Ion-driven space probe set for lunar mission

Ion-driven space probe set for lunar mission

Ion-driven space probe set for lunar mission

A space craft the size of a washing machine and driven by a revolutionary ion motor will begin a braking sequence on Monday that should make it the first European mission to enter lunar orbit.

SMART-1, which weighs 370kg but is driven by an engine with a thrust of just7g, is packed with tiny instruments that will scan and photograph every inch of the moon’s surface seeking a base for future deep space expeditions.

“SMART-1 is a precursor mission for interplanetary exploration,” Bernard Foing, the European Space Agency’s chief scientist, told a news conference on Thursday.

The aim of SMART – an acronym of Small Missions for Advanced Research and Technology – is to trial cutting-edge small science to see if it could work in extended and even manned missions to the planets.

One of the features of future deep space missions is the need for off-Earth launch bases from which rockets could be launched with a minimum of propulsion as the moon’s gravity is only one-sixth that of Earth.

SMART-1, which was launched from French Guiana in September 2003, has repeatedly circled the Earth, gradually nearing the moon and building up speed from the stream of charged particles emitted by the solar-powered ion engine.

In the engine, electrons collide with atoms from the propellant gas creating charged atoms or ions which are ejected through a magnetic field and appear as a tongue of blue flame.

Because the thrust is so small, the engine is fired for hundreds of hours at a time to build momentum.

If the braking sequence that starts at dawn on Monday is successful, the craft will transfer from Earth to moon orbit and gradually spiral down by January to a stable elliptical orbit ranging from 300km to 3 000km above the surface.

Although it will scan the entire surface, the moon mission will focus on the poles of Earth’s only satellite where the temperature is a stable minus 20 centigrade – compared with the equator where it varies from plus 120 to minus 170 degrees.

“There is one area called the pinnacle of eternal light near the south pole which is particularly interesting,” Foing said.

Not only is it bathed in perpetual sunlight, it also appears to be flat.

An even greater advantage is the fact that there are some very deep craters nearby which scientists hope may hold frozen water which could be used both to drink and to create oxygen for moonbase dwellers.

The mission will also try to determine the origin of the moon, which current theory believes is the result of a massive impact by a giant meteorite striking the Earth during its early formative phase.

“We want to understand better the relationship between the Earth and the moon,” Foing said. “We believe the moon is the daughter of Earth.”