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Mccord, Thomas B.

Publications and source records attributed to Mccord, Thomas B..

11 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Galileo infrared imaging spectrometry measurements at the Moon

Imaging spectrometer observations were made of the surface of the Moon during the December 1990 flyby of the Earth-Moon system by the Galileo spacecraft. This article documents this data set and presents analyses of some of the data. The near infrared mapping spectrometer (NIMS) investigation obtained 17 separate mosaics of the Moon in 408 spectral channels between about 0.7 and 5.2 micrometers. The instrument was originally designed to operate in orbit about Jupiter and therefore saturates at many spectral channels for most measurement situations at 1 AU. However, sufficient measurements were made of the Moon to verify the proper operation of the instrument and to demonstrate its capabilities. Analysis of these data show that the NIMS worked as expected and produced measurements consistent with previous ground-based telescopic studies. These are the first imaging spectrometer measurements of this type from space for the Moon, and they illustrate several major points concerning this type of observation and about the NIMS capabilities specifically. Of major importance are the difference between framing and scanning instruments and the effects of the spacecraft and the scan platform on the performance of such and experiment. The science return of subsequent NIMS and other investigation measurements will be significantly enhanced by the experience and results gained.

Mccord, Thomas B.↗
NASA NTRS1993

Planetary Instrument Definition and Development Program (PIDDP). Instrument for future planetary flight missions: A visible-infrared imaging spectrometer for planetary missions

The objective of this project is to develop and prove a small, light-weight, efficient imaging spectrometer design to cover the VIS/NIR spectral range for applications particularly but not exclusively to NASA inner solar system space missions. A design and a brassboard prototype will be developed and tested. Progress over the first year of this project includes design specification, optical design layout, grating specifications, infrared detector selection, and mechanical design. Mechanical and grating manufacturing drawings were begun. We developed an agreement in principle to cooperate with the German space group, DLR, to apply some of their electronics microminiaturization technology to this imaging spectrometer project, mostly or entirely at their expense. Funds from NASA for the second year of this effort have been received and the effort is on track. Release of funds for the third year of this award will be requested later this year in order to accelerate this work and bring it to a conclusion in time for new NASA missions considerations as well as to make effective use of the DLR contributions.

Mccord, Thomas B.↗
NASA NTRS1992

Charge-coupled device imaging spectroscopy of Mars. I - Instrumentation and data reduction/analysis procedures

This paper describes the collection, reduction, and analysis of 0.4-1.0-micron Mars imaging spectroscopy data obtained during the 1988 and 1990 oppositions from Mauna Kea Observatory and provides a general outline for the acquisition and analysis of similar imaging spectroscopy data sets. The U.H. 2.24-m Wide Field Grism CCD Spectrograph was used to collect 13 3D image cubes covering 90 percent of the planet south of 50 deg N in the 0.4-0.8 micron region and covering 55 percent of the planet south of 50 deg N in the 0.5-1.0 micron region. Spectra extracted from these image cubes reveal the detailed character of the Martian near-UV to visible spectrum. Images at red wavelengths reveal the 'classical' albedo markings at 100-500 km spatial resolution while images at blue wavelengths show little surface feature contrast and are dominated by condensate clouds/hazes and polar ice.

Bell, James F., III↗
NASA NTRS1990

Observational evidence of crystalline iron oxides on Mars

A series of new spectral observations of Mars was obtained at Mauna Kea Observatory in the 0.4-1.0-micron wavelength range during the extremely favorable 1988 opposition, which yielded new spectral reflectance and relative reflectance data for a number of distinct spots on the Martian surface at 500-600 km spatial resolution. The new spectra revealed absorptions at 0.62-0.72 micron and at 0.81-0.94 micron, both seen clearly for the first time. These absorption features are interpreted as Fe(3+) electronic transition bands that indicate the presence of crystalline ferric oxide or hydroxide minerals on the Martian surface.

Bell, James F., III↗
NASA NTRS1989

Mars - Near-infrared comparative spectroscopy during the 1986 opposition

Near-IR, 0.7-2.5 micron spectra were obtained for several Martian locations during the 1986 opposition, using a continuously variable filter spectrometer; approximately 60 distinct spots were observed at 0.5-1.5 arcsec (200-460 km) resolution which are distinguishable into eight distinct geologic types: (1) volcanic regions, (2) ridged plains, (3) ridged volcanic plains, (4) scoured plains, (5) impact basins, (6) channels and canyons, (7) densely-cratered regions, and (8) layered terrain and ice. Spectral features observed in the spot-to-spot ratios for spectra from different geologic regions are used as indicators of mineralogic differences. Little difference is found among spectra from areas that appear to have very different morphologies in Viking Orbiter images.

Bell, James F., III↗
NASA NTRS1988

Research in planetary astronomy

The objective is the continuation of a long-term research program designed to study the composition, structure and processes operating on the surfaces of solar system objects using the Mauna Kea Observatory with techniques and modern instrumentation. Reflectance spectroscopy and multispectral imaging in the spectral region, 0.3 to 5.0 micrometer are the major techniques used, although thermal (10 micrometer and 20 micrometer) radiometry are used in some aspects of the research. Some specific projects include: (1) systematic spectral imaging observations of the Moon; (2) systematic spectral imaging and spectral monitoring of the Martian surface; (3) thermal radiometry of asteroids as part of the IRAS follow-up and other target specific programs; (4) searches for asteroid satellites and dust belts using a stellar coronagraph; and (5) studies of circumstellar disks using a stellar coronagraph. Progress for each of the programs included is discussed. minerals; (2) completed observations of lunar multi-ringed basins and crater deposits in search of high-Ca spectral anomalies; (3) completed data reduction of an additional 5 asteroids observed by the coronagraphic technique in the search for asteroids satellites and debris clouds; and (4) completed the reduction and calibration of 350 asteroids observed at 10 micron and 20 micron using the NASA IRTF.

Mccord, Thomas B.↗
NASA NTRS1987

Reflectance spectroscopy in planetary science: Review and strategy for the future

Reflectance spectroscopy is a remote sensing technique used to study the surfaces and atmospheres of solar system bodies. It provides first-order information on the presence and amounts of certain ions, molecules, and minerals on a surface or in an atmosphere. Reflectance spectroscopy has become one of the most important investigations conducted on most current and planned NASA Solar System Exploration Program space missions. This book reviews the field of reflectance spectroscopy, including information on the scientific technique, contributions, present conditions, and future directions and needs.

Mccord, Thomas B.↗
NASA NTRS1987

Reflectance spectra of mafic silicates and phyllosilicates from .6 to 4.6 microns

The results of spectral measurements for mafic silicates are given. The study provided valuable spectral reflectance information about mafic silicates and phyllosilicates in the 2.5 to 4.6 micron wavelength region. It was shown that the reflectance of these materials is strongly affected by the presence of H2O and OH. Therefore, the identification of these absorbing species is greatly enhanced.

Roush, Ted L.↗
NASA NTRS1987

Mars: Near-infrared comparative spectroscopy during the 1986 opposition

Near-infrared spectral observations of Mars during the 1986 opposition were performed at the Mauna Kea Observatory utilizing the University of Hawaii's 88 inch telescope. Spectra were obtained of several Martian locations using a continuously variable filter (CVF) spectrometer with a resolution of 1.25 percent. Spot-to-spot ratios were produced between spectra taken in different geological regions.

Bell, James F., III↗
NASA NTRS1987

Mars: Spectral signatures seen and unseen

Intrepretation of Mars surface reflectance spectra and geochemical modeling of the surface material are different approaches to the same problem (determining the compositional nature and evolution of the surface of Mars). The degree to which these two approaches agree is studied. This study involves: current understanding of the reflectance of Mars, and reflectance spectra of proposed Mars constituents.

Blaney, Diana L.↗