DULLES, Va.Aug. 15, 2005--Orbital Sciences Corporation (NYSE:ORB) announced today that the Galaxy 14 geosynchronous (GEO) communications satellite the company built for PanAmSat Corporation (NYSE:PA) was successfully launched aboard a Starsem Soyuz rocket on Saturday, August 13, 2005. The mission originated from the Baikonour Cosmodrome in Kazakhstan at approximately 7:28 p.m. (EDT). The Galaxy 14 satellite was deployed into a transfer orbit about 90 minutes after lift-off. Initial communications with the satellite have been established and it is performing as expected in the early stages of the mission. The Galaxy 14 satellite is the seventh Orbital-built GEO satellite to be completed and launched and the company has another six GEO satellites in various stages of design, development and manufacturing that will be launched over the next several years.

During the next several days, Galaxy 14 will perform a series of orbit-raising "burns" of its on-board rocket engine to achieve a circular orbit approximately 22,300 miles above the Earth. For several weeks afterward, a team of Orbital and PanAmSat engineers will conduct a comprehensive series of tests to ensure the spacecraft is ready for its final hand-over to PanAmSat, which is currently scheduled to occur in September.

The Galaxy 14 satellite will operate in C-band frequencies from its orbital location at 125 degrees West longitude. It is designed to provide digital video programming, high-definition television (HDTV) and other fixed satellite services. The spacecraft is optimized for a 15-year design life and will provide capacity for PanAmSat's satellite network over the continental United States, Alaska and Hawaii.

Orbital is one of the leading suppliers of GEO communications satellites, which are based on the STAR family of smaller GEO satellite platforms and are capable of accommodating all types of commercial communications payloads. For many applications, the STAR design is an attractive alternative to the larger, more costly GEO satellites offered by other industry suppliers. The STAR satellites are smaller and are significantly less expensive to manufacture and launch. They are a perfect fit for customers in the early stages of building their business or for established companies that wish to replace or add capacity to their network.

About PanAmSat

Through its owned and operated fleet of 24 satellites, PanAmSat is a leading global provider of video, broadcasting and network distribution and delivery services. It transmits 1,991 television channels worldwide and, as such, is the leading carrier of standard and high-definition signals. In total, the company's in-orbit fleet is capable of reaching over 98 percent of the world's population through cable television systems, broadcast affiliates, direct-to-home operators, Internet service providers and telecommunications companies. In addition, PanAmSat supports the largest concentration of satellite-based business networks in the U.S., as well as specialized communications services in remote areas throughout the world. For more information, visit the company's web site at www.panamsat.com

About Orbital

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

Notes to editors:

A high-resolution (300+ d.p.i.) artist rendering of the Orbital-built Galaxy satellites in orbit is available on Orbital's web site at: http://www.orbital.com/NewsInfo/Images/GEO/

A Fact Sheet on the GEO satellites Orbital is building for PanAmSat is also available at: http://www.orbital.com/NewsInfo/Publications/

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

    SOURCE: Orbital Sciences Corporation