The distribution of titanium abundance on the lunar surface is important knowledge for lunar geologic studies and future resource utilization.In this paper,we develop a preliminary model based on"ground truths&qu...The distribution of titanium abundance on the lunar surface is important knowledge for lunar geologic studies and future resource utilization.In this paper,we develop a preliminary model based on"ground truths"from Apollo and Luna sample-return sites to produce a titanium abundance map from Chang’E-1 Imaging Interferometer(IIM) images.The derived TiO2 abundances are validated with Clementine UVVIS results in several regions,including lunar highlands neighboring the Apollo 16 landing site,and high-Ti and low-Ti maria near the standard site of Mare Serenitatis(MS2) .The validation results show that TiO2 abundances modeled with Chang’E-1 IIM data are overestimated for highlands(～0.7 wt.%) and low-Ti maria(～1.5 wt.%) and underestimated for high-Ti maria(～0.8 wt.%).展开更多
Based on the tracking observations of radio ranges and VLBI delays of Chang’E-1 (CE-1) satellite during the controlled landing on the Moon on March 1, 2009, the landing trajectory and the coordinates of the landing p...Based on the tracking observations of radio ranges and VLBI delays of Chang’E-1 (CE-1) satellite during the controlled landing on the Moon on March 1, 2009, the landing trajectory and the coordinates of the landing point are determined by positioning analysis. It is shown that the landing epoch (the emission epoch of the last signal) of CE-1 satellite on the Moon was at UTC8h13m6.51s. The lunar longitude, latitude and surface height of the landing point in the lunar primary axes frame are respectively 52.2732°, 1.6440° and –3.56 km (the reference lunar radius is 1738 km). The uncertainties are 0.0040°, 0.0168° and 0.18 km. The corresponding uncertainty in the tangential direction of the lunar surface is 0.52 km and the three-dimensional (3D) positioning uncertainty is 0.55 km. It is accordingly deduced that even with the present technical specifications of the radio ranges and VLBI delays, the 1 km 3D positioning precision could be guaranteed for the lander in the second stage of China’s Lunar Explora- tion Project. Concerning the trace determination of the rover on the lunar surface, because only telemetry signal will be emitted, VLBI would be the sole tracking technique from the Earth. The application of the constraint of geocentric distance is shown to be helpful to improving the positioning precision. It is worthy to pay close attention to the applications of the same beam VLBI technique, the lunar topographic model and the on-board observations of the lander and rover to the position/trace determination of the rover.展开更多
基金supported by the National High-Tech Research and Development Program of China(2008AA12A212/211/213,2009AA122201, 2010AA122203)China Postdoctoral Science Foundation(20090450580)National Natural Science Foundation of China(11003012)
文摘The distribution of titanium abundance on the lunar surface is important knowledge for lunar geologic studies and future resource utilization.In this paper,we develop a preliminary model based on"ground truths"from Apollo and Luna sample-return sites to produce a titanium abundance map from Chang’E-1 Imaging Interferometer(IIM) images.The derived TiO2 abundances are validated with Clementine UVVIS results in several regions,including lunar highlands neighboring the Apollo 16 landing site,and high-Ti and low-Ti maria near the standard site of Mare Serenitatis(MS2) .The validation results show that TiO2 abundances modeled with Chang’E-1 IIM data are overestimated for highlands(～0.7 wt.%) and low-Ti maria(～1.5 wt.%) and underestimated for high-Ti maria(～0.8 wt.%).
基金supported by the National Natural Science Foundation of China (Grant Nos. 10778635 and 10973030)China’s Lunar Exploration Project (CE-1)+1 种基金National High-Tech Research and Development Program of China (Grant Nos. 2008AA12A209 and 2008AA12A210)STC of Shanghai Munici-pality (Grant No. 06DZ22101)
文摘Based on the tracking observations of radio ranges and VLBI delays of Chang’E-1 (CE-1) satellite during the controlled landing on the Moon on March 1, 2009, the landing trajectory and the coordinates of the landing point are determined by positioning analysis. It is shown that the landing epoch (the emission epoch of the last signal) of CE-1 satellite on the Moon was at UTC8h13m6.51s. The lunar longitude, latitude and surface height of the landing point in the lunar primary axes frame are respectively 52.2732°, 1.6440° and –3.56 km (the reference lunar radius is 1738 km). The uncertainties are 0.0040°, 0.0168° and 0.18 km. The corresponding uncertainty in the tangential direction of the lunar surface is 0.52 km and the three-dimensional (3D) positioning uncertainty is 0.55 km. It is accordingly deduced that even with the present technical specifications of the radio ranges and VLBI delays, the 1 km 3D positioning precision could be guaranteed for the lander in the second stage of China’s Lunar Explora- tion Project. Concerning the trace determination of the rover on the lunar surface, because only telemetry signal will be emitted, VLBI would be the sole tracking technique from the Earth. The application of the constraint of geocentric distance is shown to be helpful to improving the positioning precision. It is worthy to pay close attention to the applications of the same beam VLBI technique, the lunar topographic model and the on-board observations of the lander and rover to the position/trace determination of the rover.
