-- Pierce Transit Will Receive Orbital's Latest Fleet Management
   System to Assist in Effective Management of Its Growing Number of
                Fixed Route and Paratransit Vehicles --

DULLES, Va.Feb. 22, 2007--Orbital Sciences Corporation (NYSE:ORB) announced today that its Transportation Management Systems (TMS) division has signed a $6.2 million contract to provide its OrbCAD XP Computer Aided Dispatch (CAD) and Automatic Vehicle Location (AVL) system for Pierce Transit in Tacoma, Washington. The company will also supply Pierce Transit with a suite of real-time information and analytical tools that will assist in the day-to-day management of the 391-vehicle fleet of local, paratransit and demand responsive bus services.

"Pierce Transit is looking forward to the installation of Orbital's fleet management system. It will enhance our ability to supervise fleet operations and improve our situational awareness of all our transit services," stated Lynne Griffith, Chief Executive Officer of Pierce Transit.

"We are confident the Orbital system will be especially beneficial for the management of our demand responsive bus services such as the SHUTTLE and Bus Plus. The ability for a SHUTTLE driver to view his schedule in real-time on the vehicle's mobile data terminal during the workday will translate into greater productivity and more flexible and timely service for our customers. It's a win-win situation for Pierce Transit and for our customers," Ms. Griffith added.

In addition to OrbCAD's suite of fleet management tools, Orbital will integrate wireless internet connections to over forty mobile workstations in the vehicles of Pierce Transit's supervisors. This new mobile workstation feature enables supervisors to access the same information and perform the same functions as a dispatcher in Pierce Transit's Operations Control Center. Supervisors will be able to manage situations with up-to-date operational information. This ability ultimately will benefit Pierce Transit's passengers through improved information flow to supervisors who will be able to respond more effectively to events requiring their attention.

Orbital is teamed with Motorola Corporation (NYSE:MOT), which will serve as the project's prime contractor. The entire system will feature the latest technologies in public transit system management. In addition to the capabilities described above, the Orbital system will give Pierce Transit the ability to provide "next-stop" automated voice announcements and to capture detailed ridership information from automatic passenger counters for service planning efforts.

Mr. A. David Kachemov, Senior Vice President and General Manager of Orbital TMS, said, "Orbital is eager to begin working with Motorola and Pierce Transit to bring our latest suite of innovative products to the people of Tacoma, Washington. Our OrbCAD XP system's open architecture will allow Pierce Transit to add new features in the future as the public transit system continues to expand in the dynamic Puget Sound area. Orbital's products are proven and our other public transit customers have benefited from their use. We look forward to working with Pierce Transit so that they can receive the full benefits of the OrbCAD system."

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 Computer Aided Dispatch (CAD) and Automatic Vehicle Location (AVL) solutions for sixty 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
             Barron Beneski, 703-406-5528
             Public and Investor Relations

    SOURCE: Orbital Sciences Corporation