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Experts: Asteroid flyby no threat to Earth or satellites
BY STEPHEN CLARK
SPACEFLIGHT NOW

Posted: 15 February 2013


Analysts surveying the path of a 150-foot-wide asteroid on course to swing by Earth on Friday say the object poses no threat to any satellites.

Asteroid 2012 DA14 is on a course to fly about 17,200 miles from Earth's surface, making its closest approach at 1925 GMT (2:25 p.m. EST). NASA says there is no chance the object will strike Earth.

The flyby is a near-miss in cosmic terms, and it's the closest-ever buzz by Earth of a known asteroid.

Astronomy Now's Greg Smye–Rumsby gives an overview of asteroid 2012 DA14's fleeting flyby of Earth.
 
Experts compared the asteroid's trajectory with the orbits of 15,000 satellites, rocket bodies, and debris fragments and concluded no satellites are threatened during the asteroid's flyby.

"There is no reason to believe that this asteroid poses a threat to any satellites in Earth orbit," said T.S. Kelso, a respected analyst for Analytical Graphics Inc. and the Space Data Association, a non-profit organization formed by leading commercial satellite operators to ensure safety of spacecraft from collisions in orbit.

Kelso, who runs a data center for the Space Data Association, said he used trajectory data on asteroid 2012 DA14 in a simulation incorporating positions of 15,000 space objects. The result? None of the satellites will come within 1,000 kilometers, or about 620 miles, of the asteroid as it zips by Earth at 17,450 mph.

Any collision between the asteroid and a satellite would destroy the spacecraft.

Officials with the U.S. Air Force said they expect no impact to satellite operations from the asteroid. The Air Force is not tracking the asteroid, but the monitors space debris and would respond in the event of a collision, a military spokesperson told Spaceflight Now.

Earth is surrounded by a cloud of satellites, spent rocket bodies and space junk, but most of the material is cluttered in low Earth orbit, in a beehive of medium-altitude GPS satellites, or in the geostationary belt encircling the planet about 22,300 miles above the equator.

Intelsat, the world's largest operator of geostationary satellites, also said it anticipated no operational affects from the asteroid. This animation shows the asteroid's path by Earth. Credit: Analytical Graphics Inc.
 
NASA officials say the asteroid will pass 5,000 miles inside the arc of geostationary communications satellites but above the altitude of GPS satellites.

"This asteroid seems to passing in the sweet spot between the GPS satellites and the communications and weather satellites, so it's extremely unlikely that any of these satellites would be threatened," said Donald Yeomans, director of the near-Earth object office at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Asteroid 2012 DA14 was discovered by astronomers at the La Sagra Observatory in Spain in February 2012. Precise tracking of the asteroid indicates it will pass through a narrow corridor with a margin of error of less than 50 miles, leaving zero chance the object will strike Earth.

Scientists estimate about 500,000 objects at least the size of asteroid 2012 DA14 are in the solar system, and astronomers have discovered less than 1 percent of them.

A 150-foot-wide asteroid like 2012 DA14 should reach the same distance from Earth every 40 years, and an impact with the planet would occur every 1,200 years on average, according to Yeomans.

Observers in Australia, Asia and Eastern Europe are best positioned to observe the asteroid passing from south to north around the time of closest approach to Earth.

The asteroid, likely composed of silica rock, will brighten only to magnitude 7.5, meaning skywatchers will need binoculars or a small telescope to see the flyby.

For more information on how to observe the historic asteroid flyby, see a story by our colleagues at Astronomy Now.

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