What we've seen in movies might just become a reality one day and we'll have a big astroid coming our way to destroy the Earth. What'd you do in such a case? Being prepared to handle such situation is the first step - and it's the ESA's Astroid deflection mission.

The mission will officially be called "Asteroid Impact and Deflection mission – AIDA". It will have a set of two spacecrafts sent on the mission. The first of the two, Double Asteroid Redirection Test (DART) will be responsible for will collide with the smaller of the two astroids approaching Earth. The second spacecraft, Asteroid Impact Monitor will monitor the collision and record various parameters of the collision (before and after).

How the actual deflection mechanism will work is yet to be known, but the ADM folks are working hard on it. I'm sure they'll come up with a solution quickly.