Orbital Sciences
Corporation (NYSE: ORB) announced today that Mr. Robert M. Hanisee of Trust
Company of the West, Los Angeles, and Dr. Robert J. Hermann of Global
Technology Partners, Boston, have joined the company’s Board of Directors.
Dr. Hermann has also been appointed to the Board’s five-member Strategy and
Technology Committee, while Mr. Hanisee has been named to its five-member
Audit and Finance Committee.

Mr. Hanisee is Managing Director and Chief Investment Officer of the
Private Client Group at Trust Company of the West (TCW), a large west coast
institutional investment firm where he has worked since 1990.
He is the past
manager of TCW’s $2.0 billion convertible securities group and of its global
telecom trust mutual fund.
During his years with TCW, he served as the firm’s
Director of Research and Chairman of its Equity Policy Committee.
Previously,
he was President and Director of Research for Seidler Amdec Securities for 10
years, and a partner, research director and investment analyst with Crowell
Weedon, Merrill Lynch and J.P. Morgan earlier in his career.
He serves on the
Boards of Titan Corporation and EDO Corporation, NYSE-listed defense
technology companies.
Mr. Hanisee holds a B.S. degree from Cal State
Northridge and an M.S. degree from The University of California at Berkley,
and is a Certified Financial Advisor.

Dr. Hermann is a Senior Partner of Global Technology Partners, an
aerospace, defense, and technology investment firm.
He served as Senior Vice
President/Science and Technology at United Technologies Corporation from 1987
until 1998 and, earlier, was Director of the National Reconnaissance Office,
Assistant Secretary of the Air Force for R&D and Logistics, and Principal
Deputy Assistant Secretary of Defense for Communications, Command, Control and
Intelligence.
He also spent 20 years with the National Security Agency in
R&D, operations and NATO assignments.
He is a member of the Defense Science
Board and was Chairman of the Board at Draper Laboratory from 1995 to 2001 and
a member of the President’s Foreign Intelligence Advisory Board from 1993 to
2001.
He received B.S., M.S. and Ph.D. degrees in electrical engineering from
Iowa State University, and is a member of the National Academy of Engineering.

“We are extremely fortunate to have Bob Hanisee and Bob Hermann join
Orbital’s Board.
Mr. Hanisee has 35 years of experience in investment
banking, securities research and portfolio management, with extensive work in
public and private equity, debt and venture capital financings.
Dr. Hermann
brings a comparably impressive background in U.S. Government and industrial
research, development, manufacturing and operations in defense, space and
related areas.
We look forward to benefiting from their strong guidance and
expertise in the years ahead,” said Mr. David W. Thompson, Orbital’s Chairman
and Chief Executive Officer.

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 are spacecraft and launch vehicles,
including geostationary and low-orbit satellites 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 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 .

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