Earth's close encounter with Asteroid 2005 YU 55 will occur at 6:28 p.m. EST (2328 GMT) Tuesday, as the space rock sails about 201,000 miles from the planet.
"It is the first time since 1976 that an object of this size has passed this closely to the Earth. It gives us a great -- and rare -- chance to study a near-Earth object like this," astronomer Scott Fisher, a program director with the National Science Foundation, said Thursday during a Web chat with reporters.
The orbit and position of the asteroid, which is about 1,312 feet in diameter, is well known, added senior research scientist Don Yeomans, with NASA's Jet Propulsion Laboratory in Pasadena, California.
"There is no chance that this object will collide with the Earth or moon," Yeomans said.