The 5 - 12 metre wide asteroid 2011 UD21 will make a close pass (21.3 lunar distances, 0.0547 AU), travelling at 1.46 km/second, to the Earth-Moon system on the 22nd April, 2012 @ 03:49 UT ±00:03.
Orbital elements:
2011 UD21 Earth MOID = 0.0016 AU
Epoch 2011 Aug. 27.0 TT = JDT 2455800.5 MPC
M 13.80680 (2000.0) P Q
n 0.97006009 Peri. 279.79627 +0.73247715 +0.68076428
a 1.0106566 Node 37.30074 -0.62060134 +0.67137472
e 0.0294423 Incl. 0.57686 -0.27987712 +0.29294366
P 1.02 H 28.6 G 0.15 U 5