Company’s Satellite Manufacturing Business Bolstered by Strong Demand for Low-Earth Orbit Scientific Spacecraft

(Dulles, VA 6 August 2003) – Orbital Sciences Corporation (NYSE: ORB)
announced today that it has been awarded the initial phase of a $25 million
satellite manufacturing contract from a university team led by Hampton
University (HU) in Hampton, Virginia, with the University of Colorado’s
Laboratory for Atmospheric and Space Physics (LASP) in Boulder, Colorado
managing the satellite development for HU. Dr. James M. Russell III of HU is
the Principal Investigator of the Aeronomy of Ice in the Mesosphere (AIM)
program, with oversight conducted by the Small Explorers Office of NASA’s
Goddard Space Flight Center. Under the contract, Orbital will complete the
design and development, and will manufacture and test the AIM satellite at
the company’s Dulles, Virginia satellite manufacturing facility. The
NASA-sponsored satellite is scheduled to be delivered in 2006 and will be
launched aboard Orbital’s Pegasus XL rocket.

"We are exceptionally pleased to be chosen as a major participant in the AIM
mission, together with Hampton University, a fellow Virginia-based
institution. We are also very pleased to be extending our long-term and
productive affiliation with the University of Colorado’s LASP, with which we
recently teamed on the highly successful SORCE satellite program for NASA,"
said Mr. Jack Danko, Orbital’s Executive Vice President and General Manager
of its Space Systems Group.

"Our low-Earth orbit (LEO) satellite manufacturing business has been a
mainstay of Orbital’s business for many years," Mr. Danko continued. "In the
last 20 years, we have built and delivered, or are now in the process of
designing and manufacturing, over 95 LEO spacecraft. Orbital’s strong
experience in this product area, combined with the top-notch engineering and
production team working on the AIM program, reflects our intense focus on
total customer satisfaction," he concluded.

The scientific mission of the AIM satellite program is focused on the study
of Polar Mesospheric Clouds (PMCs) that form about 50 miles above the
Earth’s surface in the summer months, primarily in the polar regions. The
AIM spacecraft will measure PMCs and the thermal, chemical and dynamic
environment in which they form in order to determine the connection between
PMCs and the meteorology of the polar mesosphere. This connection is
important because a significant variability in the yearly number of
noctilucent ("glow in the dark") clouds, which are a manifestation of PMCs,
has been suggested as an indicator of global climate change.

The data collected by the AIM spacecraft will provide the basis for a
rigorous study of PMCs that can be reliably used to study past changes,
present trends and the relationship of PMCs to global environmental change.
In the end, the AIM mission will expand the study of long-term variability
in the Earth’s climate.

About Orbital

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.