Results for “Mars data sets” — Page 10

NASA NTRS1991

Monsoon 1990: Preliminary SAR results

Multifrequency polarimetric synthetic aperture radar (SAR) images of the Walnut Gulch watershed near Tombstone, Arizona were acquired on 28 Mar. 1990 and on 1 Aug. 1990. Trihedral corner reflectors were deployed prior to both overflights to allow calibration of the two SAR data sets. During both overflights, gravimetric soil moisture and dielectric constant measurements were made. Detailed vegetation height, density, and water content measurements were made as part of the Monsoon 1990 Experiment. Preliminary results based on analysis of the multitemporal polarimetric SAR data are presented. Only the C-band data (5.7-cm wavelength) radar images show significant difference between Mar. and Aug., with the strongest difference observed in the HV images. Based on the radar data analysis and the in situ measurements, we conclude that these differences are mainly due to changes in the vegetation and not due to the soil moisture changes.

Vanzyl, Jakob J.↗

NASA NTRS1992

Monsoon '90 - Preliminary SAR results

Multifrequency polarimetric synthetic aperture radar (SAR) images of the Walnut Gulch watershed near Tombstone, Arizona were acquired on 28 Mar. 1990 and on 1 Aug. 1990. Trihedral corner reflectors were deployed prior to both overflights to allow calibration of the two SAR data sets. During both overflights, gravimetric soil moisture and dielectric constant measurements were made. Detailed vegetation height, density, and water content measurements were made as part of the Monsoon 1990 Experiment. Preliminary results based on analysis of the multitemporal polarimetric SAR data are presented. Only the C-band data (5.7-cm wavelength) radar images show significant difference between Mar. and Aug., with the strongest difference observed in the HV images. Based on the radar data analysis and the in situ measurements, we conclude that these differences are mainly due to changes in the vegetation and not due to the soil moisture changes.

Dubois, Pascale C.↗

NASA NTRS2004

Mars Exploration Rover airbag landing loads testing and analsysis

This paper presents a summary of the testing and analysis used to quantify the expected airbag landing loads for the Mars Exploration Rovers. The airbag drop test setup, lander instrumentation, and the test data reduction method are discussed in order to provide an understanding of the empirical loads. A set of limiting cases that bound the empirical data are developed for use in finite element modeling of the lander and rover models.

modeling↗

NASA NTRS1987

Interannual variability of Mars' south polar cap

Published observational data on the seasonal recession of the south polar cap on Mars (covering the period 1903-1977) are compiled in tables and graphs and analyzed statistically. The basic data set (photographic observations obtained at Lowell Observatory) of Fischbacher et al. (1960) and James and Lumme (1982) and the reduction procedures described by Baum and Martin (1973) are employed, and Viking data from 1977 are used for comparison; the early onset (relative to the mean) of the 1956 recession is characterized in detail. A list of photographically documented large dust storms is provided, and it is suggested that in years with early spring storms, recession may be slower than in years without such storms.

James, Philip B.↗

NASA NTRS2000

Visible Wavelength Spectroscopy of Ferric Minerals: A Key Tool for Identification of Ancient Martian Aqueous Environments

The mineralogic signatures of past aqueous alteration of a basaltic Martian crust may include iron oxides and oxyhydroxides, zeolites, carbonates, phyllosilicates, and silica. The identities, relative abundances, and crystallinities of the phases formed in a particular environment depend on physicochemical conditions. At one extreme, hot spring environments may be characterized by smectite-chlorite to talc-kaolinite silicate assemblages, plus crystalline ferric oxides dominated by hematite. However, most environments, including cold springs, pedogenic layers, and ponded surface water, are expected to deposit iron oxides and oxyhydroxides, carbonates, and smectite-dominated phyllosilicates. A substantial fraction of the ferric iron is expected to occur in nanophase form, with the exact mineralogy strongly influenced by Eh-pH conditions. Detection of these phases has been an objective of a large body of terrestrial telescopic, Mars orbital, and landed spectral investigations and in situ compositional measurements. However, clear identifications of many of these phases is lacking. Neither carbonate nor silica has been unequivocally detected by any method. Although phyllosilicates may occur near the limit of detection by remote sensing, in general they appear to occur in only poorly crystalline form. In contrast, compelling evidence for ferric iron minerals has been gathered by recent telescopic investigations, the Imager for Mars Pathfinder (IMP), and the Thermal Emission Spectrometer (TES) on the Mars Global Surveyor (MGS). These data yield two crucial findings: (1) In the global, high spatial resolution TES data set, highly crystalline ferric iron (as coarse-grained 'gray' hematite) has been recognized but with only very limited spatial occurrence and (2) Low-resolution telescopic reflectance spectroscopy, very limited orbital reflectance spectroscopy, and landed multispectral imaging provide strong indications that at least two broad classes of ferric iron minerals are commonplace in non-dust covered regions.

Murchie, Scott L.↗

NASA NTRS2005

Interactive Display of Scenes with Annotations

ThreeDView is a computer program that enables high-performance interactive display of real-world scenes with annotations. ThreeDView was developed primarily as a component of the Science Activity Planner (SAP) software, wherein it is to be used to display annotated images of terrain acquired by exploratory robots on Mars and possibly other remote planets. The images can be generated from sets of multiple-texture image data in the Visible Scalable Terrain (ViSTa) format, which was described in "Format for Interchange and Display of 3D Terrain Data" (NPO-30600) NASA Tech Briefs, Vol. 28, No. 12 (December 2004), page 25. In ThreeDView, terrain data can be loaded rapidly, the geometric level of detail and texture resolution can be selected, false colors can be used to represent scientific data mapped onto terrain, and the user can select among navigation modes. ThreeDView consists largely of modular Java software components that can easily be reused and extended to produce new high-performance, application-specific software systems for displaying images of three-dimensional real-world scenes.

Vona, Marsette↗

NASA NTRS2005

Static Aerodynamics of the Mars Exploration Rover Entry Capsule

The static aerodynamics for the Mars Exploration Rover (MER) aeroshell are presented. This aerodynamic database was an integral part of the end-to-end simulation used in pre- entry analysis for determining the MER entry design requirements for development of the MER entry system, as well as targeting the MER landing sites. The database was constructed using the same approach used for Mars Pathfinder (MPF). However, the MER aerodynamic database is of much higher fidelity and tailored to the MER entry trajectories. This set of data includes direct simulation Monte Carlo calculations covering the transitional regime of the entry trajectory and computational fluid dynamics calculations describing the aerodynamics in the hypersonic and supersonic continuum regimes. An overview of the methodology used to generate the data is given along with comparisons to important features in the MPF aerodynamics and related heritage data. The MER and MPF comparison indicates that trajectory specific data is required to properly model the flight characteristics of a.blunt entry capsule at Mars.

Schoenenberger, Mark↗

NASA NTRS2004

MGS Radio Science Electron Density Profiles: Interannual Variability and Implications for the Martian Neutral Atmosphere

Martian electron density profiles provided by the Mars Global Surveyor (MGS) Radio Science (RS) experiment over the 95-200 km altitude range indicate what the height of the electron peak and the longitudinal structure of the peak height are sensitive indicators of the physical state of the Mars lower and upper atmospheres. The present analysis is carried out on five sets of occultation profiles, all at high solar zenith angles (SZA). Variations spanning 2 Martian years are investigated near aphelion conditions at high northern latitudes (64.7 - 77.6 N) making use of four of these data sets. A mean ionospheric peak height of 133.5 - 135 km is obtained near SZA = 78 - 82 deg.; a corresponding mean peak density of 7.3 - 8.5 x l0(exp 4)/ qu cm is also measured during solar moderate conditions at Mars. Strong wave number 2 - 3 oscillations in peak heights are consistently observed as a function of longitude over the 2 Martian years. These observed ionospheric features are remarkably similar during aphelion conditions 1 Martian year apart. This year-to-year repeatability in the thermosphere-ionosphere structure is consistent with that observed in multiyear aphelion temperature data of the Mars lower atmosphere. Coupled Mars general circulation model (MGCM) and Mars thermospheric general circulation model (MTGCM) codes are run for Mars aphelion conditions, yielding mean and longitude variable ionospheric peak heights that reasonably match RS observations. A tidal decomposition of MTGCM thermospheric densities shows that observed ionospheric wave number 3 features are linked to a non-migrating tidal mode with semidiurnal period (sigma = 2) and zonal wave number 1 (s = -1) characteristics. The height of this photochemically determined ionospheric peak should be monitored regularly.

Bougher, S. W.↗

NASA NTRS1973

Ultraviolet observations of Mars made by the Orbiting Astronomical Observatory.

Ultraviolet albedos of Mars in the region from 2000 to 3600 A are discussed. When the reflectivity due to the known amount of CO2 on Mars is accounted for, the remaining reflectivity may be used to set an upper limit for the surface albedo. The result disagrees qualitatively with published ultraviolet reflectivities of limonite and carbon suboxide. An alternate interpretation of the observations leads to the conclusion that CO2 comprises at least 60% of the molecular atmosphere of Mars, assuming the remainder to be argon. A comparison of the OAO results with 1969 Mariner ultraviolet data reveals some important areas of conflict. Attempts to detect Mars at wavelengths less than 2000 A were unsuccessful, with only very high upper limits being set.

Caldwell, J.↗

NASA NTRS1993

SLR data screening; location of peak of data distribution

At the 5th Laser Ranging Instrumentation Workshop held at Herstmonceux in 1984, consideration was given to the formation of on-site normal points by laser stations, and an algorithm was formulated. The algorithm included a recommendation that an iterated 3.0 x rms rejection criterion should be used to screen the data, and that arithmetic means should be formed within the normal point bins of the retained data. From Sept. 1990 onwards, this algorithm and screening criterion have been brought into effect by various laser stations for forming on-site normal points, and small variants of the algorithm are used by most analysis centers for forming normal points from full-rate data, although the data screening criterion they use ranges from about 2.5 to 3.0 x rms. At the CSTG Satellite Laser Ranging (SLR) Subcommission, a working group was set up in Mar. 1991 to review the recommended screening procedure. This paper has been influenced by the discussions of this working group, although the views expressed are primarily those of this author. The main thrust of this paper is that, particularly for single photon systems, a more important issue than data screening is the determination of the peak of a data distribution and hence, the determination of the bias of the peak from the mean. Several methods of determining the peak are discussed.

Sinclair, Andrew T.↗

NASA NTRS1993

NASA space and Earth science data on CD-ROM

The National Space Science Data Center (NSSDC) is very interested in facilitating the widest possible use of the scientific data acquired through NASA spaceflight missions. Therefore, NSSDC has participated with projects and data management elements throughout the NASA science environment in the creation, archiving, and dissemination of data using Compact Disk-Read Only Memory (CD-ROM). This CD-ROM technology has the potential to enable the dissemination of very large data volumes at very low prices to a great many researchers, students and their teachers, and others. This catalog identifies and describes the scientific CD-ROM's now available from NSSDC including the following data sets: Einstein Observatory CD-ROM, Galileo Cruise Imaging on CD-ROM, International Halley Watch, IRAS Sky Survey Atlas, Infrared Thermal Mapper (IRTM), Magellan (MIDR), Magellan (ARCDR's), Magellan (GxDR's), Mars Digital Image Map (MDIM), Outer Planets Fields & Particles Data, Pre-Magellan, Selected Astronomical Catalogs, TOMS Gridded Ozone Data, TOMS Ozone Image Data, TOMS Update, Viking Orbiter Images of Mars, and Voyager Image.

Towheed, Syed S.↗

NASA NTRSDate not supplied

Towards a Common Basis of Comparison Across a Broad Trade Space of Mars Architecture Options

Humanity’s fascination with Mars predates the advent of space access, but the coming-of-age of rocket propulsion in the mid-20th century provided the technological foundation for considering a human visit to the red planet. Werner von Braun’s “The Mars Project,” published in 1953, is acknowledged as the first integrated Mars mission architecture plan [1]; since then, the reformulation and refinement of Mars architectures and system concepts has been an ongoing activity, as continued study and planning for human Mars missions is necessary in order to incorporate evolving mission objectives, technology advancements, and the increasing body of knowledge regarding human factors and the various environments of space. Historical Mars architecture studies represent an enormous body of work, but apart from a couple of high-level reviews [2], tapping into the findings and philosophies of these varied works entails a tedious and time-consuming individual effort. The unfortunate result of the widely scattered corpus of Mars architectures is that knowledge and understanding acquired in previous studies is not consistently and effectively brought to bear in the studies of today. The primary vehicle for bringing forward past learning is human recall, which both is imperfect and experiences significant attrition. An effort is underway in the Advanced Concepts Office (ACO) at NASA’s Marshall Space Flight Center to recapture and re-baseline previous architecture studies in order to establish a broad basis of comparison for future Mars architecture studies. Recapturing involves gathering and organizing data and documentation from previous efforts; re-baselining entails developing models capable of reproducing the original results, and then utilizing these models to implement a common set of ground rules and assumptions across the resulting trade space of Mars architecture options. This paper will present the methodology ACO is employing in performing this architecture meta-study, including a discussion on the challenges involved in re-baselining without losing the intent behind previous concepts. As part of this discussion some initial results will be presented, along with a list of studies targeted for inclusion. It is expected that the completed basis of comparison results will be presented as a follow-on paper in the following year.

Stephen James Edwards↗

NASA NTRS1993

A new MAP for Mars

A Mars Aerial Platform (MAP) mission capable of generating thousands of very-high-resolution (20 cm/pixel) pictures of the Martian surface is considered. The MAP entry vehicle will map the global circulation of the planet's atmosphere and examine the surface and subsurface. Data acquisition will use instruments carried aboard balloons flying at nominal altitude of about 7 km over the Martian surface. The MAP balloons will take high- and medium-resolution photographs of Mars, sound its surface with radar, and provide tracking data to chart its winds. Mars vehicle design is based on the fourth-generation NTP, NEP, SEP vehicle set that provides a solid database for determining transportation system costs. Interference analysis and 3D image generation are performed using manual system sizing and sketching in conjunction with precise CAD modeling.

Zubrin, Robert↗

NASA NTRS1999

Recent Advances in Mars Tectonics

Since the publication of the "Stress and Tectonics on Mars" chapter in the Mars book (the last comprehensive summary of our knowledge on the topic) considerable advances have been made in certain areas of Martian tectonics and significant advances are expected with the return of Mars Global Surveyor data. This abstract will summarize the advances in our knowledge of tectonic features and processes on Mars since the Mars book and point towards new areas of research that can be expected from the Mars Global Surveyor data. Two out of three areas of study that were discussed as future directions of work in the Mars chapter have had significant work directed towards them. One area is the field of structural mapping and understanding the timing of tectonic activity on Mars in the framework of the global stratigraphy. Although the general development and relative timing of the development of the Tharsis province on Mars had been understood for some time, actual placement of mapped tectonic features in a global stratigraphic framework has only recently been completed. The second area of study mentioned in the Mars chapter was the impact of improved topography and gravity on modeling loads and deriving stresses in the Martian lithosphere. Mars Global Surveyor is on the brink of returning vastly improved topographic and gravity fields and these newer data sets can be used to better define the size and shape of Tharsis and to quantify loads and derived stresses in the Martian lithosphere. Additional information is contained in the original extended abstract.

Golombek, M. P.↗

NASA NTRS2005

An Inventory of Impact Craters on the Martian South Polar Layered Deposits

The polar layered deposits (PLD) of Mars continue to be a focus of study due to the possibility that these finely layered, volatile-rich deposits hold a record of recent eras in Martian climate history. Recently, the visible sensor on 2001 Mars Odyssey s Thermal Emission Imaging System (THEMIS) has acquired 36 meter/pixel contiguous single-band visible image data sets of both the north and the south polar layered deposits, during the local spring and summer seasons. In addition, significant coverage has been obtained at the THEMIS visible sensor s full resolution of 18 meters/pixel. This paper reports on the use of these data sets to further characterize the population of impact craters on the south polar layered deposits (SPLD), and the implications of the observed population for the age and evolution of the SPLD.

Plaut, J. J.↗

NASA NTRS2009

Telemetry-Enhancing Scripts

Scripts Providing a Cool Kit of Telemetry Enhancing Tools (SPACKLE) is a set of software tools that fill gaps in capabilities of other software used in processing downlinked data in the Mars Exploration Rovers (MER) flight and test-bed operations. SPACKLE tools have helped to accelerate the automatic processing and interpretation of MER mission data, enabling non-experts to understand and/or use MER query and data product command simulation software tools more effectively. SPACKLE has greatly accelerated some operations and provides new capabilities. The tools of SPACKLE are written, variously, in Perl or the C or C++ language. They perform a variety of search and shortcut functions that include the following: Generating text-only, Event Report-annotated, and Web-enhanced views of command sequences; Labeling integer enumerations with their symbolic meanings in text messages and engineering channels; Systematic detecting of corruption within data products; Generating text-only displays of data-product catalogs including downlink status; Validating and labeling of commands related to data products; Performing of convenient searches of detailed engineering data spanning multiple Martian solar days; Generating tables of initial conditions pertaining to engineering, health, and accountability data; Simplified construction and simulation of command sequences; and Fast time format conversions and sorting.

Maimone, Mark W.↗

NASA NTRSDate not supplied

Lessons Learned from Aerothermal Flight Data on NASA Mars Entry Vehicles

The NASA Mars Science Laboratory (MSL) and Mars 2020 entry vehicles included temperature measurements inside and direct heat flux on the surface of the thermal protection system (TPS) material. The instrumentation was included to begin addressing predictive capabilities for aerodynamic heating and ablative TPS material response. The MSL aeroshell included temperature measurements at seven heatshield locations, from which total aerodynamic heating was reconstructed. The Mars 2020 instrumentation suite included eleven heatshield measurement locations and new backshell measurements at nine locations: six with temperature sensors, two with sensors to directly measure total heat flux, and one to measure radiative heat flux. Both instrumentation suites returned full sets of data, with all temperature sensors nearest to the surface surviving entry, indicating minimal material recession. Heatshield boundary layer transition (BLT) was observed for both vehicles prior to the time of peak heating, with transition starting near the shoulder and progressing towards the stagnation area. MSL’s higher speed on approach to Mars resulted in higher total heating compared to Mars 2020, with the maximum occurring near the heatshield’s leeside shoulder. The Mars 2020 backshell heating data indicate significant contributions from shock layer radiation. Heating from Navier-Stokes flowfield calculations are in family with reconstructed heating. The paper covers the instrumentation, BLT and reconstructed heating on both heatshields, backshell heating for Mars 2020, TPS performance, and predicted versus reconstructed heat fluxes. Opportunities for improved design approaches for future Mars missions are discussed, especially for the upcoming Mars Sample Return mission.

Mars Science Laboratory↗

NASA NTRSDate not supplied

Lessons Learned from Aerothermal Flight Data on NASA Mars Entry Vehicles

The NASA Mars Science Laboratory (MSL) and Mars 2020 entry vehicles included temperature measurements inside and direct heat flux on the surface of the thermal protection system (TPS) material. The instrumentation was included to begin addressing predictive capabilities for aerodynamic heating and ablative TPS material response. The MSL aeroshell included temperature measurements at seven heatshield locations, from which total aerodynamic heating was reconstructed. The Mars 2020 instrumentation suite included eleven heatshield measurement locations and new backshell measurements at nine locations: six with temperature sensors, two with sensors to directly measure total heat flux, and one to measure radiative heat flux. Both instrumentation suites returned full sets of data, with all temperature sensors nearest to the surface surviving entry, indicating minimal material recession. Heatshield boundary layer transition (BLT) was observed for both vehicles prior to the time of peak heating, with transition starting near the shoulder and progressing towards the stagnation area. MSL’s higher speed on approach to Mars resulted in higher total heating compared to Mars 2020, with the maximum occurring near the heatshield’s leeside shoulder. The Mars 2020 backshell heating data indicate significant contributions from shock layer radiation. Heating from Navier-Stokes flowfield calculations are in family with reconstructed heating. The paper covers the instrumentation, BLT and reconstructed heating on both heatshields, backshell heating for Mars 2020, TPS performance, and predicted versus reconstructed heat fluxes. Opportunities for improved design approaches for future Mars missions are discussed, especially for the upcoming Mars Sample Return mission.

Mars Science Laboratory↗