The plan to protect Earth from hazardous asteroids

NARRATOR: The forests of Neuschwanstein in Germany. During the night of the sixth of April, 2002, something gleaming lights up the night. It soon becomes clear that a meteorite has landed in southern Bavaria. Most of it burned up on entering the earth's atmosphere, but parts of it reached the surface of the Earth. Amateur astronomers begin searching for them, and ultimately find them. The Neuschwanstein meteorite was named after the site where it was discovered. Celestial bodies charging towards Earth are nothing new. January of 2004, an object 500 meters in diameter approaches the Earth. Astronomers calculate the chances of impact at 25 percent. On this occasion we were fortunate, it raced past Earth, barely missing. But what if...? Researchers at the German Aerospace Center in Berlin are addressing this question. Dr. Alan Harris is one of the world's foremost asteroid researchers. He's a physicist working for the European Space Agency (ESA) to devise a system to ward off dangerous objects from space.

DR. ALAN HARRIS: "With today's technology we're in a position to send space missions to Mars and, indeed, to the outer planets of the Solar System. But if a large asteroid or comet were to be discovered on course for the Earth there's really very little we could do at the present time because there's no plan set up - international plan set up - to cope with this sort of thing."

NARRATOR: ESA has already decided which type of defense strategy it deems to be the only realistic and effective one. The project name: Don Quixote. Two space probes will be sent successively to meet the asteroid. The first, Sancho, is designed to orbit the asteroid for six months, gathering as much data as possible about its form, thickness and gravitational field. Hidalgo, the second probe, will use this information to strike the celestial body with immense force in the most advantageous spot. The experiment is designed to demonstrate whether it is possible to throw an asteroid heading for Earth off course with this strategy. At ESA in Noordwijk, Netherlands, the probes are run through a comprehensive examination. A multitude of factors could determine the success or failure of the mission. Sancho and Hidalgo will not be sent on their journey for at least another seven years as there's much to be done.

IAN CARNELLI: "What we do here is turn on one equipment after the other and check that they don't interfere with one another. Imagine you're driving your car and you're listening to the radio. All of a sudden your mobile phone rings and you hear this noise on the radio. If you're talking to the space craft through the radio you don't want it to, for example, close a solar panel because the electromagnetic field interferes with it."

NARRATOR: But even in the best case scenario, with all the mission's components functioning perfectly, there is no guarantee of success.

HARRIS: "The goal of every deflection mission must be to move ground zero right off the surface of the Earth. But if there is a break down during the mission we might simply move ground zero from one part of the Earth to another. For instance, from the United States over to Russia."

NARRATOR: This could turn a cosmic catastrophe into a massive political headache.