DULLES, Va., Apr 18, 2002 /PRNewswire-FirstCall via COMTEX/ --

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

Orbital Sciences Corporation (NYSE: ORB) will release its first quarter 2002 financial results prior to the opening of the market on Tuesday, April 23, 2002, the company announced today. 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 the company's senior executives, including:

    *  Mr. David W. Thompson, Chairman and Chief Executive Officer
    *  Mr. James R. Thompson, President and Chief Operating Officer
    *  Mr. Garrett E. Pierce, Executive Vice President and
        Chief Financial Officer
To listen to the conference call, dial 888-541-8767, and use the password "Orbital." A replay of the conference call will be available approximately two hours after the end of the call and will remain active for one week, until Tuesday, April 30. For access to the conference call replay, dial 800-642-1687 (international callers should dial 706-645-9291) and use the conference ID number 3884012.

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

Orbital is one of the world's leading developers and manufacturers of affordable space systems for commercial, civil government and military customers. The company's primary products include low-orbit, geostationary and planetary spacecraft for communications, scientific and remote sensing missions; ground- and air-launched rockets that deliver satellites into orbit; and missile defense boosters that are used as target and interceptor 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
CONTACT: Barron Beneski, Public and Investor Relations of Orbital Sciences Corporation, +1-703-406-5528, or beneski.barron@orbital.com

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SOURCE Orbital Sciences Corporation

CONTACT:          Barron Beneski, Public and Investor Relations of Orbital
                  Sciences Corporation, +1-703-406-5528, or beneski.barron@orbital.com

URL:              http://www.orbital.com
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