An asteroid around the size of a football field is expected to zoom by Earth on Tuesday, but at a safe distance, the US space agency said.
The space rock was discovered in 2010, but only recently did astronomers determine it would not collide with our planet, instead passing at a distance about halfway between the Earth and Moon.
Asteroid 2010 WC9 will make a "close approach" to Earth at 2204 GMT, NASA said in a statement.
"At the time of closest approach, the asteroid will be no closer to Earth's surface than about 120,000 miles (193,000 kilometers)."
The asteroid is believed to be about 200 to 400 feet (60 to 120 meters) across.
Its speed should clock in at about 29,000 miles per hour, or eight miles (12.9 kilometers) per second.
NASA said this approach will be the closest to Earth -- for this particular asteroid -- for at least two centuries.
More than 10,000 asteroids are known to be orbiting near Earth, and scientists regularly keep track of them to monitor for potential strikes.