An American probe in orbit above the Moon has beamed back exciting new images showing the first objects from China to be discovered on the lunar surface.
Lander at the top, Rabbit at the bottom
The objects in question are the small "Jade Rabbit" crawler robot and the Chang'e 3 lander which delivered it to our neighbouring body. Chang'e 3 set down in the Mare Imbrium on 14 December, but NASA's Lunar Reconnaissance Orbiter was at that point above a completely different lunar region.
Ten days later, on Christmas Eve, however, the LRO finally swept past 150 kilometres above Chang'e 3's landing site and alert NASA boffins got some snaps, which they have now released to the world.
From 150km up, the pixel size of the LRO's Narrow Angle Camera is around 150cm across, and the little Rabbit itself is only 150cm across. However the NASA snappers are confident they have their target:
The rover is only about 150 cm wide, yet it shows up in the NAC images for two reasons: the solar panels are very effective at reflecting light so the rover shows up as two bright pixels, and the Sun is setting thus the rover casts a distinct shadow (as does the lander).
Since the rover is close to the size of a pixel, how can we be sure we are seeing the rover and not a comparably sized boulder? Fortuitously, the NAC acquired a "before" image of the landing site, with nearly identical lighting, on 30 June 2013. By comparing the before and after landing site images, the LROC team confirmed the position of the lander and rover, and derived accurate map coordinates for the lander (44.1214°N, 340.4884°E, -2640 meters elevation).
Which the accompanying .gif shows rather well:
Disappearing and reappearing rabbit-out-of-a-lander
More pics and explanation can be found courtesy of the LRO team and NASA here. ®