Engineering topics
Wall, S.
Publications and source records attributed to Wall, S..
Cassini radar views the surface of Titan
The Cassini Titan Radar Mapper imaged about 1% of Titan's surface at a resolution of approximately 0.5 kilometer, and larger areas of the globe in lower resolution modes. The images reveal a complex surface, with areas of low relief and a variety of geologic features suggestive of dome-like volcanic constructs, flows, and sinuous channels. The surface appears to be young, with few impact craters. Scattering and dielectric properties are consistent with porous ice or organics. Dark patches in the radar images show high brightness temperatures and high emissivity and are consistent with frozen hydrocarbons.
Cassini radar views the surface of Titan
The Cassini Titan Radar Mapper imaged about 1% of Titan’s surface at a resolution of È0.5 kilometer, and larger areas of the globe in lower resolution modes. The images reveal a complex surface, with areas of low relief and a variety of geologic features suggestive of dome-like volcanic constructs, flows, and sinuous channels. The surface appears to be young, with few impact craters. Scattering and dielectric properties are consistent with porous ice or organics. Dark patches in the radar images show high brightness temperatures and high emissivity and are consistent with frozen hydrocarbons.
The Use of Concurrent Engineering in Space Mission Design
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Use of Concurrent Engineering in Space Mission Design
In recent years, conceptual-phase (proposal level) design of space missions has been improved considerably. Team structures, tool linkage, specialized facilities known as design centers and scripted processes have been demonstrated to cut proposal-level engineering design time from a few months to a few weeks.
Cassini Radar Mission: Reconnaissance of Titan
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Design Process Enhancements for Planetary Missions
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Team Efficiencies Within a Model-Driven Design Process
(Smith & Koenig 1998) formulated a model-based design process describing a triad of people, process, and technology (PPT) within an aerospace culture.
Reinventing the Design Process: Teams and Models
The future of space mission designing will be dramatically different from the past. Formerly, performance-driven paradigms emphasized data return with cost and schedule being secondary issues.
Team Structures and Processes in the Design of Space Missions
We consider team dynamics a component of the engineering design process for space missions and explore the possibility of improvements in management of team dynamics to gain additional efficiencies.
Cassini Radar Investigation of Titan
Saturn's largest moon, Titan, boasts organic chemistry that may hold clues to how life formed on the primitive Earth. The Cassini Mission, to be launched in October 1997, will explore Saturn and its moons, especially Titan. Mapping the surface of Titan will be accomplished with a radar instrument that acts as a 14 GHz synthetic aperture radar, microwave radiometer, altimeter, and scatterometer.
Overview of Results from the SIR-C/X-SAR Mission
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Use of Radar Backscatter to Infer Aerodynamic Roughness
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Overview of Results from the SIR-C/X-SAR Mission
The US Space Transportation System, or Shuttle, has shown itself to be a useful platform from which to evaluate remote sensing instrumentation for later use in a free-flying satellite.
Overview of Results from the SIR-C/X-SAR Mission
The US Space Shuttle is a useful platform from which to evaluate remote sensing instrumentation.
Accurate Inventories Of Irrigated Land
System for taking land-use inventories overcomes two problems in estimating extent of irrigated land: only small portion of large state surveyed in given year, and aerial photographs made on 1 day out of year do not provide adequate picture of areas growing more than one crop per year. Developed for state of California as guide to controlling, protecting, conserving, and distributing water within state. Adapted to any large area in which large amounts of irrigation water needed for agriculture. Combination of satellite images, aerial photography, and ground surveys yields data for computer analysis. Analyst also consults agricultural statistics, current farm reports, weather reports, and maps. These information sources aid in interpreting patterns, colors, textures, and shapes on Landsat-images.
Radar-aeolian roughness project
The objective is to establish an empirical relationship between measurements of radar, aeolian, and surface roughness on a variety of natural surfaces and to understand the underlying physical causes. This relationship will form the basis for developing a predictive equation to derive aeolian roughness from radar backscatter. Results are given from investigations carried out in 1989 on the principal elements of the project, with separate sections on field studies, radar data analysis, laboratory simulations, and development of theory for planetary applications.
Relationships between topographic roughness and aeolian processes
The interaction between winds and desert surfaces has important implications for sediment transport on Earth, Mars, and Venus, and for understanding the relationships between radar backscatter and aerodynamic roughness as part of the NASA Shuttle Imaging radar (SIR-C) Mission. Here, researchers report results from measurements of boundary layer wind profiles and surface roughness at sites in Death Valley and discuss their implications. The sites included a flat to undulating gravel and sand reg, alluvial fans, and a playa. Estimates of average particle size composition of Death Valley sites and arithmetic mean values of aerodynamic roughness are given in tabular form.