DULLES, Va., 9 July 2009. Orbital Sciences Corp. has been selected by the National Aeronautics and Space Administration (NASA) to design, manufacture, integrate, and test a new low-Earth orbit (LEO) space science satellite that will study X-ray polarization in space.

Under the $40 million contract, Orbital will provide the spacecraft bus and conduct mission operations for the Goddard Space Flight Center's (GSFC) Gravity and Extreme Magnetism (GEMS) mission.

The GEMS contract was awarded to Orbital under the space agency's Small Explorer (SMEX) series of cost-efficient, highly productive space science satellites. Orbital has built other SMEX satellites for NASA, including the in-orbit GALEX, AIM, and IBEX spacecraft, and is currently developing the NuSTAR spacecraft that is scheduled for launch in 2011.

The GEMS mission is led by the project's Principal Investigator Dr. Jean Swank and is being managed by GSFC. It is scheduled to launch no later than 2015.

The GEMS satellite will be the first observatory to measure X-ray polarization, which encodes information about the structure of cosmic sources. Polarization measurements will allow scientists to study scattering, magnetic fields and strong gravitational fields.

The GEMS satellite will be based on Orbital's LEOStar-2 spacecraft bus design. GEMS will be the eighth satellite to be based on the LEOStar-2 platform.

In addition to its program management role, NASA's GSFC will provide the X-ray polarimeter instrument and oversee the Science Operations Center, science data processing, systems engineering and education, and public outreach. Other program partners include NASA's Ames Research Center, the University of Iowa, and ATK Inc.