posted 01-25-2003 04:34 PM            

Radiation Streaming Toward Earth
By Marcia Dunn The Associated Press
Published: Jan 25, 2003

CAPE CANAVERAL, Fla. (AP) - NASA launched a spacecraft into orbit Saturday to measure all of the radiation streaming toward Earth from the sun.
The satellite began its $122 million, five-year mission with a plane ride over the Atlantic.

At the command "three, two, one, drop," the satellite was released from the jet about 140 miles offshore, fell for five seconds and then shot toward space with the firing of its attached Pegasus rocket.

The small satellite, called Sorce - short for Solar Radiation and Climate Experiment - has five state-of-the-art instruments that will help scientists better understand how the sun affects Earth's climate. They had to go to space to measure incoming solar radiation because so much of it is absorbed by Earth's atmosphere.

Not only will Sorce measure the total radiation from the sun, its spectrometers will analyze the light in all its various colors, or wavelengths, said the lead scientist, Gary Rottman of the University of Colorado's Laboratory for Atmospheric and Space Physics.

"In order to understand perhaps the impacts of global change produced by mankind, we certainly need to understand how the sun is varying," said Donald Anderson, NASA's program manager. Other solar observatories already in space will help in this effort, he noted.

Sorce's high-precision measurements hopefully will benefit future scientists, too, Rottman said.

"We're building a long-term climate data set that I really hope that generations from now, people refer back to the measurements we make. What is the output of the sun today to what their future measurements are," he said.

The University of Colorado at Boulder will operate the Sorce science instruments, which it also developed and built. Orbital Sciences Corp. provided the Pegasus rocket.