NASA To Test Defense System During Asteroid Flyby

PHILADELPHIA (CBS)--NASA is planning to test its "Planetary Defense System" this fall when an asteroid is expected to pass by Earth.

The agency says it last tracked the asteroid in 2012. Since then, it's been too far away. The 30-foot-by-100 foot space rock is expected to make a brief fly-by on

Since then, it's been too far away. The 30-foot-by-100 foot space rock is expected to make a brief fly-by on

The 30-foot-by-100 foot space rock is expected to make a brief fly-by on October 12.

Scientists don't expect it to get closer than 4,200 miles from earth's surface.

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• NASA