Society

China's second lunar probe ready to launch

By Xin Dingding (China Daily)
Updated: 2010-09-30 07:57

XICHANG, Sichuan - China will launch its second lunar probe, Chang'e-2, between Friday and Sunday, with Friday being the first choice, the country's space authority said on Wednesday.

Fuel loading was scheduled to begin on Thursday to inject propellants into the carrier rocket, a Long March 3-C.

The fuel loading will be under way until the last three minutes before the launch, said a spokesman for the Xichang Satellite Launch Center in southwestern China's Sichuan province.

The Chang'e-2 probe, named for the character in the legend of a Chinese fairy who flew to the moon, is expected to test parts of key technologies for Chang'e-3, which is expected to land on the moon in about 2013.

Chang'e-2 will also refine scientific research findings conducted by its predecessor, Chang'e-1, the spokesman said.

China's lunar exploration program, which has been designed to eventually land a Chinese craft on the moon, calls for the launch of three satellites at the second stage: Chang'e-2, Chang'e-3 and Chang'e-4.

Chang'e-4 will be a backup satellite for Chang'e-3.

China's first lunar probe circled around the Earth before entering the Earth-moon transfer orbit.

The second lunar probe will be directly sent into the Earth-moon transfer orbit at 200 kilometers perigee (the point closest to Earth) and 380,000 km apogee (the point farthest from Earth).

Thanks to two boosters attached, the Long March 3-C rocket is more powerful than the Long March 3-A that sent Chang'e-1 into space.

This will be the fifth mission of the Long March 3-C. The launch vehicle already has sent four satellites into space, including three Beidou satellites used to form China's version of the Global Positioning System.

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Without the need to circle Earth first this time, the travel time for Chang'e-2 is expected to be shortened from the previous 12 days to only 112 hours, or less than five days, the spokesman said.

When the probe is close to the moon, it will be maneuvered to slow down to enter an orbit 100 km away from the moon's surface.

The circumlunar satellite will then orbit the moon in an orbit at a distance of 15 km closest to the moon and at 100 km at its farthest distance from the moon.

At 15 km from the moon's surface, the Chang'e-2 probe will take photographs of the area around the moon's Bay of Rainbows, where Chang'e-3 is expected to land during China's next lunar mission.

Chang'e-2 then will return to the 100-km orbit to conduct other scientific exploration experiments, the space authority said.

During China's first lunar mission, the cameras aboard Chang'e-1 captured lunar images with a resolution of 120 meters. Chang'e-2, with improved cameras on board, will take photographs with a resolution of 10 meters.

"Photos taken 15 km from the moon's surface can be very clear with a resolution of 1 meter," Wu Weiren, chief designer of China's lunar probe program, said in an interview with China Central Television on Tuesday.

All four pre-launch tests for the satellite and launch vehicle were completed by Tuesday, the spokesman said.

Liu Siqing, deputy director of the Space Environment Prediction Center under the Chinese Academy of Sciences, said that the space environment in the next few days is expected to be suitable for the launch of the Chang'e-2 probe.

What could influence the launch date would be solar proton events or geomagnetic storms , she said.