Dietz, J. B. | Engineering Papers

NASA NTRS1993

Expert system-based mineral mapping in northern Death Valley, California/Nevada, using the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)

Integrated analysis of imaging spectrometer data and field spectral measurements were used in conjunction with conventional geologic field mapping to characterize bedrock and surficial geology at the northern end of Death Valley, California and Nevada. A knowledge-based expert system was used to automatically produce image maps showing the principal surface mineralogy from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data. Linear spectral unmixing of the AVIRIS data allowed further determination of relative mineral, abundances and identification of mineral assemblages and mixtures. The imaging spectrometer data show the spatial distribution of spectrally distinct minerals occurring both as primary rockforming minerals and as alteration and weathering products. Field spectral measurements were used to verify the mineral maps and field mapping was used to extend the remote sensing results. Geographically referenced image maps produced from these data form new base maps from which to develop improved understanding of the processes of deposition and erosion affecting the present land surface.

Kruse, F. A.↗

NASA NTRS1992

Expert system-based mineral mapping using AVIRIS

Integrated analysis of imaging spectrometer data and field spectral measurements were used in conjunction with conventional geologic field mapping to characterize bedrock and surficial geology at the northern end of Death Valley, California and Nevada. A knowledge-based expert system was used to automatically produce image maps from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data showing the principal surface mineralogy. The imaging spectrometer data show the spatial distribution of spectrally distinct minerals occurring both as primary rock-forming minerals and as alteration and weathering products. Field spectral measurements were used to verify the mineral maps and field mapping was used to extend the remote sensing results. Geographically referenced image-maps produced from these data form new base maps from which to develop improved understanding of the processes of deposition and erosion affecting the present land surface. The 'northern Grapevine Mountains' (NGM) study area was reported on in numerous papers. This area is an unnamed northwestward extension of the range. Most of the research here has concentrated on mapping of Jurassic-age plutons and associated hydrothermal alteration, however, the nature and scope of these studies is much broader, pertaining to the geologic history and development of the entire Death Valley region. AVIRIS data for the NGM site were obtained during May 1989. Additional AVIRIS data were acquired during September 1989 as part of the Geologic Remote Sensing Field Experiment (GRSFE). The area covered by these data overlaps slightly with the May 1989 data. Three and one-half AVIRIS scenes total were analyzed.

Kruse, Fred A.↗

NASA NTRS1976

Flash evaporator systems test

A flash evaporator heat rejection system representative of that proposed for the space shuttle orbiter underwent extensive system testing at the NASA Johnson Space Center (JSC) to determine its operational suitability and to establish system performance/operational characteristics for use in the shuttle system. During the tests the evaporator system demonstrated its suitability to meet the shuttle requirements by: (1) efficient operation with 90 to 95% water evaporation efficiency, (2) control of outlet temperature to 40 + or - 2 F for partial heat load operation, (3) stability of control system for rapid changes in Freon inlet temperature, and (4) repeated dormant-to-active device operation without any startup procedures.

Dietz, J. B.↗

NASA NTRS1976

Deployable radiators for waste heat dissipation from Shuttle payloads

Prototypes of two types of modularized, deployable radiator systems with a high degree of configuration and component commonality to minimize design, development and fabrication costs are currently under development for Shuttle payloads with high waste heat: a rigid radiator system which utilizes aluminum honeycomb panels that are deployed by a scissors mechanism; and two 'flexible' radiator systems which use panels constructed from flexible metal/dielectric composite materials that are deployed by 'unrolling' or 'extending' in orbit. Detail descriptions of these deployable radiator systems along with design and performance features are presented.

Cox, R. L.↗

NASA NTRS1976

Deployable radiators for waste heat dissipation from Shuttle payloads

Thermal control of Shuttle instruments will require the use of a pumped fluid space radiator system to reject large quantities of waste heat. Many payloads, however, will have insufficient vehicle surface area available for radiators to reject this waste heat and will, therefore, require the use of deployed panels. It is desirable to utilize modularized, deployable radiator systems which have a high degree of configuration and component commonality to minimize the design, development, and fabrication costs. Prototypes of two radiator systems which meet these criteria are currently under development for Shuttle payload utilization: a 'rigid' radiator system which utilizes aluminum honeycomb panels of the Shuttle Orbiter configuration that are deployed by an Apollo Telescope Mount type scissors mechanism; and two 'flexible' radiator systems which use panels constructed from flexible metal/dielectric composite materials that are deployed by 'unrolling' or 'extending' in orbit. Detailed descriptions of these deployable radiator systems, along with design and performance features, are presented.

Cox, R. L.↗

NASA NTRS1975

Development and parametric evaluation of the prototype 2 and 3 flash evaporators

Development of the Prototype 2 and 3 flash evaporator heat sinks which vaporize an expendable fluid to cool a heat transport fluid loop is reported. The units utilize Freon 21 as the heat transport fluid and water as the expendable fluid to meet the projected performance requirements of the space shuttle for both on-orbit and ascent/reentry operations. The evaporant is pulse-sprayed by on-off control onto heat transfer surfaces containing the transport fluid and exhausted to the vacuum environment through fixed area exhaust ducts.

Hixon, C. W.↗

NASA NTRS1973

The environmental heat flux routine, version 4 (EHFR-4) and Multiple Reflections Routine (MRR), volume 1

The environmental heat flux routine version 4, (EHFR-4) is a generalized computer program which calculates the steady state and/or transient thermal environments experienced by a space system during lunar surface, deep space, or thermal vacuum chamber operation. The specific environments possible for EHFR analysis include: lunar plain, lunar crater, combined lunar plain and crater, lunar plain in the region of spacecraft surfaces, intervehicular, deep space in the region of spacecraft surfaces, and thermal vacuum chamber generation. The EHFR was used for Extra Vehicular Mobility Unit environment analysis of the Apollo 11-17 missions, EMU manned and unmanned thermal vacuum qualification testing, and EMU-LRV interface environmental analyses.

Dietz, J. B.↗

NASA NTRS1973

The Environmental Heat Flux Routine, Version 4 (EHFR-4) and Multiple Reflections Routine (MRR). Volume 2: Programmers reference manual

The EHFR program reference information which is presented consists of the following subprogram detailed data: purpose-description of the routine, a list of the calling programs, an argument list description, nomenclature definition, flow charts, and a compilation listing of each subprogram. Each of the EHFR subprograms were developed specifically for this routine and do not have an applicability of a general nature. Single precision accuracy available on the Univac 1108 is used exclusively in all but two of the 31 EHFR subprograms. The double precision variables required are identified in the nomenclature definition of the two subprograms that require them. A concise definition of the purpose, function, and capabilities is made in the subprogram description. The description references the appropriate Volume 1 sections of the report which contain the applicable detailed definitions, governing equations, and assumptions used. The compilation listing of each subprogram defines the program/data storage requirements, identifies the labeled block common data required, and identifies other subprograms called during execution. For Vol. 1, see N73-31842.

Dietz, J. B.↗

NASA NTRS1972

Modular radiator system development for shuttle and advanced spacecraft.

Previous spacecraft heat rejection systems have been tailored to a specific spacecraft and a specific mission. Many different panel designs, fluids, and control methods have been used with no significant degree of commonality. For future spacecraft, it is desirable to have heat rejection systems which can accommodate widely varying loads and have a high degree of commonality to minimize development requirements. A modular radiator system which satisfies this requirement and is adaptable to a variety of future vehicles and missions is described. A test program with two modular panels connected in several flow arrangements, which are representative of candidate shuttle orbiter and other future spacecraft applications, is described.

Dietz, J. B.↗

NASA NTRS1971

Radiator design system computer programs

Minimum weight space radiator subsystems which can operate over heat load ranges wider than the capabilities of current subsystems are investigated according to projected trends of future long duration space vehicles. Special consideration is given to maximum heat rejection requirements of the low temperature radiators needed for environmental control systems. The set of radiator design programs that have resulted from this investigation are presented in order to provide the analyst with a capability to generate optimum weight radiator panels or sets of panels from practical design considerations, including transient performance. Modifications are also provided for existing programs to improve capability and user convenience.

Wiggins, C. L.↗