SMART-1 probe heading for crash landing

The European Space Agency (ESA) is plotting the demise of the SMART-1 lunar probe, the first ever European mission to the moon. ESA says the probe, which has been orbiting our largest natural satellite for almost 16 months, will be crashed into the surface on 3 September.

The craft, launched in September 2003, was designed to test a variety of new technologies, including an ion-propulsion engine which could one day be used for interplanetary travel. Its six month mission began when it arrived in its lunar orbit in November 2004. The mission was later extended by a year.

Mission managers used the little craft to try out communications techniques that could be used on deep space missions, as well as techniques for autonomous navigation. The craft also carried pint-sized scientific instruments for, presumably, pint-sized experimenting in lunar orbit.

Left to itself, of course, SMART-1 would crash into the lunar surface on 17 August. However, the landing site would be on the far side, and we wouldn't get to see anything.

So, ESA is giving it a couple of little nudges, enough to put it onto a new orbit that will bring it into the surface of the moon some time between 05:41 and 00:37, universal time on 3 September, just over a fortnight after it would have crashed on its own.

ESA would be more specific about the landing time, it says, but it doesn't know enough about the surface of the moon in that region.

Scientists do know that the so-called "Lake of Excellence", located at mid-southern latitudes, is a volcanic plain, surrounded by highlands. The soil in the area is also known to contain a variety of minerals.

As the craft comes in for its landing, Earth-based observers will get a good view of the local topography.

The Lake of Excellence will be on the moon's dark side when the probe hits, but will be gently lit by scattered Earthlight. This, ESA says, makes for perfect observation conditions. A bright surface would have totally obscured the landing, and a new moon is visible for such a short time every evening, that it would have been very difficult to time the landing right.

Researchers hope when it hits, SMART-1's impact will throw up a plume of dust that will be visible from Earth, and will reveal more about the composition of the ground. ®