-- Initial Spacecraft Testing and Activation Now Underway; Mission s Science Operations to Begin Later This Year --

-- OCO-2 Is NASA s First Satellite Dedicated to Making Space-Based Measurements of Atmospheric Carbon Dioxide --

DULLES, Va.Jul. 2, 2014-- Orbital Sciences Corporation (NYSE: ORB), one of the world s leading space technology companies, today announced the Orbiting Carbon Observatory-2 (OCO-2) satellite, built by the company for NASA s Jet Propulsion Laboratory (JPL) in Pasadena, CA, was successfully launched into orbit aboard a Delta II rocket earlier today. Lift-off occurred at 2:56 a.m. (PDT) from Vandenberg Air Force Base, CA. The satellite was successfully deployed into its targeted 430-mile (690-kilometer) altitude orbit approximately 56 minutes after launch. JPL and Orbital engineers have begun a comprehensive series of in-orbit tests to verify all spacecraft systems are functioning properly. Orbital will manage day-to-day in-orbit operations of the satellite from the company s Mission Operations Center at its Dulles, VA campus for the duration of the program. JPL expects OCO-2 science operations to begin later in 2014.

The initial check-out and testing process indicates the OCO-2 mission is proceeding smoothly, said Mr. Mike Miller, Orbital s Senior Vice President of Science and Environmental Satellite Programs. OCO-2 will help scientists understand the sources of carbon dioxide emissions and the natural process that removes it from the atmosphere. We are proud to team with JPL in this important mission and we look forward to the successful commissioning of the spacecraft in the coming weeks.

At launch, the OCO-2 satellite weighed approximately 990 pounds (450 kilograms). The observatory has single-axis articulated arrays and three-axis attitude control to ensure high precision in positioning. It will operate in a 435-mile (700-kilometer) altitude, near-polar orbit with five other satellites as part of the Afternoon (A-Train) Constellation. This international fleet of Earth-observing satellites circle the globe once every 98 minutes in a sun-synchronous orbit that crosses the equator near 1:30 p.m. local time and repeats the same ground track every 16 days. OCO-2 will be inserted at the head of the A-Train where it is designed to operate for at least two years.

OCO-2 is the 151st satellite Orbital has built and delivered to commercial, civil government and national security customers over the past 32 years. Orbital-built satellites have now amassed approximately 1,100 years of in-orbit experience, a number that will continue to grow as the company is scheduled to deploy up to nine spacecraft in 2014 for commercial communications, space station logistics, scientific research and national security missions.

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 exploration 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 U.S. 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