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Pieters, C.

Publications and source records attributed to Pieters, C..

41 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Lunar black spots and nature of the Apollo 17 landing area.

A few small areas on the moon with extremely low albedo are shown also to have similar spectral reflectivity and radar backscatter characteristics. These lunar 'black spots' include the dark mantling material of the Apollo 17 landing site as well as areas of the Sulpicious Gallus formation. Excluded from the black spot group are the dark haloed craters of Alphonsus and the normal dark mare areas such as northern Mare Tranquillitatis. Earth-based radar and optical measurements indicate that these lunar black spots have rock-free surfaces with a very low proportion of crystalline material to amorphous material. The glassy soil is rich in iron and titanium, at least to the concentrations found at the Apollo 11 site. Crystalline pyroxene is present also. The data for the black spots are consistent with a mantling material of ash or cinder.

Pieters, C.↗
NASA NTRS1973

Mare Humorum - An integrated study of spectral reflectivity.

A detailed study was made of the spectral reflectivity of 31 areas in the Humorum basic region. There are at least two units in the mare portion of Humorum which are distinguishable by spectral properties. One of these units (T-type) has a spectral reflectivity resembling that of the Apollo 11 site and also some areas in Oceanus Procellarum. The other unit in southwest Mare Humorum resembles Mare Serenitatis in spectral character (S-type). The continuity of T-type material through the break in the northeast wall of Mare Humorum and its spectral similarity to areas in Procellarum suggest that the T-type material may result from an event that flooded parts of Mare Procellarum at a period later than the original Humorum basin filling (S-type).

Johnson, T. V.↗
NASA NTRS1972

Spectrophotometry /0.3 to 1.1 micron/ of visited and proposed Apollo lunar landing sites.

The study uses information gained by analysis of the spectral properties of lunar samples in the laboratory, and telescope spectra of over 100 lunar areas, to provide information regarding the composition and mineralogy of each proposed lunar landing site. Attention is given to (1) the presence of pyroxenes which cause an absorption band near 0.95 micron in the lunar reflection spectrum, (2) the proportion of crystalline to glassy material present in the soil which is derived from the slope of the reflectivity curve between 0.4 and 0.7 micron and the strength of the 0.95 micron absorption band, and (3) the presence of Ti(3+) ions in the glasses on the lunar surface, which affects the reflection spectrum at blue and ultraviolet wavelengths.

Mccord, T. B.↗
NASA NTRS1972

Lunar spectral types.

Results of observations of the spectral reflectance properties (0.3 to 1.1 micron) of a number of lunar mare, upland, and bright crater areas with the use of ground-based telescopes. These new data are discussed in view of earlier studies in an attempt to provide a basis for more detailed interpretation. The spectral reflectivity curves (0.3 to 1.1 micron) for all lunar areas studied consist of a positive sloping continuum with a superimposed symmetric absorption band centered at 0.95 micron. Upland, mare, and bright crater materials can be identified by their spectral curves. The curves for upland and mare regions show a range of shapes from fresh, bright craters to progressively darker background material that correlates with the apparent age of the surface features. The observed upland material has uniform spectral properties, but the mare material shows some variety, probably due to Ti(3+) dispersed in lunar-soil glass. Copernicus and Aristarchus appear to have exposed upland material from beneath the mare but Kepler has not. This observation suggests that the mare is no deeper than about 15 km in the Copernicus area and about 6 km deep in the Aristarchus area, but in the Kepler area the mare must be at least about 5 km deep.

Mccord, T. B.↗