of drag force to rolling resistance necessary to initiate motion from rest on the Mars surface. One Tumbleweed design concept that satisfies these considerations is called the Eggbeater-Dandelion. This paper describes the basic design considerations and a proposed dynamics model of the concept for use in simulation studies. It includes a summary of rolling/bouncing dynamics tests that used videogrammetry to better understand, characterize, and validate the dynamics model assumptions, especially the effective rolling resistance in bouncing/rolling dynamic conditions. The dynamics test used cameras to capture the motion of 32 targets affixed to a test article s outer structure. Proper placement of the cameras and alignment of their respective fields of view provided adequate image resolution of multiple targets along the trajectory as the test article proceeded down the ramp. Image processing of the frames from multiple cameras was used to determine the target positions. Position data from a set of these test runs was compared with results of a three dimensional, flexible dynamics model. Model input parameters were adjusted to match the test data for runs conducted. This process presented herein provided the means to characterize the dynamics and validate the simulation of the Eggbeater-Dandelion concept. The simulation model was used to demonstrate full scale Tumbleweed motion from a stationary condition on a flat-sloped terrain using representative Mars environment parameters.

Wet Tectonics: A New Planetary Synthesis

NASA Astrophysics Data System (ADS)

Grimm, K. A.

2005-12-01

Most geoscientists (and geoscience textbooks) describe plate tectonics as a `solid-Earth' phenomenon, with fluids playing an important role in discrete geodynamic processes. As a community of diverse research specialists, the critical role of water is being widely elucidated, however these diverse studies do not address the fundamental origin and operation of the global plate tectonic phenomenon, and its expressions in planetary geodynamics and geomorphology. The Wet Tectonics hypothesis extends well beyond the plate tectonics paradigm, to constitute a new synthesis of diverse geoscience specializations and self-organizing complexity into a simple, internally consistent and explicitly testable model. The Wet Tectonics hypothesis asserts that Earth's plate tectonic system arose from and is the explicit and dynamic result of water interacting with the hot silicate mantle. The tectosphere is defined as an interactive functional (rather than structural, compositional or rheological) entity, a planetary-scale dynamic system of plate formation, plate motion, and rock/volatile recycling. Earth's tectosphere extends from the base of the asthenosphere to the top of the crust, arising and evolving as a dynamic pattern of organization that creates, orders and perpetuates itself. Earth's tectosphere is energetically-open, materially ajar (steady-state operation may not require sub-asthenospheric inputs; shifts between distinct tectonic modes may result from changes in coupling between the tectosphere and subasthenospheric reservoirs) and chemically-closed (i.e. the tectosphere recycles its own wastes). Water is a fundamental requirement in all of the constituent processes of Earth's tectosphere, including seafloor spreading, slab cooling/subsidence, plate motion, asthenosphere rheology, and subduction (where crustal and volatile recycling occur). As a working hypothesis, we suggest that the dynamic and persistent hydrosphere and tectosphere on planet Earth are fully interdependent and co-evolving phenomena. The concept of autocatalytic hypercycles has been adapted from molecular biology to resolve the apparent paradox of circular causality amongst the coupled phenomena of liquid water oceans and `plate tectonics'. This new planetary synthesis presents fundamental implications for geological, geophysical, Earth system and planetary sciences, as well as novel hypotheses concerning plate drive (gravity sliding ± slab pull), origin of plate tectonics (Hadean, >=4.4Ga), biogeochemical cycling (balanced global fluxes of water into and out of the tectosphere; is the asthenosphere continuously rehydrated via lateral advection) and planetary geomorphology (simple contrasts between Mars, Earth and Venus).

Planetary Nomenclature: An Overview and Update for 2017

NASA Astrophysics Data System (ADS)

Gaither, Tenielle; Hayward, Rose; IAU Working GroupPlanetary System Nomenclature

2017-10-01

The task of naming planetary surface features, rings, and natural satellites is managed by the International Astronomical Union’s (IAU) Working Group for Planetary System Nomenclature (WGPSN). There are currently 15,361 IAU-approved surface feature names on 41 planetary bodies, including moons and asteroids. The members of the WGPSN and its task groups have worked since the early 1970s to provide a clear, unambiguous system of planetary nomenclature that represents cultures and countries from all regions of Earth. WGPSN members include Rita Schulz (Chair) and 9 other members representing countries around the globe. The participation of knowledgeable scientists and experts in this process is vital to its success of the IAU WGPSN . Planetary nomenclature is a tool used to uniquely identify features on the surfaces of planets or satellites so they can be located, described, and discussed in publications, including peer-review journals, maps and conference presentations. Approved names are listed in the Transactions of the IAU and on the Gazetteer of Planetary Nomenclature website. Any names currently in use that are not listed the Gazetteer are not official. Planetary names must adhere to rules and conventions established by the IAU WGPSN (see http://planetarynames.wr.usgs.gov/Page/Rules for the complete list). The gazetteer includes an online Name Request Form (http://planetarynames.wr.usgs.gov/FeatureNameRequest) that can be used by members of the professional science community. Name requests are first reviewed by one of six task groups (Mercury, Venus, Moon, Mars, Outer Solar System, and Small Bodies). After a task group has reviewed a proposal, it is submitted to the WGPSN. Allow four to six weeks for the review and approval process. Upon WGPSN approval, names are considered formally approved and it is then appropriate to use them in publications. Approved names are immediately entered into the database and shown on the website. Questions about the nomenclature database and the naming process can be sent to Rosalyn Hayward, USGS Astrogeology Science Center, 2255 N. Gemini Dr., Flagstaff, AZ 86001, or by email to rhayward@usgs.gov.

Detection of the Magnetospheric Emissions from Extrasolar Planets

NASA Astrophysics Data System (ADS)

Lazio, J.

2014-12-01

Planetary-scale magnetic fields are a window to a planet's interior and provide shielding of the planet's atmosphere. The Earth, Mercury, Ganymede, and the giant planets of the solar system all contain internal dynamo currents that generate planetary-scale magnetic fields. These internal dynamo currents arise from differential rotation, convection, compositional dynamics, or a combination of these. If coupled to an energy source, such as the incident kinetic or magnetic energy from the solar wind, a planet's magnetic field can produce electron cyclotron masers in its magnetic polar regions. The most well known example of this process is the Jovian decametric emission, but all of the giant planets and the Earth contain similar electron cyclotron masers within their magnetospheres. Extrapolated to extrasolar planets, the remote detection of the magnetic field of an extrasolar planet would provide a means of obtaining constraints on the thermal state, composition, and dynamics of its interior as well as improved understanding of the basic planetary dynamo process. The magnetospheric emissions from solar system planets and the discovery of extrasolar planets have motivated both theoretical and observational work on magnetospheric emissions from extrasolar planets. Stimulated by these advances, the W.M. Keck Institute for Space Studies hosted a workshop entitled "Planetary Magnetic Fields: Planetary Interiors and Habitability." I summarize the current observational status of searches for magnetospheric emissions from extrasolar planets, based on observations from a number of ground-based radio telescopes, and future prospects for ground-based studies. Using the solar system planetary magnetic fields as a guide, future space-based missions will be required to study planets with magnetic field strengths lower than that of Jupiter. I summarize mission concepts identified in the KISS workshop, with a focus on the detection of planetary electron cyclotron maser emission. The authors acknowledge ideas and advice from the participants in the "Planetary Magnetic Fields: Planetary Interiors and Habitability" workshop organized by the Keck Institute for Space Studies. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.

Remote sensor support requirements for planetary missions

NASA Technical Reports Server (NTRS)

Weddell, J. B.; Wheeler, A. E.

1971-01-01

The study approach, methods, results, and conclusions of remote sensor support requirements for planetary missions are summarized. Major efforts were made to (1) establish the scientific and engineering knowledge and observation requirements for planetary exploration in the 1975 to 1985 period; (2) define the state of the art and expected development of instrument systems appropriate for sensing planetary environments; (3) establish scaling laws relating performance and support requirements of candidate remote sensor systems; (4) establish fundamental remote sensor system capabilities, limitations, and support requirements during encounter and other dynamical conditions for specific missions; and (5) construct families of candidate remote sensors compatible with selected missions. It was recommended that these data be integrated with earlier results to enhance utility, and that more restrictions be placed on the system.

Role of quasiresonant planetary wave dynamics in recent boreal spring-to-autumn extreme events

PubMed Central

Petoukhov, Vladimir; Petri, Stefan; Rahmstorf, Stefan; Coumou, Dim; Kornhuber, Kai; Schellnhuber, Hans Joachim

2016-01-01

In boreal spring-to-autumn (May-to-September) 2012 and 2013, the Northern Hemisphere (NH) has experienced a large number of severe midlatitude regional weather extremes. Here we show that a considerable part of these extremes were accompanied by highly magnified quasistationary midlatitude planetary waves with zonal wave numbers m = 6, 7, and 8. We further show that resonance conditions for these planetary waves were, in many cases, present before the onset of high-amplitude wave events, with a lead time up to 2 wk, suggesting that quasiresonant amplification (QRA) of these waves had occurred. Our results support earlier findings of an important role of the QRA mechanism in amplifying planetary waves, favoring recent NH weather extremes. PMID:27274064

Dynamical Evolution of Planetary Embryos

NASA Technical Reports Server (NTRS)

Wetherill, George W.

2002-01-01

During the past decade, progress has been made by relating the 'standard model' for the formation of planetary systems to computational and observational advances. A significant contribution to this has been provided by this grant. The consequence of this is that the rigor of the physical modeling has improved considerably. This has identified discrepancies between the predictions of the standard model and recent observations of extrasolar planets. In some cases, the discrepancies can be resolved by recognition of the stochastic nature of the planetary formation process, leading to variations in the final state of a planetary system. In other cases, it seems more likely that there are major deficiencies in the standard model, requiring our identifying variations to the model that are not so strongly constrained to our Solar System.

Quasi-microscope concept for planetary missions.

PubMed

Huck, F O; Arvidson, R E; Burcher, E E; Giat, O; Wall, S D

1977-09-01

Viking lander cameras have returned stereo and multispectral views of the Martian surface with a resolution that approaches 2 mm/lp in the near field. A two-orders-of-magnitude increase in resolution could be obtained for collected surface samples by augmenting these cameras with auxiliary optics that would neither impose special camera design requirements nor limit the cameras field of view of the terrain. Quasi-microscope images would provide valuable data on the physical and chemical characteristics of planetary regoliths.

Wave tilt sounding of multilayered structures. [for probing of stratified planetary surface electrical properties and thickness

NASA Technical Reports Server (NTRS)

Warne, L.; Jaggard, D. L.; Elachi, C.

1979-01-01

The relationship between the wave tilt and the electrical parameters of a multilayered structure is investigated. Particular emphasis is placed on the inverse problem associated with the sounding planetary surfaces. An inversion technique, based on multifrequency wave tilt, is proposed and demonstrated with several computer models. It is determined that there is close agreement between the electrical parameters used in the models and those in the inversion values.

Planetary geosciences, 1989-1990

NASA Technical Reports Server (NTRS)

Zuber, Maria T. (Editor); James, Odette B. (Editor); Lunine, Jonathan I. (Editor); Macpherson, Glenn J. (Editor); Phillips, Roger J. (Editor)

1992-01-01

NASA's Planetary Geosciences Programs (the Planetary Geology and Geophysics and the Planetary Material and Geochemistry Programs) provide support and an organizational framework for scientific research on solid bodies of the solar system. These research and analysis programs support scientific research aimed at increasing our understanding of the physical, chemical, and dynamic nature of the solid bodies of the solar system: the Moon, the terrestrial planets, the satellites of the outer planets, the rings, the asteroids, and the comets. This research is conducted using a variety of methods: laboratory experiments, theoretical approaches, data analysis, and Earth analog techniques. Through research supported by these programs, we are expanding our understanding of the origin and evolution of the solar system. This document is intended to provide an overview of the more significant scientific findings and discoveries made this year by scientists supported by the Planetary Geosciences Program. To a large degree, these results and discoveries are the measure of success of the programs.

Accumulation of planets into the proto-planetary cloud as a process of occurring an amount of characteristic scales into the nonlinear self organized dynamical systems

NASA Astrophysics Data System (ADS)

Professor Khachay, Yurie

2015-04-01

Two characteristic times are significant for evolution the interior of the homogeneous proto-planetary cloud: the time of bodies free fall towards the clouds mass center and the time of sound distribution through the cloud. With the beginning of proto-planetary disk fragmentation and accumulation of the proto-planets from the bodies and particles there are formed matter content heterogeneities of the finite dimension, heterogeneities of temperature, density and values of kinetic coefficients. The system became more and more complicated with interior interconnections. By the growing of the bodies the difference between the values of the characteristic times and dimensions become larger. The dynamical evolution of the system we could observe with use the numerical modeling of the Earth and Moon formation into the 3-D model [1,2]. The fact, that the linear dimensions of the objects during the accumulation process change from the centimeter and meter dimensions to some thousands of kilometers significantly prevent the mathematical description of these processes. The corresponding values of the no dimensional similarity criterions, which are included into the systems of differential equations, which describe the proto-planetary growing, the conditions for entropy and mass on the growing surface, the equations of the impulse balance, energy and mass into the interior parts of the planet change on an orders of values. Therefore we used very detailed space and time grids for solution the problem using the method of finite differences. The additional complications occur according to necessity to take into account the nonlinear dependence of matter viscosity from the temperature, pressure and chemical matter content. At last we took into account the principal random distribution of heterogeneities, stipulated by bodies and particles falling. Only progression towards that direction and constructing corresponding systems of observation and interpretation allow to hope receiving more and more realistic models of self organizing structures and to understand the laws of their reconstruction during the complicated process of planetary accumulation. The work is fulfilled by partly support of RFBR (grant N13-05-00138). References. 1. Y. Khachay , V. Anfilogov , and A. Antipin (2014) Numerical Results of 3-D Modeling of Moon Accumulation // Geophysical Research Abstracts, Vol. 16, EGU2014-1011 2. Y.Khachay, A.Antipin and V.Anfilogov (2014)Numerical modeling of temperature distribution on the stage of Earth's accumulation in a frame of 3-D model and peculiarities of its initial minerageny. Ural geophysical bulletin 1: 81-85.

Collecting, Managing, and Visualizing Data during Planetary Surface Exploration

NASA Astrophysics Data System (ADS)

Young, K. E.; Graff, T. G.; Bleacher, J. E.; Whelley, P.; Garry, W. B.; Rogers, A. D.; Glotch, T. D.; Coan, D.; Reagan, M.; Evans, C. A.; Garrison, D. H.

2017-12-01

While the Apollo lunar surface missions were highly successful in collecting valuable samples to help us understand the history and evolution of the Moon, technological advancements since 1969 point us toward a new generation of planetary surface exploration characterized by large volumes of data being collected and used to inform traverse execution real-time. Specifically, the advent of field portable technologies mean that future planetary explorers will have vast quantities of in situ geochemical and geophysical data that can be used to inform sample collection and curation as well as strategic and tactical decision making that will impact mission planning real-time. The RIS4E SSERVI (Remote, In Situ and Synchrotron Studies for Science and Exploration; Solar System Exploration Research Virtual Institute) team has been working for several years to deploy a variety of in situ instrumentation in relevant analog environments. RIS4E seeks both to determine ideal instrumentation suites for planetary surface exploration as well as to develop a framework for EVA (extravehicular activity) mission planning that incorporates this new generation of technology. Results from the last several field campaigns will be discussed, as will recommendations for how to rapidly mine in situ datasets for tactical and strategic planning. Initial thoughts about autonomy in mining field data will also be presented. The NASA Extreme Environments Mission Operations (NEEMO) missions focus on a combination of Science, Science Operations, and Technology objectives in a planetary analog environment. Recently, the increase of high-fidelity marine science objectives during NEEMO EVAs have led to the ability to evaluate how real-time data collection and visualization can influence tactical and strategic planning for traverse execution and mission planning. Results of the last few NEEMO missions will be discussed in the context of data visualization strategies for real-time operations.

Shock wave properties of anorthosite and gabbro. [to model hypervelocity impact cratering on planetary surfaces

NASA Technical Reports Server (NTRS)

Boslough, M. B.; Ahrens, T. J.

1985-01-01

Huyoniot data on San Gabriel anorthosite and San Marcos gabbro to 11 GPA are presented. Release paths in the stress-density plane and sound velocities are reported as determined from partial velocity data. Electrical interference effects precluded the determination of accurate release paths for the gabbro. Because of the loss of shear strength in the shocked state, the plastic behavior exhibited by anorthosite indicates that calculations of energy partitioning due to impact onto planetary surfaces based on elastic-plastic models may underestimate the amount of internal energy deposited in the impacted surface material.

Dynamics of Populations of Planetary Systems (IAU C197)

NASA Astrophysics Data System (ADS)

Knezevic, Zoran; Milani, Andrea

2005-05-01

1. Resonances and stability of extra-solar planetary systems C. Beaugé, N. Callegari, S. Ferraz-Mello and T. A. Michtchenko; 2. Formation, migration, and stability of extrasolar planetary systems Fred C. Adams; 3. Dynamical evolution of extrasolar planetary systems Ji-Lin Zhou and Yi-Sui Sun; 4. Dynamics of planetesimals: the role of two-body relaxation Eiichiro Kokubo; 5. Fitting orbits Andrzej J. Maciejewski, Krzysztof Gozdziewski and Szymon Kozlowski; 6. The secular planetary three body problem revisited Jacques Henrard and Anne-Sophie Libert; 7. Dynamics of extrasolar systems at the 5/2 resonance: application to 47 UMa Dionyssia Psychoyos and John D. Hadjidemetriou; 8. Our solar system as model for exosolar planetary systems Rudolf Dvorak, Áron Süli and Florian Freistetter; 9. Planetary motion in double stars: the influence of the secondary Elke Pilat-Lohinger; 10. Planetary orbits in double stars: influence of the binary's orbital eccentricity Daniel Benest and Robert Gonczi; 11. Astrometric observations of 51 Peg and Gliese 623 at Pulkovo observatory with 65 cm refractor N. A. Shakht; 12. Observations of 61 Cyg at Pulkovo Denis L. Gorshanov, N. A. Shakht, A. A. Kisselev and E. V. Poliakow; 13. Formation of the solar system by instability Evgeny Griv and Michael Gedalin; 14. Behaviour of a two-planetary system on a cosmogonic time-scale Konstantin V. Kholshevnikov and Eduard D. Kuznetsov; 15. Boundaries of the habitable zone: unifying dynamics, astrophysics, and astrobiology Milan M. Cirkovic; 16. Asteroid proper elements: recent computational progress Fernando Roig and Cristian Beaugé; 17. Asteroid family classification from very large catalogues Anne Lemaitre; 18. Non-gravitational perturbations and evolution of the asteroid main belt David Vokrouhlicky, M. Broz and W. F. Bottke, D. Nesvorny and A. Morbidelli; 19. Diffusion in the asteroid belt Harry Varvoglis; 20. Accurate model for the Yarkovsky effect David Capek and David Vokrouhlicky; 21. The population of asteroids in the 2:1 mean motion resonance with Jupiter revised Miroslav Broz, D. Vokrouhlicky, F. Roig, D. Nesvorny, W. F. Bottke and A. Morbidelli; 22. On the reliability of computation of maximum Lyapunov Characteristic Exponents for asteroids Zoran Knezevic and Slobodan Ninkovic; 23. Nekhoroshev stability estimates for different models of the Trojan asteroids Christos Efthymiopoulos; 24. The role of the resonant 'stickiness' in the dynamical evolution of Jupiter family comets A. Alvarez-Canda and F. Roig; 25. Regimes of stability and scaling relations for the removal time in the asteroid belt: a simple kinetic model and numerical tests Mihailo Cubrovic; 26. Virtual asteroids and virtual impactors Andrea Milani; 27. Asteroid population models Alessandro Morbidelli; 28. Linking Very Large Telescope asteroid observations M. Granvik, K. Muinonen, J. Virtanen, M. Delbó, L. Saba, G. De Sanctis, R. Morbidelli, A. Cellino and E. Tedesco; 29. Collision orbits and phase transition for 2004 AS1 at discovery Jenni Virtanen, K. Muinonen, M. Granvik and T. Laakso; 30. The size of collision solutions in orbital elements space G. B. Valsecchi, A. Rossi, A. Milani and S. R. Chesley; 31. Very short arc orbit determination: the case of asteroid 2004 FU162 Steven R. Chesley; 32. Nonlinear impact monitoring: 2-dimensional sampling Giacomo Tommei; 33. Searching for gravity assisted trajectories to accessible near-Earth asteroids Stefan Berinde; 34. KLENOT - Near Earth and other unusual objects observations Michal Kocer, Jana Tichá and M. Tichy; 35. Transport of comets to the Inner Solar System Hans Rickman; 36. Nongravitational Accelerations on Comets Steven R. Chesley and Donald K. Yeomans; 37. Interaction of planetesimals with the giant planets and the shaping of the trans-Neptunian belt Harold F. Levison and Alessandro Morbidelli; 38. Transport of comets to the outer p

Jupiter's and Saturn's ice moons: geophysical aspects and opportunities of geophysical survey of the planetary geoelectrical markers and oreols of the subsurface liquid ocean on the surface ice moons

NASA Astrophysics Data System (ADS)

Ozorovich, Yuri; Linkin, Vacheslav; Kosov, Alexandr; Fournier-Sicre, Alain; Klimov, Stanislav; Novikov, Denis; Ivanov, Anton; Skulachev, Dmitriy; Menshenin, Yaroslav

2016-04-01

This paper presents a new conceptual and methodological approach for geophysical survey of the planetary geoelectrical markers and oreols of the subsurface liquid ocean on the surface ice moons on the base "conceptual design phase" of the future space missions on the ice moons. At the design stage of such projects is considered the use of various space instruments and tools for the full the complex geophysical studies of the manifestations and planetary processes of the subsurface liquid ocean on the surface ice moons. The existence of various forms of the cryolithozone on terrestrial planets and their moons: advanced Martian permafrost zone in the form of existing of the frozen polar caps, subsurface frozen horizons, geological markers and oreols of the martian ancient (relict) ocean, subsurface oceans of Jupiter's and Saturn's moons-Europe and Enceladus, with the advanced form of permafrost freezes planetary caps, it allows to develop a common methodological basis and operational geophysical instruments (tools) for the future space program and planning space missions on these unique objects of the solar system, specialized for specific scientific problems of planetary missions. Geophysical practices and methodological principles, used in 1985-2015 by aurthors [ 1-5 ], respectively, as an example of the comprehensive geophysical experiment MARSES to study of the Martian permafrost zone and the martian ancient (relict) ocean, creating the preconditions for complex experimental setting and geo-physical monitoring of operational satellites of Jupiter and Saturn- Europe and Enceladus. This range of different planetary (like) planets with its geological history and prehistory of the common planetology formation processes of the planets formation and to define the role of a liquid ocean under the ice as a climate indicator of such planets, which is extremely important for the future construction of the geological and climatic history of the Earth. Main publications: [1]https://www.researchgate.net/publication/282151921_JUPITER%27S_MOON_EUROPA_PLANETARY_GEOELECTRICAL_MARKER_AND_OREOLS_UNDER_ICE_SUBSUEFACE_OCEAN_ON_THE_SURFACE_OF_THE_JUPITER%27S_MOON_EUROPA?ev=prf_pub [2]https://www.researchgate.net/publication/281270655_YUPITERS_MOON_EUROPA_PLANETARY_GEOELECTRICAL_MARKERS_AND_OREOPLS_OF_THE_LIQUID_OCEAN_UNDER_THE_ICE_ON_THE_SURFACE_OF_THE_YUPITERS_MOON_EUROPE [3] https://www.researchgate.net/publication/276005128_Science-technology_aspects_and_opportunities_of_em_sounding_frozen_%28_permafrost%29_soil [4]https://www.researchgate.net/publication/275638508_Cryolitozone_of_Mars_-_as_the_climatic_indicator_of_the_Martian_relict_ocean [5]https://www.researchgate.net/publication/275266762_Microwave_remote_sensing_of_Martian_cryolitozone

Space station impact experiments

NASA Technical Reports Server (NTRS)

Schultz, P.; Ahrens, T.; Alexander, W. M.; Cintala, M.; Gault, D.; Greeley, R.; Hawke, B. R.; Housen, K.; Schmidt, R.

1986-01-01

Four processes serve to illustrate potential areas of study and their implications for general problems in planetary science. First, accretional processes reflect the success of collisional aggregation over collisional destruction during the early history of the solar system. Second, both catastrophic and less severe effects of impacts on planetary bodies survivng from the time of the early solar system may be expressed by asteroid/planetary spin rates, spin orientations, asteroid size distributions, and perhaps the origin of the Moon. Third, the surfaces of planetary bodies directly record the effects of impacts in the form of craters; these records have wide-ranging implications. Fourth, regoliths evolution of asteroidal surfaces is a consequence of cumulative impacts, but the absence of a significant gravity term may profoundly affect the retention of shocked fractions and agglutinate build-up, thereby biasing the correct interpretations of spectral reflectance data. An impact facility on the Space Station would provide the controlled conditions necessary to explore such processes either through direct simulation of conditions or indirect simulation of certain parameters.

Full-lifetime simulations of multiple planets across all phases of stellar evolution

NASA Astrophysics Data System (ADS)

Veras, D.; Mustill, A. J.; Gänsicke, B. T.; Redfield, S.; Georgakarakos, N.; Bowler, A. B.; Lloyd, M. J. S.

2017-09-01

We know that planetary systems are just as common around white dwarfs as around main-sequence stars. However, self-consistently linking a planetary system across these two phases of stellar evolution through the violent giant branch poses computational challenges, and previous studies restricted architectures to equal-mass planets. Here, we remove this constraint and perform over 450 numerical integrations over a Hubble time (14 Gyr) of packed planetary systems with unequal-mass planets. We characterize the resulting trends as a function of planet order and mass. We find that intrusive radial incursions in the vicinity of the white dwarf become less likely as the dispersion amongst planet masses increases. The orbital meandering which may sustain a sufficiently dynamic environment around a white dwarf to explain observations is more dependent on the presence of terrestrial-mass planets than any variation in planetary mass. Triggering unpacking or instability during the white dwarf phase is comparably easy for systems of unequal-mass planets and systems of equal-mass planets; instabilities during the giant branch phase remain rare and require fine-tuning of initial conditions. We list the key dynamical features of each simulation individually as a potential guide for upcoming discoveries.

Electrical sensing of the dynamical structure of the planetary boundary layer

NASA Astrophysics Data System (ADS)

Nicoll, K. A.; Harrison, R. G.; Silva, H. G.; Salgado, R.; Melgâo, M.; Bortoli, D.

2018-04-01

Turbulent and convective processes within the planetary boundary layer are responsible for the transport of moisture, momentum and particulate matter, but are also important in determining the electrical charge transport of the lower atmosphere. This paper presents the first high resolution vertical charge profiles during fair weather conditions, obtained with instrumented radiosonde balloons over Alqueva, Portugal during the summer of 2014. The short intervals (4 h) between balloon flights enabled the diurnal variation in the vertical profile of charge within the boundary layer to be examined in detail, with much smaller charges (up to 20 pC m- 3) observed during stable night time periods than during the day. Following sunrise, the evolution of the charge profile was complex, demonstrating charged ultrafine aerosol, lofted upwards by daytime convection. This produced charge up to 92 pC m- 3 up to 500 m above the surface. The diurnal variation in the integrated column of charge above the site tracked closely with the diurnal variation in near surface charge as derived from a nearby electric field sensor, confirming the importance of the link between surface charge generation processes and aloft. The local aerosol vertical profiles were estimated using backscatter measurements from a collocated ceilometer. These were utilised in a simple model to calculate the charge expected due to vertical conduction current flow in the global electric circuit through aerosol layers. The analysis presented here demonstrates that charge can provide detailed information about boundary layer transport, particularly in regard to the ultrafine aerosol structure, that conventional thermodynamic and ceilometer measurements do not.

Simulating airless and/or hot planetary surfaces in the Planetary Emissivity Laboratory (PEL)

NASA Astrophysics Data System (ADS)

Maturilli, A.; Helbert, J.; D'Amore, M.

2010-12-01

A complete and extensive mineralogical survey of extraterrestrial bodies is actually possible only by means of remote sensing spectrometers, measuring the planetary surfaces in a spectral range that goes from the visible to the far infrared. The list of instruments still active today, observing the most interesting planets and bodies in our solar system is far too long to list them in this abstract. The important message is that all of them are sending to Earth a huge amount of data that needs to be correctly analysed, to infer the mineralogical composition of the observed regions on different targets. This requires laboratory data of relevant analogue materials under relevant conditions measured on a wide spectral range. At the Planetary Emissivity Laboratory (PEL) of DLR in Berlin two separate instruments, a Bruker IFS 88 and a Bruker Vertex 80V are operated in parallel and independently to measure reflectance and emissivity of planetary analogue materials to cover the 0.4 to 100 µm spectral range. The older IFS 88 is used to measure under room pressure and for emissivity measurements from low to moderate temperatures (up to 180° C), while the new Vertex 80V can be evacuated (below 1 mbar) and used to measure emissivity of moderate to very hot surfaces, reaching temperatures typical of the daily Mercury (beyond 500° C). The laboratory set-up and the already obtained results will be described, together with details about the online-archival and the standardized structure of the existing dataset.

Strata-1: An International Space Station Experiment into Fundamental Regolith Processes in Microgravity

NASA Technical Reports Server (NTRS)

Fries, M.; Abell, P.; Brisset, J.; Britt, D.; Colwell, J.; Durda, D.; Dove, A.; Graham, L.; Hartzell, C.; John, K.;

Mixing Paints

NASA Image and Video Library

2014-11-17

Nature is an artist, and this time she seems to have let her paints swirl together a bit. What the viewer might perceive to be Saturn's surface is really just the tops of its uppermost cloud layers. Everything we see is the result of fluid dynamics. Astronomers study Saturn's cloud dynamics in part to test and improve our understanding of fluid flows. Hopefully, what we learn will be useful for understanding our own atmosphere and that of other planetary bodies. This view looks toward the sunlit side of the rings from about 25 degrees above the ringplane. The image was taken in red light with the Cassini spacecraft narrow-angle camera on Aug. 23, 2014. The view was obtained at a distance of approximately 1.1 million miles (1.7 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 23 degrees. Image scale is 63 miles (102 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18290

Diverse Eruptions at Approximately 2,200 Years B.P. on the Great Rift, Idaho: Inferences for Magma Dynamics Along Volcanic Rift Zones

NASA Technical Reports Server (NTRS)

Hughes, S. S.; Nawotniak, S. E. Kobs; Borg, C.; Mallonee, H. C.; Purcell, S.; Neish, C.; Garry, W. B.; Haberle, C. W.; Lim, D. S. S.; Heldmann, J. L.

2016-01-01

Compositionally and morphologically diverse lava flows erupted on the Great Rift of Idaho approximately 2.2 ka (kilo-annum, 1000 years ago) during a volcanic "flare-up" of activity following an approximately 2 ky (kiloyear, 1000 years) hiatus in eruptions. Volcanism at Craters of the Moon (COTM), Wapi and Kings Bowl lava fields around this time included primitive and evolved compositions, separated over 75 kilometers along the approximately 85 kilometers-long rift, with striking variability in lava flow emplacement mechanisms and surface morphologies. Although the temporal associations may be coincidental, the system provides a planetary analog to better understand magma dynamics along rift systems, including that associated with lunar floor-fractured craters. This study aims to help bridge the knowledge gap between ancient rift volcanism evident on the Moon and other terrestrial planets, and active rift volcanism, e.g., at Hawai'i and Iceland.

Automatic Feature Extraction from Planetary Images

NASA Technical Reports Server (NTRS)

Troglio, Giulia; Le Moigne, Jacqueline; Benediktsson, Jon A.; Moser, Gabriele; Serpico, Sebastiano B.

2010-01-01

With the launch of several planetary missions in the last decade, a large amount of planetary images has already been acquired and much more will be available for analysis in the coming years. The image data need to be analyzed, preferably by automatic processing techniques because of the huge amount of data. Although many automatic feature extraction methods have been proposed and utilized for Earth remote sensing images, these methods are not always applicable to planetary data that often present low contrast and uneven illumination characteristics. Different methods have already been presented for crater extraction from planetary images, but the detection of other types of planetary features has not been addressed yet. Here, we propose a new unsupervised method for the extraction of different features from the surface of the analyzed planet, based on the combination of several image processing techniques, including a watershed segmentation and the generalized Hough Transform. The method has many applications, among which image registration and can be applied to arbitrary planetary images.

Modeling Io's Sublimation-Driven Atmosphere: Gas Dynamics and Radiation Emission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, Andrew C.; Goldstein, David B.; Varghese, Philip L.

2008-12-31

Io's sublimation-driven atmosphere is modeled using the direct simulation Monte Carlo method. These rarefied gas dynamics simulations improve upon earlier models by using a three-dimensional domain encompassing the entire planet computed in parallel. The effects of plasma impact heating, planetary rotation, and inhomogeneous surface frost are investigated. Circumplanetary flow is predicted to develop from the warm subsolar region toward the colder night-side. The non-equilibrium thermal structure of the atmosphere, including vibrational and rotational temperatures, is also presented. Io's rotation leads to an asymmetric surface temperature distribution which is found to strengthen circumplanetary flow near the dusk terminator. Plasma heating ismore » found to significantly inflate the atmosphere on both day- and night-sides. The plasma energy flux also causes high temperatures at high altitudes but permits relatively cooler temperatures at low altitudes near the dense subsolar point due to plasma energy depletion. To validate the atmospheric model, a radiative transfer model was developed utilizing the backward Monte Carlo method. The model allows the calculation of the atmospheric radiation from emitting/absorbing and scattering gas using an arbitrary scattering law and an arbitrary surface reflectivity. The model calculates the spectra in the {nu}{sub 2} vibrational band of SO{sub 2} which are then compared to the observational data.« less

Multi-Annual Data Products on Turbulent Heat Fluxes at the Local and Continental Scale Using AATSR and FY-2 Data

NASA Astrophysics Data System (ADS)

Menenti, M.; Ghafarian, H.; Tang, B.; Faivre, R.; Colin, J.; Jia, L.; Roupios, L.

2013-01-01

This paper summarizes the results of studies carried in the framework of the Dragon 2 Program - Project 5322 Key Eco-Hydrological Parameters Retrieval and Land Data Assimilation System Development in a Typical Inland River Basin of Chinas Arid Region. The investigations were focused on monitoring the fluxes of energy and water at the land-atmosphere interface across a range of spatial scales, using multi-spectral radiometric data collected by space-borne imaging radiometers. At the local scale a new approach to parameterize heat and vapour fluxes was developed and applied using Computational Fluid Dynamics to describe state and dynamics of the boundary layer over the heterogeneous and 3D structured land surface. An airborne scanning LIDAR was used to capture in detail surface geometry. Over the large area of the Qinghai-Tibet Plateau a land-atmospheric model was used to characterize the atmospheric Planetary Boundary Layer. The effect of land surface heterogeneity and structure on the exchange of heat and water was captured using the bi-angular observations of brightness temperature provided by the AATSR imaging radiometer. The heat and water flux densities were calculated hourly with Feng-Yun C, D and E VISSR data over the Qinghai-Tibet Plateau and the headwaters of main rivers around it.

Advances in planetary geology

NASA Technical Reports Server (NTRS)

1984-01-01

A wide variety of topics on planetary geology are presented. Subjects include stratigraphy and geomorphology of Copernicus, the Mamers valle region, and other selected regions of Mars and the Moon. Crater density and distribution are discussed for Callisto and the lunar surface. Spectroscopic analysis is described for Europa and Ganymede.

Impact Processes in the Solar System

NASA Technical Reports Server (NTRS)

Ahrens, Thomas J.

2004-01-01

Our laboratory has previously conducted impact fracture and dynamic failure tests. Polanskey and Ahrens [1990] mapped the fractures from a series of laboratory craters (Fig. 1) and Ahrens and Rubin [ 1993] inferred that the usually further extending radial cracks resulted from tensional failure during the compression of the shock propagation. The radial spreading induced by the particle velocity field caused the stresses perpendicular to the shock front to become sufficiently large and tensile. This induces "radial fractures." The concentric fractures are attributed to the tensional failure occurring after the initial compressive phase. Upon radial propagation of the stress wave the negative tension behind the stress-wave front caused failure along the quasi-spherical concentric fractures. The near-surface and spall fractures are attributed to the fractures described by Melosh [1984]. These are activated by impact and can launch relatively unshocked samples of planetary surfaces to speeds exceeding escape velocity. In the case of Mars, some of these surface samples presumably become the SNC (Mars) meteorites.

Teaching Planetary Science as Part of the Search for Extraterrestrial Intelligence (SETI)

NASA Astrophysics Data System (ADS)

Margot, Jean-Luc; Greenberg, Adam H.

2017-10-01

In Spring 2016 and 2017, UCLA offered a course titled "EPSS C179/279 - Search for Extraterrestrial Intelligence: Theory and Applications". The course is designed for advanced undergraduate students and graduate students in the science, technical, engineering, and mathematical fields. Each year, students designed an observing sequence for the Green Bank telescope, observed known planetary systems remotely, wrote a sophisticated and modular data processing pipeline, analyzed the data, and presented their results. In 2016, 15 students participated in the course (9U, 5G; 11M, 3F) and observed 14 planetary systems in the Kepler field. In 2017, 17 students participated (15U, 2G; 10M, 7F) and observed 10 planetary systems in the Kepler field, TRAPPIST-1, and LHS 1140. In order to select suitable targets, students learned about planetary systems, planetary habitability, and planetary dynamics. In addition to planetary science fundamentals, students learned radio astronomy fundamentals, collaborative software development, signal processing techniques, and statistics. Evaluations indicate that the course is challenging but that students are eager to learn because of the engrossing nature of SETI. Students particularly value the teamwork approach, the observing experience, and working with their own data. The next offering of the course will be in Spring 2018. Additional information about our SETI work is available at seti.ucla.edu.

Pickup Ion Mass Spectrometry for Surface Bounded Exospheres and Composition Mapping of Lunar and Planetary Surfaces

NASA Technical Reports Server (NTRS)

Keller, J. W.; Zurbuchen, T. H.; Baragiola, R. A.; Cassidy, T. A.; Chornay, D. J.; Collier, M. R.; Hartle, R. E.; Johnson, R. E.; Killen, R. M.; Koehn, P.

2005-01-01

Many of the small to medium sized objects in the solar system can be characterized as having surface bounded exospheres, or atmospheres so tenuous that scale lengths for inter-particle collisions are much larger than the dimensions of the objects. The atmospheres of these objects are the product of their surfaces, both the surface composition and the interactions that occur on them and also their interiors when gases escape from there. Thus by studying surface bounded exospheres it is possible to develop insight into the composition and processes that are taking place on the surface and interiors of these objects. The Moon and Mercury are two examples of planetary bodies with surface bounded exospheres that have been studied through spectroscopic observations of sodium, potassium, and, on the moon, mass spectrometric measurements of lunar gases such as argon and helium.

Strontium iodide gamma ray spectrometers for planetary science (Conference Presentation)

NASA Astrophysics Data System (ADS)

Prettyman, Thomas H.; Rowe, Emmanuel; Butler, Jarrhett; Groza, Michael; Burger, Arnold; Yamashita, Naoyuki; Lambert, James L.; Stassun, Keivan G.; Beck, Patrick R.; Cherepy, Nerine J.; Payne, Stephen A.; Castillo-Rogez, Julie C.; Feldman, Sabrina M.; Raymond, Carol A.

2016-09-01

Gamma rays produced passively by cosmic ray interactions and by the decay of radioelements convey information about the elemental makeup of planetary surfaces and atmospheres. Orbital missions mapped the composition of the Moon, Mars, Mercury, Vesta, and now Ceres. Active neutron interrogation will enable and/or enhance in situ measurements (rovers, landers, and sondes). Elemental measurements support planetary science objectives as well as resource utilization and planetary defense initiatives. Strontium iodide, an ultra-bright scintillator with low nonproportionality, offers significantly better energy resolution than most previously flown scintillators, enabling improved accuracy for identification and quantification of key elements. Lanthanum bromide achieves similar resolution; however, radiolanthanum emissions obscure planetary gamma rays from radioelements K, Th, and U. The response of silicon-based optical sensors optimally overlaps the emission spectrum of strontium iodide, enabling the development of compact, low-power sensors required for space applications, including burgeoning microsatellite programs. While crystals of the size needed for planetary measurements (>100 cm3) are on the way, pulse-shape corrections to account for variations in absorption/re-emission of light are needed to achieve maximum resolution. Additional challenges for implementation of large-volume detectors include optimization of light collection using silicon-based sensors and assessment of radiation damage effects and energetic-particle induced backgrounds. Using laboratory experiments, archived planetary data, and modeling, we evaluate the performance of strontium iodide for future missions to small bodies (asteroids and comets) and surfaces of the Moon and Venus. We report progress on instrument design and preliminary assessment of radiation damage effects in comparison to technology with flight heritage.

Simulation of collisional transport processes and the stability of planetary rings

NASA Technical Reports Server (NTRS)

Brophy, Thomas G.; Esposito, Larry W.

1989-01-01

The utility of the phase-space fluid method for the study of planetary ring dynamics is presently demonstrated through the numerical solution of a model kinetic equation for a flattened Keplerian disk. Attention is given to ringlets composed of single-sized particles, as well as to ringlets composed of two different-sized particles; in the latter case, the ringlets evolve in such a way that the lighter particles are confined by the heavier ones. The results obtained indicate that some natural process may sharpen the optical depth profile of edges even without an external forcing mechanism, and that intermediate optical depths are dynamically preferred in some cases.

The composition and structure of planetary rings

NASA Technical Reports Server (NTRS)

Burns, J. A.

1985-01-01

The properties of planetary ring systems are summarized herein; emphasis is given to the available evidence on their compositions and to their dynamical attributes. Somewhat contaminated water ice makes up the vast expanse of Saturn's rings. Modified methane ice may comprise Uranus' rings while silicates are the likely material of the Jovian ring. Saturn's rings form an elaborate system whose characteristics are still being documented and whose nature is being unravelled following the Voyager flybys. Uranus' nine narrow bands display an intriguing dynamical structure thought to be caused by unseen shephard satellites. Jupiter's ring system is a mere wisp, probably derived as ejecta off hidden parent bodies.

Equilibrium Conditions of Sediment Suspending Flows on Earth, Mars and Titan

NASA Astrophysics Data System (ADS)

Amy, L. A.; Dorrell, R. M.

2016-12-01

Sediment entrainment, erosion and deposition by liquid water on Earth is one of the key processes controlling planetary surface evolution. Similar modification of planetary surfaces by liquids associated with a volatile cycle are also inferred to have occurred on other planets (e.g., water on Mars and methane-ethane on Titan). Here we explore conditions for equilibrium flow - the threshold between net sediment erosion and deposition - on different planets. We use a new theoretical model for particle erosion-suspension-deposition: this model shows a better fit to empirical data than comparative suspension criterions (e.g., Rouse Number) since it takes into account both flow competence and capacity, and particle size distribution effects. Shear stresses required to initially entrain sediment and maintain equilibrium flow vary significantly, being several times lower on Mars and more than ten times lower on Titan resulting principally from lower gravities. On all planets it is harder to maintain equilibrium flow as sediment mixtures become poorer sorted (higher shear stresses are needed as standard deviation increases). In comparison to large differences in critical shear stresses, critical slopes for equilibrium flow are similar for planets. Compared to Earth, equilibrium slopes on Mars should be slightly lower whilst those on Titan will be higher or lower for organic and ice particle systems, respectively. Particle size distribution has a similar, order of magnitude effect, on equilibrium slope on each planet. The results highlight that whilst reduced gravity on Titan and Mars significantly decreases the bed shear stress required for particle transport, it also proportionally effects the bed shear stress of moving fluid, such that similar slope gradients are required for equilibrium flow; minor variations in equilibrium slopes are related to differences in the particle-fluid density contrasts as well as fluid viscosities. These results help explain why planetary surfaces share striking similarities in their present or past landscapes and shows that particle size distribution is critical to sediment transport dynamics. Interestingly, particle distribution may vary between planets depending on the particle compositions and weathering regimes, imposing differences in equilibrium conditions.

Navigating the MESSENGER Spacecraft through End of Mission

NASA Astrophysics Data System (ADS)

Bryan, C. G.; Williams, B. G.; Williams, K. E.; Taylor, A. H.; Carranza, E.; Page, B. R.; Stanbridge, D. R.; Mazarico, E.; Neumann, G. A.; O'Shaughnessy, D. J.; McAdams, J. V.; Calloway, A. B.

2015-12-01

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft orbited the planet Mercury from March 2011 until the end of April 2015, when it impacted the planetary surface after propellant reserves used to maintain the orbit were depleted. This highly successful mission was led by the principal investigator, Sean C. Solomon, of Columbia University. The Johns Hopkins University Applied Physics Laboratory (JHU/APL) designed and assembled the spacecraft and served as the home for spacecraft operations. Spacecraft navigation for the entirety of the mission was provided by the Space Navigation and Flight Dynamics Practice (SNAFD) of KinetX Aerospace. Orbit determination (OD) solutions were generated through processing of radiometric tracking data provided by NASA's Deep Space Network (DSN) using the MIRAGE suite of orbital analysis tools. The MESSENGER orbit was highly eccentric, with periapsis at a high northern latitude and periapsis altitude in the range 200-500 km for most of the orbital mission phase. In a low-altitude "hover campaign" during the final two months of the mission, periapsis altitudes were maintained within a narrow range between about 35 km and 5 km. Navigating a spacecraft so near a planetary surface presented special challenges. Tasks required to meet those challenges included the modeling and estimation of Mercury's gravity field and of solar and planetary radiation pressure, and the design of frequent orbit-correction maneuvers. Superior solar conjunction also presented observational modeling issues. One key to the overall success of the low-altitude hover campaign was a strategy to utilize data from an onboard laser altimeter as a cross-check on the navigation team's reconstructed and predicted estimates of periapsis altitude. Data obtained from the Mercury Laser Altimeter (MLA) on a daily basis provided near-real-time feedback that proved invaluable in evaluating alternative orbit estimation strategies, and eventually allowed the navigation team to settle on an approach that gave consistently accurate predictions. Thus, final mission success was truly the result of a collaborative effort between members of the science, mission operations, mission design, and navigation teams.

MESSENGER Observations of Mercury's Dynamic Magnetosphere During Three Flybys

NASA Astrophysics Data System (ADS)

Slavin, James; Krimigis, Stamatios; Anderson, Brian J.; Benna, Mehdi; Gold, Robert E.; Ho, George; McNutt, Ralph; Raines, James; Schriver, David; Solomon, Sean C.

MESSENGER's 14 January and 6 October 2008 and 29 September 2009 encounters with Mer-cury have provided new measurements of dynamic variations in the planet's coupled atmo-sphere-magnetosphere system. The three flybys took place under very different interplanetary magnetic field (IMF) conditions. Consistent with predictions of magnetospheric models for northward IMF, the neutral atmosphere was observed to have its strongest sources in the high latitude northern hemisphere for the first flyby. The southward IMF for the second encounter revealed a highly dynamic magnetosphere. Reconnection between the interplanetary and plan-etary magnetic fields is known to control the rate of energy transfer from the solar wind and to drive magnetospheric convection. The MESSENGER magnetic field measurements revealed that the rate at which interplanetary magnetic fields were reconnecting to the planetary fields was a factor of 10 greater than is usually observed at Earth. This extremely high reconnection rate results in a large magnetic field component normal to the magnetopause and the formation of flux transfer events that are much larger relative to the size of the forward magnetosphere than is observed at Earth. The resulting magnetospheric configuration allows the solar wind access to much of the dayside surface of Mercury. During MESSENGER's third Mercury flyby, a variable interplanetary magnetic field produced a series of several-minute-long enhancements of the tail magnetic field by factors of 2 to 3.5. The magnetic field flaring during these intervals indicates that they resulted from loading of the tail with magnetic flux transferred from the dayside magnetosphere. The unloading intervals were associated with plasmoids and traveling compression regions, signatures of tail reconnection. The peak tail magnetic flux during the smallest loading events equaled 30

A Modular Habitation System for Human Planetary and Space Exploration

NASA Technical Reports Server (NTRS)

Howe, A. Scott

2015-01-01

A small-diameter modular pressure vessel system is devised that can be applied to planetary surface and deep space human exploration missions. As one of the recommendations prepared for the NASA Human Spaceflight Architecture Team (HAT) Evolvable Mars Campaign (EMC), a compact modular system can provide a Mars-forward approach to a variety of missions and environments. Small cabins derived from the system can fit into the Space Launch System (SLS) Orion "trunk", or can be mounted with mobility systems to function as pressurized rovers, in-space taxis, ascent stage cabins, or propellant tanks. Larger volumes can be created using inflatable elements for long-duration deep space missions and planetary surface outposts. This paper discusses how a small-diameter modular system can address functional requirements, mass and volume constraints, and operational scenarios.

Robots and Humans in Planetary Exploration: Working Together?

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Lyons, Valerie (Technical Monitor)

2002-01-01

Today's approach to human-robotic cooperation in planetary exploration focuses on using robotic probes as precursors to human exploration. A large portion of current NASA planetary surface exploration is focussed on Mars, and robotic probes are seen as precursors to human exploration in: Learning about operation and mobility on Mars; Learning about the environment of Mars; Mapping the planet and selecting landing sites for human mission; Demonstration of critical technology; Manufacture fuel before human presence, and emplace elements of human-support infrastructure

Micro-technology for planetary exploration and education

NASA Technical Reports Server (NTRS)

Miller, David P.; Varsi, Giulio

1991-01-01

The use of combined miniaturization technology and distributed information systems in planetary exploration is discussed. Missions in which teams of microrovers collect samples from planetary surfaces are addressed, emphasizing the ability of rovers to provide coverage of large areas, reliability through redundancy, and participation of a large group of investigators. The latter could involve people from a variety of institutions, increasing the opportunity for wide education and the increased interest of society in general in space exploration. A three-phase program to develop the present approach is suggested.

Space telescopes planetary monitoring (PM) and Zvezdny (eng. star) patrol (ZP) for planetary science and exoplanets exploration

NASA Astrophysics Data System (ADS)

Tavrov, Alexander; Frolov, Pavel; Korablev, Oleg; Vedenkin, Nikolai; Barabanov, Sergey

2017-11-01

Solar System planetology requires a wide use of observing spectroscopy for surface geology to atmosphere climatology. A high-contrast imaging is required to study and to characterize extra-solar planetary systems among other faint astronomical targets observed in the vicinity of bright objects. Two middle class space telescopes projects aimed to observe Solar system planets by a long term monitoring via spectroscopy and polarimetry. Extra solar planets (exoplanets) engineering and scientific explorations are included in science program.

Regolith-Derived Heat Shield for Planetary Body Entry and Descent System with In-Situ Fabrication

NASA Technical Reports Server (NTRS)

Hogue, Michael D.; Mueller, Robert P.; Sibille, Laurent; Hintze, Paul E.; Rasky, Daniel J.

2012-01-01

High-mass planetary surface access is one of NASA's Grand Challenges involving entry, descent, and landing (EDL). Heat shields fabricated in-situ can provide a thermal protection system for spacecraft that routinely enter a planetary atmosphere. Fabricating the heat shield from extraterrestrial regolith will avoid the costs of launching the heat shield mass from Earth. This project investigated three methods to fabricate heat shield using extraterrestrial regolith and performed preliminary work on mission architectures.

Mass Wasting in Planetary Environments: Implications for Seismicity

NASA Technical Reports Server (NTRS)

Weber, Renee; Nahm, Amanda; Schmerr, Nick

2015-01-01

On Earth, mass wasting events such as rock falls and landslides are well known consequences of seismic activity. Here we investigate the regional effects of seismicity in planetary environments with the goal of determining whether such surface features on the Moon, Mars, and Mercury could be triggered by fault motion.

Detection techniques for tenuous planetary atmospheres

NASA Technical Reports Server (NTRS)

Hoenig, S. A.

1972-01-01

The research for the development of new types of detectors for analysis of planetary atmospheres is summarized. Topics discussed include: corona discharge humidity detector, surface catalysis and exo-electron emission, and analysis of soil samples by means of exo-electron emission. A report on the exo-electron emission during heterogeneous catalysis is included.

Technological innovations for human outposts on planetary bodies

NASA Technical Reports Server (NTRS)

Clark, Benton C.

1988-01-01

Technology developments which have applications for establishing man-tended outposts on the moon and Mars are reviewed. The development of pressurized rovers and computer-aided control, repair, and manufacturing is discussed. The possibility of utilizing aerodynamic drag by optimizing dynamic pressure to accomplish the necessary spacecraft velocity reduction for planetary orbital capture is considered and research in the development of artificial gravity is examined.

Microwave Processing of Planetary Surfaces for the Extraction of Volatiles

NASA Technical Reports Server (NTRS)

Ethridge, Edwin C.; Kaukler, William

2011-01-01

In-Situ Resource Utilization will be necessary for sustained exploration of space. Volatiles are present in planetary soils, but water by far has the most potential for effective utilization. The presence of water at the lunar poles, Mars, and possibly on Phobos opens the possibility of producing LOX for propellant. Water is also a useful radiation shielding material , and valuable to replenish expendables (water and oxygen) required for habitation in space. Because of the strong function of water vapor pressure with temperature, heating soil effectively liberates water vapor by sublimation. Microwave energy will penetrate soil and heat from within much more efficiently than heating from the surface with radiant heat. This is especially true under vacuum conditions since the heat transfer rate is very low. The depth of microwave penetration is a strong function of the microwave frequency and to a lesser extent on soil dielectric properties. Methods for complex electric permittivity and magnetic permeability measurement are being developed and used for measurements of lunar soil simulants. A new method for delivery of microwaves deep into a planetary surface is being prototyped with laboratory experiments and modeled with COMSOL MultiPhysics. We are planning to set up a planetary testbed in a large vacuum chamber in the coming year. Recent results are discussed.

Applications of Time-Reversal Processing for Planetary Surface Communications

NASA Technical Reports Server (NTRS)

Barton, Richard J.

2007-01-01

Due to the power constraints imposed on wireless sensor and communication networks deployed on a planetary surface during exploration, energy efficient transfer of data becomes a critical issue. In situations where groups of nodes within a network are located in relatively close proximity, cooperative communication techniques can be utilized to improve the range, data rate, power efficiency, and lifetime of the network. In particular, if the point-to-point communication channels on the network are well modeled as frequency non-selective, distributed or cooperative beamforming can employed. For frequency-selective channels, beamforming itself is not generally appropriate, but a natural generalization of it, time-reversal communication (TRC), can still be effective. Time-reversal processing has been proposed and studied previously for other applications, including acoustical imaging, electromagnetic imaging, underwater acoustic communication, and wireless communication channels. In this paper, we study both the theoretical advantages and the experimental performance of cooperative TRC for wireless communication on planetary surfaces. We give a brief introduction to TRC and present several scenarios where TRC could be profitably employed during planetary exploration. We also present simulation results illustrating the performance of cooperative TRC employed in a complex multipath environment and discuss the optimality of cooperative TRC for data aggregation in wireless sensor networks

Directly Imaged L-T Transition Exoplanets in the Mid-infrared

NASA Astrophysics Data System (ADS)

Skemer, Andrew J.; Marley, Mark S.; Hinz, Philip M.; Morzinski, Katie M.; Skrutskie, Michael F.; Leisenring, Jarron M.; Close, Laird M.; Saumon, Didier; Bailey, Vanessa P.; Briguglio, Runa; Defrere, Denis; Esposito, Simone; Follette, Katherine B.; Hill, John M.; Males, Jared R.; Puglisi, Alfio; Rodigas, Timothy J.; Xompero, Marco

2014-09-01

Gas-giant planets emit a large fraction of their light in the mid-infrared (gsim3 μm), where photometry and spectroscopy are critical to our understanding of the bulk properties of extrasolar planets. Of particular importance are the L- and M-band atmospheric windows (3-5 μm), which are the longest wavelengths currently accessible to ground-based, high-contrast imagers. We present binocular LBT adaptive optics (AO) images of the HR 8799 planetary system in six narrow-band filters from 3 to 4 μm, and a Magellan AO image of the 2M1207 planetary system in a broader 3.3 μm band. These systems encompass the five known exoplanets with luminosities consistent with L → T transition brown dwarfs. Our results show that the exoplanets are brighter and have shallower spectral slopes than equivalent temperature brown dwarfs in a wavelength range that contains the methane fundamental absorption feature (spanned by the narrow-band filters and encompassed by the broader 3.3 μm filter). For 2M1207 b, we find that thick clouds and non-equilibrium chemistry caused by vertical mixing can explain the object's appearance. For the HR 8799 planets, we present new models that suggest the atmospheres must have patchy clouds, along with non-equilibrium chemistry. Together, the presence of a heterogeneous surface and vertical mixing presents a picture of dynamic planetary atmospheres in which both horizontal and vertical motions influence the chemical and condensate profiles.

Formation of moon induced gaps in dense planetary rings

NASA Astrophysics Data System (ADS)

Grätz, F.; Seiß, M.; Spahn, F.

2017-09-01

Recent works have shown that bodies embedded in planetary rings create S-shaped density modula- tions called propellers if their mass deceeds a certain threshold or cause a gap around the entire circumference of the disc if the embedded bodies mass exceeds it. Two counteracting physical processes govern the dynamics and determine what structure is created: The gravitational disturber excerts a torque on nearby disc particles, sweeping them away from itself on both sides thus depleting the discs density and forming a gap. Diffusive spreading of the disc material due to collisions counteracts the gravitational scattering and has the tendency to fill the gap. We develop a nonlinear diffusion model that accounts for those two counteracting processes and describes the azimutally averaged surface density profile an embedded moon creates in planetary rings. The gaps width depends on the moons mass, its radial position and the rings viscosity allowing us to estimate the rings viscosity in the vicinity of the Encke and Keeler gap in Saturns A-Ring and compare it to previous measurements. We show that for the Keeler gap the time derivative of the semi-major axis as derived by Goldreich and Tremaine 1980 is underestimated yielding an underestimated viscosity for the ring. We therefore derive a corrected expression for said time derivative by fitting the solutions of Hill's equations for an ensemble of test particles. Furthermore we estimate the masses for potentionally unseen moonlets in the C-Ring and Cassini division.

Directly imaged L-T transition exoplanets in the mid-infrared {sup ,}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skemer, Andrew J.; Hinz, Philip M.; Morzinski, Katie M.

2014-09-01

Gas-giant planets emit a large fraction of their light in the mid-infrared (≳3 μm), where photometry and spectroscopy are critical to our understanding of the bulk properties of extrasolar planets. Of particular importance are the L- and M-band atmospheric windows (3-5 μm), which are the longest wavelengths currently accessible to ground-based, high-contrast imagers. We present binocular LBT adaptive optics (AO) images of the HR 8799 planetary system in six narrow-band filters from 3 to 4 μm, and a Magellan AO image of the 2M1207 planetary system in a broader 3.3 μm band. These systems encompass the five known exoplanets withmore » luminosities consistent with L → T transition brown dwarfs. Our results show that the exoplanets are brighter and have shallower spectral slopes than equivalent temperature brown dwarfs in a wavelength range that contains the methane fundamental absorption feature (spanned by the narrow-band filters and encompassed by the broader 3.3 μm filter). For 2M1207 b, we find that thick clouds and non-equilibrium chemistry caused by vertical mixing can explain the object's appearance. For the HR 8799 planets, we present new models that suggest the atmospheres must have patchy clouds, along with non-equilibrium chemistry. Together, the presence of a heterogeneous surface and vertical mixing presents a picture of dynamic planetary atmospheres in which both horizontal and vertical motions influence the chemical and condensate profiles.« less

Measurement of lunar and planetary magnetic fields by reflection of low energy electrons

NASA Technical Reports Server (NTRS)

Anderson, K. A.; Lin, R. P.; Mcguire, R. E.; Mccoy, J. E.

1975-01-01

The paper describes the technique of planetary electron reflection magnetometry (PERM), a method for measuring the magnitude, direction, and scale size of magnetic fields near the surface of the moon and other planetary bodies with weak and small-scale-size surface fields. It is noted that the PERM technique is based on the ability of magnetic fields to reflect charged particles. A qualitative account of the implementation of the technique is presented along with some results obtained by the Apollo 15 and 16 Particles and Fields subsatellites. The quantitative aspects of PERM are treated by examining solutions to the equation of motion of a charged particle in a magnetic field, computing reflection coefficients on the basis of trajectory calculations, and determining the direction of the lunar surface magnetic field. The sensitivity of the PERM technique is calculated, and effects of lunar electric fields and spacecraft potentials on the measurements are described. Extension of the technique to Mars and Venus is discussed.

Managing Science Operations During Planetary Surface: The 2010 Desert RATS Test

NASA Technical Reports Server (NTRS)

Eppler, Dean B.; Ming, D. W.

2011-01-01

Desert Research and Technology Studies (Desert RATS) is a multi-year series of hardware and operations tests carried out annually in the high desert of Arizona on the San Francisco Volcanic Field. Conducted since 1997, these activities are designed to exercise planetary surface hardware and operations in conditions where long-distance, multi-day roving is achievable. Such activities not only test vehicle subsystems through extended rough-terrain driving, they also stress communications and operations systems and allow testing of science operations approaches to advance human and robotic surface capabilities. Desert RATS is a venue where new ideas can be tested, both individually and as part of an operation with multiple elements. By conducting operations over multiple yearly cycles, ideas that make the cut can be iterated and tested during follow-on years. This ultimately gives both the hardware and the personnel experience in the kind of multi-element integrated operations that will be necessary in future human planetary exploration.

A gravitational potential finding for rotating cosmological body in the context of proto-planetary dynamics problem solving

NASA Astrophysics Data System (ADS)

Krot, Alexander M.

2008-09-01

The statistical theory for a cosmological body forming (so-called the spheroidal body model) has been proposed in [1]-[9]. Within the framework of this theory, bodies have fuzzy outlines and are represented by means of spheroidal forms [1],[2]. In the work [3], it has been investigated a slowly evolving in time process of a gravitational compression of a spheroidal body close to an unstable equilibrium state. In the papers [4],[5], the equation of motion of particles inside the weakly gravitating spheroidal body modeled by means of an ideal liquid has been obtained. Using Schwarzschild's and Kerr's metrics a consistency of the proposed statistical model with the general relativity has been shown in [6]. The proposed theory follows from the conception for forming a spheroidal body from protoplanetary nebula [7],[8]; it permits to derive the form of distribution functions for an immovable [1]-[5] and rotating spheroidal body [6]-[8] as well as their density masses and also the distribution function of specific angular momentum of the rotating uniformly spheroidal body [7],[8]. It is well-known there is not a statistical equilibrium in a gas-dust proto-planetary cloud because of long relaxation time for proto-planets formation in own gravitational field. This proto-planetary system behavior can be described by Jeans' equation in partial derivations relative to a distribution function [9]. The problem for finding a general solution of Jeans' equation is connected directly with an analytical expression for potential of gravitational field. Thus, the determination of gravitational potential is the main problem of statistical dynamics for proto-planetary system [9]. This work shows this task of proto-planetary dynamics can be solved on the basis of spheroidal bodies theory. The proposed theory permits to derive the form of gravitational potential for a rotating spheroidal body at a long distance from its center. Using the obtained analytical expression for potential of gravitational field, the gravitational strength (as well as angular momentum space function) in a remote zone of a slowly gravitational compressed rotating spheroidal body is obtained. As a result, a distribution function describing mechanical state of proto-planetary system can be found from the Jeans' equation. References: [1] Krot AM. The statistical model of gravitational interaction of particles. Uspekhi Sovremennoï Radioelektroniki (special issue "Cosmic Radiophysics", Moscow) 1996; 8: 66-81 (in Russian). [2] Krot AM. Use of the statistical model of gravity for analysis of nonhomogeneity in earth surface. Proc. SPIE's 13th Annual Intern. Symposium "AeroSense", Orlando, Florida, USA, April 5-9, 1999; 3710: 1248-1259. [3] Krot AM. Statistical description of gravitational field: a new approach. Proc. SPIE's 14th Annual Intern.Symposium "AeroSense", Orlando, Florida, USA, April 24-28, 2000; 4038: 1318-1329. [4] Krot AM. Gravidynamical equations for a weakly gravitating spheroidal body. Proc. SPIE's 15th Annual Intern. Symposium "AeroSense", Orlando, Florida, USA, April 16-20, 2001; 4394: 1271-1282. [5] Krot AM. Development of gravidynamical equations for a weakly gravitating body in the vicinity of absolute zero temperature. Proc. 53rd Intern. Astronautical Congress (IAC) - The 2nd World Space Congress-2002, Houston, Texas, USA, October 10-19, 2002; Preprint IAC-02-J.P.01: 1-11. [6] Krot AM. The statistical model of rotating and gravitating spheroidal body with the point of view of general relativity. Proc. 35th COSPAR Scientific Assembly, Paris, France, July 18-25, 2004; Abstract-Nr. COSPAR 04-A- 00162. [7] Krot A. The statistical approach to exploring formation of Solar system. Proc. European Geoscinces Union (EGU) General Assembly, Vienna, Austria, April 02-07, 2006; Geophysical Research Abstracts, vol. 8: EGU06-A- 00216, SRef-ID: 1607-7962/gra/. [8] Krot AM. The statistical model of original and evolution planets of Solar system and planetary satellities. Proc. European Planetary Science Congress, Berlin, Germany, September 18-22, 2006; Planetary Research Abstracts, ESPC2006-A-00014. [9] Krot A. On the principal difficulties and ways to their solution in the theory of gravitational condensation of infinitely distributed dust substance. Proc. XXIV IUGG General Assembly, Perugia, Italy, July 2-13, 2007; GS002 Symposium "Gravity Field", Abstract GS002-3598: 143-144.

Properties of thermospheric gravity waves on earth, Venus and Mars

NASA Technical Reports Server (NTRS)

Mayr, H. G.; Harris, I.; Pesnell, W. D.

1992-01-01

A spectral model with spherical harmonics and Fourier components that can simulate atmospheric perturbations in the global geometry of a multiconstituent atmosphere is presented. The boundaries are the planetary surface where the transport velocities vanish and the exobase where molecular heat conduction and viscosity dominate. The time consuming integration of the conservation equations is reduced to computing the transfer function (TF) which describes the dynamic properties of the medium divorced from the complexities in the temporal and horizontal variations of the excitation source. Given the TF, the atmospheric response to a chosen source distribution is then obtained in short order. Theoretical studies are presented to illuminate some properties of gravity waves on earth, Venus and Mars.

MECA Workshop on Atmospheric H2O Observations of Earth and Mars. Physical Processes, Measurements and Interpretations

NASA Technical Reports Server (NTRS)

Clifford, Stephen M. (Editor); Haberle, Robert M. (Editor)

1988-01-01

The workshop was held to discuss a variety of questions related to the detection and cycling of atmospheric water. Among the questions addressed were: what factors govern the storage and exchange of water between planetary surfaces and atmospheres; what instruments are best suited for the measurement and mapping of atmospheric water; do regolith sources and sinks of water have uniquely identifiable column abundance signatures; what degree of time and spatial resolution in column abundance data is necessary to determine dynamic behavior. Of special importance is the question, does the understanding of how atmospheric water is cycled on Earth provide any insights for the interpretation of Mars atmospheric data.

Characterization of Moving Dust Particles

NASA Technical Reports Server (NTRS)

Bos, Brent J.; Antonille, Scott R.; Memarsadeghi, Nargess

2010-01-01

A large depth-of-field Particle Image Velocimeter (PIV) has been developed at NASA GSFC to characterize dynamic dust environments on planetary surfaces. This instrument detects and senses lofted dust particles. We have been developing an autonomous image analysis algorithm architecture for the PIV instrument to greatly reduce the amount of data that it has to store and downlink. The algorithm analyzes PIV images and reduces the image information down to only the particle measurement data we are interested in receiving on the ground - typically reducing the amount of data to be handled by more than two orders of magnitude. We give a general description of PIV algorithms and describe only the algorithm for estimating the velocity of the traveling particles.

Bibliography. [of articles on moon and planets

NASA Technical Reports Server (NTRS)

Kopal, Z.; Moutsoulas, M.; Waranius, F. B.

1983-01-01

A bibliography of articles entered into the data base at the Lunar and Planetary Institute Library from November 1982 through January 1983 is presented. An abstract of each article is given. The subjects covered by the articles include: the motion of the moon and dynamics of the earth-moon system: shape and gravity field of the moon; the physical structure of the moon, its thermal and stress history; the morphology of the lunar surface, the origin and stratigraphy of lunar formations, and mapping of the moon; the chemical composition of the moon, lunar petrology, mineralogy, and crystallography; electromagnetic properties of the moon; the planets; and other objects, including asteroids, comets, meteorites, and cosmic dust.

DAME: planetary-prototype drilling automation.

PubMed

Glass, B; Cannon, H; Branson, M; Hanagud, S; Paulsen, G

2008-06-01

We describe results from the Drilling Automation for Mars Exploration (DAME) project, including those of the summer 2006 tests from an Arctic analog site. The drill hardware is a hardened, evolved version of the Advanced Deep Drill by Honeybee Robotics. DAME has developed diagnostic and executive software for hands-off surface operations of the evolved version of this drill. The DAME drill automation tested from 2004 through 2006 included adaptively controlled drilling operations and the downhole diagnosis of drilling faults. It also included dynamic recovery capabilities when unexpected failures or drilling conditions were discovered. DAME has developed and tested drill automation software and hardware under stressful operating conditions during its Arctic field testing campaigns at a Mars analog site.

DAME: Planetary-Prototype Drilling Automation

NASA Astrophysics Data System (ADS)

Glass, B.; Cannon, H.; Branson, M.; Hanagud, S.; Paulsen, G.

2008-06-01

We describe results from the Drilling Automation for Mars Exploration (DAME) project, including those of the summer 2006 tests from an Arctic analog site. The drill hardware is a hardened, evolved version of the Advanced Deep Drill by Honeybee Robotics. DAME has developed diagnostic and executive software for hands-off surface operations of the evolved version of this drill. The DAME drill automation tested from 2004 through 2006 included adaptively controlled drilling operations and the downhole diagnosis of drilling faults. It also included dynamic recovery capabilities when unexpected failures or drilling conditions were discovered. DAME has developed and tested drill automation software and hardware under stressful operating conditions during its Arctic field testing campaigns at a Mars analog site.

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration

NASA Technical Reports Server (NTRS)

Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Smith, E. J.; Yerazunis, S. W.

1971-01-01

Investigation of problems related to control of a mobile planetary vehicle according to a systematic plan for the exploration of Mars has been undertaken. Problem areas receiving attention include: (1) overall systems analysis; (2) vehicle configuration and dynamics; (3) toroidal wheel design and evaluation; (4) on-board navigation systems; (5) satellite-vehicle navigation systems; (6) obstacle detection systems; (7) terrain sensing, interpretation and modeling; (8) computer simulation of terrain sensor-path selection systems; and (9) chromatographic systems design concept studies. The specific tasks which have been undertaken are defined and the progress which has been achieved during the period July 1, 1971 to December 31, 1971 is summarized.

Assessment of surface turbulent fluxes using geostationary satellite surface skin temperatures and a mixed layer planetary boundary layer scheme

NASA Technical Reports Server (NTRS)

Diak, George R.; Stewart, Tod R.

1989-01-01

A method is presented for evaluating the fluxes of sensible and latent heating at the land surface, using satellite-measured surface temperature changes in a composite surface layer-mixed layer representation of the planetary boundary layer. The basic prognostic model is tested by comparison with synoptic station information at sites where surface evaporation climatology is well known. The remote sensing version of the model, using satellite-measured surface temperature changes, is then used to quantify the sharp spatial gradient in surface heating/evaporation across the central United States. An error analysis indicates that perhaps five levels of evaporation are recognizable by these methods and that the chief cause of error is the interaction of errors in the measurement of surface temperature change with errors in the assigment of surface roughness character. Finally, two new potential methods for remote sensing of the land-surface energy balance are suggested which will relay on space-borne instrumentation planned for the 1990s.

Lithosphere deformation methods and models constrained by surface fault data on Mars

NASA Astrophysics Data System (ADS)

Dimitrova, Lada L.

Models of lithospheric deformation tie observed field measurements of gravity and topography with surface observations of tectonic features. An understanding of the sources of stress, and the expected style, orientation, and magnitudes of stress and associated elastic strain is important for understanding the evolution of faulting on Mars and its relationship to loading. At the same time, theoretical models of deformation mechanisms and forces, when tied to tectonic observations, can be interpreted in terms of major tectonic events and allow insights into the planet's history and evolution as well as its internal structure and processes. This is particularly important for understanding solid planetary bodies other than Earth where the seismic data is either sparse, e.g. the Moon, or non-existent, e.g. Mars. This kind of research has implications for, and benefits from, an understanding of the petrology and surface processes. In this work, I use MGS MOLA and Radio Science data products (topography and gravity) to systematically test new geodynamic models and evaluate lithosphere dynamics on Mars as a function of time, while satisfying geologic surface observations (surface features) that have been and are being catalogued and studied from Viking, MOLA, MOC, and THEMIS IR images. I investigate (1) the role of internal loads (internal body force effects), (2) loading from the surface and base of lithosphere, and the effects of this loading on membrane and flexural strains and stresses, and (3) the role of global contraction, all viewed in the context of how the surface elastic layer has changed as the planet has evolved. I show that deviatoric stresses associated with gravitational potential differences do a good job at matching the normal faults; however, fitting all the surface-breaking faults is more difficult. I argue that global planetary contraction is an unlikely source of significant deformation. Instead, the simplest inverse models show that small lateral variations (1¡6%) in crust and mantle density in conjunction with small vertical displacement, O(100m), provide sufficient additional GPE and membrane stress to fit the majority of the data. These inverse models are consistent with lithosphere modification by erosion from running water.

Earthwalk

NASA Astrophysics Data System (ADS)

Muller, E.

2006-12-01

When the weather is nice, I like to take my students on a walk to the center of the earth. Earthwalk is a hands-on and feet-on activity that gets students outdoors, having fun, moving and learning about the structures of the earth. Earthwalk is a lesson to help students visualize our planets size and scale. This activity has students calculate the ratio of a scaled 100m cross-sectional earth, mark the boundaries between major planetary layers, walk from the center of the earth to the surface and draw proportional manmade and natural surface features (mountains, building, mine shafts, etc). This lesson effectively integrates content and pedagogy while touching on skills and topics such as math, measurement, science, writing skills (they have to take notes), reading, listening and group dynamics. This activity fits well into the earth science curriculum by introducing basic seismology; tectonic, geochemistry and heat transfer concepts. Besides showcasing this lesson, a limited number of Earth Anatomy posters will be distributed.

Exoplanets, extremophiles and habitability

NASA Astrophysics Data System (ADS)

Janot Pacheco, E.; Bernardes, L.

2012-09-01

Estimates of the average surface temperature and CO2 partial atmospheric pressure of already discovered exoplanets supposed to be in their Habitable Zone of their stars were surveyed from the Exoplanet Encyclopedia database. Moreover, since planetary surface temperature strongly depends on its albedo and geodynamic conditions, we have been feeding exoplanetary data into a comprehensive model of Earth's atmosphere to get better estimations. We also investigated the possible presence of "exomoons" belonging to giant planets capable of harbour dynamic stability and to retain atmospheric layers and keep geodynamic activity for long time spans. Collected information on biological data of micro-organisms classified as "extremophiles" indicate that such kind of microbial species could dwell in many of them. We thus propose an extension of the more astronomically defined "Habitable Zone" concept into the more astrobiologically "Extremophile Zone", taking into account other refined parameters allowing survival of more robust life forms.

Data Compression Algorithm Architecture for Large Depth-of-Field Particle Image Velocimeters

NASA Technical Reports Server (NTRS)

Bos, Brent; Memarsadeghi, Nargess; Kizhner, Semion; Antonille, Scott

2013-01-01

A large depth-of-field particle image velocimeter (PIV) is designed to characterize dynamic dust environments on planetary surfaces. This instrument detects lofted dust particles, and senses the number of particles per unit volume, measuring their sizes, velocities (both speed and direction), and shape factors when the particles are large. To measure these particle characteristics in-flight, the instrument gathers two-dimensional image data at a high frame rate, typically >4,000 Hz, generating large amounts of data for every second of operation, approximately 6 GB/s. To characterize a planetary dust environment that is dynamic, the instrument would have to operate for at least several minutes during an observation period, easily producing more than a terabyte of data per observation. Given current technology, this amount of data would be very difficult to store onboard a spacecraft, and downlink to Earth. Since 2007, innovators have been developing an autonomous image analysis algorithm architecture for the PIV instrument to greatly reduce the amount of data that it has to store and downlink. The algorithm analyzes PIV images and automatically reduces the image information down to only the particle measurement data that is of interest, reducing the amount of data that is handled by more than 10(exp 3). The state of development for this innovation is now fairly mature, with a functional algorithm architecture, along with several key pieces of algorithm logic, that has been proven through field test data acquired with a proof-of-concept PIV instrument.

Planetary landing-zone reconnaissance using ice-penetrating radar data: Concept validation in Antarctica

NASA Astrophysics Data System (ADS)

Grima, Cyril; Schroeder, Dustin M.; Blankenship, Donald D.; Young, Duncan A.

2014-11-01

The potential for a nadir-looking radar sounder to retrieve significant surface roughness/permittivity information valuable for planetary landing site selection is demonstrated using data from an airborne survey of the Thwaites Glacier Catchment, West Antarctica using the High Capability Airborne Radar Sounder (HiCARS). The statistical method introduced by Grima et al. (2012. Icarus 220, 84-99. http://dx.doi.org/10.1007/s11214-012-9916-y) for surface characterization is applied systematically along the survey flights. The coherent and incoherent components of the surface signal, along with an internally generated confidence factor, are extracted and mapped in order to show how a radar sounder can be used as both a reflectometer and a scatterometer to identify regions of low surface roughness compatible with a planetary lander. These signal components are used with a backscattering model to produce a landing risk assessment map by considering the following surface properties: Root mean square (RMS) heights, RMS slopes, roughness homogeneity/stationarity over the landing ellipse, and soil porosity. Comparing these radar-derived surface properties with simultaneously acquired nadir-looking imagery and laser-altimetry validates this method. The ability to assess all of these parameters with an ice penetrating radar expands the demonstrated capability of a principle instrument in icy planet satellite science to include statistical reconnaissance of the surface roughness to identify suitable sites for a follow-on lander mission.

Convective dynamics and chemical disequilibrium in the atmospheres of substellar objects

NASA Astrophysics Data System (ADS)

Bordwell, Baylee; Brown, Benjamin P.; Oishi, Jeffrey S.

2017-11-01

The thousands of substellar objects now known provide a unique opportunity to test our understanding of atmospheric dynamics across a range of environments. The chemical timescales of certain species transition from being much shorter than the dynamical timescales to being much longer than them at a point in the atmosphere known as the quench point. This transition leads to a state of dynamical disequilibrium, the effects of which can be used to probe the atmospheric dynamics of these objects. Unfortunately, due to computational constraints, models that inform the interpretation of these observations are run at dynamical parameters which are far from realistic values. In this study, we explore the behavior of a disequilibrium chemical process with increasingly realistic planetary conditions, to quantify the effects of the approximations used in current models. We simulate convection in 2-D, plane-parallel, polytropically-stratified atmospheres, into which we add reactive passive tracers that explore disequilibrium behavior. We find that as we increase the Rayleigh number, and thus achieve more realistic planetary conditions, the behavior of these tracers does not conform to the classical predictions of disequilibrium chemistry.

Nonlinear dynamics of global atmospheric and Earth-system processes

NASA Technical Reports Server (NTRS)

Saltzman, Barry; Ebisuzaki, Wesley; Maasch, Kirk A.; Oglesby, Robert; Pandolfo, Lionel

1990-01-01

Researchers are continuing their studies of the nonlinear dynamics of global weather systems. Sensitivity analyses of large-scale dynamical models of the atmosphere (i.e., general circulation models i.e., GCM's) were performed to establish the role of satellite-signatures of soil moisture, sea surface temperature, snow cover, and sea ice as crucial boundary conditions determining global weather variability. To complete their study of the bimodality of the planetary wave states, they are using the dynamical systems approach to construct a low-order theoretical explanation of this phenomenon. This work should have important implications for extended range forecasting of low-frequency oscillations, elucidating the mechanisms for the transitions between the two wave modes. Researchers are using the methods of jump analysis and attractor dimension analysis to examine the long-term satellite records of significant variables (e.g., long wave radiation, and cloud amount), to explore the nature of mode transitions in the atmosphere, and to determine the minimum number of equations needed to describe the main weather variations with a low-order dynamical system. Where feasible they will continue to explore the applicability of the methods of complex dynamical systems analysis to the study of the global earth-system from an integrative viewpoint involving the roles of geochemical cycling and the interactive behavior of the atmosphere, hydrosphere, and biosphere.

RESONANCES REQUIRED: DYNAMICAL ANALYSIS OF THE 24 Sex AND HD 200964 PLANETARY SYSTEMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wittenmyer, Robert A.; Horner, Jonathan; Tinney, C. G., E-mail: rob@phys.unsw.edu.au

We perform several suites of highly detailed dynamical simulations to investigate the architectures of the 24 Sextantis and HD 200964 planetary systems. The best-fit orbital solution for the two planets in the 24 Sex system places them on orbits with periods that lie very close to 2:1 commensurability, while that for the HD 200964 system places the two planets therein in orbits whose periods lie close to a 4:3 commensurability. In both cases, the proposed best-fit orbits are mutually crossing-a scenario that is only dynamically feasible if the planets are protected from close encounters by the effects of mutual mean-motionmore » resonance (MMR). Our simulations reveal that the best-fit orbits for both systems lie within narrow islands of dynamical stability, and are surrounded by much larger regions of extreme instability. As such, we show that the planets are only feasible if they are currently trapped in mutual MMR-the 2:1 resonance in the case of 24 Sex b and c, and the 4:3 resonance in the case of HD 200964 b and c. In both cases, the region of stability is strongest and most pronounced when the planetary orbits are mutually coplanar. As the inclination of planet c with respect to planet b is increased, the stability of both systems rapidly collapses.« less

Spacing of Kepler Planets: Sculpting by Dynamical Instability

NASA Astrophysics Data System (ADS)

Pu, Bonan; Wu, Yanqin

2015-07-01

We study the orbital architecture of multi-planet systems detected by the Kepler transit mission using N-body simulations, focusing on the orbital spacing between adjacent planets in systems showing four or more transiting planets. We find that the observed spacings are tightly clustered around 12 mutual Hill radii, when transit geometry and sensitivity limits are accounted for. In comparison, dynamical integrations reveal that the minimum spacing required for systems of similar masses to survive dynamical instability for as long as 1 billion yr is ∼10 if all orbits are circular and coplanar and ∼12 if planetary orbits have eccentricities of ∼0.02 (a value suggested by studies of planet transit-time variations). This apparent coincidence, between the observed spacing and the theoretical stability threshold, leads us to propose that typical planetary systems were formed with even tighter spacing, but most, except for the widest ones, have undergone dynamical instability, and are pared down to a more anemic version of their former selves, with fewer planets and larger spacings. So while the high-multiple systems (five or more transiting planets) are primordial systems that remain stable, the single or double planetary systems, abundantly discovered by the Kepler mission, may be the descendants of more closely packed high-multiple systems. If this hypothesis is correct, we infer that the formation environment of Kepler systems should be more dissipative than that of the terrestrial planets.

A modeling study of the thermosphere-ionosphere interactions during the boreal winter and spring 2015-2016: Tidal and planetary-scale waves effect on the ionospheric structure.

NASA Astrophysics Data System (ADS)

Sassi, F.; McDonald, S. E.; McCormack, J. P.; Tate, J.; Liu, H.; Kuhl, D.

2017-12-01

The 2015-2016 boreal winter and spring is a dynamically very interesting time in the lower atmosphere: a minor high latitude stratospheric warming occurred in February 2016; an interrupted descent of the QBO was found in the tropical stratosphere; and a large warm ENSO took place in the tropical Pacific Ocean. The stratospheric warming, the QBO and ENSO are known to affect in different ways the meteorology of the upper atmosphere in different ways: low latitude solar tides and high latitude planetary-scale waves have potentially important implications on the structure of the ionosphere. In this study, we use global atmospheric analyses from a high-altitude version of the High-Altitude Navy Global Environmental Model (HA-NAVGEM) to constrain the meteorology of numerical simulations of the Specified Dynamics Whole Atmosphere Community Climate Model, extended version (SD-WACCM-X). We describe the large-scale behavior of tropical tides and mid-latitude planetary waves that emerge in the lower thermosphere. The effect on the ionosphere is captured by numerical simulations of the Navy Highly Integrated Thermosphere Ionosphere Demonstration System (Navy-HITIDES) that uses the meteorology generated by SD-WACCM-X to drive ionospheric simulations during this time period. We will analyze the impact of various dynamical fields on the zonal behavior of the ionosphere by selectively filtering the relevant dynamical modes.

Photopolarimetry of scattering surfaces and their interpretation by computer model

NASA Technical Reports Server (NTRS)

Wolff, M.

1979-01-01

Wolff's computer model of a rough planetary surface was simplified and revised. Close adherence to the actual geometry of a pitted surface and the inclusion of a function for diffuse light resulted in a quantitative model comparable to observations by planetary satellites and asteroids. A function is also derived to describe diffuse light emitted from a particulate surface. The function is in terms of the indices of refraction of the surface material, particle size, and viewing angles. Computer-generated plots describe the observable and theoretical light components for the Moon, Mercury, Mars and a spectrum of asteroids. Other plots describe the effects of changing surface material properties. Mathematical results are generated to relate the parameters of the negative polarization branch to the properties of surface pitting. An explanation is offered for the polarization of the rings of Saturn, and the average diameter of ring objects is found to be 30 to 40 centimeters.

Improved data reduction algorithm for the needle probe method applied to in-situ thermal conductivity measurements of lunar and planetary regoliths

NASA Astrophysics Data System (ADS)

Nagihara, Seiichi; Hedlund, Magnus; Zacny, Kris; Taylor, Patrick T.

2014-03-01

The needle probe method (also known as the ‘hot wire’ or ‘line heat source’ method) is widely used for in-situ thermal conductivity measurements on terrestrial soils and marine sediments. Variants of this method have also been used (or planned) for measuring regolith on the surfaces of extra-terrestrial bodies (e.g., the Moon, Mars, and comets). In the near-vacuum condition on the lunar and planetary surfaces, the measurement method used on the earth cannot be simply duplicated, because thermal conductivity of the regolith can be ~2 orders of magnitude lower. In addition, the planetary probes have much greater diameters, due to engineering requirements associated with the robotic deployment on extra-terrestrial bodies. All of these factors contribute to the planetary probes requiring a much longer time of measurement, several tens of (if not over a hundred) hours, while a conventional terrestrial needle probe needs only 1 to 2 min. The long measurement time complicates the surface operation logistics of the lander. It also negatively affects accuracy of the thermal conductivity measurement, because the cumulative heat loss along the probe is no longer negligible. The present study improves the data reduction algorithm of the needle probe method by shortening the measurement time on planetary surfaces by an order of magnitude. The main difference between the new scheme and the conventional one is that the former uses the exact mathematical solution to the thermal model on which the needle probe measurement theory is based, while the latter uses an approximate solution that is valid only for large times. The present study demonstrates the benefit of the new data reduction technique by applying it to data from a series of needle probe experiments carried out in a vacuum chamber on a lunar regolith simulant, JSC-1A. The use of the exact solution has some disadvantage, however, in requiring three additional parameters, but two of them (the diameter and the volumetric heat capacity of the probe) can be measured and the other (the volumetric heat capacity of the regolith/stimulant) may be estimated from the surface geologic observation and temperature measurements. Therefore, overall, the new data reduction scheme would make in-situ thermal conductivity measurement more practical on planetary missions.

Improved Data Reduction Algorithm for the Needle Probe Method Applied to In-Situ Thermal Conductivity Measurements of Lunar and Planetary Regoliths

NASA Technical Reports Server (NTRS)

Nagihara, S.; Hedlund, M.; Zacny, K.; Taylor, P. T.

2013-01-01

The needle probe method (also known as the' hot wire' or 'line heat source' method) is widely used for in-situ thermal conductivity measurements on soils and marine sediments on the earth. Variants of this method have also been used (or planned) for measuring regolith on the surfaces of extra-terrestrial bodies (e.g., the Moon, Mars, and comets). In the near-vacuum condition on the lunar and planetary surfaces, the measurement method used on the earth cannot be simply duplicated, because thermal conductivity of the regolith can be approximately 2 orders of magnitude lower. In addition, the planetary probes have much greater diameters, due to engineering requirements associated with the robotic deployment on extra-terrestrial bodies. All of these factors contribute to the planetary probes requiring much longer time of measurement, several tens of (if not over a hundred) hours, while a conventional terrestrial needle probe needs only 1 to 2 minutes. The long measurement time complicates the surface operation logistics of the lander. It also negatively affects accuracy of the thermal conductivity measurement, because the cumulative heat loss along the probe is no longer negligible. The present study improves the data reduction algorithm of the needle probe method by shortening the measurement time on planetary surfaces by an order of magnitude. The main difference between the new scheme and the conventional one is that the former uses the exact mathematical solution to the thermal model on which the needle probe measurement theory is based, while the latter uses an approximate solution that is valid only for large times. The present study demonstrates the benefit of the new data reduction technique by applying it to data from a series of needle probe experiments carried out in a vacuum chamber on JSC-1A lunar regolith stimulant. The use of the exact solution has some disadvantage, however, in requiring three additional parameters, but two of them (the diameter and the volumetric heat capacity of the probe) can be measured and the other (the volumetric heat capacity of the regolith/stimulant) may be estimated from the surface geologic observation and temperature measurements. Therefore, overall, the new data reduction scheme would make in-situ thermal conductivity measurement more practical on planetary missions.

Updated symbol catalogue for geologic and geomorphologic mapping in Planetary Scinces

NASA Astrophysics Data System (ADS)

Nass, Andrea; Fortezzo, Corey; Skinner, James, Jr.; Hunter, Marc; Hare, Trent

2017-04-01

Maps are one of the most powerful communication tools for spatial data. This is true for terrestrial data, as well as the many types of planetary data. Geologic and/or geomorphologic maps of planetary surfaces, in particular those of the Moon, Mars, and Venus, are standardized products and often prepared as a part of hypothesis-driven science investigations. The NASA-funded Planetary Geologic Mapping program, coordinated by the USGS Astrogeology Science Center (ASC), produces high-quality, standardized, and refereed geologic maps and digital databases of planetary bodies. In this context, 242 geologic, geomorphologic, and thematic map sheets and map series have been published since the 1962. However, outside of this program, numerous non-USGS published maps are created as result of scientific investigations and published, e.g. as figures or supplemental materials within a peer-reviewed journal article. Due to the complexity of planetary surfaces, diversity between different planet surfaces, and the varied resolution of the data, geomorphologic and geologic mapping is a challenging task. Because of these limiting conditions, the mapping process is a highly interpretative work and is mostly limited to remotely sensed satellite data - with a few expetions from rover data. Uniform and an unambiguous data are fundamental to make quality observations that lead to unbiased and supported interpretations, especially when there is no current groundtruthing. To allow for correlation between different map products (digital or analog), the most commonly used spatial objects are predefined cartographic symbols. The Federal Geographic Data Committee (FGDC) Digital Cartographic Standard for Geologic Map Symbolization (DCSGMS) defines the most commonly used symbols, colors, and hatch patterns in one comprehensive document. Chapter 25 of the DCSGMS defines the Planetary Geology Features based on the symbols defined in the Venus Mapper's Handbook. After reviewing the 242 planetary geological maps, we propose to 1) review standardized symbols for planetary maps, and 2) recommend an updated symbol collection for adoption by the planetary mapping community. Within these points, the focus is on the changing of symbology with respect to time and how it effects communication within and between the maps. Two key questions to address are 1) does chapter 25 provides enough variability within the subcategories (e.g., faults) to represent the data within the maps? 2) How recommendations to the mapping community and their steering committees could be delivered to enhance a map's communicability, and convey information succinctly but thoroughly. For determining the most representative symbol collection of existing maps to support future map results (within or outside of USGS mapping program) we defined a stepwise task list: 1) Statistical review of existing symbol sets and collections, 2) Establish a representative symbol set for planetary mapping, 3) Update cartographic symbols, 4) Implementation into GIS-based mapping software (this implementation will mimic the 2010 application of the planetary symbol set into ArcGIS (more information https://planetarymapping.wr.usgs.gov/Project). 6) Platform to provide the symbol set to the mapping community. This project was initiated within an ongoing cooperation work between the USGS ASC and the German Aerospace Center (DLR), Dept. of Planetary Geology.

Charged dust dynamics - Orbital resonance due to planetary shadows

NASA Technical Reports Server (NTRS)

Horanyi, M.; Burns, J. A.

1991-01-01

The dynamics of a weakly charged dust grain orbiting in the equatorial plane of a planet surrounded by a rigidly corotating magnetospehre is examined. It is shown that an introduction of an effectilve 1D potential causes a perturbation due to electrostatic forces, which induces a motion of the pericenter, similar to the effect of the planetary oblateness. A case is examined where the charge varies periodically due to the modulation of the photoelectron current occurring as the grain enters and leaves the planetary shadow, causing the electromagnetic perturbation to resonate with the orbital period and to modify the size and eccentricity of the orbit. This effect is demonstrated both numerically and analytically for small grains comprising the Jovian ring, showing that their resulting changes are periodic, and their amplitude is much larger than that of the periodic changes due to light-pressure perturbation or the secular changes due to resonant charge variations that develop over a comparable time span.

A non-ideal MHD model for structure formation

NASA Astrophysics Data System (ADS)

Karmakar, Pralay Kumar; Sarma, Pankaj

2018-02-01

The evolutionary initiation dynamics of triggered planetary structure formation is indeed a complex process yet to be well understood. We herein develop a theoretical classical model to see the gravitational fragmentation kinetics of the viscoelastic non-ideal magneto-hydro-dynamic (MHD) fabric. The inhomogeneous planetary disk is primarily composed of heavier dust grains (strongly correlated) together with relatively lighter electrons, ions and neutrals (weakly correlated) in a mean-fluidic approximation. A normal harmonic mode analysis results in a quadratic dispersion relation of a unique shape. It is demonstrated that the growth rate of the MHD fluctuations (magnetosonic) contributing to the planet formation rate, apart from the wave vector and its projection orientation, has a pure explicit dependency on the viscoelastic parameters. The analysis specifically shows that the effective generalized viscosity (χ) , viscoelastic relaxation time (τm) , and K-orientation (θ) play as destabilizing agencies against the non-local gravitational disk collapse. The relevancy is briefly indicated in the real astronomical context of bounded planetary structure formation and evolution.

Planetary Magnetic Fields: Planetary Interiors and Habitability

NASA Astrophysics Data System (ADS)

Lazio, T. Joseph W.; Shkolnik, Evgenya; Hallinan, Gregg; Planetary Habitability Study Team

2016-06-01

The W. M. Keck Institute for Space Studies (KISS) sponsored the Planetary Magnetic Fields: Planetary Interiors and Habitability Study to review the state of knowledge of extrasolar planetary magnetic fields and the prospects for their detection. There were multiple motivations for this Study. Planetary-scale magnetic fields are a window to a planet's interior and provide shielding of the planet's atmosphere. The Earth, Mercury, Ganymede, and the giant planets of the solar system all contain internal dynamo currents that generate planetary-scale magnetic fields. In turn, these internal dynamo currents arise from differential rotation, convection, compositional dynamics, or a combination of these in objects' interiors. If coupled to an energy source, such as the incident kinetic or magnetic energy from the solar wind or an orbiting satellite, a planet's magnetic field can produce intense electron cyclotron masers in its magnetic polar regions. The most well known example of this process in the solar system is the Jovian decametric emission, but all of the giant planets and the Earth contain similar electron cyclotron masers within their magnetospheres. Extrapolated to extrasolar planets, the remote detection of the magnetic field of an extrasolar planet would provide a means of obtaining constraints on the thermal state, composition, and dynamics of its interior--all of which will be difficult to determine by other means--as well as improved understanding of the basic planetary dynamo process. This report presents the findings from the Study, including potential mission concepts that emerged and future work in both modeling and observations. There was also an identification of that radio wavelength observations would likely be key to making significant progress in this field. The entire Study program would not have been possible without the generous support of the W. M. Keck Foundation. We thank Michele Judd, Tom Prince, and the staff of the W. M. Keck Institute for Space Studies for their hospitality and attention to detail, such that the Study participants could turn their attention to focused discussions and innovative ideas. We also thank Charles ("Chuck") Carter of Eagre Games, Inc., for his assistance with graphics.

Future Lunar Sampling Missions: Big Returns on Small Samples

NASA Astrophysics Data System (ADS)

Shearer, C. K.; Borg, L.

2002-01-01

The next sampling missions to the Moon will result in the return of sample mass (100g to 1 kg) substantially smaller than those returned by the Apollo missions (380 kg). Lunar samples to be returned by these missions are vital for: (1) calibrating the late impact history of the inner solar system that can then be extended to other planetary surfaces; (2) deciphering the effects of catastrophic impacts on a planetary body (i.e. Aitken crater); (3) understanding the very late-stage thermal and magmatic evolution of a cooling planet; (4) exploring the interior of a planet; and (5) examining volatile reservoirs and transport on an airless planetary body. Can small lunar samples be used to answer these and other pressing questions concerning important solar system processes? Two potential problems with small, robotically collected samples are placing them in a geologic context and extracting robust planetary information. Although geologic context will always be a potential problem with any planetary sample, new lunar samples can be placed within the context of the important Apollo - Luna collections and the burgeoning planet-scale data sets for the lunar surface and interior. Here we illustrate the usefulness of applying both new or refined analytical approaches in deciphering information locked in small lunar samples.

Proceedings of the 40th Lunar and Planetary Science Conference

NASA Technical Reports Server (NTRS)

2009-01-01

The 40th Lunar and Planetary Science Conference included sessions on: Phoenix: Exploration of the Martian Arctic; Origin and Early Evolution of the Moon; Comet Wild 2: Mineralogy and More; Astrobiology: Meteorites, Microbes, Hydrous Habitats, and Irradiated Ices; Phoenix: Soil, Chemistry, and Habitability; Planetary Differentiation; Presolar Grains: Structures and Origins; SPECIAL SESSION: Venus Atmosphere: Venus Express and Future Missions; Mars Polar Caps: Past and Present; SPECIAL SESSION: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1, Part I; 5 Early Nebula Processes and Models; SPECIAL SESSION: Icy Satellites of Jupiter and Saturn: Cosmic Gymnasts; Mars: Ground Ice and Climate Change; SPECIAL SESSION: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1, Part II; Chondrite Parent-Body Processes; SPECIAL SESSION: Icy Satellites of Jupiter and Saturn: Salubrious Surfaces; SNC Meteorites; Ancient Martian Crust: Primary Mineralogy and Aqueous Alteration; SPECIAL SESSION: Messenger at Mercury: A Global Perspective on the Innermost Planet; CAIs and Chondrules: Records of Early Solar System Processes; Small Bodies: Shapes of Things to Come; Sulfur on Mars: Rocks, Soils, and Cycling Processes; Mercury: Evolution and Tectonics; Venus Geology, Volcanism, Tectonics, and Resurfacing; Asteroid-Meteorite Connections; Impacts I: Models and Experiments; Solar Wind and Genesis: Measurements and Interpretation; Mars: Aqueous Processes; Magmatic Volatiles and Eruptive Conditions of Lunar Basalts; Comparative Planetology; Interstellar Matter: Origins and Relationships; Impacts II: Craters and Ejecta Mars: Tectonics and Dynamics; Mars Analogs I: Geological; Exploring the Diversity of Lunar Lithologies with Sample Analyses and Remote Sensing; Chondrite Accretion and Early History; Science Instruments for the Mars Science Lander; . Martian Gullies: Morphology and Origins; Mars: Dunes, Dust, and Wind; Mars: Volcanism; Early Solar System Chronology; Seek Out and Explore: Upcoming and Future Missions; Mars: Early History and Impact Processes; Mars Analogs II: Chemical and Spectral; Achondrites and their Parent Bodies; and Planning for Future Exploration of the Moon The poster sessions were: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1; LRO and LCROSS; Geophysical Analysis of the Lunar Surface and Interior; Remote Observation and Geologic Mapping of the Lunar Surface; Lunar Spectroscopy; Venus Geology, Geophysics, Mapping, and Sampling; Planetary Differentiation; Bunburra and Buzzard Coulee: Recent Meteorite Falls; Meteorites: Terrestrial History; CAIs and Chondrules: Records of Early Solar System Processes; Volatile and Organic Compounds in Chondrites; Crashing Chondrites: Impact, Shock, and Melting; Ureilite Studies; Petrology and Mineralogy of the SNC Meteorites; Martian Meteorites; Phoenix Landing Site: Perchlorate and Other Tasty Treats; Mars Polar Atmospheres and Climate Modeling; Mars Polar Investigations; Mars Near-Surface Ice; Mars: A Volatile-Rich Planet; Mars: Geochemistry and Alteration Processes; Martian Phyllosilicates: Identification, Formation, and Alteration; Astrobiology; Instrument Concepts, Systems, and Probes for Investigating Rocks and Regolith; Seeing is Believing: UV, VIS, IR, X- and Gamma-Ray Camera and Spectrometer Instruments; Up Close and Personal: In Situ Analysis with Laser-Induced Breakdown Spectroscopy and Mass Spectrometry; Jupiter and Inscrutable Io; Tantalizing Titan; Enigmatic Enceladus and Intriguing Iapetus; Icy Satellites: Cryptic Craters; Icy Satellites: Gelid Geology/Geophysics; Icy Satellites: Cool Chemistry and Spectacular Spectroscopy; Asteroids and Comets; Comet Wild 2: Mineralogy and More; Hypervelocity Impacts: Stardust Models, LDEF, and ISPE; Presolar Grains; Early Nebular Processes: Models and Isotopes; Solar Wind and Genesis: Measurements and Interpretation; Education and Public Outreach; Mercury; Pursuing Lunar Exploration; Sources and Eruptionf Lunar Basalts; Chemical and Physical Properties of the Lunar Regolith; Lunar Dust and Transient Surface Phenomena; Lunar Databases and Data Restoration; Meteoritic Samples of the Moon; Chondrites, Their Clasts, and Alteration; Achondrites: Primitive and Not So Primitive; Iron Meteorites; Meteorite Methodology; Antarctic Micrometeorites; HEDs and Vesta; Dust Formation and Transformation; Interstellar Organic Matter; Early Solar System Chronology; Comparative Planetology; Impacts I: Models and Experiments; Impacts II: Craters and Ejecta; Mars: Volcanism; Mars: Tectonics and Dynamics; Martian Stratigraphy: Understanding the Geologic History of Mars Through the Sedimentary Rock Record; Mars: Valleys and Valley Networks; Mars: Aqueous Processes in Valles Marineris and the Southern Highlands; Mars: Aqueous Geomorphology; Martian Gullies: Morphology and Origins; Mars: Dunes, Dust, and Wind; Mars: Remote Sensing; Mars: Geologic Mapping, Photogrammetry, and Cratering; Martian Mineralogy: Constraints from Missions and Laboratory Investigations; Mars Analogs: Chemical and Physical; Mars Analogs: Sulfates and Sulfides; Missions: Approaches, Architectures, Analogs, and Actualities; Not Just Skin Deep: Electron Microscopy, Heat Flow, Radar, and Seismology Instruments and Planetary Data Systems, Techniques, and Interpretation.

Dynamical effects of stellar companions

NASA Astrophysics Data System (ADS)

Naoz, Smadar

2015-08-01

The fraction of stellar binaries in the field is extremely high (about 40% - 70% for > 1 Msun stars), and thus, given this frequency, a large fraction of all exoplanetary systems may reside in binaries. While close-in giant planets tend to be found preferentially in binary stellar systems it seems that the frequency of giant planets in close binaries (<100 AU) is significantly lower than in the overall population. Stellar companions’ gravitational perturbations may significantly alter the planetary orbits around their partner on secular timescales. They can drive planets to large eccentric orbits which can either result in plunging these planets into the star or shrinking their orbits and forming short period planets. I will review the dynamical effects stellar binaries have on a planetary systems. I will also present new results on the influence that stellar evolution has on the dynamical processes in these systems.

Special issue on enabling open and interoperable access to Planetary Science and Heliophysics databases and tools

NASA Astrophysics Data System (ADS)

2018-01-01

The large amount of data generated by modern space missions calls for a change of organization of data distribution and access procedures. Although long term archives exist for telescopic and space-borne observations, high-level functions need to be developed on top of these repositories to make Planetary Science and Heliophysics data more accessible and to favor interoperability. Results of simulations and reference laboratory data also need to be integrated to support and interpret the observations. Interoperable software and interfaces have recently been developed in many scientific domains. The Virtual Observatory (VO) interoperable standards developed for Astronomy by the International Virtual Observatory Alliance (IVOA) can be adapted to Planetary Sciences, as demonstrated by the VESPA (Virtual European Solar and Planetary Access) team within the Europlanet-H2020-RI project. Other communities have developed their own standards: GIS (Geographic Information System) for Earth and planetary surfaces tools, SPASE (Space Physics Archive Search and Extract) for space plasma, PDS4 (NASA Planetary Data System, version 4) and IPDA (International Planetary Data Alliance) for planetary mission archives, etc, and an effort to make them interoperable altogether is starting, including automated workflows to process related data from different sources.

REVIEWS OF TOPICAL PROBLEMS: Generation of large-scale eddies and zonal winds in planetary atmospheres

NASA Astrophysics Data System (ADS)

Onishchenko, O. G.; Pokhotelov, O. A.; Astafieva, N. M.

2008-06-01

The review deals with a theoretical description of the generation of zonal winds and vortices in a turbulent barotropic atmosphere. These large-scale structures largely determine the dynamics and transport processes in planetary atmospheres. The role of nonlinear effects on the formation of mesoscale vortical structures (cyclones and anticyclones) is examined. A new mechanism for zonal wind generation in planetary atmospheres is discussed. It is based on the parametric generation of convective cells by finite-amplitude Rossby waves. Weakly turbulent spectra of Rossby waves are considered. The theoretical results are compared to the results of satellite microwave monitoring of the Earth's atmosphere.

Planet formation

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.

1993-01-01

Models of planetary formation are developed using the present single example of a planetary system, supplemented by limited astrophysical observations of star-forming regions and circumstellar disks. The solar nebula theory and the planetesimal hypothesis are discussed. The latter is found to provide a viable theory of the growth of the terrestrial planets, the cores of the giant planets, and the smaller bodies present in the solar system. The formation of solid bodies of planetary size should be a common event, at least around young stars which do not have binary companions orbiting at planetary distances. Stochastic impacts of large bodies provide sufficient angular momentum to produce the obliquities of the planets. The masses and bulk compositions of the planets can be understood in a gross sense as resulting from planetary growth within a disk whose temperature and surface density decreased with distance from the growing sun.

An IFU-view of Planetary Nebulae: Exploring NGC 6720 (Ring Nebula) with KCWI

NASA Astrophysics Data System (ADS)

Hoadley, Keri; Matuszewski, Matt; Hamden, Erika; Martin, Christopher; Neill, Don; Kyne, Gillian

2018-01-01

Studying the interaction between the ejected stellar material and interstellar clouds is important for understanding how stellar deaths influences the pollution of matter that will later form other stars. Planetary nebulae provide ideal laboratories to study such interactions. I will present on a case study of one close-by planetary nebula, the Ring Nebula (M 57, NGC 6720), to infer the abundances, temperatures, structures, and dynamics of important atomic and ionic species in two distinct regions of the nebula using a newly-commissioned integral field spectrograph (IFS) on Keck: the Keck Cosmic Web Imager (KCWI). The advantage of an IFS over traditional filter-imaging techniques is the ability to simultaneously observe the spectrum of any given pixel in the imaging area, which provides crucial information about the dynamics of the observed region. This technique is powerful for diffuse or extended astrophysical objects, and I will demonstrate the different imaging and spectral modes of KCWI used to observe the Ring Nebula.KCWI observations of the Ring Nebula focused mainly on the innermost region of the nebula, with a little coverage of the Inner Ring. We also observed the length of the Ring in one set of observations, for which we will estimate the elemental abundances, temperatures, and dynamics of the region. KCWI observations also capture an inner arc and blob that have distinctly difference characteristics than the Ring itself and may be a direct observation of either the planetary nebula ramming into an interstellar cloud projected onto the sightline or a dense interstellar cloud being illuminated by the stellar continuum from the hot central white dwarf.

The impact of boundary layer turbulence on snow growth and precipitation: Idealized Large Eddy Simulations

NASA Astrophysics Data System (ADS)

Chu, Xia; Xue, Lulin; Geerts, Bart; Kosović, Branko

2018-05-01

Ice particles and supercooled droplets often co-exist in planetary boundary-layer (PBL) clouds. The question examined in this numerical study is how large turbulent PBL eddies affect snow growth and surface precipitation from mixed-phase PBL clouds. In order to simplify this question, this study assumes an idealized BL with well-developed turbulence but no surface heat fluxes or radiative heat exchanges. Large Eddy Simulations with and without resolved PBL turbulence are compared. This comparison demonstrates that the impact on snow growth in mixed-phase clouds is controlled by two opposing mechanisms, a microphysical and a dynamical one. The cloud microphysical impact of large turbulent eddies is based on the difference in saturation vapor pressure over water and over ice. The net outcome of alternating turbulent up- and downdrafts is snow growth by diffusion and/or accretion (riming). On the other hand, turbulence-induced entrainment and detrainment may suppress snow growth. In the case presented herein, the net effect of these microphysical and dynamical processes is positive, but in general the net effect depends on ambient conditions, in particular the profiles of temperature, humidity, and wind.

Photoelectric Emission Measurements on the Analogs of Individual Cosmic Dust Grains

NASA Technical Reports Server (NTRS)

Abbas, M. M.; Tankosic, D.; Craven, P. D.; Spann, J. F.; LeClair, A.; West, E. A.; Weingartner, J. C.; Tielens, A. G. G. M.; Nuth, J. a.; Camata, R. P.

2006-01-01

The photoelectric emission process is considered to be the dominant mechanism for charging of cosmic dust grains in many astrophysical environments. The grain charge and equilibrium potentials play an important role in the dynamical and physical processes that include heating of the neutral gas in the interstellar medium, coagulation processes in the dust clouds, and levitation and dynamical processes in the interplanetary medium and planetary surfaces and rings. An accurate evaluation of photoelectric emission processes requires knowledge of the photoelectric yields of individual dust grains of astrophysical composition as opposed to the values obtained from measurements on flat surfaces of bulk materials, as it is generally assumed on theoretical considerations that the yields for the small grains are much different from the bulk values. We present laboratory measurements of the photoelectric yields of individual dust grains of silica, olivine, and graphite of approx. 0.09-5 micrometer radii levitated in an electrodynamic balance and illuminated with ultraviolet radiation at 120-160 nm wavelengths. The measured yields are found to be substantially higher than the bulk values given in the literature and indicate a size dependence with larger particles having order-of-magnitude higher values than for submicron-size grains.

Phototelectric Emission Measurements on the Analogs of Individual Cosmic Dust Grains

NASA Technical Reports Server (NTRS)

Abbas, Mian M.; Tankosic, D.; Craven, P. D.; Spann, J. F.; LeClair, A.; West, E. A.; Weingartner, J. C.; Tielens, A. G. G. M.; Nuth, J. A.; Camata, R. P.;

Studies of planetary upper atmospheres through occultations

NASA Technical Reports Server (NTRS)

Elliot, J. L.

1982-01-01

The structure, composition, dynamics and energy balance of planetary upper atmospheres through interpretation of steller occultation data from Uranus is discussed. The wave-optical problem of modelling strong scintillation for arbitrary turbulent atmospheres is studied, as well as influence of turbulence. It was concluded that quasi-global features of atmospheric structure are accurately determined by numerical inversion. Horizontally inhomogeneous structures are filtered out and have little effect on temperature profiles.

Visualization experiences and issues in Deep Space Exploration

NASA Technical Reports Server (NTRS)

Wright, John; Burleigh, Scott; Maruya, Makoto; Maxwell, Scott; Pischel, Rene

2003-01-01

The panelists will discuss their experiences in collecting data in deep space, transmitting it to Earth, processing and visualizing it here, and using the visualization to drive the continued mission. This closes the loop, making missions more responsive to their environment, particularly in-situ operations on planetary surfaces and within planetary atmospheres.

Planetary quarantine. Space research and technology

NASA Technical Reports Server (NTRS)

1973-01-01

The impact of satisfying satellite quarantine constraints on outer planet missions and spacecraft design are studied by considering the effects of planetary radiation belts, solar wind radiation, and space vacuum on microorganism survival. Post launch recontamination studies evaluate the effects of mission environments on particle distributions on spacecraft surfaces and effective cleaning and decontamination techniques.

A Vertically Resolved Planetary Boundary Layer

NASA Technical Reports Server (NTRS)

Helfand, H. M.

1984-01-01

Increase of the vertical resolution of the GLAS Fourth Order General Circulation Model (GCM) near the Earth's surface and installation of a new package of parameterization schemes for subgrid-scale physical processes were sought so that the GLAS Model GCM will predict the resolved vertical structure of the planetary boundary layer (PBL) for all grid points.

A geographic comparison of selected large-scale planetary surface features

NASA Technical Reports Server (NTRS)

Meszaros, S. P.

1984-01-01

Photographic and cartographic comparisons of geographic features on Mercury, the Moon, Earth, Mars, Ganymede, Callisto, Mimas, and Tethys are presented. Planetary structures caused by impacts, volcanism, tectonics, and other natural forces are included. Each feature is discussed individually and then those of similar origin are compared at the same scale.

Lunar and Planetary Science Conference, 9th, Houston, Tex., March 13-17, 1978, Proceedings. Volume 2 - Lunar and planetary surfaces

NASA Technical Reports Server (NTRS)

Merrill, R. B.

1978-01-01

Regolith studies are summarized with attention given to isotope and solar wind effects, core studies, and soil maturation and agglutinates. Consideration is also given to radiometric, cosmic-ray and track chronologies for meteorites and lunar samples and to lunar impact phenomena.

A high performance neutron spectrometer for planetary hydrogen measurement

NASA Astrophysics Data System (ADS)

Naito, Masayuki; Hasebe, Nobuyuki; Nagaoka, Hiroshi; Ishii, Junya; Aoki, Daisuke; Shibamura, Eido; Kim, Kyeong J.; Matias-Lopes, José A.; Martínez-Frías, Jesús

2017-08-01

The elemental composition and its distribution on planetary surface provide important constraints on the origin and evolution of the planetary body. The nuclear spectrometer consisting of a neutron spectrometer and a gamma-ray spectrometer obtains elemental compositions by remote sensing. Especially, the neutron spectrometer is able to determine the hydrogen concentration, a piece of information that plays an important role in thermal history of the planets. In this work, numerical and experimental studies on the neutron spectrometer for micro-satellite application were conducted. It is found that background count rate of neutron produced from micro-satellite is very small, which enables to obtain successful results in short time observation. The neutron spectrometer combining a lithium-6 glass scintillator with a boron loaded plastic scintillator was used to be able to detect neutrons in different energy ranges. It was experimentally confirmed that the neutron signals from these scintillators were successfully discriminated by the difference of scintillation decay time between two detectors. The measurement of neutron count rates of two scintillators is found to determine hydrogen concentration on the planetary surfaces in the future missions.

The signatures of the parental cluster on field planetary systems

NASA Astrophysics Data System (ADS)

Cai, Maxwell Xu; Portegies Zwart, Simon; van Elteren, Arjen

2018-03-01

Due to the high stellar densities in young clusters, planetary systems formed in these environments are likely to have experienced perturbations from encounters with other stars. We carry out direct N-body simulations of multiplanet systems in star clusters to study the combined effects of stellar encounters and internal planetary dynamics. These planetary systems eventually become part of the Galactic field population as the parental cluster dissolves, which is where most presently known exoplanets are observed. We show that perturbations induced by stellar encounters lead to distinct signatures in the field planetary systems, most prominently, the excited orbital inclinations and eccentricities. Planetary systems that form within the cluster's half-mass radius are more prone to such perturbations. The orbital elements are most strongly excited in the outermost orbit, but the effect propagates to the entire planetary system through secular evolution. Planet ejections may occur long after a stellar encounter. The surviving planets in these reduced systems tend to have, on average, higher inclinations and larger eccentricities compared to systems that were perturbed less strongly. As soon as the parental star cluster dissolves, external perturbations stop affecting the escaped planetary systems, and further evolution proceeds on a relaxation time-scale. The outer regions of these ejected planetary systems tend to relax so slowly that their state carries the memory of their last strong encounter in the star cluster. Regardless of the stellar density, we observe a robust anticorrelation between multiplicity and mean inclination/eccentricity. We speculate that the `Kepler dichotomy' observed in field planetary systems is a natural consequence of their early evolution in the parental cluster.

Simulated CO2 Snowfalls and Baroclinic Waves in the Northern Winter Polar Atmosphere on Mars: Feasibility of Forecasts

NASA Astrophysics Data System (ADS)

Kuroda, T.; Medvedev, A. S.; Kasaba, Y.; Hartogh, P.

2013-12-01

The seasonal CO2 polar cap is formed from ice particles that have fallen from the atmosphere as well as those condensed directly on the surface. The possible occurrence of CO2 snowfall in the winter polar regions have been observed, and previous simulation studies have indicated that the longitudinal irregularities of CO2 ice clouds in the northern polar region seemed to be linked to local weather phenomena. Transient planetary waves are the prominent dynamical feature during northern winters in the martian atmosphere, and this study focuses on revealing the mechanism of how the dynamical influence of transient planetary waves affects the occurrences of CO2 ice clouds, snowfalls and formations of seasonal CO2 polar cap in high latitudes during northern winters. The DRAMATIC (Dynamics, RAdiation, MAterial Transport and their mutual InteraCtions) MGCM, which is used for this study, is based on a Japanese terrestrial model (CCSR/NIES/FRCGC MIROC) with a spectral solver for the three-dimensional primitive equations. In this simulation the horizontal resolution is set at about 5.6° × 5.6° (~333 km at equator), the vertical grid consists of 69 σ-levels with the top of the model at about 100 km. Realistic topography, albedo, thermal inertia and roughness data for the Mars surface are included. Radiative effects of CO2 gas (considering only LTE) and dust, in solar and infrared wavelengths, are taken into account. We have implemented a simple scheme representing the formation and transport of CO2 ice clouds into our MGCM, and investigated snowfall in high latitudes during northern winters. The MGCM simulations showed that the CO2 ice clouds are formed at altitudes of up to ~40 km in the northern polar region (northward of 70° N) during winter, which is consistent with the observations (MRO-MCS and MGS-MOLA). In addition, we found that the occurrence of the CO2 ice clouds correlated to a large degree with the cold phases of transient planetary waves. In the altitudes above ~15 km, the cloud formations are very much aligned with the baroclinic waves with zonal wavenumber of 1 and 5-6 sols period. In the lower altitudes the baroclinic waves components with shorter periods (~3 sols) also affect the cloud formations. The fate of ice particles during sedimentation depends on the thermal structure below because it takes ~0.2 sols for particles to descend from 25 km to the surface, which is much shorter than the periods of the transient waves. We found that ice particles formed up to ~20 km can reach the surface in the form of snowfall in certain longitude regions (in 30° W-60° E), while in others these particles likely sublimate in the lower warmer atmospheric layers. Given the regular nature of such atmospheric waves on Mars, the results of this study suggest that the snowstorms may be predicted several weeks in advance. It is simply impossible to predict the snowfall somewhere on Earth in such a long time ahead, but this may be different on Mars. For missions to Mars aiming to explore these regions with rovers, such weather forecasts would offer the possibility of choosing a route that avoids heavy snow storms.

Dynamical ocean-atmospheric drivers of floods and droughts

NASA Astrophysics Data System (ADS)

Perdigão, Rui A. P.; Hall, Julia

2014-05-01

The present study contributes to a better depiction and understanding of the "facial expression" of the Earth in terms of dynamical ocean-atmospheric processes associated to both floods and droughts. For this purpose, the study focuses on nonlinear dynamical and statistical analysis of ocean-atmospheric mechanisms contributing to hydrological extremes, broadening the analytical hydro-meteorological perspective of floods and hydrological droughts to driving mechanisms and feedbacks at the global scale. In doing so, the analysis of the climate-related causality of hydrological extremes is not limited to the synoptic situation in the region where the events take place. Rather, it goes further in the train of causality, peering into dynamical interactions between planetary-scale ocean and atmospheric processes that drive weather regimes and influence the antecedent and event conditions associated to hydrological extremes. In order to illustrate the approach, dynamical ocean-atmospheric drivers are investigated for a selection of floods and droughts. Despite occurring in different regions with different timings, common underlying mechanisms are identified for both kinds of hydrological extremes. For instance, several analysed events are seen to have resulted from a large-scale atmospheric situation consisting on standing planetary waves encircling the northern hemisphere. These correspond to wider vortices locked in phase, resulting in wider and more persistent synoptic weather patterns, i.e. with larger spatial and temporal coherence. A standing train of anticyclones and depressions thus encircled the mid and upper latitudes of the northern hemisphere. The stationary regime of planetary waves occurs when the mean eastward zonal flow decreases up to a point in which it no longer exceeds the westward phase propagation of the Rossby waves produced by the latitude-varying Coriolis effect. The ocean-atmospheric causes for this behaviour and consequences on hydrological extremes are investigated and the findings supported with spatiotemporal geostatistical analysis and nonlinear geophysical models. Overall, the study provides a three-fold contribution to the research on hydrological extremes: Firstly, it improves their physical attribution by better understanding the dynamical reasons behind the meteorological drivers. Secondly, it brings out fundamental early warning signs for potential hydrological extremes, by bringing out global ocean-atmospheric features that manifest themselves much earlier than the regional weather patterns. Thirdly, it provides tools for addressing and understanding hydrological regime changes at wider spatiotemporal scales, by providing links to planetary-scale dynamical processes that play a crucial role in multi-decadal global climate variability.

Self-Shadowing of a Spacecraft in the Computation of Surface Forces. An Example in Planetary Geodesy

NASA Astrophysics Data System (ADS)

Balmino, G.; Marty, J. C.

2018-03-01

We describe in details the algorithms used in modelling the self-shadowing between spacecraft components, which appears when computing the surface forces as precisely as possible and especially when moving parts are involved. This becomes necessary in planetary geodesy inverse problems using more and more precise orbital information to derive fundamental parameters of geophysical interest. Examples are given with two Mars orbiters, which show significant improvement on drag and solar radiation pressure model multiplying factors, a prerequisite for improving in turn the determination of other global models.

Perspectives future space on robotics

NASA Technical Reports Server (NTRS)

Lavery, Dave

1994-01-01

Last year's flight of the German ROTEX robot flight experiment heralded the start of a new era for space robotics. ROTEX is the first of at least 10 new robotic systems and experiments that will fly before 2000. These robots will augment astronaut on-orbit capabilities and extend virtual human presence to lunar and planetary surfaces. The robotic systems to be flown in the next five years fall into three categories: extravehicular robotic (EVR) servicers, science payload servicers, and planetary surface rovers. A description of the work on these systems is presented.

What's new on the moon?

NASA Technical Reports Server (NTRS)

1976-01-01

As a result of the Apollo program and other lunar probes, questions that remained unsolved during centuries of speculation and scientific study can now be answered concerning the composition, core, surface, age, and history of the moon. Data obtained from lunar samples and instruments on the lunar surface are being used to gain insight into the history of the earth and the other planets, planetary evolution, the development of planetary magnetic fields, the nature of the solar wind, and how the Sun operates. Projects suggested for using the moon to increase understanding of geophysics are described.

Photodegradation of selected organics on Mars

NASA Astrophysics Data System (ADS)

ten Kate, I. L.; Boosman, A.; Fornaro, T.; King, H. E.; Kopacz, K. A.; Wolthers, M.

2017-09-01

At least as much as 2.4 million kg of unaltered organic material is estimated to be delivered to the Martian surface each year. However, intense UV irradiation and the highly oxidizing and acidic nature of Martian soil cause degradation of organic compounds. Here we present first results obtained with the recently developed PALLAS facility at Utrecht University. This facility is specifically designed to simulate planetary and asteroid surface conditions to study the photocatalytic properties of relevant planetary minerals. Our results tentatively show degradation of several compounds and preservation of others.

Two-step Laser Time-of-Flight Mass Spectrometry to Elucidate Organic Diversity in Planetary Surface Materials.

NASA Technical Reports Server (NTRS)

Getty, Stephanie A.; Brinckerhoff, William B.; Cornish, Timothy; Li, Xiang; Floyd, Melissa; Arevalo, Ricardo Jr.; Cook, Jamie Elsila; Callahan, Michael P.

2013-01-01

Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) holds promise to be a low-mass, compact in situ analytical capability for future landed missions to planetary surfaces. The ability to analyze a solid sample for both mineralogical and preserved organic content with laser ionization could be compelling as part of a scientific mission pay-load that must be prepared for unanticipated discoveries. Targeted missions for this instrument capability include Mars, Europa, Enceladus, and small icy bodies, such as asteroids and comets.

Dynamical lifetime of the new Oort Cloud comets under planetary perturbations

NASA Astrophysics Data System (ADS)

Ito, T.; Higuchi, A.

2014-07-01

Nearly-isotropic comets with very long orbital period are supposed to come from the Oort Cloud. Recent observational and theoretical studies have greatly revealed the dynamical nature of this cloud and its evolutional history, but many issues are yet to be known. Our goal is to trace the dynamical evolution of the Oort Cloud new comets (OCNCs) produced by an evolving comet cloud, hopefully estimating the fraction of OCNCs embedded in the current populations of the solar system small bodies. We combine two models to follow the dynamical evolution of OCNCs beginning from their production until their ejection out of the solar system, obtaining statistics of the dynamical lifetime of OCNCs: The first model is a semi-analytical one about the OCNC production in an evolving comet cloud under the perturbation of the galactic tide and stellar encounters. The second model numerically deals with planetary perturbation over OCNCs' dynamics in planetary region. The main results of the present study are: (1) Typical dynamical lifetime of OCNCs in our models turned out to be O(10^7) years. Once entering into the planetary region, most OCNCs stay there just for this timespan, then get ejected out of the solar system on hyperbolic orbits. (2) While average orbital inclination of OCNCs is small, the so-called ''planet barrier'' works rather effectively, preventing some OCNCs from penetrating into the terrestrial planetary region. Models. Recently a series of detailed dynamical studies with similar scientific objects to ours are published [1-3]. Our present study is an extension of our own independent project [4], using a pair of dynamical models. The first model is for the evolving Oort Cloud that produces OCNCs along its evolution [5,6]. The model initially starts from a planar planetesimal disk, which evolves into a three- dimensional, nearly isotropic shape over a timespan of Gyr under the perturbation by the galactic tide and stellar encounters. This model is largely analytical in order to reduce the amount of computation. The second one is a numerical model for incorporating planetary perturbation from the major seven planets except Mercury, similar to the framework of our previous studies [7,8]. It receives OCNCs from the first model, and traces the orbital evolution of the comets up to 500 Myr until they get ejected out of the solar system by being scattered away. The second model does not include the galactic tide or stellar perturbation. For further reduction of computation amount, we assume that OCNCs go along their Keplerian orbits beyond r = 800 au without any perturbations. The effect of the galactic tide that OCNCs would have during this period is separately evaluated using a perturbation function that includes the galactic tide used in the first model. Results. We selected two different eras among the Oort Cloud history: (a) the initial 1 Gyr while the comet cloud is still nearly planar with a high OCNC production rate, and (b) the period t =4-5 Gyr when the comet cloud is almost in an isotropic shape with nearly constant supply of OCNCs. It turned out that most of the OCNCs got scattered away by the four giant planets (i.e being ejected out of the system with r > 800 au and e > 1, or aphelion distance becoming larger than Q >2 × 10^5 au) with a typical timespan of O(10^7) years in the planetary region. This timescale is roughly consistent with an analytical estimate in [9]. Also, this timescale does not strongly dependent on which era we choose, as the range of OCNC's semimajor axis is similar to each other. To get an estimate as to which planet has the largest dynamical influence on the fate of OCNCs, we calculated the number of planetary encounters defined by OCNC's close approaches within 500 × scatter radius of planets, r_{s} (r_{s} is a typical distance when a massless body's orbit gets bent 90 degrees by scattering. It is proportional to (relative velocity){}^{-2}). A simple analysis shows that Jupiter and Saturn play a dominant role on scattering OCNCs away from the system. There has been a concept called the ''Jupiter barrier'' where giant planets such as Jupiter protect the Earth from cometary bombardments (e.g. [10,11]). Our study partially validates this hypothesis, showing that the planetary barrier actually works when the incoming OCNC flux is nearly planar as in the era (a). The main barrier is composed by Saturn with an aid by Jupiter, making OCNCs' perihelia stick around Saturn's orbit. Once the comet cloud has become isotropic as in the era (b), OCNCs come from almost any directions, and the barrier no longer works. This is just the situation in the current solar system.

Natural motion around the Martian moon Phobos: the dynamical substitutes of the Libration Point Orbits in an elliptic three-body problem with gravity harmonics

NASA Astrophysics Data System (ADS)

Zamaro, M.; Biggs, J. D.

2015-07-01

The Martian moon Phobos is becoming an appealing destination for future scientific missions. The orbital dynamics around this planetary satellite is particularly complex due to the unique combination of both small mass-ratio and length-scale of the Mars-Phobos couple: the resulting sphere of influence of the moon is very close to its surface, therefore both the classical two-body problem and circular restricted three-body problem (CR3BP) do not provide an accurate approximation to describe the spacecraft's dynamics in the vicinity of Phobos. The aim of this paper is to extend the model of the CR3BP to consider the orbital eccentricity and the highly-inhomogeneous gravity field of Phobos, by incorporating the gravity harmonics series expansion into an elliptic R3BP, named ER3BP-GH. Following this, the dynamical substitutes of the Libration Point Orbits (LPOs) are computed in this more realistic model of the relative dynamics around Phobos, combining methodologies from dynamical systems theory and numerical continuation techniques. Results obtained show that the structure of the periodic and quasi-periodic LPOs differs substantially from the classical case without harmonics. Several potential applications of these natural orbits are presented to enable unique low-cost operations in the proximity of Phobos, such as close-range observation, communication, and passive radiation shielding for human spaceflight. Furthermore, their invariant manifolds are demonstrated to provide high-performance natural landing and take-off pathways to and from Phobos' surface, and transfers from and to Martian orbits. These orbits could be exploited in upcoming and future space missions targeting the exploration of this Martian moon.

MicroMED: a dust particle counter for the characterization of airborne dust close to the surface of Mars

NASA Astrophysics Data System (ADS)

Cozzolino, Fabio; Esposito, Francesca; Molfese, Cesare; Cortecchia, Fausto; Saggin, Bortolino; D'amato, Francesco

2015-04-01

Monitoring of airborne dust is very important in planetary climatology. Indeed, dust absorbs and scatter solar and thermal radiation, severely affecting atmospheric thermal structure, balance and dynamics (in terms of circulations). Wind-driven blowing of sand and dust is also responsible for shaping planetary surfaces through the formation of sand dunes and ripples, the erosion of rocks, and the creation and transport of soil particles. Dust is permanently present in the atmosphere of Mars and its amount varies with seasons. During regional or global dust storms, more than 80% of the incoming sunlight is absorbed by dust causing an intense atmospheric heating. Airborne dust is therefore a crucial climate component on Mars which impacts atmospheric circulations at all scales. Main dust parameters influencing the atmosphere heating are size distribution, abundance, albedo, single scattering phase function, imaginary part of the index of refraction. Moreover, major improvements of Mars climate models require, in addition to the standard meteorological parameters, quantitative information about dust lifting, transport and removal mechanisms. In this context, two major quantities need to be measured for the dust source to be understood: surface flux and granulometry. While many observations have constrained the size distribution of the dust haze seen from the orbit, it is still not known what the primary airborne dust (e.g. the recently lifted dust) is made of, size-wise. MicroMED has been designed to fill this gap. It will measure the abundance and size distribution of dust, not in the atmospheric column, but close to the surface, where dust is lifted, so to be able to monitor dust injection into the atmosphere. This has never been performed in Mars and other planets exploration. MicroMED is an Optical Particle Counter, analyzing light scattered from single dust particles to measure their size and abundance. A proper fluid-dynamic system, including a pump and a sampling head, allows the sampling of Martian atmosphere with embedded dust. The captured dust grains are detected by an Optical System and then ejected into the atmosphere. MicroMED is a miniaturization of the instrument MEDUSA, developed for the Humboldt payload of the ExoMars mission. An Elegant Breadboard has been developed and tested and successfully demonstrates the instrument performances. The design and performance test results will be discussed.

Planetary Geologic Mapping Handbook - 2010. Appendix

NASA Technical Reports Server (NTRS)

Tanaka, K. L.; Skinner, J. A., Jr.; Hare, T. M.

2010-01-01

Geologic maps present, in an historical context, fundamental syntheses of interpretations of the materials, landforms, structures, and processes that characterize planetary surfaces and shallow subsurfaces. Such maps also provide a contextual framework for summarizing and evaluating thematic research for a given region or body. In planetary exploration, for example, geologic maps are used for specialized investigations such as targeting regions of interest for data collection and for characterizing sites for landed missions. Whereas most modern terrestrial geologic maps are constructed from regional views provided by remote sensing data and supplemented in detail by field-based observations and measurements, planetary maps have been largely based on analyses of orbital photography. For planetary bodies in particular, geologic maps commonly represent a snapshot of a surface, because they are based on available information at a time when new data are still being acquired. Thus the field of planetary geologic mapping has been evolving rapidly to embrace the use of new data and modern technology and to accommodate the growing needs of planetary exploration. Planetary geologic maps have been published by the U.S. Geological Survey (USGS) since 1962. Over this time, numerous maps of several planetary bodies have been prepared at a variety of scales and projections using the best available image and topographic bases. Early geologic map bases commonly consisted of hand-mosaicked photographs or airbrushed shaded-relief views and geologic linework was manually drafted using mylar bases and ink drafting pens. Map publishing required a tedious process of scribing, color peel-coat preparation, typesetting, and photo-laboratory work. Beginning in the 1990s, inexpensive computing, display capability and user-friendly illustration software allowed maps to be drawn using digital tools rather than pen and ink, and mylar bases became obsolete. Terrestrial geologic maps published by the USGS now are primarily digital products using geographic information system (GIS) software and file formats. GIS mapping tools permit easy spatial comparison, generation, importation, manipulation, and analysis of multiple raster image, gridded, and vector data sets. GIS software has also permitted the development of projectspecific tools and the sharing of geospatial products among researchers. GIS approaches are now being used in planetary geologic mapping as well. Guidelines or handbooks on techniques in planetary geologic mapping have been developed periodically. As records of the heritage of mapping methods and data, these remain extremely useful guides. However, many of the fundamental aspects of earlier mapping handbooks have evolved significantly, and a comprehensive review of currently accepted mapping methodologies is now warranted. As documented in this handbook, such a review incorporates additional guidelines developed in recent years for planetary geologic mapping by the NASA Planetary Geology and Geophysics (PGG) Program's Planetary Cartography and Geologic Mapping Working Group's (PCGMWG) Geologic Mapping Subcommittee (GEMS) on the selection and use of map bases as well as map preparation, review, publication, and distribution. In light of the current boom in planetary exploration and the ongoing rapid evolution of available data for planetary mapping, this handbook is especially timely.

Investigations of charged particle motion on the surfaces of dusty, airless solar system bodies (Invited)

NASA Astrophysics Data System (ADS)

Dove, A.; Colwell, J. E.

2013-12-01

Dynamic charging conditions exist on the dusty surfaces of planetary bodies such as the Moon, asteroids, and the moons of Mars. On these so-called 'airless bodies', the motions of dust particles above the surface become complex due to grain-grain and grain-plasma interactions. For example, tribocharging and other charge transfer processes can occur due to relative dust grain movements, and charged dust grains immersed in plasma interact with local electromagnetic forces. This is thought to lead to effects such as the lunar 'horizon glow,' (Rennilson and Criswell, 1974, The Moon, 10) and potential dusty 'fountains' above the lunar surface (Stubbs et al., 2006, Adv. Sp. Res., 37). Regolith grains can be mobilized by impacts or other mechanical disturbances, or simply by the Coulomb force acting on grains. Previous work has increased our theoretical understanding of the behavior of charged particles in these low-gravity environments (i.e. Poppe and Horanyi, 2010, JGR, A115; Colwell et al., 2007, Rev. Geophys., 45 (and references therein)). Experimental work has also analyzed grain surface charging due to plasma or tribocharging (Sickafoose et al., 2001, JGR, 106) and the motion of grains on surfaces in the presence of an electric field (Wang et al., 2009, JGR, 114). Occasionally, there is disagreement between theoretical predictions and observations. We present the results of new laboratory experiments aimed at understanding particle charging and the dynamics of charged particles on the surfaces of airless bodies. In the initial experiments, we analyze the motion of particles in the presence of an electric field in vacuum, either in a bell-jar or in a 0.75-second microgravity drop tower experiment box. Prior to motion, particles may be charged due to triboelectric effects, plasma interactions, or a combination of the two. Motion is induced by shaking or by low-velocity impacts in order to simulate the natural motion of slow-moving objects on regolith surfaces, or induced motion such as that due to a spacecraft. The resulting particle dynamics are tracked using high-speed, high-resolution video. Future exploration on or near the surfaces of airless bodies will certainly experience complications arising from these dusty environments, where particles may contaminate or interfere with the operation of almost any mechanical equipment. By exploring the dynamic behavior of charged particles in these environments, we can work towards solutions that will enable exploration.

Radiation pressure dynamics in planetary exospheres - A 'natural' framework

NASA Technical Reports Server (NTRS)

Bishop, James; Chamberlain, Joseph W.

1989-01-01

Exospheric theory is reformulated to provide for the analysis of dynamical underpinning of exospheric features. The formulation is based on the parabolic-cylindrical separability of the Hamiltonian that describes particle motions in the combined fields of planetary gravity and solar radiation pressure. An approximate solution for trajectory evolution in terms of orbital elements is derived and the role of the exopause in the tail phenomenon is discussed. Also, an expression is obtained for the bound constituent atom densities at outer planetocoronal positions along the planet-sun axis for the case of an evaporative, uniform exobase. This expression is used to estimate midnight density enhancements as a function of radial distance for the terrestrial planets.

Dynamics of the middle atmosphere as observed by the ARISE project

NASA Astrophysics Data System (ADS)

Blanc, Elisabeth

2015-04-01

The atmosphere is a complex system submitted to disturbances in a wide range of scales, including high frequency sources as volcanoes, thunderstorms, tornadoes and at larger scales, gravity waves from deep convection or wind over mountains, atmospheric tides and planetary waves. These waves affect the different atmospheric layers submitted to different temperature and wind systems which strongly control the general atmospheric circulation. The full description of gravity and planetary waves constitutes a challenge for the development of future models of atmosphere and climate. The objective of this paper is to present a review of recent advances obtained in this topic, especially in the framework of the ARISE (Atmospheric dynamics Research InfraStructure in Europe) project

Use of satellite data and modeling to asses the influence of stratospheric processes on the troposphere

NASA Technical Reports Server (NTRS)

Nathan, Terrence R.; Yarger, Douglas N.

1989-01-01

The research is comprised of the following tasks: use of simple analytical and numerical models of a coupled troposphere-stratosphere system to examine the effects of radiation and ozone on planetary wave dynamics and the tropospheric circulation; use of satellite data obtained from the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) instrument and Solar Backscattered Ultraviolet (SBUV) experiment, in conjunction with National Meteorological Center (NMC) data, to determine the planetary wave vertical structures, dominant wave spectra, ozone spectra, and time variations in diabatic heating rate; and synthesis of the modeling and observational results to provide a better understanding of the effects that stratospheric processes have on tropospheric dynamics.

Titan Meteorology

NASA Astrophysics Data System (ADS)

Mitchell, Jonathan

2012-04-01

Titan’s methane clouds have received much attention since they were first discovered spectroscopically (Griffith et al. 1998). Titan's seasons evolve slowly, and there is growing evidence of a seasonal response in the regions of methane cloud formation (e.g. Rodriguez et al. 2009). A complete, three-dimensional view of Titan’s clouds is possible through the determination of cloud-top heights from Cassini images (e.g., Ádámkovics et al. 2010). Even though Titan’s surface is warmed by very little sunlight, we now know Titan’s methane clouds are convective, evolving through tens of kilometers of altitude on timescales of hours to days with dynamics similar to clouds that appear on Earth (Porco et al. 2005). Cassini ISS has also shown evidence of rain storms on Titan that produce surface accumulation of methane (Turtle et al. 2009). Most recently, Cassini has revealed a 1000-km-scale, arrow-shaped cloud at the equator followed by changes that appear to be evidence of surface precipitation (Turtle et al. 2011b). Individual convective towers simulated with high fidelity indicate that surface convergence of methane humidity and dynamic lifting are required to trigger deep, precipitating convection (e.g. Barth & Rafkin 2010). The global expanses of these cloud outbursts, the evidence for surface precipitation, and the requirement of dynamic convergence and lifting at the surface to trigger deep convection motivate an analysis of storm formation in the context of Titan’s global circulation. I will review our current understanding of Titan’s methane meteorology using Cassini and ground-based observations and, in particular, global circulation model simulations of Titan’s methane cycle. When compared with cloud observations, our simulations indicate an essential role for planetary-scale atmospheric waves in organizing convective storms on large scales (Mitchell et al. 2011). I will end with predictions of Titan’s weather during the upcoming northern hemisphere summer.

Numerical evaluation of surface modifications at landing site due to spacecraft (soft) landing on the moon

NASA Astrophysics Data System (ADS)

Mishra, Sanjeev Kumar; Prasad, K. Durga

2018-07-01

Understanding surface modifications at landing site during spacecraft landing on planetary surfaces is important for planetary missions from scientific as well as engineering perspectives. An attempt has been made in this work to numerically investigate the disturbance caused to the lunar surface during soft landing. The variability of eject velocity of dust, eject mass flux rate, ejecta amount etc. has been studied. The effect of lander hovering time and hovering altitude on the extent of disturbance is also evaluated. The study thus carried out will help us in understanding the surface modifications during landing thereby making it easier to plan a descent trajectory that minimizes the extent of disturbance. The information about the extent of damage will also be helpful in interpreting the data obtained from experiments carried on the lunar surface in vicinity of the lander.

Impact cratering experiments in Bingham materials and the morphology of craters on Mars and Ganymede

NASA Technical Reports Server (NTRS)

Fink, J. H.; Greeley, R.; Gault, D. E.

1982-01-01

Results from a series of laboratory impacts into clay slurry targets are compared with photographs of impact craters on Mars and Ganymede. The interior and ejecta lobe morphology of rampart-type craters, as well as the progression of crater forms seen with increasing diameter on both Mars and Ganymede, are equalitatively explained by a model for impact into Bingham materials. For increasing impact energies and constant target rheology, laboratory craters exhibit a morphologic progression from bowl-shaped forms that are typical of dry planetary surfaces to craters with ejecta flow lobes and decreasing interior relief, characteristic of more volatile-rich planets. A similar sequence is seen for uniform impact energy in slurries of decreasing yield strength. The planetary progressions are explained by assuming that volatile-rich or icy planetary surfaces behave locally in the same way as Bingham materials and produce ejecta slurries with yield strenghs and viscosities comparable to terrestrial debris flows. Hypothetical impact into Mars and Ganymede are compared, and it is concluded that less ejecta would be produced on Ganymede owing to its lower gravitational acceleration, surface temperature, and density of surface materials.

Effects of orography on planetary scale flow

NASA Technical Reports Server (NTRS)

Smith, R. B.

1986-01-01

The earth's orography is composed of a wide variety of scales, each contributing to the spectrum of atmospheric motions. A well studied subject (originating with Charney and Eliassen) is the direct forcing of planetary scale waves by the planetary scale orography: primarily the Tibetan plateau and the Rockies. However, because of the non-linear terms in the equations of dynamic meteorology, even the smallest scales of mountain induced flow can contribute to the planetary scale if the amplitude of the small scale disturbance is sufficintly large. Two possible mechanisms for this are illustrated. First, preferentially located lee cyclones can force planetary waves by their meridional transport of heat and momentum (Hansen and Chen). Recent theories are helping to explain the phenomena of lee cyclogenesis (e.g., Smith, 1984, J.A.S.). Second, mesoscale mountain wave and severe downslope wind phenomena produce such a large local drag, that planetary scale waves can be produced. The mechanism of upscale transfer is easy to understand in this case as the standing planetary scale wave has a wavelength which depends on the mean structure of the atmosphere, and not on the width of the mountain (just as in small scale lee wave theory). An example of a theoretical description of a severe wind flow with very large drag is shown.

Dry Rainbelts: Understanding Boundary Layer Controls on the ITCZ Using a Dry Dynamical Core

NASA Astrophysics Data System (ADS)

Hill, S. A.; Bordoni, S.; Mitchell, J.

2017-12-01

Though migrations of Earth's Intertropical Convergence Zone (ITCZ) are often interpreted in terms of meridional energy transports, a recent study using an idealized, aquaplanet GCM indicates that the ITCZ's position is also linked to the character of the boundary layer momentum budget. Namely, moist convection within the ITCZ roughly coincides with a transition in the role of relative vorticity advection in the boundary layer, from being of leading-order to lower-order importance. This is insensitive to the presence of mid-latitude eddies or thermal inertia and holds over a range of planetary rotation rates, with this transitional regime and the ITCZ extending farther poleward the slower the planet is rotating. We use an even simpler model, a dry dynamical core, to further refine the theoretical understanding of these results, via simulations analogous to and extending the aforementioned moist cases. The importance of planetary rotation and lack thereof for both baroclinic eddies and thermal inertia emerge in the dry simulations also, implying base causes rooted in simpler, steady-state, solsticial, axisymmetric, dry dynamics. We further elucidate the role of the boundary layer dynamical processes through comparison with arguments dating to at least 1972 (although largely overlooked in recent literature) that convection is forced by convergence driven by a shallowing of the boundary layer depth, with this shallowing resulting from the transition from an advective to an Ekman balance on frictional drag. We discuss the potential links between this dynamical perspective and the popular energetic framework for ITCZ migrations and the resulting implications for moist convection on Earth and other planetary bodies.

Spaceborne imaging radar research in the 90's

NASA Technical Reports Server (NTRS)

Elachi, Charles

1986-01-01

The imaging radar experiments on SEASAT and on the space shuttle (SIR-A and SIR-B) have led to a wide interest in the use of spaceborne imaging radars in Earth and planetary sciences. The radar sensors provide unique and complimentary information to what is acquired with visible and infrared imagers. This includes subsurface imaging in arid regions, all weather observation of ocean surface dynamic phenomena, structural mapping, soil moisture mapping, stereo imaging and resulting topographic mapping. However, experiments up to now have exploited only a very limited range of the generic capability of radar sensors. With planned sensor developments in the late 80's and early 90's, a quantum jump will be made in our ability to fully exploit the potential of these sensors. These developments include: multiparameter research sensors such as SIR-C and X-SAR, long-term and global monitoring sensors such as ERS-1, JERS-1, EOS, Radarsat, GLORI and the spaceborne sounder, planetary mapping sensors such as the Magellan and Cassini/Titan mappers, topographic three-dimensional imagers such as the scanning radar altimeter and three-dimensional rain mapping. These sensors and their associated research are briefly described.

First quantification of relationship between dune orientation and sediment availability, Olympia Undae, Mars

NASA Astrophysics Data System (ADS)

Fernandez-Cascales, Laura; Lucas, Antoine; Rodriguez, Sébastien; Gao, Xin; Spiga, Aymeric; Narteau, Clément

2018-05-01

Dunes provide unique information about wind regimes on planetary bodies where there is no direct meteorological data. At the eastern margin of Olympia Undae on Mars, dune orientation is measured from satellite imagery and sediment cover is estimated using the high contrast between the dune material and substrate. The analysis of these data provide the first quantification of relationship between sediment availability and dune orientation. Abrupt and smooth dune reorientations are associated with inward and outward dynamics of dunes approaching and ejecting from major sedimentary bodies, respectively. These reorientation patterns along sediment transport pathways are interpreted using a new generation dune model based on the coexistence of two dune growth mechanisms. This model also permits solving of the inverse problem of predicting the wind regime from dune orientation. For bidirectional wind regimes, solutions of this inverse problem show substantial differences in the distributions of sediment flux orientation, which can be attributed to atmospheric flow variations induced by changes in albedo at the boundaries of major dune fields. Then, we conclude that relationships between sediment cover and dune orientation can be used to constrain wind regime and dune field development on Mars and other planetary surfaces.

Next Generation Simulation Framework for Robotic and Human Space Missions

NASA Technical Reports Server (NTRS)

Cameron, Jonathan M.; Balaram, J.; Jain, Abhinandan; Kuo, Calvin; Lim, Christopher; Myint, Steven

2012-01-01

The Dartslab team at NASA's Jet Propulsion Laboratory (JPL) has a long history of developing physics-based simulations based on the Darts/Dshell simulation framework that have been used to simulate many planetary robotic missions, such as the Cassini spacecraft and the rovers that are currently driving on Mars. Recent collaboration efforts between the Dartslab team at JPL and the Mission Operations Directorate (MOD) at NASA Johnson Space Center (JSC) have led to significant enhancements to the Dartslab DSENDS (Dynamics Simulator for Entry, Descent and Surface landing) software framework. The new version of DSENDS is now being used for new planetary mission simulations at JPL. JSC is using DSENDS as the foundation for a suite of software known as COMPASS (Core Operations, Mission Planning, and Analysis Spacecraft Simulation) that is the basis for their new human space mission simulations and analysis. In this paper, we will describe the collaborative process with the JPL Dartslab and the JSC MOD team that resulted in the redesign and enhancement of the DSENDS software. We will outline the improvements in DSENDS that simplify creation of new high-fidelity robotic/spacecraft simulations. We will illustrate how DSENDS simulations are assembled and show results from several mission simulations.

Studies of hydrodynamic events in stellar evolution. 3: Ejection of planetary nebulae

NASA Technical Reports Server (NTRS)

Sparks, W. M.; Kutter, G. S.

1973-01-01

The dynamic behavior of the H-rich envelope (0.101 solar mass) of an evolved star (1.1 solar mass) as the luminosity rises to 19000 solar luminosity during the second ascent of the red giant branch. For luminosities in the range 3100 L 19000 solar luminosity the H-rich envelope pulsates like a long-period variable (LPV) with periods of the order of a year. As L reaches 19000 solar luminosity, the entire H-rich envelope is ejected as a shell with speeds of a few 10 km/s. The ejection occurs on a timescale of a few LPV pulsation periods. This ejection is associated with the formation of a planetary nebula. The computations are based on an implicit hydrodynamic computer code. T- and RHO-dependent opacities and excitation and ionization energies are included. As the H-rich envelope is accelerated off the stellar core, the gap between envelope and core is approximated by a vacuum, filled with radiation. Across the vacuum, the luminosity is conserved and the anisotropy of the radiation is considered as well as the solid angle subtended by the remnant star at the inner surface of the H-rich envelope. Spherical symmetry and the diffusion approximation are assumed.

Environmental Control and Life Support Systems for Mars Exploration: Issues and Concerns for Planetary Protection and the Protection of Science

NASA Astrophysics Data System (ADS)

Barta, Daniel J.; Lange, Kevin; Anderson, Molly; Vonau, Walter

2016-07-01

Planetary protection represents an additional set of requirements that generally have not been considered by developers of technologies for Environmental Control and Life Support Systems (ECLSS). Forward contamination concerns will affect release of gases and discharge of liquids and solids, including what may be left behind after planetary vehicles are abandoned upon return to Earth. A crew of four using a state of the art ECLSS could generate as much as 4.3 metric tons of gaseous, liquid and solid wastes and trash during a 500-day surface stay. These may present issues and concerns for both planetary protection and planetary science. Certainly, further closure of ECLSS systems will be of benefit by greater reuse of consumable products and reduced generation of waste products. It can be presumed that planetary protection will affect technology development by constraining how technologies can operate: limiting or prohibiting certain kinds of operations or processes (e.g. venting); necessitating that other kinds of operations be performed (e.g. sterilization; filtration of vent lines); prohibiting what can be brought on a mission (e.g. extremophiles); creating needs for new capabilities/ technologies (e.g. containment). Although any planned venting could include filtration to eliminate micro-organisms from inadvertently exiting the spacecraft, it may be impossible to eliminate or filter habitat structural leakage. Filtration will add pressure drops impacting size of lines and ducts, affect fan size and energy requirements, and add consumable mass. Technologies that may be employed to remove biomarkers and microbial contamination from liquid and solid wastes prior to storage or release may include mineralization technologies such as incineration, super critical wet oxidation and pyrolysis. These technologies, however, come with significant penalties for mass, power and consumables. This paper will estimate the nature and amounts of materials generated during Mars transit and surface stays that may be impacted by planetary protection requirements or be controlled for the protection of planetary science.

The applications of chemical thermodynamics and chemical kinetics to planetary atmospheres research

NASA Technical Reports Server (NTRS)

Fegley, Bruce, Jr.

1990-01-01

A review of the applications of chemical thermodynamics and chemical kinetics to planetary atmospheres research during the past four decades is presented with an emphasis on chemical equilibrium models and thermochemical kinetics. Several current problems in planetary atmospheres research such as the origin of the atmospheres of the terrestrial planets, atmosphere-surface interactions on Venus and Mars, deep mixing in the atmospheres of the gas giant planets, and the origin of the atmospheres of outer planet satellites all require laboratory data on the kinetics of thermochemical reactions for their solution.

Analysis of a planetary-rotation system for evaporated optical coatings.

PubMed

Oliver, J B

2016-10-20

The impact of planetary design considerations for optical coating deposition is analyzed, including the ideal number of planets, variations in system performance, and the deviation of planet motion from the ideal. System capacity is maximized for four planets, although substrate size can significantly influence this result. Guidance is provided in the design of high-performance deposition systems based on the relative impact of different error modes. Errors in planet mounting such that the planet surface is not perpendicular to the axis of rotation are particularly problematic, suggesting planetary design modifications would be appropriate.

A study of the far infrared counterparts of new candidates for planetary nebulae

NASA Astrophysics Data System (ADS)

Iyengar, K. V. K.

1986-05-01

The IRAS Point Source Catalog was searched for infrared counterparts of the fourteen new candidates for planetary nebulae of low surface brightness detected by Hartl and Tritton (1985). Five of these candidates were identified with sources in the Catalog. All five nebulae are found in regions of high cirrus flux at 100 microns, and all have both point sources and small size extended sources with numbers varying from field to field. The infrared emission from these nebulae is connected with dust temperatures of about 100 K, characteristic of planetary nebulae.

The observational basis for JPL's DE 200, the planetary ephemerides of the Astronomical Almanac

NASA Astrophysics Data System (ADS)

Standish, E. M., Jr.

1990-07-01

This paper documents the planetary observational data used in a series of ephemerides produced at JPL over six years preceding the creation of DE118/LE62, the set which transformed directly into the JD2000-based set, DE200/LE200. Details of the data reduction procedures are presented, and techniques to overcome the uncertainties due to planetary topography are described. For the spacecraft data, the basic reductions are augmented by formulations for locating the transponder, whether in orbit or landed on the surface of a planet.

Next Generation P-Band Planetary Synthetic Aperture Radar

NASA Technical Reports Server (NTRS)

Rincon, Rafael; Carter, Lynn; Lu, Dee Pong Daniel

2016-01-01

The Space Exploration Synthetic Aperture Radar (SESAR) is an advanced P-band beamforming radar instrument concept to enable a new class of observations suitable to meet Decadal Survey science goals for planetary exploration. The radar operates at full polarimetry and fine (meter scale) resolution, and achieves beam agility through programmable waveform generation and digital beamforming. The radar architecture employs a novel low power, lightweight design approach to meet stringent planetary instrument requirements. This instrument concept has the potential to provide unprecedented surface and near- subsurface measurements applicable to multiple DecadalSurvey Science Goals.

Next Generation P-Band Planetary Synthetic Aperture Radar

NASA Technical Reports Server (NTRS)

Rincon, Rafael; Carter, Lynn; Lu, Dee Pong Daniel

2017-01-01

The Space Exploration Synthetic Aperture Radar (SESAR) is an advanced P-band beamforming radar instrument concept to enable a new class of observations suitable to meet Decadal Survey science goals for planetary exploration. The radar operates at full polarimetry and fine (meter scale) resolution, and achieves beam agility through programmable waveform generation and digital beamforming. The radar architecture employs a novel low power, lightweight design approach to meet stringent planetary instrument requirements. This instrument concept has the potential to provide unprecedented surface and near- subsurface measurements applicable to multiple Decadal Survey Science Goals.

The Source of Planetary Period Oscillations in Saturn's Magnetosphere

NASA Astrophysics Data System (ADS)

Khurana, Krishan K.; Mitchell, Jonathan L.; Mueller, Ingo C. F.

2017-04-01

In this presentation, we resolve a three-decades old mystery of how Saturn is able to modulate its kilometric wave radiation and many field and plasma parameters at the planetary rotation period even though its magnetic field is extremely axisymmetric. Such waves emanating from the auroral regions of planets lacking solid surfaces have been used as clocks to measure the lengths of their days, because asymmetric internal magnetic fields spin-modulate wave amplitudes. A review by Carbary and Mitchell (2013, Periodicities in Saturn's magnetosphere, Reviews of Geophysics, 51, 1-30) on the topic summarized findings from over 200 research articles, on what the phenomena is, how it is manifested in a host of magnetospheric and auroral parameters; examined several proposed models and pointed out their shortcomings. The topic has now been explored in several topical international workshops, but the problem has remained unsolved so far. By quantitatively modeling the amplitudes and phases of these oscillations in the magnetic field observed by the Cassini spacecraft, we have now uncovered the generation mechanism responsible for these oscillations. We show that the observed oscillations are the manifestations of two global convectional conveyor belts excited in Saturn's upper atmosphere by auroral heating below its northern and southern auroral belts. We demonstrate that a feedback process develops in Saturn system such that the magnetosphere expends energy to drive convection in Saturn's upper stratosphere but gains back an amplified share in the form of angular momentum that it uses to enforce corotation in the magnetosphere and power its aurorae and radio waves. In essence, we have uncovered a new mechanism (convection assisted loss of angular momentum in an atmosphere) by which gaseous planets lose their angular momentum to their magnetospheres and outflowing plasma at rates far above previous predictions. We next show how the m = 1 convection system in the upper atmosphere generates the observed plasma and magnetic field periodicities. This breakthrough in our understanding of an important planetary physics problem has immediate and extensive applications in fields as diverse as theoretical fluid dynamics, planetary angular momentum loss, maintenance of corotation in planetary magnetospheres, astrophysical magneto-braking and future telescopic observations of planets and exoplanets.

Nonlinear dynamics of global atmospheric and Earth system processes

NASA Technical Reports Server (NTRS)

Saltzman, Barry

1993-01-01

During the past eight years, we have been engaged in a NASA-supported program of research aimed at establishing the connection between satellite signatures of the earth's environmental state and the nonlinear dynamics of the global weather and climate system. Thirty-five publications and four theses have resulted from this work, which included contributions in five main areas of study: (1) cloud and latent heat processes in finite-amplitude baroclinic waves; (2) application of satellite radiation data in global weather analysis; (3) studies of planetary waves and low-frequency weather variability; (4) GCM studies of the atmospheric response to variable boundary conditions measurable from satellites; and (5) dynamics of long-term earth system changes. Significant accomplishments from the three main lines of investigation pursued during the past year are presented and include the following: (1) planetary atmospheric waves and low frequency variability; (2) GCM studies of the atmospheric response to changed boundary conditions; and (3) dynamics of long-term changes in the global earth system.

Convection driven zonal flows and vortices in the major planets.

PubMed

Busse, F. H.

1994-06-01

The dynamical properties of convection in rotating cylindrical annuli and spherical shells are reviewed. Simple theoretical models and experimental simulations of planetary convection through the use of the centrifugal force in the laboratory are emphasized. The model of columnar convection in a cylindrical annulus not only serves as a guide to the dynamical properties of convection in rotating sphere; it also is of interest as a basic physical system that exhibits several dynamical properties in their most simple form. The generation of zonal mean flows is discussed in some detail and examples of recent numerical computations are presented. The exploration of the parameter space for the annulus model is not yet complete and the theoretical exploration of convection in rotating spheres is still in the beginning phase. Quantitative comparisons with the observations of the dynamics of planetary atmospheres will have to await the consideration in the models of the effects of magnetic fields and the deviations from the Boussinesq approximation.

Dynamical simulations of the HR8799 planetary system

NASA Astrophysics Data System (ADS)

Marshall, J.; Horner, J.; Carter, A.

2010-10-01

HR8799 is a young (20-160 Myr) A-dwarf main sequence star with a debris disc detected by IRAS (InfraRed Astronomical Satellite). In 2008, it was one of two stars around which exoplanets were directly imaged for the first time. The presence of three Jupiter-mass planets around HR8799 provoked much interest in modelling the dynamical stability of the system. Initial simulations indicated that the observed planetary architecture was unstable on timescales much shorter than the lifetime of the star (~105 yr). Subsequent models suggested that the system could be stable if the planets were locked in a 1:2:4 mutual mean motion resonance (MMR). In this work, we have examined the influence of varying orbital eccentricity and the semi-major axis on the stability of the three-planet system, through dynamical simulations using the MERCURY n-body integrator. We find that, in agreement with previous work on this system, the 1:2:4 MMR is the most stable planetary configuration, and that the system stability is dominated by the interaction between the inner pair of planets. In contrast to previous results, we find that with small eccentricities, the three-planet system can be stable for timescales comparable to the system lifetime and, potentially, much longer.

Critical issues in connection with human planetary missions: protection of and from the environment.

PubMed

Horneck, G; Facius, R; Reitz, G; Rettberg, P; Baumstark-Khan, C; Gerzer, R

2001-01-01

Activities associated with human missions to the Moon or to Mars will interact with the environment in two reciprocal ways: (i) the mission needs to be protected from the natural environmental elements that can be harmful to human health, the equipment or to their operations: (ii) the specific natural environment of the Moon or Mars should be protected so that it retains its value for scientific and other purposes. The following environmental elements need to be considered in order to protect humans and the equipment on the planetary surface: (i) cosmic ionizing radiation, (ii) solar particle events; (iii) solar ultraviolet radiation; (iv) reduced gravity; (v) thin atmosphere; (vi) extremes in temperatures and their fluctuations; (vii) surface dust; (viii) impacts by meteorites and micrometeorites. In order to protect the planetary environment. the requirements for planetary protection as adopted by COSPAR for lander missions need to be revised in view of human presence on the planet. Landers carrying equipment for exobiological investigations require special consideration to reduce contamination by terrestrial microorganisms and organic matter to the Greatest feasible extent. Records of human activities on the planet's surface should be maintained in sufficient detail that future scientific experimenters can determine whether environmental modifications have resulted from explorations. Grant numbers: 14056/99/NL/PA. c 2001. Elsevier Science Ltd. All rights reserved.

The Radiolytic Destruction of Glycine Diluted in H2O and CO2 Ice: Implications for Mars and Other Planetary Environments

NASA Astrophysics Data System (ADS)

Gerakines, Perry A.; Hudson, R. L.

2013-10-01

Future missions to Mars and other planetary surfaces will probe under the surfaces of these worlds for signs of organic chemistry. In previous studies we have shown that glycine and other amino acids have radiolytic destruction rates that depend on temperature and on dilution within an H2O ice matrix (Gerakines et al., 2012; Gerakines and Hudson 2013). In the new work presented here, we have examined the destruction of glycine diluted in CO2 ice at various concentrations and irradiated with protons at 0.8 MeV, typical of cosmic rays and solar energetic particles. Destruction rates for glycine were measured by infrared spectroscopy in situ, without removing or warming the ice samples. New results on the half life of glycine in solid CO2 will be compared to those found in H2O ice matrices. The survivability of glycine in icy planetary surfaces rich in H2O and CO2 ice will be discussed, and the implications for planetary science missions will be considered. References: Gerakines, P. A., Hudson, R. L., Moore, M. H., and Bell, J-L. (2012). In-situ Measurements of the Radiation Stability of Amino Acids at 15 - 140 K. Icarus, 220, 647-659. Gerakines, P. A. and Hudson, R. L. (2013). Glycine's Radiolytic Destruction in Ices: First in situ Laboratory Measurements for Mars. Astrobiology, 13, 647-655.

The Lidnis Instrument: Atmosphere And Surface Studies

NASA Astrophysics Data System (ADS)

Leblanc, F.; Chassefiere, E.; Porteneuve, J.; Berthelier, J.-J.; Sarkissian, A.; Meftha, M.; Johnson, R. E.; Chaussidon, M.; Jambon, A.

LIDNIS is a surface instrument for rocky planetary bodies (in particular for Mercury, Mars, the Moon or asteroids) which simultaneously studies the chemical composi- tion of surface material, its gaseous environment and the nature and importance of the atmosphere/surface interaction. A multipurpose mass spectrometer (called NIS for Neutral and Ion spectrometer) placed at the surface of a planetary body would first of all give us information on the local atmosphere, its elementary and isotopic compo- sition and temporal variation. It will also give us the access to the precipitation from the interplanetary space and the products due to this precipitation. The association to NIS of a laser induced desorption (LID) system strong enough to desorb and volatilize the first few tens micro meters of the surface will allow the analysis of the different species present in this layer that is the atmospheric species (volatiles, refractories and products of the interior outgassing), the energetic implanted species along the history of this body (Solar Wind, Solar Energetic Particles and Cosmic Rays) and the inter- nal composition. In the same way as it is usually done in laboratories for the Moon samples, LIDNIS, through a progressive outgassing of the regolith or the rock at the surface, will measure these different groups of species. The purpose of this poster is to describe such an instrument and to show its capabilities with low mass and power to measure efficiently fundamental parameters for our understanding of the origin and evolution of planetary bodies in the solar system.

Compositional Mapping of Planetary moons by Mass Spectrometry of Dust Ejecta

NASA Astrophysics Data System (ADS)

Postberg, F.; Gruen, E.; Horanyi, M.; Kempf, S.; Krüger, H.; Schmidt, J.; Spahn, F.; Srama, R.; Sternovsky, Z.; Trieloff, M.

2011-12-01

Classical methods to analyze the surface composition of planetary objects from a space craft are IR and gamma ray spectroscopy and neutron backscatter measurements. We present a complementary method to analyze rocky or icy dust particles as samples of planetary objects from where they were ejected. Such particles, generated by the ambient meteoroid bombardment that erodes the surface, are naturally present on all atmosphereless moons and planets - they are enshrouded in clouds of ballistic dust particles. In situ mass spectroscopic analysis of these grains impacting on to a detector on a spacecraft reveals their composition as characteristic samples of planetary surfaces at flybys or from an orbiter. The well established approach of dust detection by impact ionization has recently shown its capabilities by analyzing ice particles expelled by subsurface salt water on Saturn's moon Enceladus. Applying the method on micro-meteoroid ejecta of less active moons would allow for the qualitative and quantitative analysis of a huge number of samples from various surface areas, thus combining the advantages of remote sensing and a lander. Utilizing the heritage of the dust detectors onboard Ghiotto, Ulysses, Galileo, and Cassini a variety of improved, low-mass lab-models have been build and tested. They allow the chemical characterization of ice and dust particles encountered at speeds as low as 1 km/s and an accurate reconstruction of their trajectories. Depending on the sampling altitude, a dust trajectory sensor can trace back the origin of each analyzed grain with about 10 km accuracy at the surface. Since achievable detection rates are on the order of thousand per orbit, an orbiter can create a compositional map of samples taken from a greater part of the surface. Flybies allow an investigation of certain surface areas of interest. Dust impact velocities are in general sufficiently high for impact ionization at orbiters about planetary objects with a radius of at least 1000km and with only a thin or no atmosphere. Thus, this method is ideal on a spacecraft orbiting Earth's Moon or Jupiter's Galilean satellites. The approach has a ppm-level sensitivity to salts and many rock forming materials as well as water and organic compounds. It provides key chemical and isotopic constraints for varying provinces or geological formations on the surfaces, leading to better understanding of the body's geological evolution. Regions which were subject to endogenic or exogenic alteration (resurfacing, radiation, old/new regions) could be distinguished and investigated. In particular exchange processes with subsurface ocean on the Galileian moons could be determined with high quantitative precision.

Re-analysis of previous laboratory phase curves: 1. Variations of the opposition effect morphology with the textural properties, and an application to planetary surfaces

NASA Astrophysics Data System (ADS)

Déau, Estelle; Flandes, Alberto; Spilker, Linda J.; Petazzoni, Jérôme

2013-11-01

Typical variations in the opposition effect morphology of laboratory samples at optical wavelengths are investigated to probe the role of the textural properties of the surface (roughness, porosity and grain size). A previously published dataset of 34 laboratory phase curves is re-analyzed and fit with several morphological models. The retrieved morphological parameters that characterize the opposition surge, amplitude, width and slope (A, HWHM and S respectively) are correlated to the single scattering albedo, the roughness, the porosity and the grain size of the samples. To test the universality of the laboratory samples’ trends, we use previously published phase curves of planetary surfaces, including the Moon, satellites and rings of the giant planets. The morphological parameters of the surge (A and HWHM) for planetary surfaces are found to have a non-monotonic variation with the single scattering albedo, similar to that observed in asteroids (Belskaya, I.N., Shevchenko, V.G. [2000]. Icarus 147, 94-105), which is unexplained so far. The morphological parameters of the surge (A and HWHM) for laboratory samples seem to exhibit the same non-monotonic variation with single scattering albedo. While the non-monotonic variation with albedo was already observed by Nelson et al. (Nelson, R.M., Hapke, B.W., Smythe, W.D., Hale, A.S., Piatek, J.L. [2004]. Planetary regolith microstructure: An unexpected opposition effect result. In: Mackwell, S., Stansbery, E. (Eds.), Proc. Lunar Sci. Conf. 35, p. 1089), we report here the same variation for the angular width.

The Explorer's Guide to Impact Craters

NASA Astrophysics Data System (ADS)

Pierazzo, E.; Osinski, G.; Chuang, F.

2004-12-01

Impact cratering is a fundamental geologic process of our solar system. It competes with other processes, such as plate tectonics, volcanism, or fluvial, glacial and eolian activity, in shaping the surfaces of planetary bodies. In some cases, like the Moon and Mercury, impact craters are the dominant landform. On other planetary bodies impact craters are being continuously erased by the action of other geological processes, like volcanism on Io, erosion and plate tectonics on the Earth, tectonic and volcanic resurfacing on Venus, or ancient erosion periods on Mars. The study of crater populations is one of the principal tools for understanding the geologic history of a planetary surface. Among the general public, impact cratering has drawn wide attention through its portrayal in several Hollywood movies. Questions that are raised after watching these movies include: ``How do scientists learn about impact cratering?'', and ``What information do impact craters provide in understanding the evolution of a planetary surface?'' Fundamental approaches used by scientists to learn about impact cratering include field work at known terrestrial craters, remote sensing studies of craters on various solid surfaces of solar system bodies, and theoretical and laboratory studies using the known physics of impact cratering. We will provide students, science teachers, and the general public an opportunity to experience the scientific endeavor of understanding and exploring impact craters through a multi-level approach including images, videos, and rock samples. This type of interactive learning can also be made available to the general public in the form of a website, which can be addressed worldwide at any time.

Research at the Stanford Center for Radar Astronomy

NASA Technical Reports Server (NTRS)

1973-01-01

Theoretical and experimental radio and radar studies are presented concerning lunar and planetary atmospheres and surfaces; the sun and interplanetary medium; and software and hardware conceived while doing research. Emphasis is given to probe and radio accumulation measurements of planetary atmospheres. A list is included of recent publications, technical and scientific reports, and symposia with papers.

Definition phase of Grand Tour missions/radio science investigations study for outer planets missions

NASA Technical Reports Server (NTRS)

Tyler, G. L.

1972-01-01

Scientific instrumentation for satellite communication and radio tracking systems in the outer planet exploration mission is discussed. Mission planning considers observations of planetary and satellite-masses, -atmospheres, -magnetic fields, -surfaces, -gravitational fields, solar wind composition, planetary radio emissions, and tests of general relativity in time delay and ray bending experiments.