Orbital Sciences Corporation announced today that the launch of its Pegasus XL rocket carrying
NASA’s High Energy Solar Spectroscopic (HESSI) satellite has been postponed.
Orbital is supporting a NASA-led investigation to determine if there may be
any associated technical issues between the X-43A/Hyper-X launch failure at
Edwards Air Force Base on Saturday, June 2, and the Pegasus XL vehicle
awaiting launch at Cape Canaveral Air Force Base, Florida.
A new launch date
for the HESSI mission, originally scheduled for June 7, will be announced once
NASA and Orbital have completed the investigation.

Orbital is one of the world’s leading manufacturers of low-cost space
systems, including satellites, launch vehicles and electronics and sensors
Orbital is also involved with satellite-based networks that provide
wireless data communications and high-resolution Earth imagery to customers
all around the world.

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

CONTACT: Media: Barron Beneski, 703-406-5528 or
beneski.barron@orbital.com, or Investors: Tim Perrott, 703-406-5997 or
perrott.tim@orbital.com, both of Orbital Sciences Corporation.