Paris - The European Space Agency (ESA) said it had shortlisted three European consortia to submit proposals for its Don Quijote project, which seeks to deflect any future asteroid on a collision course with Earth.

The teams are respectively led by Alcatel Alenia Space, Qinetiq of Britain and EADS Astrium, each of which has long experience in European space projects, ESA said in a press release on Monday.

ESA, helped by an independent panel of experts, will assess their submissions in October, and the outcome will be made public in 2007.

The Don Quijote mission will comprise two spacecraft.

One of them, called Hidalgo, will smash into the asteroid at relatively high speed, while a second one, Sancho, will arrive earlier at the same asteroid to measure the variation on the asteroid's orbital parameters after the impact.

The risk of an asteroid collision with Earth is extremely remote.

But if such an event were to occur, and the rock were big, the immediate devastation could be continent-wide and there could be lasting changes to the planet's weather system.

The long reign of the dinosaurs is believed to have come to an abrupt end 65 million years ago when an asteroid or comet smashed into modern-day Mexico.

The collision kicked up so much dust that heat and light from the Sun were diminished, destroying much of Earth's vegetation and the larger species of land animals that depended on it.

Deflection is considered a safer bet than blowing up a dangerous asteroid with nuclear bombs. An explosion would break the asteroid into chunks, with the risk these pieces could hit Earth in turn.