Still There!

Four views Chang'e 3 landing site
Four LROC NAC views of the Chang'e 3 landing site: A) before landing, 30 June 2013, B) after landing, 25 December 2013, C) 21 January 2014, D) 17 February 2014. Each image is enlarged by a factor of two, width of each is 200 meters (656 feet). Follow Yutu's path clockwise around the lander in panel D [NASA/GSFC/Arizona State University].

Chang'e 3 landed on Mare Imbrium (Sea of Rains) on 14 December 2013. LROC has now imaged the lander and rover three times: 25 December 2013 (M1142582775R), 21 January 2014 (M1144936321L), and 17 February 2014 (M1147290066R). From month-to-month the solar incidence angle decreased steadily from 77° to 45° (incidence angle at sunset is 90°); due to the latitude of the site (44.1214°N, 340.4884°E, -2630 meters elevation) the incidence angle cannot get much smaller. Solar incidence angle is a measure of the Sun above the horizon; at noon on the equator the Sun is overhead and the incidence angle is 0°, at dawn or dusk the incidence angle is 90°.

Chang'e 3 Four Views Animation
Four views of the Chang'e 3 landing site from before the landing until Feb 2014 [NASA/GSFC/Arizona State University].

As the Sun gets higher above the horizon, topography appears subdued and reflectance differences become more apparent. In the case of the Chang'e 3 site, with the Sun higher in the sky one can now see Yutu's tracks (February image). In the opening image you can see Yutu about 30 meters south of the lander, then it moved to the northwest and parked 17 meters southwest of the lander. In the February image it is apparent that Yutu did not move appreciably from the January location.

LROC February Chang'e 3 Site Image
LROC February 2014 image of Chang'e 3 site. Blue arrow indicates Chang'e 3 lander, yellow arrow points to Yutu (rover), and white arrow marks the December location of Yutu. Yutu's tracks can be followed clockwise around the lander to its current location. Image enlarged 2x, width 200 meters [NASA/GSFC/Arizona State University].

Owing to the lower solar incidence angle the latest NAC image better shows Yutu's tracks and the lander engine blast zone (high reflectance) that runs north-to-south relative to the lander. Next month the solar incidence angle will again increase and subtle landforms will begin to dominate the landscape.

LROC NAC Oblique Chang'e 3
LRO slewed 54° to the East on 16 February to allow LROC to snap a dramatic oblique view of the Chang'e 3 site (arrow).  Crater in front of lander is 450 m diameter, image width 2900 meters (9500 ft) at the center M1145007448LR, [NASA/GSFC/Arizona State University].

Related LROC Featured Images

Chang'e 3 Lander and Rover From Above

Safe on the Surface of the Moon

Recent Impact

Coordinates of Robotic Spacecraft


Posted by Mark Robinson on March 04, 2014 10:48.