X0306 4 2013-07-25 0 0000820736 ORBITAL SCIENCES CORP /DE/ ORB 0001045853 THOMPSON DAVID W C/O ORBITAL SCIENCES CORPORATION 45101 WARP DRIVE DULLES VA 20166 1 1 0 0 Chairman, President and CEO Common Stock 2013-04-26 5 G 0 500 0 D 189284 D Common Stock 2013-05-14 5 G 0 750 0 D 188534 D Common Stock 2013-06-04 5 G 0 1000 0 D 187534 D Common Stock 2013-07-25 4 A 0 60000 0 A 247534 D Common Stock 2013-07-25 4 F 0 4423 18.93 D 243111 D Common Stock 2013-07-27 4 F 0 4753 18.7300 D 238358 D Common Stock 2013-07-28 4 F 0 7156 18.7300 D 231202 D Common Stock 23000 I By Spouse Grant of Restricted Stock Units under the issuer's Amended and Restated 2005 Stock Incentive Plan. The reporting person received the Restricted Stock Units as a grant for no consideration. Shares forfeited to meet tax withholding obligation in connection with the vesting of a previous grant of restricted stock units. /s/ James S. Black II, Attorney-in-Fact 2013-07-29