-- Company's Newest Spacecraft for NASA to Continue Landsat Program's 40-Year History of Collecting Critical Environmental Data for Earth Science Studies --

-- 145th Orbital Satellite Extends Company's Legacy of Support for Marquee U.S. Environmental Monitoring Program --

(Dulles, VA 11 February 2013) - Orbital Sciences Corporation (NYSE: ORB), one of the world's leading space technology companies, announced that the Landsat Data Continuity Mission (LDCM) satellite was successfully launched into orbit aboard an Atlas V rocket from Vandenberg Air Force Base earlier today. Orbital designed, built and tested the LDCM satellite under a contract from NASA's Goddard Space Flight Center (GSFC) at the company's Gilbert, AZ manufacturing facility.

Lift-off took place at 10:02 a.m. (PST) and the satellite successfully separated from the rocket's final stage 78 minutes into the mission, placing it into an initial orbit about 410 miles above the Earth, from where LDCM will later raise its orbit to a final altitude of 438 miles. The mission operations team has confirmed that it is able to command and communicate with the satellite and that its solar array, which provides electrical power to the two onboard scientific instruments, is fully deployed and operating as designed.

NASA and the U.S. Geological Survey (USGS) share responsibility for the LDCM program. NASA's GSFC oversaw development of the flight systems including the LDCM spacecraft and the onboard instruments, and is responsible for mission operations, launch, and in-orbit checkout. The USGS will operate the satellite and the Landsat ground network, image-processing and archive facilities. USGS disseminates Landsat data to the worldwide user community free of charge. This data is used to positively impact a wide variety of industries including agriculture, geology, forestry, regional planning, education, mapping, global climate change research, emergency response and disaster relief.

"It was a smooth launch and deployment for the LDCM satellite earlier today and it is now performing very well early in its mission," said Mr. Mike Miller, Orbital's Senior Vice President of Science and Environmental Satellite Programs. "The LDCM satellite will enable the USGS and NASA to maintain the longest continuous record of Earth environmental data gathered from space. We are honored to have been an integral part of this legendary program that provides critical Earth observation data that benefits millions of people and a wide variety of industries worldwide."

LDCM is the company's 145th satellite to be launched since 1982, including 76 commercial and 69 government spacecraft. Once its checkout is completed, it will join Landsat 4 and Landsat 5, two earlier Orbital legacy spacecraft that have supported the Landsat program for three decades.

Over the next several weeks, Orbital's LDCM engineering team will support NASA and USGS with in-orbit testing of the satellite to verify all systems are operating as planned. Once LDCM is fully tested, USGS will operate the spacecraft and collect data from multiple ground stations worldwide.

"We are incredibly proud of our dedicated team who designed, built, tested and participated in the launch of this remarkable observatory," said Daren Iverson, Orbital's LDCM Program Manager. "Today's launch is the culmination of over five years of precise engineering and high-tech craftsmanship, along with proven science-gathering technology, coming together to provide a closer look at our planet. It has been an extraordinary experience to be part of this program and to partner with our NASA and USGS customers. In the future, we hope to continue our critical role in their mission by building the next generation of Landsat spacecraft."

With an anticipated service life of five years, LDCM is based on the company's flight-proven LEOStar-3 standard modular spacecraft platform that reduces assembly and test-cycle times. This low-Earth orbit "bus" has served as the platform for several other highly successful NASA-sponsored Earth and space science missions, such as Swift and Fermi.

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.

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

Notes to editors:

1. A high-resolution photograph of the LDCM satellite in Orbital's Gilbert, AZ. satellite production facility is available at: http://www.orbital.com/images/High/LCDM_in_space_high.jpg

2. More information about the Landsat program can be found at:

3. Broadcast quality video can be found at: