Search for Asteroids Identifies Two Fly-Bys
September 14, 2010 -- NASA announced last week that two asteroids flew inside the moon's orbit of Earth on Sept. 8, but posed no danger. The event highlights NASA's ongoing efforts to track near-Earth objects (NEOs) -- asteroids and comets that could pose harm if they cross Earth's orbit -- and mitigate against any hazards.
Both asteroids that went by last week were discovered during routine monitoring by the Catalina Sky Survey supported by NASA funding. The Minor Planet Center in Cambridge, Mass., reviewed the observations and determined the asteroids' preliminary orbits. One of the asteroids, 2010 RX30, was approximately 10 to 20 meters in diameter and passed within approximately 154,000 miles of Earth. The second, 2010 RF12, was 6 to 14 meters in diameter and passed within approximately 49,000 miles. Neither asteroid was large enough to cause damage had they entered Earth’s atmosphere.
A recent report by the National Research Council, Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies, lays out options that NASA could follow to detect more NEOs. The report says the $4 million the U.S. spends annually to search for NEOs is insufficient to meet congressionally mandated requirements that NASA identify 90 percent of NEOs with diameters approximately 140 meters or greater by 2020. The report presents two approaches that would allow NASA to complete its goal soon after 2020, as well as recommends that NASA monitor for smaller objects -- those down to approximately 30 to 50 meters in diameter. One of those approaches involves using a powerful wide-field-of-view telescope, such as the proposed Large Synoptic Survey Telescope, a project recommended by another recent Research Council report, the astronomy and astrophysics decadal survey New Worlds, New Horizons in Astronomy and Astrophysics.
In addition, a 2008 Research Council report, Launching Science: Science Opportunities Provided by NASA's Constellation System, provides reasons for sending humans in spacecraft to an NEO, including collecting samples from various terrains on the space object's surface and investigating and determining the interior characteristics of a target NEO.