DULLES, Va., July 24 /PRNewswire/ -- Orbital Sciences Corporation (NYSE: ORB) announced today that its MacDonald, Dettwiler and Associates Ltd. subsidiary (Toronto: MDA) was selected by the British Government's Land Registry and Improvement and Development Agency to provide a state-of-the-art e-commerce system for electronic delivery of comprehensive land ownership information for England and Wales.

With a combined population of about 59 million people, England and Wales generate a total demand for land ownership information exceeding 1.5 million transactions each year, which is currently valued at about $135 million annually. Today, this process is mostly manual and can take days or even weeks to complete a single land data search. Over the next several years, MDA will modernize the process, using the advanced online data management and delivery systems that it has already developed in the U.S. and Canada, to automate the search process and make property data available in near real- time. MDA then will operate the new British national online system on an exclusive basis for at least seven years.

Mr. David W. Thompson, Orbital's Chairman and Chief Executive Officer, said, "MDA's selection by the British Government to supply online land information for England and Wales is a major milestone in the development of our e-commerce business on a global scale. Beyond introducing digital technology to enhance the current land information delivery system, we hope to expand its existing information content to include high-quality imagery and other descriptive property data in the years ahead."

Mr. Daniel E. Friedmann, MDA's President and Chief Executive Officer, added, "This license expands our reach into one of the largest land information markets in the world. This is a tremendous accomplishment for MDA and we are excited to be working with British authorities on their ambitious modernization plan."

Over the past several years, MDA has invested in internal systems development, strategic acquisitions and joint ventures to create a fast- growing e-commerce unit serving major business customers in the real estate financial, insurance and legal sectors. In addition to its 1998 start in Canada, MDA's e-commerce unit recently expanded into the U.S. market. Major customers already include many of North America's top primary and secondary mortgage lenders, title and property insurance companies, land appraisers and real estate professionals, as well as numerous city, county, state and national government agencies.

MDA's partners include Halifax Bank, The Law Society (of England and Wales), Hays plc and Laser-Scan. Halifax Bank is the largest mortgage lender in the U.K. with over 20 million customers. The Law Society is the professional body for over 80,000 solicitors in England and Wales serving society by improving access to the law, providing support services for solicitors and setting legal standards. Hays plc provides a range of high- quality business-to-business services to industrial, commercial and professional customers throughout Europe. Laser-Scan is an industry leader in providing Geographic Information Systems solutions.

About MDA

MDA is an information company that provides essential information for decision making in the work place. The company operates its business through two principal groups: the Information Products Group and the Information Systems Group. MDA's Information Products Group delivers essential land information products and services in three main categories: legal, asset and geographic. MDA employs 1,700 people around the world through a network of offices, subsidiaries and distributors.

About Orbital

Orbital is one of the largest space technology and satellite services companies in the world, with 1999 total enterprise revenues (including revenues from unconsolidated affiliates) of approximately $915 million. The company, headquartered in Dulles, Virginia, employs about 5,500 people at major facilities in the United States, Canada and several overseas locations.

Orbital is the world's leading manufacturer of low-cost space systems, including satellites and space robotics, launch vehicles, electronics and sensors, satellite ground systems and related digital infrastructure. Its Magellan subsidiary is a pioneer in satellite-based navigation and communications products for consumer and industrial markets. Through its ORBCOMM and ORBIMAGE affiliates and ORBNAV subsidiary, Orbital is also a major operator of satellite-based networks that provide data communications, high- resolution imagery and automotive information services to customers around the world.

To learn more about Orbital and its MDA subsidiary, please visit the Web sites at http://www.orbital.com and http://www.mda.ca 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.tim@orbital.com, both of Orbital Sciences Corporation/