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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6
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NASA NTRS1978

Viking infrared thermal mapper

The infrared thermal mapper (IRTM) was designed to measure the emitted and reflected radiance of Mars. Carried by the Viking Orbiter, the IRTM contains four small Cassegrainian telescopes which each image the same, seven circular areas. There is a total of twenty-eight channels in four surface and one atmospheric thermal bands from 6 to 30 microns and a broad solar reflectance band. All channels are sampled simultaneously, using the spacecraft scanning capability to map the radiance over small and large areas of the planet. All channels use thermopile detectors; spectral passbands are determined by a combination of interference filters, detector lense materials, antireflection coatings, and restrahlen optics.

Chase, S. C., Jr.↗
NASA NTRS1978

Time-delay-and-integration charge coupled devices /CCDs/ applied to the Thematic Mapper

The visible focal plane of the Thematic Mapper, the next generation sensor system for application to earth resource survey, uses complex hybrid assembly techniques to interface silicon photodiodes to JFET preamplifiers. This complexity can be ameliorated by the use of a 20-channel time-delay-and-integration (TDI) CCD with nine stages of integration per channel. By going to a CCD array operating in a TDI mode, over 700 individual op amps can be replaced with only 48 op amps. Smooth spectral response and 70% quantum efficiency have been provided by using doped tin oxide gates over the imaging region.

Thompson, L. L.↗
NASA NTRS1980

The JPL flux mapper

The flux mapper is a device that can map the intensity distribution in three dimensions of concentrated solar energy at the focus of a concentrator. Intensities to 10,000 solar constants can be measured. Constructed to assist in concentrator and receiver development, it consists of a radiometer which is moved through the concentrated sunlight in a series of planes perpendicular to the optical axis by means of a mechanical rastering device. Various radiometer probes can be utilized depending on the time and accuracy requirements of the program. Energy levels are recorded as a function of location. Reduction of this data can be in various formats, e.g., contour maps, digital arrays, isometric visualizations and other displays as the user requires.

Owen, W. A.↗
NASA NTRS1980

The time-space relationship of the data point (Pixels) of the thematic mapper and multispectral scanner or the myth of simultaneity

A simplified explanation of the time space relationships among scanner pixels is presented. The examples of the multispectral scanner (MSS) on Landsats 1, 2, and 3 and the thematic mapper (TM) of Landsat D are used to describe the concept and degree of nonsimultaneity of scanning system data. The time aspects of scanner data acquisition and those parts of the MSS and TM systems related to that phenomena are addressed.

Gordon, F., Jr.↗
NASA NTRS1976

Thematic mapper studies band correlation analysis

Spectral data representative of thematic mapper candidate bands 1 and 3 to 7 were obtained by selecting appropriate combinations of bands from the JSC 24 channel multispectral scanner. Of all the bands assigned, only candidate bands 4 (.74 mu to .80 mu) and 5 (.80 mu to .91 mu) showed consistently high intercorrelation from region to region and time to time. This extremely high correlation persisted when looking at the composite data set in a multitemporal, multilocation domain. The GISS investigations lend positive confirmation to the hypothesis, that TM bands 4 and 5 are redundant.

Ungar, S. G.↗
NASA NTRS1979

Thematic mapper design description and performance prediction

The new generation of satellite-borne earth resources scanners, the Thematic Mapper, is being built for launch on the Landsat-D spacecraft. It will gather data for applications such as crop inventory, land use planning, forest management, and geology. This paper gives an overall design description, further discussion of principal design features, performance achievements where data are available, and system performance predictions.

Lansing, J. C., Jr.↗
NASA NTRS1980

Pioneer Venus Orbiter Radar Mapper - Design and operation

The Radar Mapper Experiment, carried aboard the Pioneer Venus Orbiter spacecraft, is designed to obtain a near-global picture of the topography, meter-scale surface slopes and reflectivity of Venus. Constraints imposed by the choice of orbit limit radar coverage to a latitude band lying between 74 deg N and 61 deg S completely around the planet. In addition to the altimetry objectives, the experiment seeks an image of the radar scattering properties of the surface at oblique incidence. Sensitivity limits the imaged region to a band around the planet lying between 45 deg N and 10 deg S. Altimetric error is less than 200 m; altimetric surface 'footprint' size varies from about 10 km in diameter at a spacecraft altitude of 200 km, to 50 km at a maximum altitude of 4700 km. Imaging varies from 20 to 40 km, depending on spacecraft altitude.

Pettengill, G. H.↗
NASA NTRS1980

Design challenges of the thematic mapper

The paper discusses the Thematic Mapper (TM), a multispectral earth resources sensor that will be launched on the Landsat-D satellite. The TM will operate in a circular, near-polar orbit of 750-km altitude and will scan a swath of earth 185 km wide. One TM mirror is a moving scan mirror, active during the forward and reverse scans; the final design of this component incorporates a mirror which has the required linearity and is not influenced by structural vibration. Another TM component that presented a design difficulty was the optical metering structure which has to be thermally stable across the temperature range in the instrument's orbital environment and duty cycle.

Blanchard, L. E.↗
NASA NTRS1981

Waveband evaluation of proposed thematic mapper in forest cover classification

This study involved the evaluation of the characteristics of multispectral scanner data relative to forest cover type mapping, using NASA's NS-001 multispectral scanner to simulate the proposed Thematic Mapper (TM). The objectives were to determine: (1) the optimum number of wavebands to utilize in computer classifications of TM data; (2) which channel combinations provide the highest expected classification accuracy; and (3) the relative merit of each channel in the context of the cover classes examined. Transformed divergence was used as a measure of statistical distance between spectral class densities associated with each of twelve cover classes. The maximum overall mean pair-wise transformed divergence was used as the basis for evaluating all possible waveband combinations available for use in computer-assisted forest cover classifications.

Latty, R. S.↗
NASA NTRS1981

Earth applications orbit analysis for a shuttle-mounted Multispectral Mapper

The earth remote sensing problem of orbit design to acquire images with inherent geometric and geodetic accuracy is addressed. The basis for precise orbit modeling is discussed. Various orbit propagation tools are compared. Orbit characteristics for a nominal case at shuttle altitude are displayed. Modeling Parameter sensitivities are evaluated to determine limits on orbit propagation accuracy versus time. It is found that attainable propagation accuracies are sufficient for image quality assessment over the short term at the 15m pixel size desired for a Multispectral Mapper.

Driver, J. M.↗
NASA NTRS1982

LANDSAT D to test thematic mapper, inaugurate operational system

NASA will launch the Landsat D spacecraft on July 9, 1982 aboard a new, up-rated Delta 3920 expendable launch vehicle. LANDSAT D will incorporate two highly sophisticated sensors; the flight proven multispectral scanner; and a new instrument expected to advance considerably the remote sensing capabilities of Earth resources satellites. The new sensor, the thematic mapper, provides data in seven spectral (light) bands with greatly improved spectral, spatial and radiometric resolution.

Source record↗
NASA NTRS1982

Mars' atmospheric behavior from Viking infra-red thermal mapper measurements

Data from the 15 micron band of CO2 readings with the two Viking IR thermal mappers are discussed. Contrasts were observed to be strong between clear and dusty conditions, with a latitudinal gradient and a diurnal amplitude variation in the winter southern hemisphere. Consistency was found in zonal mean temperatures in the absence of dust, with a peak temperature of 180 K at the poles and a diurnal amplitude of 15 K at the equator. Large temperature increases occur in dusty conditions, with global dust storms being present in the northern, but not southern, hemisphere. Estimations of the surface and atmospheric temperatures are calculated in order to derive optical depths from the IR measurements of atmospheric opacity. The optical depth around the whole planet is found to be relatively uniform at any given moment. Finally, the diurnal behavior of the brightness temperature is outlined for 1.4 Mars years.

Martin, T. Z.↗
NASA NTRS1981

Thematic mapper - An overview of spectral band registration

The Thematic Mapper (TM) is a high-resolution radiometer designed for earth resources classification and mapping. The TM employs multispectral scanning in a near polar orbit to sweep a 185-km swath. Data are obtained through a combination of spacecraft motion and the sweeping action of the scan mirror. These data are transmitted either directly to ground stations around the world or through a relay to the central data processing facility at White Sands, NM. Seven spectral passbands are employed, and applications include coastal water mapping, soil vegetation differentiation, biomass surveys, water body delineation, vegetation moisture measurement, plant heat stress management, and hydrothermal mapping. Attention is given to the scan mirror assembly, scan nonlinearities, the characterization and compensation of scan profiles, experimental performance, and a procedure for midscan correction.

Freudenstein, W. H.↗
NASA NTRS1981

Multispectral mapper - Imaging spectroscopy as applied to the mapping of earth resources

An instrument concept that uses solid-state array imaging has been developed for a future land observing system. The design concept is responsive to a variety of use needs and provides improved capabilities over the planned Landsat Thematic Mapper. A comparison of the differing approaches to the instrument design was made, resulting in the selection of a concept which uses a spectrograph coupled to a line-array imager to provide simultaneous spatial and spectral resolution. The design provides an inherent solution to the problem of achieving precise registration among the spectral bands. Data processing on the focal plane is used to select the spectral bands and their band widths. Onboard capabilities include radiometric correction, selection of instantaneous field-of-view and swath width, and data compression.

Wellman, J. B.↗
NASA NTRS1981

Landsat D Thematic Mapper image resampling for scan geometry correction

The Landsat D system is described, and the geometric correction processing for the Thematic Mapper (TM) is reviewed. The resampling procedure (the generation of a TM output image) is analyzed with emphasis on the effect of sampling geometry on output image. Effects of scan gaps and spacecraft jitter on output image are studied by means of a simulation of the sampling and resampling processes for three sampling geometries. Visual inspection of the resampling results shows that the resampling algorithm works excellently under all conditions and that distortion is visible only in the rare case of large gaps between scans.

Prakash, A.↗
NASA NTRS1980

The use of thematic mapper simulator calibration data for assessment of data quality

In flight calibration data collected from the thematic mapper simulator (TMS) were used to assess the quality of Earth scan data. The following results are indicated: (1) based on limited samples, individual TMS channels have noise which varies from channel to channel, but remains constant within a channel; (2) short term variations of more than 5% in the average values of calibration source responses indicate problems; and (3) absolute radiometric calibration is unlikely to be meaningful in a temporal sense due to single point calibration methods used.

Forman, M. L.↗
NASA NTRS1979

Evaluation of SLAR and thematic mapper MSS data for forest cover mapping using computer-aided analysis techniques

A literature review on radar and spectral band information was conducted and a NC-130 mission was flown carrying the NS001 scanner system which basically corresponds to the channel configuration of the proposed thematic mapper. Aerial photography and other reference data were obtained for the study site, an area approximately 290 sq miles in north central South Carolina. A cover type map was prepared and methods were devised for reformatting and geometrically correcting MSS CRT data. Arrangements were made to obtain LANDSAT data for dates approximating the NC-130 mission. Because of the waveband employed to obtain SEASAT radar data, it was decided to determine if X-band (2.40 cm to 3.75 cm wavelength) imagery is available.

Hoffer, R. M.↗