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Noble, S. K.

Publications and source records attributed to Noble, S. K..

23 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

The Optical Properties of Nanophase Iron: Investigation of a Space Weathering Analog

It is known that space weathering, in particular the nanophase iron (npFe(sup 0)) created via vapor and/or sputter deposition, has distinct and predictable effects on the optical properties of lunar soils. In addition to the attenuation of absorption bands, weathering introduces a characteristic continuum which is controlled by the amount of npFe(sup 0) present. The shape of this continuum may also be controlled by the size of the npFe(sup 0) grains. It is thought that small npFe(sup 0) grains result in reddening, while larger grains only darken the material. To investigate this phenomenon we have created a lunar weathering analog by impregnating silica gel powders with npFe(sup 0) following the methods presented.

Noble, S. K.↗
NASA NTRS2003

Making a Regolith Breccia

Regolith breccias are created when regolith is fused together by shock from nearby impacts. Some of these breccias are so friable that they crumble easily back into the soils from which they formed. Others are compacted enough to survive being launched off a parent body and landing on Earth, as evidenced by our collection of regolith breccia meteorites from both the moon and the asteroids. By comparing and contrasting de-lithified soils to their regolith counterparts, insight can be gained into the breccia forming process.

Noble, S. K.↗
NASA NTRS2002

Space Weathering Processes on Mercury

Like the Moon, Mercury has no atmosphere to protect it from the harsh space environment and therefore it is expected that it will incur the effects of space weathering. These weathering processes are capable of both creating regolith and altering its optical properties. However, there are many important differences between the environments of Mercury and the Moon. These environmental differences will almost certainly affect the weathering processes as well as the products of those processes. It should be possible to observe the effects of these differences in Vis/NIR spectra of the type expected to be returned by MESSENGER. More importantly, understanding these weathering processes and their consequences is essential for evaluating the spectral data returned from MESSENGER and other missions in order to determine the mineralogy and the iron content of the Mercurian surface. Theoretical and experimental work has been undertaken in order to better understand these consequences.

Noble, S. K.↗
NASA NTRS2001

Space Weathering in the Mercurian Environment

Space weathering processes are known to be important on the Moon. These processes both create the lunar regolith and alter its optical properties. Like the Moon, Mercury has no atmosphere to protect it from the harsh space environment and therefore it is expected that it will also incur the effects of space weathering. However, there are many important differences between the environments of Mercury and the Moon. These environmental differences will almost certainly affect the weathering processes and the products of those processes. It should be possible to observe the effects of these differences in Vis (visible)/NIR (near infrared) spectra of the type expected to be returned by MESSENGER. More importantly, understanding these weathering processes and their consequences is essential for evaluating the spectral data returned from MESSENGER and other missions in order to determine the mineralogy and the Fe content of the Mercurian surface. Additional information is contained in the original extended abstract.

Noble, S. K.↗