NASA's Mars Reconnaissance Orbiter, depicted above Mars in this artist's concept illustration, began orbiting Mars on March 10, 2006. It carries three cameras, a ground-penetrating radar, a mineral-mapping spectrometer and a sounding instrument to examine the atmosphere. These science instruments are the High Resolution Imaging Science Experiment, the Context Camera, the Mars Color Imager, the Shallow Subsurface Radar, the Compact Reconnaissance Imaging Spectrometer for Mars and the Mars Climate Sounder.