-- Launch, Rendezvous and Berthing Operations of Company s Third Space Station Cargo Logistics Mission Proceeded Smoothly --

-- Unloading of Over 3,600 Pounds of Cargo Scheduled to Begin Tomorrow with 30-Day Stay at Station Planned --

DULLES, Va.Jul. 16, 2014-- 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 40 astronaut crew earlier this morning. After Cygnus was launched into orbit by Orbital s Antares rocket on Sunday, July 13, from the Mid-Atlantic Regional Spaceport at NASA s Wallops Flight Facility in eastern Virginia, it completed a series of thruster firings and other maneuvers bringing the spacecraft 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 6:36 a.m. when it was about 30 feet (10 meters) from the ISS. Cygnus was then guided to its berthing port on the nadir side of the ISS Harmony module where its installation was completed shortly before 10:00 a.m. this morning.

Our third cargo mission for NASA has proceeded very smoothly, from the Antares launch from Wallops this past Sunday to this morning s rendezvous, grapple and installation at the Space Station, said Mr. David W. Thompson, Orbital s President and Chief Executive Officer. I am very proud of our Antares and Cygnus teams for their exceptional performance on the mission to deliver vital equipment and supplies to the crew aboard the Station. I also want to pay tribute to our former Orbital colleague and NASA astronaut, the late Dr. Janice Voss, for whom this spacecraft is dedicated.

Cygnus is delivering approximately 3,670 pounds (1,665 kilograms) of cargo and science payloads to the Expedition 40 astronauts. The crew plans to open the Cygnus hatch and make initial ingress into its cargo module tomorrow. Cygnus will remain berthed at the ISS for approximately 30 days before departing with an estimated 2,800 pounds (1,300 kilograms) of disposable cargo. Orbital will also conduct a series of in-orbit tests designed to provide data to help enhance the vehicle s performance for future uses. It is scheduled for a safe destructive reentry over the Pacific Ocean five days after departing the Station. Including a demonstration mission conducted in 2013, this is the third berthing with the ISS by a Cygnus spacecraft, which collectively have delivered approximately 8,400 pounds (3,800 kilograms) of supplies and science experiments to the orbiting laboratory.

Under a $1.9 billion contract with NASA, Orbital will use Antares and Cygnus to deliver up to 44,000 pounds (20,000 kilograms) of cargo to the ISS over eight missions, including the mission currently underway, through late 2016. For these missions, NASA will manifest a variety of essential items based on ISS program needs, including food, clothing, crew supplies, spare parts and equipment, and scientific experiments.

About Cygnus

Orbital developed the Cygnus cargo spacecraft under a joint research and development program 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 kilograms at launch and generates 3.5 kilowatts 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
beneski.barron@orbital.com