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| Titel |
Data Processing and Primary results of Lunar Penetrating Radar on Board the Chinese Yutu Rover |
| VerfasserIn |
Yan Su, Shuguo Xing, Jianqing Feng, Shun Dai, Chunyu Ding, Yuan Xiao, Hongbo Zhang, Shu Zhao, Xiping Xue, Xiaoxia Zhang, Bin Liu, Meijuan Yao, ChunLai Li |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250104843
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| Publikation (Nr.) |
 EGU/EGU2015-4282.pdf |
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| Zusammenfassung |
| Radar is an attractive and powerful technique to observe the Moon. Radar mapping of the
Moon’s topography was first done by the Arecibo telescope at a wave- length of 70 cm in
1964 (Thompson & Dyce 1966). Chang’e-3 (CE-3) was successfully launched on 2013
December 2, and the landing place is in Mare Imbrium, about 40km south of the 6km
diameter Laplace F crater, at 44.1214ON, 19.5116OW. The Lunar ground-Penetrating Radar
(LPR) is one of scientific payloads of the Yutu rover, aiming to achieve the first direct
measurements and explore the lunar subsurface structure. Compared with ALSE and
LRS, LPR works at higher frequencies of 60 MHz and 500 MHz. Thus it can probe
regions with shallower depth including the regolith and lunar crust at higher range
resolution.
The LPR uses one transmitting and one receiving dipole antenna for 60 MHz which are
installed at the back of the rover. For 500 MHz, one transmitting and two bow-tie receiving
antennas are attached to the bottom of the rover. It transmits a pulsed signal and receives the
radar echo signal along the path that the Yutu rover traverses. The free space range
resolutions are ~ 50 cm and ~ 25 m for 60 MHz and 500 MHz respectively. The radar data
stop being sampled and are sent back to Earth when Yutu is stationary. Observations
are simultaneously carried out at frequencies of 60 MHz and 500 MHz. Since the
Yutu rover had severe problems during its second lunar day, it is pity that the Yutu
rover only transversed a limited distance of 114.8m. In total, 566 MB of data were
obtained.
The scientific data are archived and distributed by National Astronomical Observatories,
Chinese Academy of Sciences. Data processing has been done in order to eliminate the effect
of the instrument. To obtain clear radar images, more data processing need to be applied such
as coordinate transformation, data editing, background removal, the operations of smoothing
and gain resetting. The radar signal could detect hundreds of meters deep at 60MHz and tens
of meters at 500MHz. Based on the previous lunar subsurface research and Apollo samples
analysis, the dielectric constantÉr of the lunar rock is set to be 7 and the dielectric
constantÉr of the lunar regolith is set to be 3.1 The LPR observations reveal that Mare
Imbrium has subsurface stratifications. The regolith is not uniform and structures
with multiple layers have been observed. The results indicate the thickness of the
regolith is 4–6 m. The typical hyperbolic shapes that might be caused by rocks
underneath the regolith have been found. Furthermore, several prominent reflective
layers at depths of hundreds of meters have been clearly derived. The buried regolith
layer might have been accumulated during the depositional hiatus of mare basalts. |
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