The 230 - 520 metre wide asteroid 2015 BU512 will make a close pass (52.7 LD, 0.1354 AU) travelling at 26.95 km/second, to the Earth-Moon system on the 4th March 2015 @ 06:58 UT ±00:01.
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The Lunar Distance (LD), the distance between Earth and the Moon, equals 384,401 km, (or 0.00256 AU).