NASA's New Asteroid Mission Could Save the Planet  By Tariq Malik SPACE.com Managing Editorposted: 16 April 2010 07:39 pm ET

President Barack Obama set a lofty next goal this week for Americans in space: Visiting an asteroid by 2025. But reaching a space rock in a mere 15 years is a daunting mission, and one that might also carry the ultimate safety of the planet on its shoulders.

"It is probably the hardest thing we can do because the asteroid is not coming on a schedule," NASA chief Charles Bolden told reporters late Thursday after Obama announced his space vision.

And when a specific asteroid is eventually selected, the window to launch a spaceship toward it will be much less forgiving than the windows for NASA space shuttles bound for the International Space Station, Bolden said.