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

DULLES, Va., Oct 23, 2006 (BUSINESS WIRE) -- Orbital Sciences Corporation (NYSE:ORB) announced today that it will release its third quarter 2006 financial results prior to the opening of the market on Friday, October 27, 2006. Orbital will also conduct a conference call with financial analysts and investors the same morning, beginning at 9:00 a.m. (Eastern). 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

-- Mr. James R. Thompson, Vice Chairman and Chief Operating Officer

To listen to the conference call, dial (888) 541-8767, and use the conference ID number 9149552. A replay of the conference call will be available approximately two hours after the end of the call and will remain active until Friday, November 3, 2006. For access to the replay of the conference call, dial (800) 642-1687 (international callers should dial (706) 645-9291) and use the same conference ID number.

For webcast registration and information, please visit Orbital's web site at http://www.orbital.com/Investor. The company advises participants to register at least 20 minutes prior to the call to download and install any necessary audio software.

About Orbital

Orbital develops and manufactures small space and rocket systems for commercial, military, and civil government customers. The company's primary products are satellites and launch vehicles, including low-orbit, geosynchronous-orbit and planetary spacecraft for communications, remote sensing, scientific and defense 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 offers space-related technical services to government agencies and develops and builds satellite-based transportation management systems for public transit agencies and private vehicle fleet operators.

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

SOURCE: Orbital Sciences Corporation

Orbital Sciences Corporation
Barron Beneski, 703-406-5528
Public and Investor Relations