Engineering topics

Moore, Henry J.

Publications and source records attributed to Moore, Henry J..

7 records

NASA NTRS1994

A perspective of landing-site selection

The problems that now confront Mars Pathfinder are much the same as those that confronted Viking, but more and better information exists today. Like Viking, Mars Pathfinder must select a landing site compatible with lander and rover designs as evidenced by available data (Viking images, radar and thermal observations, albedo and color observations, visible-infrared spectra, etc.). Most regions at low elevations probably contain favorable sites, but some sites at low elevations with weak quasispecular echoes and low thermal inertias may be unfavorable.

Moore, Henry J.↗

NASA NTRS1992

The Martian surface layer

The global characteristics of the Martian surface layer are discussed on the basis of thermal, albedo, color, and radar data for the region between approximately 60 deg S and 60 deg N. Thermal data reveal the presence of large low- and high-inertia regions of the northern hemisphere, with much of the south covered by material of moderate inertia. There is a strong anticorrelation between inertia and albedo, a correlation between inertia and rock abundance, and, over much of the planet, a correlation of radar-derived density with inertia. Viking Orbiter color data indicate the presence of three major surface materials: low-inertia, bright-red material that is presumably dust; high-inertia, dark-grey material interpreted to be lithic material mixed with palagonitelike dust; and moderate-inertia, dark-red material that is rough at subpixel scales and interpreted to be indurated. Observations from the Viking landing sites show rocks, fines of varying cohesion and crusts. These sites have indications of aeolian erosion and deposition in the recent past.

Christensen, Philip R.↗

NASA NTRS1989

Viking landing sites, remote-sensing observations, and physical properties of Martian surface materials

Consideration is given to the relations between the physical properties of the surface materials at Viking landing sites, the physical properties of other Martian surfaces inferred from radar observations from earth and thermal observations from orbit, and the geological processes that formed the materials and shaped the surfaces. The radar and thermal remote-sensing signatures of the landing site surface materials are estimated and compared with the thermal and radar measurements for the entire planet. It is shown that the surface materials at the landing sites are good analogs for the materials in most of the Martian equatorial regions.

Moore, Henry J.↗

NASA NTRS1989

The Martian surface as imaged, sampled, and analyzed by the Viking landers

Data collected by two Viking landers are analyzed. Attention is given to the characteristics of the surface inferred from Lander imaging and meteorology data, physical and magnetic properties experiments, and both inorganic and organic analyses of Martian samples. Viking Lander 1 touched down on Chryse Planitia on July 20, 1976 and continued to operate for 2252 sols, until November 20, 1982. Lander 2 touched down about 6500 km away from Lander 1, on Utopia Planitia on September 3, 1976. The chemical compositions of sediments at the two landing sites are similar, suggesting an aeolian origin. The compositions suggest an iron-rich rock an are matched by various clays and salts.

Arvidson, Raymond E.↗

NASA NTRS1987

Landform identification: Lunar radar images

Three sets of polarized radar-echo images of the Moon were examined to establish the relation between radar resolution and landform-identification resolution. After comparison with lunar maps and photographs, real and apparent landforms on the radar images were grouped into one of seven classes. Results show strong relations between radar resolution and diameter or relief of landforms that are clearly identified and those that would probably be correctly identified (class 1 and class 2). Landforms are not detected (class 5) at all diameters and reliefs, but the percentage of undetected landforms decreases with increasing mean diameter and mean relief. Landforms are simply detected (class 4) at most mean diameters and reliefs. Ambiguous arrays (class 6) portrayed by the radar constitute up to about 16, 22, and 15% of the landforms at various diameters and relief values for the 3.8 cm, 70 cm high resolution, and 70 cm low resolution images, respectively. Only a few percent of the landforms portrayed by the radar images at various diameters and relief values are fictitious (class 7).

Moore, Henry J.↗

NASA NTRS1987

The 1984 Mauna Loa eruption and planetary geolgoy

In planetary geology, lava flows on the Moon and Mars are commonly treated as relatively simple systems. Some of the complexities of actual lava flows are illustrated using the main flow system of the 1984 Mauna Loa eruption. The outline, brief narrative, and results given are based on a number of sources. The implications of the results to planetary geology are clear. Volume flow rates during an eruption depend, in part, on the volatile content of the lava. These differ from the volume flow rates calculated from post eruption flow dimensions and the duration of the eruption and from those using models that assume a constant density. Mass flow rates might be more appropriate because the masses of volatiles in lavas are usually small, but variable and sometimes unknown densities impose severe restrictions on mass estimates.

Moore, Henry J.↗

NASA NTRS1987

Ablation of Martian glaciers

Glacier like landforms are observed in the fretted terrain of Mars in the latitude belts near + or - 42 deg. It was suggested that sublimation or accumulation-ablation rates could be estimated for these glaciers if their shapes were known. To this end, photoclinometric profiles were obtained of a number of these landforms. On the basis of analyses of these profiles, it was concluded that ice is chiefly ablating from these landforms that either are inactive rock-glaciers or have materials within them that are moving exceedingly slowly at this time. These conclusions are consistent with other geologic information. The analyses were performed using a two-dimensional model of an isothermal glacier.

Moore, Henry J.↗