The 16 - 35 metre wide asteroid 2015 KW121 made a close pass (0.7 LD, 0.0019 AU) travelling at 21.00 km/second, to the Earth-Moon system on the 23rd May 2015 @ 17:58 UT ±00:05.
Orbital elements:
2015 KW121 Earth MOID = 0.0009 AU
Epoch 2015 June 27.0 TT = JDT 2457200.5 MPC
M 74.66431 (2000.0) P Q
n 0.79513951 Peri. 251.30094 -0.58784769 -0.69340647
a 1.1539150 Node 242.07321 +0.79648920 -0.58622976
e 0.5192072 Incl. 28.13819 -0.14156287 -0.41895363
P 1.24 H 26.1 G 0.15 U 9