Asteroid mission now has its target

A European mission to intercept and study an asteroid now has a target, scientist say, and it's "2-for-1" -- a pair of asteroids orbiting each other. The "binary" asteroid Didymos has been chosen as the destination for the European Space Agency's proposed Asteroid Impact and Deflection Assessment mission, a release from the ESA's Paris headquarters said Friday. ESA has been working with international partners for two years on the mission concept, dubbed AIDA, and last week research centers each side of the Atlantic agreed the spacecraft would target Didymos. In the proposed mission, a spacecraft would intercept the Didymos pair -- one is about 2,600 feet across, the other about 500 feet -- around the time of their closest approach to within 6.8 million of Earth in 2022. AIDA would send two small spacecraft to intercept the double target; as one probe smashes into the smaller asteroid at about 3.8 miles per second, the other would record and gather data about the collision. The AIDA impact at that speed would be similar to that of a large piece of space junk hitting a satellite, ESA said.