DULLES, Va.May 14, 2004--Orbital Sciences Corporation (NYSE:ORB) announced today that its Chairman and Chief Executive Officer David Thompson and Vice Chairman and Chief Financial Officer Garrett Pierce will make a presentation to investors and analysts during the Credit Suisse First Boston Aerospace Defense Conference to be held in New York City at the Credit Suisse First Boston offices. Orbital's presentation is scheduled to take place at 2:00 p.m. (EDT) on Wednesday, May 19.

On Wednesday, Orbital will provide a link to access the webcast and the PowerPoint presentation slides that Mr. Thompson and Mr. Pierce will present at the conference on the company's web site at: http://www.orbital.com/Investor/.

Orbital will maintain a link to the audio replay of the conference and will keep the presentation slides available for seven days following the conference on the company's web site under the "For Investors" section.

About Orbital

Orbital develops and manufactures small space systems for commercial, civil government and military customers. The company's primary products are satellites and launch vehicles, including low-orbit, geostationary and planetary spacecraft for communications, remote sensing and scientific missions; ground- and air-launched rockets that deliver satellites into orbit; and missile defense boosters 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.

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

    SOURCE: Orbital Sciences Corporation