The 150 - 340 metre wide asteroid 2004 RK9 will make a close pass (72.0 lunar distances, 0.1851 AU), travelling at 9.49 km/second, to the Earth-Moon system on the 28th May 2014 @ 18:41 UT ±00:01.
Update The 140 - 320 metre wide asteroid 2004 RK9 will make a close pass (50.3 Lunar Distances, 0.1292 AU), travelling at 6.30 km/s, to the Earth-Moon system on the 13th June, 2009.
Orbital elements: 2004 RK9 Earth MOID = 0.1103 AU Epoch 2009 June 18.0 TT = JDT 2455000.5 MPC M 356.50364 (2000.0) P Q n 0.39546213 Peri. 283.97424 +0.15731555 +0.98750403 a 1.8382283 Node 355.04822 -0.85904148 +0.13216301 e 0.4260957 Incl. 6.22534 -0.48713403 +0.08584133 P 2.49 H 21.4 G 0.15 U 2
The 150 - 340 metre wide asteroid 2004 RK9 will make a close pass (50.2 Lunar Distances, 0.1289 AU), travelling at 6.28 km/s, to the Earth-Moon system on the 14th June, 2009.