Orbital Designed, Manufactured and Tested AIM Satellite for NASA to Study Polar Mesospheric Clouds
DULLES, Va., Apr 24, 2007 (BUSINESS WIRE) -- Orbital Sciences Corporation (NYSE:ORB) today announced that it is in final preparations to launch the Aeronomy of Ice in the Mesosphere (AIM) satellite that the company designed, manufactured and tested for the National Aeronautics and Space Administration (NASA). The AIM satellite will be launched aboard Orbital's Pegasus(R) rocket in a mission that will originate from Vandenberg Air Force Base (VAFB), California. The mission is scheduled to take place on Wednesday, April 25 during an available launch window that extends from 1:23 p.m. to 1:30 p.m. (PDT). This operational schedule is subject to the completion of final pre-launch activities, as well as acceptable weather conditions at VAFB at the time of the launch.

The powered flight sequence for the AIM mission is expected to take approximately 11 minutes, from the time the Pegasus rocket is released from the L-1011 carrier aircraft to the time that the satellite is deployed into orbit. The targeted orbit for the 440-lb. AIM satellite is approximately 375 miles above the Earth in a polar orbit, inclined at 97.77 degrees to the equator.

About the Pegasus Rocket

Pegasus is the world's leading launch system for the deployment of small satellites into low-Earth orbit. Its patented air-launch system, in which the rocket is launched from beneath Orbital's "Stargazer" L-1011 carrier aircraft over the ocean, reduces cost and provides customers with unparalleled flexibility to operate from virtually anywhere on Earth with minimal ground support requirements. The AIM mission will be the 38th flight of the Pegasus rocket since its debut in 1990.

About the AIM Satellite

The AIM spacecraft was designed, manufactured and tested at Orbital's Dulles, Virginia satellite manufacturing facility. The spacecraft program is being overseen by prime contractor Hampton University of Hampton, Virginia, assisted by the University of Colorado and Virginia Tech University. The AIM mission is part of NASA's ongoing series of Small Explorer (SMEX) missions that use smaller-sized satellites to carry out Earth or space science missions.

The AIM mission is a two-year program to study polar mesospheric clouds, which are the highest altitude clouds that form in the Earth's atmosphere. Mesospheric clouds create an icy membrane about 50 miles above the surface at the edge of space. These clouds, which are visible from the ground with the naked eye, form in the spring and summer at higher latitudes and have been seen for over a century, reflecting the Sun's light in the twilight sky. The mission's primary goal for the three onboard instruments is to explain why these clouds form and discover what is causing them to appear more frequently and at lower latitudes.

About Orbital

Orbital develops and manufactures small space systems for commercial, civil government and military customers. The company's primary products are satellites and launch vehicles, including low-orbit, geosynchronous and planetary spacecraft for communications, remote sensing, scientific missions and national security; ground- and air-launched rockets that deliver satellites into orbit; and missile defense boosters 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.

More information about Orbital can be found at http://www.orbital.com

Note to Editors:

High-resolution photos of the Pegasus rocket are available on Orbital's web site at: http://www.orbital.com/NewsInfo/Images

Live coverage on NASA Television of the Pegasus/AIM launch will begin at 12:00 noon PDT (3:00 p.m. EDT) on April 25 and continue through spacecraft separation from the Pegasus vehicle. In the continental United States, NASA TV is available via satellite on AMC-6, Transponder 17, C-band, located at 72 degrees West longitude. The frequency is 4040.0 MHz video, 6.8 MHz audio, MPEG-2 digital signal. In Alaska and Hawaii, NASA TV is available on AMC-7, Transponder 18, C-Band, at 137 degrees West longitude. The frequency is 4060.0 MHz, also an MPEG-2 digital signal. Polarization is vertical, and audio is monaural at 6.80 MHz.

For live launch coverage and AIM mission information, go to the AIM link in the NASA Portal at: http://www.nasa.gov/aim

SOURCE: Orbital Sciences Corporation

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