For Immediate Release For More Information Contact:
Barron Beneski (703) 406-5528
Public and Investor Relations
beneski.barron@orbital.com

ORBITAL TO PRESENT AT JEFFERIES 2011 GLOBAL INDUSTRIAL AND AEROSPACE & DEFENSE CONFERENCE ON AUGUST 10

(Dulles, VA 5 August 2011) - Orbital Sciences Corporation (NYSE: ORB) announced today that its Vice Chairman and Chief Financial Officer Garrett E. Pierce, will make a presentation to investors and analysts at Jefferies 2011 Annual Global Industrial and Aerospace & Defense Conference to be held in New York City on August 10, 2011. Mr. Pierce's presentation is scheduled to begin at 3:30 p.m. (EDT).

On the day of the conference, Orbital will provide a link to the live audio webcast of the presentation and will post the informational slides that Mr. Pierce will use in his presentation on the company's web site at: http://www.orbital.com/Investor/. The slides will be posted prior to the beginning of the live presentation.

About Orbital

Orbital develops and manufactures small- and medium-class rockets and space systems for commercial, military and civil government customers. The company's primary products are satellites and launch vehicles, including low-Earth orbit, geosynchronous-Earth orbit and planetary exploration spacecraft for communications, remote sensing, scientific and defense missions; human-rated space systems for Earth-orbit, lunar and other missions; ground- and air-launched rockets that deliver satellites into orbit; and missile defense systems that are used as interceptor and target vehicles. Orbital also provides satellite subsystems and space-related technical services to U.S. Government agencies and laboratories.

More information about Orbital can be found at http://www.orbital.com

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