Images: Lunar crash course; interplanetary visitors

This is the first color image of Mars from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter, taken during a turn round the planet on March 24.

The color is not as the human eye would see it, but was generated by combining data from green and near-infrared color bandpass detectors on the camera with black-and-white images (from red-bandpass detectors). The image also has been processed to enhance subtle color variations.

That the southern half of the scene is brighter and bluer than the northern half is perhaps due to early-morning fog in the atmosphere, NASA said. Large-scale streaks in the northern half are the result of wind on surface materials. The blankets of material ejected from the many small, fresh craters are generally brighter and redder than the surrounding surface, but a few are darker and less red. In the bottom half of the image is a redder color in the rough areas, where wind and sublimation of water or carbon dioxide ice have partially eroded patches of smooth-textured deposits. Click to see more photos from NASA's Mars Reconnaissance Orbiter.