NASA Captures New Images of Large Asteroid Passing Earth

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DC Agle 818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
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Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov
News release: 2011-343 Nov. 7, 2011

NASA Captures New Images of Large Asteroid Passing Earth

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2011-343&cid=release_2011-343

PASADENA, Calif. -- NASA's Deep Space Network antenna in Goldstone, Calif. has captured new
radar images of Asteroid 2005 YU55 passing close to Earth.

The asteroid safely will safely fly past our planet slightly closer than the moon's orbit on Nov. 8. The
last time a space rock this large came as close to Earth was in 1976, although astronomers did not
know about the flyby at the time. The next known approach of an asteroid this size will be in 2028.

The image was taken on Nov. 7 at 11:45 a.m. PST (2:45 p.m. EST/1945 UTC), when the asteroid was
approximately 860,000 miles (1.38 million kilometers) away from Earth. Tracking of the aircraft
carrier-sized asteroid began at Goldstone at 9:30 a.m. PDT on Nov. 4 with the 230-foot-wide (70-
meter) antenna and lasted about two hours, with an additional four hours of tracking planned each
day from Nov. 6 - 10.

Radar observations from the Arecibo Planetary Radar Facility in Puerto Rico will begin Nov. 8, the
same day the asteroid will make its closest approach to Earth at 3:28 p.m. PST (6:28 p.m. EST/1128
UTC).

The trajectory of asteroid 2005 YU55 is well understood. At the point of closest approach, it will be
no closer than 201,700 miles (324,600 kilometers) as measured from the center of Earth, or about
0.85 times the distance from the moon to Earth. The gravitational influence of the asteroid will have
no detectable effect on Earth, including tides and tectonic plates. Although the asteroid is in an orbit
that regularly brings it to the vicinity of Earth, Venus and Mars, the 2011 encounter with Earth is the
closest it has come for at least the last 200 years.

NASA detects, tracks and characterizes asteroids and comets passing close to Earth using both
ground- and space-based telescopes. The Near-Earth Object Observations Program at NASA's Jet
Propulsion Laboratory in Pasadena, Calif., commonly called "Spaceguard," discovers these objects,
characterizes some of them, and plots their orbits to determine if any could be potentially hazardous
to our planet. JPL manages the Near-Earth Object Program Office for NASA's Science Mission
Directorate in Washington.

The new radar images are online at:
http://www.nasa.gov/mission_pages/asteroids/multimedia/yu55-20111107.html .

For more information about asteroids and near-Earth objects, visit:
http://www.jpl.nasa.gov/asteroidwatch .

More information about asteroid radar research is available online at: http://echo.jpl.nasa.gov/ .

For more information about NASA's Deep Space Network, visit: http://deepspace.jpl.nasa.gov/dsn
.

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