“This is really a call to action to find all asteroid threats to human populations and know what to do about them,” NASA Deputy Administrator Lori Garver said Monday. She said the asteroid hunt would help prove that “we’re smarter than the dinosaurs.”

There is a second, overlapping agenda at work here: The NASA human spaceflight program needs to find a target rock for what is now being called the Asteroid Redirect Mission (formerly the Asteroid Retrieval Mission), or ARM.

The proposed mission, which is early in the planning stages, would send astronauts to visit an asteroid that had been redirected into a high lunar orbit. But first a robotic spacecraft would have to rendezvous with the asteroid and capture it. And even before that, scientists would have to find the right asteroid.