DULLES, Va.Sept. 5, 2006--Orbital Sciences Corporation (NYSE: ORB) announced today that its Chairman and CEO David W. Thompson will make a presentation to investors and analysts during Kaufman Brothers Ninth Annual Investor Conference to be held in New York, NY. Orbital's presentation is scheduled to take place at 11:30 a.m. (EDT) on Wednesday, September 6.

The sponsors of the conference will present the audio portion of the conference as a live webcast, which can be accessed at the company's web site at: http://www.wsw.com/webcast/kbro11/orb. Listeners are encouraged to register in advance and to select their preferred Internet media player program prior to the start of the presentation. In addition, Orbital will make available the informational slides that Mr. Thompson will present to the live audience on the company's web site at: http://www.orbital.com/Investor/.

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.

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

    SOURCE: Orbital Sciences Corporation