X0306 4/A 2012-10-24 2012-10-26 0 0000820736 ORBITAL SCIENCES CORP /DE/ ORB 0001557458 Culbertson Frank L. Jr. C/O ORBITAL SCIENCES CORPORATION 45101 WARP DRIVE DULLES VA 20166 0 1 0 0 Executive Vice President Common Stock 2012-10-24 4 A 0 15000 0 A 42300 D 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. Includes 271 shares acquired under the issuer's employee stock purchase plan. Amended solely to reflect that the reporting person held 42,300 shares in the aggregate following the reported transaction rather than 44,904 shares as erroneously reported, which reflected a double counting of 2,604 shares held by the reporting person's 401(k) plan. This double counting also occurred in a subsequent Form 4 filed by the reporting person on November 26, 2012. /s/ James S. Black, II, Attorney-in-Fact 2013-07-29