Orbital Sciences
Corporation announced today that it intends, subject to market
conditions, to offer for sale $135 million of senior unsecured notes due 2011
pursuant to Rule 144A of the Securities Act of 1933, as amended. The company
expects to close the sale in July 2003. Orbital plans to use the proceeds
from the offering to refinance its outstanding $135 million 12% Second
Priority Secured Notes due 2006.

The securities offered will not be registered under the Securities Act of
1933, as amended, and may not be offered or sold in the United States absent
registration or an applicable exemption from registration requirements.

This announcement is not an offer by the Company to sell, nor a
solicitation of an offer to buy, any of its securities.

CONTACT: Barron Beneski, Public and Investor Relations of Orbital
Sciences Corporation, +1-703-406-5528, or Beneski.barron@orbital.com.