If hypotheses prove true, the mission will provide a wealth of information on how to better predict the magnetic storms from the sun's rays, which have proven to be very hazardous to satellites and ground-based structures in high-risk areas such as a region in northeast Canada.

"We're looking at the causes of the tail of the magnetic storm that can coil back and strike the Earth on the night side (side not facing the sun)," said Dr. Jim Spann, one of the two scientists at Marshall working on the mission. "With the instruments that we have, we'll be seeing things we've never seen before."

Spann's work has centered around the Ultraviolet Imager (UVI) ever since he came to Marshall in 1986. The UVI is essentially a camera that images ultraviolet light with clarity never before achieved. The ultraviolet rays are invisible to the human eye because oxygen in the Earth's air absorbs the wavelengths. Therefore, study on UV rays must be conducted in space.

Spann said energetic particles, including electrons and protons, emanate from the sun comprising what is called the solar wind. As these particles stream by the Earth at speeds up to 1 million mph, they are redistributed and accelerated in the Earth's magnetosphere. The redistribution results in the channeling of a large amount of energy, equivalent to as much as 100 million kilowatts of energy each day down into the Earth's atmosphere into the polar regions.

The electrons collide between 90 and 150 kilometers above the Earth and the resulting emission of light is observed in the north and south polar regions and is known as the aurora.

"The aurora can be thought of as the footprint of the magnetosphere," Spann said.

The UVI will be able to image the aurora with better time, space and wavelength resolution than ever before, he said, "It will provide both qualitative and quantative data. Before, all we got was a pretty picture. Regions of the polar cap that had been previously thought of as dark areas will be viewed with enough sensitivity to see emissions and hopefully correlate them to events in the magnetosphere."

The filter on the device, primarily designed by the University of Alabama in Huntsville, will be able to look at different wavelengths and give an image every 37 seconds. The UVI will also allow scientists to view the entire aurora in one shot in that it can clearly image an area equal to 50 degrees latitude on Earth.

The device, while intricate in technology, uses only 20 watts of energy and weighs 42 pounds. Scientists hope the data from the device can also be beneficial in garnering information about ulterior energy sourcing.

A related device to be flown on the Global Geospace Science Mission Polar spacecraft, which will fly in an elliptical orbit closest to the South Pole, was designed by fellow Marshall Scientist Tom Moore.

The TIDE, or Thermal Ion Dynamics Experiment, will be able to measure the density, winds, pressure and temperature of the ionized magnetosphere gas known as plasma with "a sensitivity approximately 100 times larger than previous ion mass spectrometers, and can collect data much more rapidly because of its seven independent apertures."

When James Van Allen, using the Marshall Center-managed Explorer I spacecraft, discovered the radiation belts that bear his name, most scientists assumed that the high energy particles of the belts came from the sun and were trapped within the Earth's magnetic field.

While that finding appears in most encyclopedias still, scientists have recently learned that matter from the Earth's own atmosphere largely dominates the planet's magnetosphere.

The TIDE, Moore said, is expected to further back the more recent assertion by providing more definite analysis of the ionized molecules in the magnetic field. Since charge oxygen normally comes from the Earth's atmosphere and multiple charge helium particles normally come from the sun.

Moore said the experiment hopes to yield clues about how energy-producing electrons escape into the Earth's atmosphere from the sun and how the Earth's atmosphere reacts. Clues from the mission could be essential in the area of environmental protection and ozone layer preservation research.

The polar satellite is the second satellite in the Global Geospace Science mission, with the first (the Wind satellite) being sent up in 1992. The mission is a part of a larger international partnership discovery mission called NASA's International Solar Terrestrial Physics program (ISTP).

Along with the polar vessel, NASA is collaborating with the European Space Agency (ESA) and the Japanese Institute of Space and Astronautical Science (ISAS) in three additional solar terrestrial missions, Geotail, HO and Cluster.

UVI instrument home page
TIDE home page