-- Five Leaders in Diverse Engineering Disciplines to Direct
   Centers of Excellence, Pursue Early-Stage R&D and Provide On-Call
                        Technical Expertise --

DULLES, Va.March 29, 2007--Orbital Sciences Corporation (NYSE:ORB), a leader in the design, manufacture and operations of innovative satellites and launch vehicles, today announced that five of its senior scientists and engineers, selected from a technical staff of over 1,500 people, have been chosen as the company's first Technical Fellows. These new appointments are intended to recognize the highest levels of technical expertise across the company's multiple business areas. The Technical Fellows will support active spacecraft, launch vehicle and other space technology programs; advance the company's research and development efforts; and provide mentorship to early-career engineers.

Orbital named the following five individuals, each with more than 10 years of experience with the company, as its inaugural class of Technical Fellows:

    --  Mr. Lee Atkinson, a specialist in radio-frequency
        communications systems, is an 11-year Orbital veteran and
        works in the company's Advanced Programs Group in Dulles, VA.
        He holds M.A. and B.S. degrees in Electrical Engineering;

    --  Mr. Doug Darnell, a software architectures expert, has been
        with Orbital for 16 years and works in the company's Launch
        Systems Group, in Chandler, AZ. He holds a B.S. degree in
        Mathematics and a B.A. in Education;

    --  Dr. Tom Dragone, an expert in the field of aerospace
        structures and materials, is a 15-year Orbital veteran and is
        based in Dulles, VA. He works in the company's Advanced
        Programs Group and holds a Ph.D. and a M.S. in Materials
        Science and Engineering, and a B.S. in Aerospace Engineering;

    --  Mr. Luis Ponce, who specializes in the area of space systems
        reliability and parts, materials and processes, is a 25-year
        company veteran. He works in the company's Space Systems Group
        in Dulles, VA, and holds a B.S. in Electrical Engineering; and

    --  Mr. Mike Ruth, a guidance, navigation and control specialist,
        has been with Orbital for 10 years and works in the company's
        Launch Systems Group in Dulles, VA. He holds an M.S. degree in
        Applied Mechanics and a B.S. in Mechanical Engineering.

Commenting on the appointments, Orbital's Chairman and Chief Executive Officer David W. Thompson, said, "I am very pleased to congratulate Lee, Doug, Tom, Luis and Mike on their appointments as Orbital's first Technical Fellows. Their high-level technical expertise and professional commitment place them among the top engineering ranks in the space industry and set high standards for our company's research and development teams."

Orbital stated that the primary functions of its Technical Fellows will fall into four broad categories, as outlined below:

    --  Conceiving new and improved product ideas and pursuing
        early-stage R&D efforts with internal and external funds;

    --  Establishing or directing technical centers of excellence or
        advanced research laboratories within the company;

    --  Providing on-call expertise to help address the most
        challenging technical problems encountered in the company's
        satellite and rocket programs; and

    --  Mentoring younger technical professionals and representing the
        company to the outside engineering and scientific communities.

The company expects that a limited number of additional Technical Fellows will be named in the future as its engineering and scientific workforce expands and its R&D needs increase.

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 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.

    Notes to Editors:

    --  High-resolution photos of Orbital's Technical Fellows are
        available on Orbital's website at:

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

    SOURCE: Orbital Sciences Corporation