Engineering topics

Hawke, B. Ray

Publications and source records attributed to Hawke, B. Ray.

27 records · Page 2

NASA NTRS1991

Remote sensing and geologic studies of the orientale basin region

Both visual and near-infrared spectral observations are combined with multispectral imaging to study the Orientale interior and exterior, the Cruger region, Grimaldi Region, the Schiller-Schickard Region, and the Humorum Region of the Moon. It was concluded that anorthosites occur in the Inner Rook Mountains of Orientale, the inner ring of Grimaldi, and the main ring of Humorum. Imaging spectroscopy shows that the entire eastern Inner Rook Mountains are composed of anorthosites. Orientale ejecta are strikingly like the surface materials in the region where Apollo 16 landed. This similarity indicates similar mineralogy, i.e., noritic anorthosite. Thus, Orientile ejecta is more mafic than the Inner Rook Mountains. This situation is also true for the Nectaris, Humorum, and Gramaldi basins. Isolated areas of the Orientale region show the presence of gabbroic rocks, but, in general, Orientale ejecta are noritic anorthosites, which contain much more low-Ca pyroxene than high-Ca pyroxene. Ancient (pre-Orientale) mare volcanism apparently occurred in several areas of the western limb.

Hawke, B. Ray↗

NASA NTRS1991

Remote sensing and geologic studies of the terrain northwest of Humorum basin

A portion of the highlands terrain northwest of the Humorum basin, a large multiringed impact structure on the southwestern portion of the lunar nearside, exhibits anomalous characteristics in several remote sensing data sets. A variety of remote sensing studies of the terrain northwest of Humorum basin were performed in order to determine the composition and origin of the anomalous unit as well as the composition of the highland material exposed by the Humorum impact event. It was found that at least a portion of the mare-bounding ring of Humorum is composed of pure anorthosite. Other details of the study are reported.

Hawke, B. Ray↗

NASA NTRS1991

The violent side of mare volcanism

In the past 15 years it has become increasingly evident that lunar pyroclastic volcanism played an important role in the formation and resurfacing of portions of the Moon. Located on mare/highland boundaries, many of these deposits formed in association with mare volcanism. Based on recently acquired geologic and remote sensing data, two generally distinct types of pyroclastic mantling deposits have been identified: regional and localized. Both the regional dark mantling deposits (RDMD) and localized dark mantling deposits (LDMD) are widely distributed across the lunar nearside. The larger RDMD are typically located in lunar highland areas adjacent to many of the major lunar maria, while the smaller LDMD are found on the floors of pre-Imbrian and Inbrian craters. Both deposits are basaltic in composition and are presumed to have originated at great depth (approx. 300 km). The composition, geometry, and vent morphology of the pyroclastic deposits have been used to infer the eruption mechanisms and emplacement styles for both types of deposits.

Coombs, Cassandra R.↗

NASA NTRS1990

Pyroclastic deposits as sites for lunar bases

Ilmenite-rich pyroclastic deposits may prove to be excellent sites for the establishment of a permanent lunar base for mining purposes. A wide variety of potentially useful by-products could be produced (e.g., Fe, Ti, H, N, C, S, Cu, Zn, Cd, Bi, and Pb). A number of ilmenite-rich pyroclastic deposits of regional extent has been studied. The physical properties of the regional pyroclastic units have important implications for lunar construction. These extensive, deep deposits of ilmenite-rich pyroclastic material are block-free and uncontaminated; they could be easily excavated and would be ideal for lunar mining operations. These deep, loose pyroclastic deposits would also be ideal for rapidly covering base modules with an adequate thickness of shielding.

Hawke, B. Ray↗

NASA NTRS1988

Composition and size of Apollo asteroid 1984 KB

The Class S object-typifying spectral signatures of olivine, pyroxene, and NiFe metal are noted in the present reflection spectra and thermal-emission radiometric data for the earth orbit-crossing Apollo object, 1984KB; a surface material akin to the rare lodranite meteorites. While the Class S object identification is strengthened by standard asteroid thermal model's indication of an about 0.7-km radius, and albedo of about 0.16, which is inconsistent with the IR spectrum, is obtained by an analysis of the same thermal data with a bare-rock thermal model. The object must have a significant regolith despite its small size.

Bell, Jeffrey F.↗

NASA NTRS1988

Materials and formation of the Imbrium basin

A study of Imbrium basin deposits has been conducted, including geologic mapping, analysis of orbital geochemical data, earth-based near-IR spectroscopy, and analytical modeling. The morphologic facies of the deposits display an unusual bilateral symmetry with respect to the main rim of the basin, which is thought to be 1160 km in diameter and composed of Apennine-Carpathian-Alpes mountain ranges. The Imbrium ring structure consists of six concentric rings ranging from 550-3200 km in diameter. The evolution of the target for the Imbrium basin impact is discussed. It is suggested that the Imbrium impact, which occurred 3.85 Gyrs ago, formed a basin predominantly by a proportional-growth crater-forming mechanism.

Spudis, Paul D.↗

NASA NTRS1988

Geologic and remote sensing studies of Rima Mozart

Geologic, photographic, and remote sensing data on Rima Mozart are analyzed to study the processes responsible for the formation of lunar sinuous rilles. The results show that it is unlikely that a complete lava tube could have existed along the Rima Mozart rille. A total eruptive volume of 6372 cu km has been determined for an open channel or tube with an eruption rate of about 80,000 cu m/s and a duration of 947 days. Near-infrared spectral reflectance data and 2.8-cm and 70-cm radar observations indicate that volcanic activity was responsible for the formation of the rille and that pyroclastic deposits are present around Kathleen and Ann as well as at the base of the Apennines.

Coombs, Cassandra R.↗

NASA NTRS1988

A remote mineralogic perspective on gabbroic units in the lunar highlands

Three lunar highland regions containing abundant high-Ca pyroxene are investigated in order to constrain the chemistry of the pyroxene assemblage of gabbroic regions and determine the state of gabbroic materials in the highland crust. The compositional gap between orthopyroxenes and clinopyroxenes noted in remote sensing observations corresponds to that found in lunar rock samples. It is found that Mg-gabbronorite or KREEP basalt with abundant high-Ca pyroxene are the most likely rock types of those thus far identified that may be responsible for gabbroic areas in the highlands. The western lunar highlands are shown to be distinct from the east in minerology.

Lucey, Paul G.↗

NASA NTRS1987

Recent comet impacts on the moon - The evidence from remote-sensing studies

Multispectral images and near-infrared reflectance spectra were obtained for the Reiner Gamma Formation, a swirllike albedo and magnetic anomaly in the western portion of the lunar near side, as well as for nearby geologic units in Oceanus Procellarum, using the University of Hawaii 2.24-m telescope at the Mauna Kea Observatory. The spectra of the high albedo swirl material are closely matched by models incorporating 90-95 percent fresh mare basalt with 5-10 percent highlands debris.

Bell, Jeffrey F.↗