DULLES, Va.Oct. 14, 2005--Orbital Sciences Corporation (NYSE:ORB) announced today that the Galaxy 15 geosynchronous (GEO) communications satellite the company built for PanAmSat Corporation (NYSE:PA) was successfully launched aboard an Ariane rocket on Thursday, October 13, 2005. The mission originated from the European Space Agency's launch complex at Kourou, French Guiana, at approximately 6:30 p.m. (Eastern). The Galaxy 15 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 15 satellite is the eighth Orbital-built GEO satellite to be completed and launched. The company also has another eight 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 15 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 afterwards, 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 in November. Once the initial in-orbit testing is complete, the satellite will occupy an orbital slot at 133 degrees West longitude over the United States.

The Galaxy 15 satellite features a unique commercial/government hybrid payload configuration. In addition to C-band communications, which will be used to distribute entertainment and informational programming to cable television system operators, the spacecraft will also broadcast Global Positioning System (GPS) navigation data using L-band frequencies. This data is part of the Federal Aviation Administration's Wide-Area Augmentation System, which is a Global Positioning System (GPS)-based navigation system that provides precision guidance to commercial and general aviation aircraft at thousands of airports and airstrips where there is no precision landing infrastructure in place.

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 most 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.

Customer demand for Orbital's STAR GEO satellites has been robust in 2005. The company has received four firm and one optional order for its STAR-based GEO satellites thus far this year. In April, PanAmSat ordered its fourth spacecraft from Orbital, the PAS-11 satellite. This order was followed by an order for the Horizons-2 satellite by a joint venture between PanAmSat and JSAT of Japan. In September, Orbital received is third order of the year when Telenor ASA of Norway contracted with the company for the THOR II-R spacecraft. Finally, in September, Orbital was selected for its fourth order of the year by a customer that wishes to remain anonymous until a formal announcement is made.

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:

    --  A Fact Sheet on the GEO satellites Orbital is building for
        PanAmSat is also available at:

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

    SOURCE: Orbital Sciences Corporation