The 79 - 180 metre wide asteroid 2015 OT78 will make a close pass (71.1 LD, 0.1826 AU) travelling at 6.78 km/second, to the Earth-Moon system on the 15th August 2015 @ 12:07 UT ±00:18.
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The Lunar Distance (LD), the distance between Earth and the Moon, equals 384,401 km, (or 0.00256 AU).