Reanalysis of Clementine Bistatic Radar Data from the Lunar South Pole
On 9 April 1994 the Clementine spacecraft high-gain antenna was aimed toward the Moon's surface and the resulting 13-cm wavelength radio echoes were received on Earth. Using these data, we have found that the lunar surface generally follows a Lambertian bistatic scattering function sigma(sub 0)...
Main Authors: | , |
---|---|
Language: | unknown |
Published: |
1998
|
Subjects: | |
Online Access: | http://hdl.handle.net/2060/19990047963 |
id |
ftnasantrs:oai:casi.ntrs.nasa.gov:19990047963 |
---|---|
record_format |
openpolar |
spelling |
ftnasantrs:oai:casi.ntrs.nasa.gov:19990047963 2023-05-15T18:21:50+02:00 Reanalysis of Clementine Bistatic Radar Data from the Lunar South Pole Simpson, Richard A. Tyler, G. Leonard Unclassified, Unlimited, Publicly available Mar. 12, 1998 application/pdf http://hdl.handle.net/2060/19990047963 unknown Document ID: 19990047963 http://hdl.handle.net/2060/19990047963 No Copyright CASI Geophysics 1998 ftnasantrs 2019-08-31T23:03:28Z On 9 April 1994 the Clementine spacecraft high-gain antenna was aimed toward the Moon's surface and the resulting 13-cm wavelength radio echoes were received on Earth. Using these data, we have found that the lunar surface generally follows a Lambertian bistatic scattering function sigma(sub 0) = K(sub D)cos(theta(sub i) with K(sub D) approx. 0.003 for the opposite (expected) sense of circular polarization and K(sub D) approx. 0.001 for the same (unexpected) sense. But there are important deviations-of up to 50% in some parts of the echo spectrum-from this simple form. Based on an earlier analysis of these same data, Nozette et al. claimed detection of an enhancement in echoes with right circular polarization from regions near the South Pole in a near-backscatter geometry. Such behavior would be consistent with presence of perhaps large quantities of water ice near the Pole. We have been unable to reproduce that result. Although we find weak suggestions of enhanced echoes at the time of South Pole backscatter, similar features are present at earlier and later times, adjacent frequencies, and in left circular polarization. If enhanced backscatter is present, it is not unique to the South Pole; if not unique to the Pole, then ice is less likely as an explanation for the enhancement. Other/Unknown Material South pole NASA Technical Reports Server (NTRS) South Pole |
institution |
Open Polar |
collection |
NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Geophysics |
spellingShingle |
Geophysics Simpson, Richard A. Tyler, G. Leonard Reanalysis of Clementine Bistatic Radar Data from the Lunar South Pole |
topic_facet |
Geophysics |
description |
On 9 April 1994 the Clementine spacecraft high-gain antenna was aimed toward the Moon's surface and the resulting 13-cm wavelength radio echoes were received on Earth. Using these data, we have found that the lunar surface generally follows a Lambertian bistatic scattering function sigma(sub 0) = K(sub D)cos(theta(sub i) with K(sub D) approx. 0.003 for the opposite (expected) sense of circular polarization and K(sub D) approx. 0.001 for the same (unexpected) sense. But there are important deviations-of up to 50% in some parts of the echo spectrum-from this simple form. Based on an earlier analysis of these same data, Nozette et al. claimed detection of an enhancement in echoes with right circular polarization from regions near the South Pole in a near-backscatter geometry. Such behavior would be consistent with presence of perhaps large quantities of water ice near the Pole. We have been unable to reproduce that result. Although we find weak suggestions of enhanced echoes at the time of South Pole backscatter, similar features are present at earlier and later times, adjacent frequencies, and in left circular polarization. If enhanced backscatter is present, it is not unique to the South Pole; if not unique to the Pole, then ice is less likely as an explanation for the enhancement. |
author |
Simpson, Richard A. Tyler, G. Leonard |
author_facet |
Simpson, Richard A. Tyler, G. Leonard |
author_sort |
Simpson, Richard A. |
title |
Reanalysis of Clementine Bistatic Radar Data from the Lunar South Pole |
title_short |
Reanalysis of Clementine Bistatic Radar Data from the Lunar South Pole |
title_full |
Reanalysis of Clementine Bistatic Radar Data from the Lunar South Pole |
title_fullStr |
Reanalysis of Clementine Bistatic Radar Data from the Lunar South Pole |
title_full_unstemmed |
Reanalysis of Clementine Bistatic Radar Data from the Lunar South Pole |
title_sort |
reanalysis of clementine bistatic radar data from the lunar south pole |
publishDate |
1998 |
url |
http://hdl.handle.net/2060/19990047963 |
op_coverage |
Unclassified, Unlimited, Publicly available |
geographic |
South Pole |
geographic_facet |
South Pole |
genre |
South pole |
genre_facet |
South pole |
op_source |
CASI |
op_relation |
Document ID: 19990047963 http://hdl.handle.net/2060/19990047963 |
op_rights |
No Copyright |
_version_ |
1766201156643586048 |