DULLES, Va., May 24 /PRNewswire/ -- MacDonald, Dettwiler and Associates Ltd. (MDA), the Vancouver, British Columbia-based subsidiary of Orbital Sciences Corporation (NYSE: ORB) announced that it has filed a preliminary prospectus in connection with an initial public offering and secondary offering of its common shares in Canada. A syndicate of Canadian underwriters will manage the MDA equity issue.

The shares have not been, and will not be, registered under the Securities Act of 1933, as amended. Accordingly, the shares may not be offered or sold in the United States, or to or for the account of U.S. persons, absent registration or an applicable exemption from registration requirements of the Securities Act and applicable state securities laws.

This announcement is neither an offer to sell nor a solicitation to buy shares.

MDA, which was acquired by Orbital in 1995, provides end-to-end spatial information systems, advanced space robotics technologies and online land information services. It develops, builds and upgrades imaging satellite ground stations and designs, manufactures and supports space robotics used on the NASA Space Shuttle and International Space Station. In addition, MDA offers electronic access to legal, asset and geographic information for property transactions in the U.S. and Canada.

Orbital is a space and information systems company that designs, manufactures, operates and markets a broad range of affordable space infrastructure systems, satellite access products and satellite services, including satellites and other space systems, launch vehicles, electronics and sensors, satellite ground systems and land information services, satellite- based navigation and communications products, and satellite-delivered communications, Earth imaging and other information services. SOURCE Orbital Sciences Corporation

CONTACT: Media: Barron Beneski, 703-406-5528 or beneski.barron@orbital.com, or Investors: Tim Perrott, 703-406-5997 or perrott.timothy@orbital.com, both of Orbital Sciences Corporation/