The 19 - 43 metre wide asteroid 2015 QR3 made a close pass (17.0 LD, 0.0437 AU) travelling at 6.93 km/second, to the Earth-Moon system on the 21st August 2015 @ 19:45 UT ±00:03.
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The Lunar Distance (LD), the distance between Earth and the Moon, equals 384,401 km, (or 0.00256 AU).