The 150 - 340 metre wide asteroid 2015 HA1 will make a close pass (30.5 LD, 0.0784 AU) travelling at 10.50 km/second, to the Earth-Moon system on the 21st May 2015 @ 10:51 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).