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China’s lunar orbiter is set to begin switching on its science instruments. The spacecraft should help determine the thickness of the lunar soil and shed new light on the Moon’s internal composition, which could help in understanding its origins.

The China National Space Administration launched the Chang’e 1 spacecraft on 24 October and it settled into orbit around the Moon on 7 November.

Chang’e 1 is named after a goddess who flew to the Moon in a Chinese legend.

The spacecraft’s capabilities are similar in many respects to those of the other three spacecraft that are either at the Moon already or heading there soon: Japan’s Kaguya spacecraft, which is already in orbit, India’s Chandrayaan-1, due to launch in early to mid 2008, and NASA’s Lunar Reconnaissance Orbiter (LRO), slated for launch in late 2008.

Unique instrument

China’s spacecraft is now set to begin the science phase of its mission by starting to gradually turn on its science instruments.

Like the other missions, Chang’e 1 has spectrometers to map the chemical composition of the Moon’s surface, a laser altimeter to map the Moon’s topography, and a camera to photograph the surface.

However it does have one unique instrument – a radiometer that operates at microwave frequencies. The microwave radiometer will measure heat radiation coming from the Moon. This will allow it to map the depth of the lunar soil across the Moon’s surface because the layer’s thickness affects the flow of heat.

These measurements may also shed light on the proportion of radioactive elements like uranium and thorium inside the Moon, since their decay produces heat and should increase the amount of heat radiated by the Moon, says Paul Spudis of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, US, who is developing radar instruments to fly on LRO and Chandrayaan-1.

The amount of these elements would give clues to the Moon’s origins, he says, since different formation scenarios lead to different compositions.

‘Race to the Moon’

In addition to returning science results on the Moon, Chang’e 1 will serve as a stepping stone for China’s space programme, Spudis says.

“If you can send a spacecraft to the Moon, operate it, map the planet, and do science, you’ve basically proven the concept,” he told New ¾«¶«´«Ã½. “You can do that in other missions, like to Mars and Venus. You’re getting your feet wet in the planetary exploration game.”

The Moon missions of the various countries aim to cooperate with one another going forward, even if the design of the missions was not coordinated to avoid duplication, Spudis says. “There’s a broad agreement, at least at the science meetings I have been to, that we’re all going to share this data, ultimately,” he says.

In the longer term, he sees a more competitive “race to the Moon” developing. “I look at a race to the Moon, or into the solar system if you will, less as a race between countries as between competing philosophies.”

He says the settlement of the Moon and the development of its resources will raise issues that will need to be confronted. “There is a question of what kind of politico-economic paradigm you will do that under,” he says, adding that he thinks these issues are still 20 to 40 years away from coming to a head.