Chang'e 1 returns its first image from the Moon
Posted By Emily Lakdawalla
2007/11/27 12:04 CST
On Monday, with much pomp and circumstance (and rightfully so), Chinese premier Wen Jiabao unveiled the first image returned from the Moon by the Chang'e 1 orbiter, China's first spacecraft to depart Earth orbit. That's something only Russia, the United States, ESA, and Japan have managed to do before.I didn't link to it yesterday because all the versions I could find online were at woefully low resolution, but thanks to a pointer from Wang Chun I now have my hands on a full-resolution version of the image, 120 meters per pixel, 2278 by 3810 pixels in size. Here it is: I feel I should point out that calling this the "first image from Chang'e 1" is slightly misleading. This is no raw data product fresh from the spacecraft; this is a highly processed image comprising 19 separate swaths, each 60 kilometers wide (they must overlap a lot at this high southern latitude). The images have been reprojected, mosaicked, and blended so well that I can't find a trace of seams separating the swaths. It's a beautiful product -- clearly the Chinese wanted to put their best foot forward.
It's very nice-looking, but how does it compare to what we have from other missions? The 120-meter resolution is comparable to the best obtained by Clementine, and also comparable to the global map that will be obtained by Lunar Reconnaissance Orbiter. It's lower-resolution than SMART-1's AMIE, and also lower than most of the cameras on Kaguya. (Which reminds me, I also have some very nice images from Kaguya's terrain camera to post -- later.) Generally speaking, you trade resolution for coverage -- meaning that if your spacecraft takes higher resolution photos, it's less likely to cover the whole planet. The resolution of this camera is a comfortable one for building a global map; Chang'e 1 should do that in stereo, creating an atlas that not only shows the landforms but also shows their topography.
You can check out some of the Lunar Orbiter photos of the same general area here and here (that's how I hunted down the names of the craters). And here's the Google Moon view of the same area, which uses the Clementine atlas as a base map. As you can see, the Clementine images are quite comparable to this one.