The 10 - 23 metre wide asteroid 2015 KO122 made a close pass (2.9 LD, 0.0075 AU) travelling at 14.73 km/second, to the Earth-Moon system on the 24th May 2015 @ 15:22 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).