Why go to an asteroid?
WASHINGTON (Reuters) - President Barack Obama made his case to NASA workers in Florida on Thursday for abandoning plans to return to the moon and instead aim for asteroids, Mars and more robotic missions.
Visiting a nearby asteroid would be a small step with a big impact.
Not only can asteroids tell scientists how planets formed, but they may contain some more primordial elements from the early solar system.
And studying them can help NASA understand how to break them up if needed.
NASA's Near Earth Object Program has identified more than 1,000 "potentially hazardous asteroids." None is on a collision course with Earth but asteroids have struck before -- one wiped out the dinosaurs 65 million years ago.
Sometimes they come really close -- in March 2009 an asteroid passed by Earth at a distance of just about 49,000 miles.
In October, a government-appointed panel led by former Lockheed Martin chief Norm Augustine recommended a trip to an asteroid instead of the moon. Lockheed builds NASA's Orion spacecraft.
NASA has already sent spacecraft to an asteroid. In February 2001, the remotely controlled NEAR spacecraft touched down on asteroid Eros, in part to practice landing on a moving object in space but also to study the make-up of asteroids.