A Long March 3A rocket sent the Chang'e-1 probe on its 239,000 mile journey to the moon, another step in China's attempt to send robotic explorers to the moon by 2020. China has four primary mission goals for the vehicle. The first will be to a comprehensive 3D model of the moon and its various surface formations, including some rarely photographed polar regions. The second is to measure 14 specific chemicals and their concentrations in the lunar atmosphere. Third will be to measure the thickness of the soil all around the surface. And finally, it will put on its meterologist hat and explore the "space weather" between the Earth and the Moon.
The European Space Agency (ESA) is cooperating with the Chinese National Space Agency (CNSA) on this endeavor. The Chang'e-1 craft itself is named after the Chinese goddss of the Moon. The space vehicle is quite large, weighing over 2.5 tons. It will operate in a low, circular orbit just 124 miles above the surface. The craft is expected to take a full year to carry out all of its measurements. It carries on board several delicate instruments to carry out its mission. These include a CCD stereo camera, laser altimeter, imaging interferometer, gamma-ray/X-ray spectrometer, microwave radiometer, high-energy particle detector, and a solar wind particle detector.
Read more at the ESA website.