What is the best use of a backup space probe, apart from displaying it in a museum? Turn it into a real space probe! After the highly successful Chang'e-1 mission, China wants to reach the Moon once again with her slightly upgraded twin sister paving the way for the first Chinese Moon rover.

A Long March 3C rocket carrying the Chinese Chang'e-2 space probe blasted off from the Xichang Satellite Lauch Center yesterday at 11:00 GMT. The probe will reach the Moon in approximately 5 days to take high-resolution images of the lunar surface for a potential future landing mission. Chang'e-2 will also be a technical experiment before the Chang’e-3 rover, practicing translunar and circumlunar operations.

Just as the their economy, Chinese space ambitions are also growing with great pace. China wants to land on the Moon, first with autonomous rovers and sample return missions and eventually with humans too. But to accomplish this, they will need accurate and detailed maps. The main goal of Chang'e-1, China's first ever Moon orbiter, was to create a photographic and altitude map of the Moon. This was however overshadowed by the swarm of other lunar explorers in those years: the more able Japanese Kaguya, Chandrayaan-1, India's own first lunar mission, and finally the return of Americans to the Moon with the highly anticipated Lunar Reconnaissance Orbiter and LCROSS missions. Nor was the mishap helpful with the first released images that showed previously unseen craters. The press claimed fraud, but it turned out shortly that the Chinese were only inexperienced and made mistakes. Later Chang'e-1 successfully mapped the whole surface of the Moon and operated half a year longer than proposed.

It was soon announced that China would return to the Moon with an almost identical probe to continue the work. Chang'e-2 originates from the backup version of the first probe, and has a number of identical systems and instruments, such as the imaging spectrometer, gamma/x-ray spectrometers, microwave detectors, and space environment monitoring system. Others are enhanced or replaced with better ones. The probe will travel on a shorter, faster route to the Moon, thanks to a more powerful rocket. The laser altimeter and the main camera will have better resolution, the latter improved from 120 m to 10 m per pixel resolving power. This will be still lower than LRO's, but identical to Kaguya's performance. Chang'e-2 will also have a lower orbit at 100 km height. This circular path will eventually be turned to an ellipse with flybys of only 15 km (!) above the lunar surface. There is a rumor that the probe carries a small lander or more likely an impactor, but official sources mention no such device.

The second phase of the Chinese lunar programme aims to land on the Moon with a rover that will move around by remote control with a maximum speed of 100 m/hour. A six-wheeled vehicle, not unlike the Mars Exploration Rovers, has been under development since 2002 at the Shanghai Aerospace System Engineering Institute. The current launch date of the proposed Chang'e-3 rover is 2013, posing as a potential deadline for any Google Lunar X-Prize contestants, since the organisers intend to change the rules from a calendar-date deadline to the event of landing a government-sponsored rover on the Moon. The biggest uncertainty of the Chinese mission is the launch vehicle: Chang'e-3 is supposed to be launched with the newly developed Long March 5 heavy-lift rocket whose first test launch is currently scheduled to no earlier than 2014.