NOAA 2003-012
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NOAA News Releases 2003
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Solar X-ray Imager Onboard GOES-12 Environmental Satellite

NOAA has finished on-orbit testing of the world’s most advanced solar storm detector aboard the nation’s newest environmental satellite, GOES-12. The Solar X-ray Imager (SXI) is providing space weather forecasters with real-time images of the sun’s explosive atmosphere, helping them issue timely warnings when solar activity might harm billions of dollars worth of assets, both in space and on the ground.

The SXI telescope provides a quantum leap in the ability to detect and forecast harmful solar storms before they reach the Earth’s atmosphere, the Commerce Department's National Oceanic and Atmospheric Administration (NOAA), NASA and the U.S. Air Force announced today.

“The Solar X-ray Imager will provide the kind of improvements in space weather forecasting that satellite imagery did for tracking hurricanes,” said retired Navy Vice Admiral Conrad C. Lautenbacher, Ph.D., undersecretary of commerce for oceans and atmosphere and NOAA administrator. “The Solar X-ray Imager will enable us to better protect both commercial and government assets in space and on the ground. In addition, it is an outstanding example of federal agencies working together on a project that benefits both civilian and military interests.”

The instrument will take a full-disk image of the sun's atmosphere once every minute. NOAA and the U.S. Air Force will use the images to monitor and forecast the sources of space weather disturbances from the sun, enabling forecasters to forecast disturbances to Earth’s space environment that can destroy satellite electronics, disrupt long-distance radio communications or surge power grids. The ability to monitor and forecast solar disturbances is valuable to operators and users of military and civilian radio and satellite communications systems, navigation systems and power networks, as well as to astronauts, high-altitude aviators and scientists.

“The SXI will detect and provide positions for 70 percent more solar flares than current ground observations,” said Ernest Hilder, director of NOAA’s Space Environment Center in Boulder, Colo. “By knowing flare longitude, a forecast can be made that would be accurate for a window of about 12 hours. Without the solar longitude of a flare, the time of maximum particle radiation cannot be accurately predicted and can vary over a range of 100 hours.”

The military is increasingly dependent on the space environment as forces deploy across the globe in support of national interests. "As competent military professionals we need to have space weather concerns mainstreamed into our thought process," said Brigadier General David L. Johnson, Air Force director of weather. The Air Force is the Department of Defense provider for space environmental information. "We need to know when and where we have an advantage across all levels of military operations, and with the information provided by SXI, we're working to better integrate space weather into environmental situational awareness for warfighters," said General Johnson.

The SXI is a small telescope that makes use of advanced technology and grazing incidence optics to allow it to see the sun’s outer atmosphere or corona in X-rays. SXI lets solar forecasters see phenomena they couldn't otherwise - such as coronal holes whose high-speed winds cause geomagnetic storms, and to infer solar activity occurring behind the sun's edge, or limb. X-ray images are also more accurate than white light imagers for identifying the location of flares.

“NASA is excited about providing another fine tool for the NOAA team to use in weather operations, including space weather forecasts,” said Martin A. Davis, NASA GOES program manager at Goddard Space Flight Center in Greenbelt, Md. GOES-12 represents a continuation of a 27-year joint program between NASA and NOAA.

NOAA operates two environmental satellites in geostationary orbit 22,300 miles over the equator. GOES-12 was launched on July 23, 2001, and placed into on-orbit storage. Controllers at NOAA’s Satellite Operations Control Center in Suitland, Md., are commanding the satellite out of storage and preparing it for operations to replace GOES-8. GOES-8 was launched April 13, 1994, to overlook the eastern part of the United States and well out into the Atlantic Ocean. GOES-10 is currently overlooking the West Coast, the Pacific Ocean and Hawaii.

NOAA's National Environmental Satellite, Data, and Information Service operates the GOES series of satellites. After the satellites complete on-orbit checkout, NOAA assumes responsibility for command and control, data receipt, product generation and distribution. NASA’s Goddard Space Flight Center manages the design, development and launch of the spacecraft for NOAA. The SXI was built by NASA’s Marshall Space Flight Center in Huntsville, Ala.

The Commerce Department’s National Oceanic and Atmospheric Administration (NOAA) is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of our nation’s coastal and marine resources.

The images taken by the Solar X-ray Imager are now available in real time to the general public via the World Wide Web, through NOAA’s National Geophysical Data Center website at:

On the Web:


SXI background, information and images visit: