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On February 15, asteroid 2012 DA14 will pass within 22,000 miles of Earth: less than a tenth of the distance to the Moon. 

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Although this 45-meter rock has a zero percent chance of hitting us, 

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near-earth asteroids in general raise a number of interesting scientific questions. 

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What makes the difference between a near-miss and an impact?  

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How would we navigate a spacecraft around an asteroid in the future?  

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And what can we learn from the asteroids themselves? 

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To answer these questions, NASA is sending the OSIRIS-REx spacecraft to another near-earth asteroid designated 1999 RQ36.

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When it arrives in the year 2018, OSIRIS-REx will study a property called the Yarkovsky Effect, 

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where the Sun's illumination of a rotating asteroid can change its direction over time. 

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As the asteroid rotates, the sun heats one side of the surface. 

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Once that side rotates away from the sun, however, it radiates the heat into space.  

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This can act as a sort of mini-thruster that slowly changes the asteroid's direction, 

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potentially making the difference between a near-miss and an impact.

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OSIRIS-REx will also study the gravitational properties of asteroids, providing useful insights for follow-up visits. 

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Because asteroids have a small and variable gravitational pull, 

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new techniques will need to be developed to help spacecraft approach and fly around them.

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Finally, OSIRIS-REx will take a direct sample of the asteroid and return it to Earth. 

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This could perhaps yield the most interesting results of all, 

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as 1999 RQ36 is thought to be a leftover from the formation of our solar system. 

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By studying its composition, scientists will be looking at a snapshot of the solar system

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taken four-and-a-half billion years ago, one that may even hold clues to understanding our own origins.

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So although 2012 DA14 will miss us when it flies by in February, 

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NASA isn't missing an opportunity to study near-earth objects,

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and OSIRIS-REx will provide the best results yet when it visits 1999 RQ36.

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