By David Adam
Science Correspondent
The Guardian - UK

More than 30 years after the last Apollo mission, European scientists have made it to the moon. Their experimental Smart-1 probe, powered by a revolutionary Star Trek-style thruster, has entered into orbit around the lunar surface.

"Europe has arrived at the moon," David Southwood, director of science at the European Space Agency, said yesterday. After a journey of more than 52m miles lasting 13 months, the photocopier-size probe swung within 3,000 miles of the moon on Monday night. Its course involved 332 orbits of the Earth.

Smart-1 will fire its gentle ion-drive engine for the rest of the week, sending it down in decreasing circles to its final elliptical orbit, which will pass 200 miles above the moon's south pole and 2,000 miles from the north pole.

From there the spacecraft will point its cameras and instruments at the surface to gain images of the ground and study its chemistry.

Smart-1 is only the third space probe to visit the moon since the Apollo era.

Ian Crawford, a planetary scientist at Birkbeck College, University of London, who works on the mission, said: "Rather than see it as the Europeans being late we should see it as Europe participating in a revived scientific interest in the moon."

Rocks brought back by Apollo astronauts were from around the lunar equator. "We've begun to realise that the lunar crust is different on the far side and in the polar regions and we don't have any samples from there," Dr Crawford said.

Smart-1 will not land, but the scientists hope that analysing x-ray and infra-red radiation bounced off the surface will offer clues to its mineral composition.

The mission will also peer into the darker parts of the moon's south pole for the first time, and search deep craters for signs of water.

Smart-1 is only the second spacecraft to be propelled by an ion drive, which does not burn fuel but uses solar power to electrically charge atoms of xenon gas. These accelerate away from the spacecraft and produce thrust.

It is slow going at first - the Apollo crew reached the moon in three days - but ion drive engines are more fuel efficient and could cut years off trips to distant planets.

"It's very different from an old-fashioned rocket where you light the blue touchpaper and it goes bang or whoosh or whatever. It's more like a sailing ship," said Manuel Grande, a project scientist at the Rutherford Appleton Laboratory near Oxford.

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