Spacecraft to Arrive at Company’s Dulles, Virginia Facility Later this Week

Orbital Sciences Corporation (NYSE:ORB – News), announced today that the TELKOM-2 communications satellite will arrive back at the company’s Dulles, Virginia satellite manufacturing facility later this week. The satellite will undergo evaluation and tests to determine the root cause of a power supply anomaly that was detected while being prepared for launch in Kourou, French Guiana. The decision to return the satellite to Orbital’s facility was made in agreement with the satellite program’s customer, PT Telekomunikasi Indonesia (PT TELKOM).

“As with all important decisions in our business, the decision to return the TELKOM-2 satellite to the Dulles manufacturing facility was made with high product quality standards as our first priority,” said Dr. Ali Atia, President of Orbital Communications International, Orbital’s communications satellite business unit. “While this action will result in additional work to be performed on the satellite and a delay in its launch, these concerns are secondary to delivering a highly reliable satellite for our customer.”

Orbital completed production of the TELKOM-2 satellite in November 2004. The satellite was shipped to French Guiana at the end of May 2005 for a launch that was scheduled in late June. Following its arrival at the Kourou launch site, a problem in the spacecraft’s power subsystem was discovered during pre-launch testing. Orbital judged that returning TELKOM-2 to the Dulles facility would be the best course of action in order to identify the root cause of the problem, perform corrective actions and thoroughly re-test the spacecraft. Orbital made this decision solely from a standpoint of achieving the highest quality satellite.

Orbital is preparing to launch two other communication satellites later this year for PanAmSat Corporation. The Galaxy-14 satellite is currently scheduled for launch aboard a Soyuz rocket in the third quarter and Galaxy-15 is also slated for a third quarter launch aboard an Ariane-5 rocket. These launch dates are not expected to be affected by the TELKOM-2 activities.

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.

Contact:

Orbital Sciences Corporation

Public and Investor Relations:

Barron Beneski, 703-406-5528
Beneski.barron@orbital.com