Scientists have urged governments to fund a mission to find out if an asteroid could be nudged off its trajectory to avoid a collision with Earth.
The European Space Agency (ESA) has teamed up with Nasa for the first planetary defence operation, which aims to study the effect of crashing into a small rock dubbed "Didymoon" orbiting an asteroid called Didymos A.
The Aida mission (Asteroid Impact and Deflection Assessment) is made up of Nasa's Double Asteroid Redirection Test (Dart) spacecraft, which will smash into the little satellite, and the ESA's Hera craft which will study the impact.
But it needs the agreement of ministers meeting in Seville later this month to decide on future funding projects.
A group of 1,200 scientists have written to ministers warning of the danger of not funding the mission. They say: "Unlike other natural disasters, an asteroid impact with Earth is not only one we know how to predict, but one we can prevent, by means that just need to be tested.
"Today, we are the first generation of humans who have the necessary technology to try to change the trajectory of an asteroid.
"We urge governments to keep the Hera mission high on the agenda, providing vital knowledge to protect ourselves and future generations."
Asteroids are leftover matter from the formation of planets and range in size from a few feet to tens of miles. They orbit the Sun, and sometimes come dangerously close to Earth, yet currently there is no way to deflect an incoming threat. (© Daily Telegraph London)