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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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NASA NTRS1984

MLA instrument concepts for future land remote sensing

The evolution of various Multispectral Linear Array (MLA) sensor concepts occurred over the past several years in response to a corresponding evolution in mission requirements. Initial efforts were concered with sensors for an Operational Land Observation System (OLOS), with free-flying spacecraft at a principal altitude of 705 km. In 1982, studies related to the definition of instruments for an Experimental Land Observation System (ELOS) were conducted. The ELOS mission involves a series of Space-Shuttle sortie flights. The ELOS MLA instrument is to perform two roles. It is to be a key tool for conducting science experiments from the Shuttle, and it is to demonstrate the technology for an eventual free-flying spacecraft. Attention is given to MLA instrument-design concepts, efforts regarding the development of sensors with many narrow spectral bands, and aspects of technology development.

Mika, A. M.↗
NASA NTRS1982

Imaging Science Panel. Multispectral Imaging Science Working Group joint meeting with Information Science Panel: Introduction

The state-of-the-art of multispectral sensing is reviewed and recommendations for future research and development are proposed. specifically, two generic sensor concepts were discussed. One is the multispectral pushbroom sensor utilizing linear array technology which operates in six spectral bands including two in the SWIR region and incorporates capabilities for stereo and crosstrack pointing. The second concept is the imaging spectrometer (IS) which incorporates a dispersive element and area arrays to provide both spectral and spatial information simultaneously. Other key technology areas included very large scale integration and the computer aided design of these devices.

Source record↗
NASA NTRS1982

Cartography

The demand for cartographic products at scales of 1:25,000 to 1:250,000 continues to increase throughout the world in order to meet requirements associated with: the survey and management of natural resources; environmental planning; and the establishment of geo-referenced data bases. A satellite system involving the use of multispectral linear array (MLA) sensors designed to meet cartographic requirements in terms of the completeness of detail and geometric accuracy standards associated with mapping programs offers great promise for rapidly providing the data with which to produce four types of map products/and data. These include topographic maps; digital terrain information (x,y,z coordinates; thematic mapping; and image maps. Each type of cartographic product/data is briefly considered in relation to current needs.

Source record↗
NASA NTRS1984

Abundancies of Ni, Cr, CO and major elements in the silicate portion of the Moon: Constraints from primary lunar magmas

The lunar volcanic glasses are samples of primary magnas derived by partial melting of the Moon mantle. The twenty-seven varieties of glass define three linear arrays having nearly constant Mg/Si ratios. The low-Ti magmas in each array approach the chondritic Ti/Al ratio. In addition, the Ca/Al ration in these low-Ti magmas trends toward the chrondritid value as one proceeds from array 1 through array 3. Using the chemistries of these primary magmas, as well as the assumption that the Moon possesses chondritic Ca/Al/Ti/Mg ratios, the silicate composition of the Moon has been estimated. The implications of these results are discussed.

Delano, J. W.↗
NASA NTRS1985

Aeroacoustic data for high Reynolds number supersonic axisymmetric jets

Both aerodynamic and near field acoustic behavior of several unheated axisymmetric shock free and shock containing high speed jet plumes are reported. The exit Mach number range for these data is from 0.9 to 2.5. The aerodynamic measurements include both mean and turbulence quantities for a shock free jet plume produced by a convergent divergent nozzle designed to have an exit Mach number of 2. The near field acoustic measurements presented include narrow band spectra, directivity and contour plots of select one third octave band data, and near field microphone correlations from a linear array. Shock noise results are also included as obtained by operating an underexpanded convergent nozzle at the design point of two supersonic exist Mach number convergent divergent nozzles.

Seiner, J. M.↗
NASA NTRS1985

Vector magnetic field observations with the Haleakala polarimeter

Several enhancements were recently made to the Haleakala polarimeter. Linear array detectors provide simultaneous resolution over a 3-A wavelength range, with spectral resolution of 40 mA. Optical fibers are now used to carry the intensity-modulated light from the rotating quarter-wave plate polarimeter to the echelle spectrometer, permitting its removal from the spar to a more stable environment. These changes, together with improved quarter-wave plates, reduced systematic errors to a few parts in 10,000 for routine observations. Examples of Stokes profiles and derived magnetic field maps are presented.

Mickey, D. L.↗
NASA NTRS1984

A case for Gohrem - Geosynchronous orbit high resolution earth monitoring

Although the constant viewing geometry of the geostationary orbit simplifies quantitative monitoring of study areas, the high satellite altitude, in conjunction with the need for high spatial resolution, leads to large and complex sensors and spacecraft. State-of-the-art linear array detectors and a telescope of 1 m diameter and 10 m focal length can meet the requirements in question, which include a scan rate of the ground of at least 25 km/sec, the ability to cover a 150 X 150-km scene every several minutes, and an instantaneous field of view of 50 m in the visible portion of the spectrum and 1000 m in the IR.

Otterman, J.↗
NASA NTRS1983

The NASA MLA program

The NASA Multispectral Linear Array (MLA) program is structured to provide for the evolutionary development of advanced sensor concepts, technologies, and scientific basis for future remote sensing missions. Program elements include the development of multispectral visible and shortwave infrared (SWIR) detector arrays, optics and on-board signal processing technologies, sensor design studies, and supporting research. The research consists of advanced airborne sensor development with data acquisitions, field measurements, and supporting science studies. At the present time, two instrument concepts, including an imaging spectrometer, are in development as payloads for a series of Shuttle remote sensing research flights beginning as early as 1987. Progressively more advanced capability instruments suitable for extended duration Shuttle, free flyer, and space platform missions in the 1990's are also being studied.

Ando, K. J.↗
NASA NTRS1983

An imaging spectrometer experiment for the Shuttle

An imaging spectrometer experiment concept for earth remote sensing, developed as part of NASA's Multispectral Linear Array program, will map a series of test sites at high spatial and spectral resolution from the vantage point of the Shuttle payload bay. The instrument covers the spectral range from 0.4 to 2.5 micrometers with a sampling interval of 10 nanometers in the visible and near infrared (to 1.0 micrometer) and 20 nanometers in the short wavelength infrared (1.0 to 2.5 micrometers). Resolution corresponding to a ground instantaneous field of view (pixel size) of 30 meters is provided over a swath width of 12 kilometers. On-board data editing is utilized to select a subset of the data stream for transmission to the ground. The instrument utilizes silicon and mercury cadmium telluride area array detectors. Pointing mirrors are included to permit specific test sites to be imaged from the Shuttle orbit.

Wellman, J. B.↗
NASA NTRS1984

Options for a new Arizona observatory - Configurations, costs and site

The process of creating a major observatory, with emphasis on the configurations, costs, and site involved, is examined. The premise that cost optimization starts with a modestly priced building block, such as a 7.5-m telescope, is considered. The telescope unit and the configurations in which it is used, ranging from a single telescope or a set of separate telescopes, to an MMT in which the light of all of the telescopes can be phased when desired, are described. It is shown that options exist for using elements in a nonredundant linear array or Michelson interferometer. A means of estimating costs of different facilities, all on the same basis, is provided. The importance of placing the observatory on a site, such as Mt. Graham in Arizona, which maximizes the output per unit cost of the facility is discussed.

Woolf, N. J.↗
NASA NTRS1985

Throughput comparison of microscope objectives and custom lenses for laser diode output beam collimation

The efficiency with which microscope objectives and custom lenses collimate laser diode emission was measured. Four microscope objectives of 10, 21, 45, and 60 power and two custom lenses of 1 and 0.8 power were used. An autocollimator system was used to measure throughput. It consisted of 1 m focal length lens, a 10 power microscope objective, and a 128-element G series Reticon linear array. Collimating throughput efficiency was defined as the ratio of measured collimated power to total laser output power. Two throughput efficiencies were obtained: one for the didoe operation below lasing and the other for the diode operation above lasing. The custom lenses had higher throughput efficiencies than the microscope objectives. The f/0.8 system provided better throughput efficiencies than the f/1.0 system.

Fuhr, P. L.↗
NASA NTRS1985

Solid-state spectral transmissometer and radiometer

An in situ instrument designed to measure the spectral attenuation coefficient of seawater and the ocean remote-sensing reflectance from 400 to 750 nm is in the test and development stage. It employs a 256 channel, charge-coupled type of linear array measuring the spectral intensities diffracted by a grating. Examples of the types of data delivered by this instrument have been simulated using a breadboard laboratory instrument and an above-water, solid-state radiometer. Algorithms developed using data from these instruments provide measures of chlorophyll a plus phaeophytin a concentrations from less than 0.1 to 77.0 mg/cu m, gelbstoff spectral absorption coefficients, and detrital spectral backscattering coefficients for waters of the west Florida shelf.

Carder, K. L.↗
NASA NTRS1985

COSMIC: A high resolution, large collecting area telescope

The spaceborne Coherent Optical System of Modular Imaging Collectors (COSMIC) is presented. It has high angular resolution and can produce images of complex, low-surface-brightness objects such as distant galaxies. If configured as a 36 m filled linear array, COSMIC can have 15 times better angular resolution and 10 times greater collecting area than the Space Telescope. Alternatively, if the collecting area is spread out to create an unfilled two-dimensional array, there is the additional advantage of not needing to rotate the array in order to build up a reconstructed image. Considerations which led to the design concept, scientific goals, and the potentially useful role of a space station for assembly are discussed.

Traub, W. A.↗
NASA NTRS1986

Zircon Lu-Hf systematics: Evidence for the episodic development of Archaean greenstone belts

A combined U-Th-Pb and Lu-Hf isotopic study of zircons was undertaken in order to determine the provenance and age of an Archean granite-greenstone terrain and to test the detailed application of the Lu-Hf system in various Archean zircons. The eastern Wawa subprovince of the Superior province consists of the low grade Michipicoten and Gamitagama greenstone belts and the granitic terrain. The Hf isotopic data indicate that the typical lithological features of a greenstone belt cycle could be accommodated in a crustal growth model that involved decreasing depth of melting in three isotopically distinct reservoirs: mantle, lower crust and upper crust. The model age of the sources given by the intersection of the lower crustal curve with the bulk earth evolution curve is about 2900 My, in good agreement with the zircon U-Pb basement age. This linear array also has a similar intersection age to that of Proterozoic carbonatite complexes. The general convergence of the other reservoir vectors around this age suggests that mantle depletion, crustal extraction and intracrustal differentiation were all part of the same episodic event. It is also apparent that recycling of older basement was important in the formation of many of the later greenstone belt rocks.

Smith, P. E.↗
NASA NTRS1986

Conceptual design study: Forest Fire Advanced System Technology (FFAST)

An integrated forest fire detection and mapping system that will be based upon technology available in the 1990s was defined. Uncertainties in emerging and advanced technologies related to the conceptual design were identified and recommended for inclusion as preferred system components. System component technologies identified for an end-to-end system include thermal infrared, linear array detectors, automatic georeferencing and signal processing, geosynchronous satellite communication links, and advanced data integration and display. Potential system configuration options were developed and examined for possible inclusion in the preferred system configuration. The preferred system configuration will provide increased performance and be cost effective over the system currently in use. Forest fire management user requirements and the system component emerging technologies were the basis for the system configuration design. A preferred system configuration was defined that warrants continued refinement and development, examined economic aspects of the current and preferred system, and provided preliminary cost estimates for follow-on system prototype development.

Nichols, J. D.↗
NASA NTRS1986

High resolution remote sensing missions of a tethered satellite

The application of the Tethered Satellite (TS) as an operational remote sensing platform is studied. It represents a new platform capable of covering the altitudes between airplanes and free flying satellites, offering an adequate lifetime, high geometric and radiometric resolution and improved cartographic accuracy. Two operational remote sensing missions are proposed: one using two linear array systems for along track stereoscopic observation and one using a synthetic aperture radar combined with an interferometric technique. These missions are able to improve significantly the accuracy of future real time cartographic systems from space, also allowing, in the case of active microwave systems, the Earth's observation both in adverse weather and at any time, day or night. Furthermore, a simulation program is described in which, in order to examine carefully the potentiality of the TS as a new remote sensing platform, the orbital and attitude dynamics description of the TSS is integrated with the sensor viewing geometry, the Earth's ellipsoid, the atmospheric effects, the Sun illumination and the digital elevation model. A preliminary experiment has been proposed which consist of a metric camera to be deployed downwards during the second Shuttle demonstration flight.

Vetrella, S.↗
NASA NTRS1984

Multiband selection device

Current science projections for future earth-imaging instruments indicate the need for as many as 25 spectral bands, with bandwidths as narrow as 20 nanometers. The desire for a multiplicity of bands has led researchers to study various spectrally dispersive instrument designs as a means of providing the desired future capability. These instrument designs, however, are costly, complex, and of high technical risk. This paper describes a 'multiband selection device' containing several spectral filters that can be placed at the exit faces of a broadband multiport beam splitter and thereby provide a multiplicity of spectral bands with a high degree of spatial coregistration while utilizing state-of-the-art linear array detectors. Fabrication of the multiband selection device has been successfully accomplished, and the design and test results are described.

Richard, H. L.↗
NASA NTRS1984

The National Symposium and Workshop on Optical Platforms, Huntsville, AL, June 12-14, 1984, Proceedings

The present conference is concerned with space-based observatories (including future systems), interplanetary observation platforms, Space Station optical utilization, orbital earth viewing systems, and Spacelab's use as an observations platform. Attention is given to the pointing system for the Space Telescope, the Advanced X-ray Astrophysics Facility, the conceptual definition of the Space IR Telescope Facility's spacecraft, satellite servicing in light of the Solar Maximum Repair Mission, a large deployable reflector telescope concept, moon-based astronomical observatories, Space Station-based remote sensing of the earth, optical systems is geosynchronous orbit, multispectral linear array detector technology, Spacelab-based space plasma and materials processing investigations, and space construction technology for large space observatories. Also discussed are military optical platforms for sea, land and air stationing.

Wyman, C. L.↗