DULLES, Va.Sept. 14, 2006--Orbital Sciences Corporation (NYSE:ORB) announced today that its Transportation Management Systems (TMS) division has been awarded a $9.7 million contract by the Westchester County Department of Transportation (WCDOT) in cooperation with the Federal Transit Administration and the New York State Department of Transportation. Under the contract, Orbital TMS will provide its latest Computer Aided Dispatch (CAD) and Automatic Vehicle Location (AVL) system, known as OrbCAD XP.

This new system is designed to be robust, reliable and easily maintainable while allowing WCDOT's Bee-Line bus operations to run more efficiently, cost-effectively and safely. The system will use real-time satellite-based Global Positioning System (GPS) information to manage WCDOT's fleet of over 400 fixed-route and support vehicles. The fully-integrated vehicle equipment suite will also simplify driver operations and automate Americans with Disabilities Act (ADA)-compliant stop announcements to the public. The project's service territory includes the approximately 450 square miles of Westchester County with routes that extend into the Bronx, Manhattan and Putnam County, New York.

"Orbital's OrbCAD XP product offering goes a long way in helping meet WCDOT's desire to implement a system that will allow full CAD/AVL management of our fixed-route buses as well as optimizing communications among our fleet by incorporating an enhanced data capability," said County Transportation Commissioner Lawrence Salley.

"The Orbital TMS products will also improve the efficiency and safety of bus operations and the passenger experience by providing passenger amenities such as next stop announcements. The system's functionality and features will aid us in keeping operational costs in check by increasing our ability to monitor, analyze and manage all aspects of our operation," Mr. Salley added.

Mr. A. David Kachemov, Senior Vice President and General Manager of Orbital TMS, said, "Orbital is very proud to have been selected to partner with Westchester County DOT to provide our OrbCAD XP solution. System features like up-to-the-minute schedule information and improved safety and security will be a great benefit to the WCDOT's passengers by providing a greater riding experience and a safer environment."

Mr. Kachemov continued, "Enhanced customer service, greater responsiveness to incidents and improved situational awareness are just some of the benefits the Orbital system brings to the Bee-Line operations. Additionally, the OrbCAD XP system is scalable and will allow WCDOT to upgrade and add features as it chooses."

About Orbital TMS

Orbital TMS is a leading integrator of products for fleet and workforce management, mobile data communications, data management and advanced traveler information systems. TMS provides integrated CAD and AVL solutions for 60 public transit and state agency customers in the U.S. and internationally, with units installed or scheduled to be installed on approximately 27,500 vehicles. More information about Orbital TMS can be found at http://www.orbitaltms.com

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

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

    SOURCE: Orbital Sciences Corporation