Built by Lockheed Martin's Space Systems Advanced Technology Center for NASA's Goddard Space Flight Center in Greenbelt, Md., the SXI was launched May 24 aboard GOES-13 from Cape Canaveral Air Force Station, Fla.

SXI is one of a suite of instruments that resides on the current generation of Geostationary Operational Environmental Satellites.

SXI will observe solar flares, coronal mass ejections, coronal holes and active regions in the X-ray region of the electromagnetic spectrum in wavelengths from 6 Angstroms to 60 Angstroms.

These features are the dominant sources of disturbances in space weather that lead to, for example, geomagnetic storms. SXI will also examine flare properties, newly emerging active regions and X-ray bright points on the Sun.

SXI will provide continuous, near real-time observation of the Sun's corona, acquiring a full-disk image every minute. The images cover a 42 arc-minute field of view with five arc-second pixels. The Sun, as viewed from Earth, is approximately 32 arc-minutes in diameter.

By recording solar images every minute, NOAA observers will be able to detect and locate the occurrence of solar flares. This is the name given to the explosive releases of vast amounts of magnetic energy in the solar atmosphere.

Scientists are not yet able to predict the occurrence, magnitude or location of solar flares, but it is necessary to continually observe the Sun to know when they are happening.

When a flare erupts, it throws out large clouds of ionized, or electrically charged, gas. A small fraction of the cloud is very energetic and can reach the Earth within a few minutes to hours of the flare being observed. These energetic particles pose a hazard to both astronauts and spacecraft.

Coronal mass ejections, which often are associated with flares, take several days to reach the Earth. Fast, powerful ejections give rise to geomagnetic storms, which can disrupt radio transmissions and induce large currents in power transmission lines and oil pipelines.

CMEs have resulted in large-scale failures of the North American power grid and greatly increased pipeline erosion. SXI also will monitor coronal holes -- persistent sources of high-speed solar wind.

As the Sun rotates, every 27 days, these sources spray across the Earth and cause recurring geomagnetic storms.

"The first image is magnificent! There is enormous satisfaction in seeing that our years of effort have borne fruit," said Mons Morrison, SXI program manager at the LM's Advanced Technology Center.

"While the other GOES instruments provide near-constant viewing of the Earth, SXI will watch the Sun and provide vital information regarding solar activity," Morrison added.

"Once it is fully operational, the SXI will capture sharp, detailed solar images for immediate use by space weather forecasters and also provide critical data for new numerical prediction models under development," said Tom Bogdan, director of NOAA's Space Environment Center in Boulder, Colo.

"By testing and calibrating the SXI in advance, we avoid a lapse in solar coverage during the transition from GOES 12 to GOES 13," he added.

The SXI will aid NOAA and U.S. Air Force personnel in issuing forecasts and alerts of space-weather conditions, and in developing a better understanding of Sun-related phenomena that affect the Earth's environment.

Turbulent space weather can affect radio communication on Earth, induce currents in electric power grids and long distance pipelines, cause navigational errors in magnetic guidance systems, upset satellite circuitry and expose astronauts to increased radiation.

A prototype SXI was developed, tested, and calibrated by NASA's Marshall Space Flight Center in Huntsville, Ala., in conjunction with GSFC, NOAA, and the Air Force, and launched aboard the GOES-M satellite in July 2001.

The new SXI on GOES 13 has twice the spatial resolution of the prototype, and like some high-end home video cameras, it has active internal jitter compensation that provides a stable picture even when the spacecraft is moving. In addition, more sophisticated computer control allows SXI to react automatically to changing solar conditions.

The Solar and Astrophysics Laboratory at the ATC has a long heritage of spaceborne solar instruments, including the Soft X-ray Telescope on the Japanese Yohkoh satellite, the Michelson Doppler Imager on the ESA/NASA Solar and Heliospheric Observatory, and the solar telescope on NASA's Transition Region and Coronal Explorer.

The laboratory also conducts basic research into understanding and predicting space weather and the behavior of the Sun, including its impacts on Earth and climate.

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