Orbital To Announce Second Quarter 2012 Financial Results on July 19

9:00 a.m. Conference Call with Financial Analysts and Investors to be Webcast

(Dulles, VA 12 July 2012) – Orbital Sciences Corporation (NYSE: ORB) announced today that it will release its second quarter 2012 financial results prior to the opening of the market on Thursday, July 19, 2012. Orbital will also conduct a conference call with financial analysts and investors the same morning, beginning at 9:00 a.m. (EDT). The conference call will be hosted by:

* Mr. David W. Thompson, Chairman and Chief Executive Officer

* Mr. Garrett E. Pierce, Vice Chairman and Chief Financial Officer

To listen to the conference call, dial (888) 541-8767 and use the conference ID number 95842625. The conference call will also be webcast to the public through a link on Orbital’s web site at www.orbital.com/investor. A replay of the conference call will be available online or by dialing (855) 859-2056 and using the same conference ID number later in the day. The replay will remain active for one week, until July 26, 2012.

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