Company to Use Net Proceeds to Retire Existing Convertible Bonds and Bank Loan
Management to Host 1:30 p.m. Conference Call With Analysts and Investors To Discuss Transaction

Orbital Sciences Corporationannounced today that it has entered into a purchase agreement for
a private offering of $135 million in second priority, secured notes plus
warrants. Interest on the new four-year notes is payable semi-annually at 12%
per annum and the notes will mature in August 2006. In connection with the
transaction, the company will also issue warrants with a four-year maturity to
purchase 16.5 million shares of the company’s common stock at an exercise
price of $3.86 per share, which represents a 10% premium to the closing price
of Orbital’s common stock on August 8, 2002. Closing of the sale of the new
notes is expected on August 22, 2002.

The initial purchaser of the debt intends to reoffer the securities only
to qualified institutional buyers and certain accredited investors in
accordance with Rule 144A of the Securities Act of 1933. Orbital stated that
it will use the net proceeds of the transaction to retire its existing $100
million in convertible bonds that mature on October 1, 2002, as well as to
repay a $25 million term loan that it drew from its primary bank lender,
Foothill Capital Corporation, earlier this year.

The company will hold a conference call with analysts and investors at
1:30 p.m. on Friday, August 9. The conference call access number is
888-541-8767 and the password is “Orbital.” The conference call will also be
available over the Internet at . Orbital’s
Chairman and Chief Executive Officer David W. Thompson and Executive Vice
President and Chief Financial Officer Garrett E. Pierce will host the call.

None of the units, the notes, the warrants or the common stock issuable
upon exercise of the warrants have been registered under the Securities Act of
1933, or any state securities laws. Unless so registered, such securities may
not be offered or sold in the United States absent an exemption from, or in a
transaction not subject to, the registration requirements of the Securities
Act and any applicable state securities laws. This announcement is neither an
offer to sell nor a solicitation of an offer to buy any of these securities.

Orbital is one of the world’s leading developers and manufacturers of
affordable space systems for commercial, civil government and military
customers. The company’s primary products include low-orbit, geosynchronous
and planetary spacecraft for communications, scientific and remote sensing
missions; ground- and air-launched rockets that deliver satellites into orbit;
and missile defense boosters that are used as target and interceptor vehicles.
Orbital also offers space-related technical services to government agencies
and develops and builds satellite-based transportation management systems for
public transit and public works agencies, as well as private vehicle fleet

More information about Orbital can be found at .

Note: “Safe Harbor” Statement Under the Private Securities Litigation
Reform Act of 1995. Some of the statements in this release constitute
“forward-looking statements” within the meaning of the Private Securities
Litigation Reform Act of 1995. All statements other than those of historical
facts included herein, including those related to the company’s financial
outlook, goals, business strategy, projected plans and objectives of
management for future operations, new order trends and liquidity are forward-
looking statements. Such “forward-looking statements” involve unknown risks
and uncertainties that may cause the actual results, performance or
achievements of the company to be materially different from any future
results, performance or achievements, expressed or implied by such forward-
looking statements. Factors such as general economic and business conditions,
availability of required capital for Orbital and its affiliates, continued
government support and funding for key space and defense programs, the
financial condition of major customers, product performance, market acceptance
of products, services and technologies, consumer demand, and dependence upon
long-term contracts and licensing agreements with commercial and government
customers may impact the company’s revenues, expenses and profit from period
to period. These factors and others related to the company’s business are
described in further detail in the company’s SEC filings, including its Form
10-K. Orbital assumes no obligation to update any such forward-looking

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