Orbital To Announce Third Quarter 2003 Financial Results on October 16

9:00 a.m. Conference Call with Financial Analysts and Investors to be Webcast

Orbital Sciences Corporation (announced today that it
will release its third quarter 2003 financial results prior to the
opening of the market on Thursday, October 16, 2003. Orbital will
conduct a conference call with financial analysts and investors the
same morning, beginning at 9:00 a.m. (EST). The conference call will
be hosted by:

-- Mr. David W. Thompson, Chairman and Chief Executive Officer
-- Mr. Garrett E. Pierce, Vice Chairman and Chief Financial Officer
-- Mr. James R. Thompson, Vice Chairman and Chief Operating Officer

To listen to the conference call, dial (888) 541-8767, and use the
conference ID number 3207669. A replay of the conference call will be
available approximately two hours after the end of the call and will
remain active for one week, until Thursday, October 23, 2003. For
access to the replay of the conference call, dial (800) 642-1687
(international callers should dial (706) 645-9291) and use the same
conference ID number.

The conference call will also be webcast. For webcast registration
and information, please visit Orbital’s web site at
http://www.orbital.com/Investor. It is advisable to register at least
20 minutes prior to the call to download and install any necessary
audio software. A transcript of the conference call will be posted on
the investor relations section of Orbital’s web site within 48 hours.

Orbital develops and manufactures small space systems for
commercial, civil government and military customers. The company’s
primary products are satellites and launch vehicles, including
low-orbit, geostationary and planetary spacecraft for communications,
remote sensing and scientific missions; ground- and air-launched
rockets that deliver satellites into orbit; and missile defense
boosters 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.

More information about Orbital can be found at
http://www.orbital.com