X0303 4 2010-07-28 0 0000820736 ORBITAL SCIENCES CORP /DE/ ORB 0001045863 THOMPSON JAMES R JR 21839 ATLANTIC BLVD. C/O ORBITAL SCIENCES CORP DULLES VA 20166 1 1 0 0 VC, Pres and COO Common Stock 2010-07-28 4 A 0 18000 0 A 268941 D Common Stock 1385 I By Spouse Grant of Restricted Stock Units under the issuer's 2005 Stock Incentive Plan. The reporting person received the Restricted Stock Units as a grant for no consideration. The reporting person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that the reporting person is the beneficial owner of the securities for purposes of Section 16 or any other purpose. /s/ James R. Thompson Jr. by Vanessa T. Hoang, Attorney-in-Fact 2010-07-29