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The Planet Earth:
Protecting Earth from Massive Eruptions on the Sun


Every eleven years, the surface of the Sun is disrupted from inside by massive ruptures, known as flares. Scientists want to know more about those enormous solar outbursts because they have the potential to threaten astronauts in space stations and disrupt satellites used for critical national security, weather forecasting, navigation and communications functions.

With one of those intense periods of solar eruptions underway now, NASA has launched a satellite to Earth orbit to be on the lookout for big upheavals on the Sun. Named TRACE, for Transition Region and Coronal Explorer, the 469-lb. satellite was launched from Vandenberg Air Force Base in California in April 1998 on a one-year mission to observe the Sun and study the complete range of solar conditions, including the connection between the Sun's magnetic fields and the heating of its corona.

The computerized satellite was lofted to space on a Pegasus XL rocket dropped from a jet airplane flying at 39,000 ft. over the Pacific Ocean off the California coast. The satellite is in an orbit ranging from 325-342 miles in altitude.

TRACE's main instrument is a Cassegrain telescope which is 30 cm. in diameter and 160 cm. long. It has an 8.66 m. focal length. It will be used to explore the three-dimensional magnetic structures that emerge through the photosphere, the visible surface of the Sun, through the upper solar atmosphere -- the Transition Region and Corona. The photosphere temperature is 6000 degrees K., while the corona is at ten million degrees.

Small Explorer Satellites

TRACE is one of several small satellites in NASA's Small Explorer (SMEX) project managed by Goddard Space Flight Center, Greenbelt, Maryland, for NASA's Office of Space Science, Washington, D.C. NASA is the National Aeronautics and Space Administration.

The SMEX satellites are:
To learn more:

Inner Planets: Mercury Venus Earth Mars
Outer Planets: Jupiter Saturn Uranus Neptune Pluto
Other Bodies: Moons Asteroids Comets The Voyagers


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