NASA Spacecraft Set To Catch Some Rays

SORCE is scheduled to launch from off the coast of the Kennedy Space Center, Fla., on January 25 aboard a Pegasus XL launch vehicle at approximately 3:14 p.m. EST. The Pegasus XL rocket is dropped from the wing of an L-1011 aircraft over the Atlantic Ocean. After falling a few seconds, the spacecraft's engines will power on and lift it into orbit. The satellite will orbit at an altitude of 397.8 miles (640 kilometers).

"This mission will help to distinguish between natural and human-induced influences in climate change. Incoming light energy from the sun is ultimately what powers our climate system. Past NASA missions showed the amount of solar radiation is not constant, but rather varies over time. SORCE will help us understand these variations, and the role of solar variability in climate change," said Dr. Ghassem Asrar, NASA's Associate Administrator for Earth Science.

SORCE is a small free-flying satellite carrying four scientific instruments to measure the solar radiation at the top of the Earth's atmosphere and how the sun influences Earth's atmosphere and climate. The four instruments on SORCE are the Total Irradiance Monitor, the Spectral Irradiance Monitor, Solar Stellar Irradiance Comparison Experiment, and the Extreme Ultraviolet Photometer System. The first three will measure solar irradiance and the solar spectrum to helpscientists understand the sun's role in climate change. The Photometer System will measure high-energy radiation from the sun.

"We are very excited as we near our launch date." said Bill Ochs, SORCE Project Manager at NASA's Goddard Space Flight Center (GSFC) in Greenbelt, Md. "This mission has been atremendous team effort between the University of Colorado, NASA, and Orbital Sciences Corporation," he said.

This mission is a joint partnership between NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP) in Boulder. SORCE is a principal investigator-led mission with GSFC providing management, scientific oversight and engineering support.

Scientists and engineers at LASP designed, built, calibrated and tested the four science instruments on SORCE. LASP subcontracted with Orbital Sciences Corporation for thespacecraft and observatory integration and testing. The Mission Operations Center and the Science Operations Center are both operated at LASP. LASP will operate the spacecraftover its five-year mission life and is responsible for the acquisition, management, processing, and distribution of the science data.

SORCE data will support studies in long-term climate change, natural variability, enhanced climate prediction, and atmospheric ozone and UV-B radiation. The SORCE measurementsare critical to studies of the variability of the sun; its effect on our Earth system; and its influence on humankind.

SORCE is a part of NASA's Earth Science Enterprise, a program dedicated to understanding the Earth as an integrated system and applying Earth system science to improve prediction ofclimate, weather, and natural hazards using the vantage point of space.

For more information about SORCE see:

http://lasp.colorado.edu/sorce

http://www.gsfc.nasa.gov/topstory/2003/0106sorce.html