-- Rendezvous and Berthing Operations of Company s First Cargo Logistics
Spacecraft Proceeded Smoothly --

-- Cargo Unloading to Begin Tomorrow with 30-Day Stay at Station Planned --

DULLES, Va.Sep. 29, 2013-- Orbital Sciences Corporation (NYSE:ORB), one of the world s leading space technology companies, today announced that its Cygnus cargo logistics spacecraft successfully completed its rendezvous and approach maneuvers with the International Space Station (ISS) and was grappled and berthed with the station by the Expedition 37 astronaut crew earlier this morning. After Cygnus was launched into orbit by Orbital s Antares rocket on Wednesday, September 18 from NASA s Wallops Flight Facility, it completed an extensive series of in-orbit tests and orbit-raising maneuvers demonstrating its readiness to operate in close proximity to the ISS. Final approach to the station began at about 3:00 a.m. (EDT) this morning, culminating with the station s robotic arm grappling the spacecraft at 7:00 a.m. when it was about 10 meters away. Cygnus was then guided to its berthing port on the nadir side of the ISS Harmony module where its installation was completed just before 8:45 a.m.

This entire COTS demonstration mission has been executed in textbook fashion by the joint NASA and Orbital teams, from Antares launch 10 days ago to Cygnus berthing at the station this morning, said Mr. David W. Thompson, Orbital s President and Chief Executive Officer. A tremendous amount of hard work has gone into this five-year effort from our launch vehicle and spacecraft teams, and we are all exceptionally proud of their accomplishments. We look forward to moving ahead with regularly scheduled ISS cargo delivery missions for NASA as early as the end of the year.

Orbital and NASA cooperatively developed the Cygnus cargo spacecraft under the Commercial Orbital Transportation Services (COTS) program that started in 2008. For the COTS demonstration mission, Cygnus carried a relatively light load of cargo to the ISS. The ISS crew will start unpacking the 700 kg of cargo and supplies tomorrow, which includes food, clothing and experimental equipment. In early October, they will begin filling the cargo module with up to 800 kg of disposal cargo prior to its departure. For future missions, Cygnus has a total cargo up-mass capacity of 2,000 kg in its standard configuration, expanding to 2,700 kg in its enhanced design for later missions. This first Cygnus will remain at the ISS for 30 days before departing for a destructive reentry over the Pacific Ocean in late October.

Following the successful completion of the COTS demonstration mission, Orbital will begin to carry out operational missions under the $1.9 billion Commercial Resupply Services (CRS) contract with NASA. The company will deliver approximately 20,000 kg of cargo to the ISS on eight more Antares/Cygnus missions through 2016. Each Cygnus cargo ship will carry crew food, clothing and other supplies; spare parts and equipment; and scientific experiments to the space station.

About Cygnus

Orbital developed the Cygnus cargo spacecraft as part of its COTS joint research and development initiative with NASA. Cygnus consists of a common Service Module (SM) and a Pressurized Cargo Module (PCM). The SM incorporates avionics, power, propulsion and communications systems already successfully flown aboard dozens of Orbital s LEOStar and GEOStar satellites. The PCM, designed and built by Thales Alenia Space under a subcontract from Orbital, is based on the Multi-Purpose Logistics Module (MPLM) previously used with the Space Shuttle. With a full load of cargo and fuel, the standard-configuration Cygnus weighs about 5,200 kg at launch and generates 3.5 kw of electrical power while in orbit. It is capable of extended-duration missions of a year or longer in space.

About Orbital

Orbital develops and manufactures small- and medium-class rockets and space systems for commercial, military and civil government customers. The company s primary products are satellites and launch vehicles, including low-Earth orbit, geosynchronous-Earth orbit and planetary spacecraft for communications, remote sensing, scientific and defense missions; human-rated space systems for Earth-orbit, lunar and other 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 provides satellite subsystems and space-related technical services to government agencies and laboratories. More information about Orbital can be found at http://www.orbital.com. Follow the company on Twitter @OrbitalSciences.

Source: Orbital Sciences Corporation

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