Launched aboard a Pegasus XL rocket from the Kennedy Space Center in Cape Canaveral, Fla., the Solar Radiation and Climate Experiment, or SORCE, was developed to study how and why variations in the sun affect Earth's atmosphere and climate.
The SORCE satellite, part of NASA's Earth Observing System, is collecting a long-term data set of natural solar variation as a tool to determine the role the sun plays in global change, said Senior Researcher Gary Rottman of CU-Boulder's Laboratory for Atmospheric and Space Physics, or LASP. Rottman is the principal investigator on the mission.
"The spacecraft and instruments all have been performing beautifully since launch, and the new solar data have exceeded our expectations," Rottman said. "The sun also has cooperated and put on an unusual display of intense activity in late October 2003, providing some of the largest sunspots ever recorded and producing major flares surpassing all previous observations."
The unexpected phenomena will help scientists better understand how the sun functions and influences Earth's terrestrial environment, said Rottman. Scientists and students at CU-Boulder are using data from SORCE, along with information from other satellites, to understand climate change, climate prediction, atmospheric ozone and ultraviolet-B radiation.
Accurate knowledge of the sun's variations at all light wavelengths that may be heating Earth's atmosphere, land and oceans is an essential step to understanding, modeling and predicting impacts of the sun on Earth.
"The science team is tremendously excited as the new observations are incorporated into our understanding of the sun," said Rottman. "We want to understand the sun's influence on Earth's atmosphere and climate so that we can more reliably determine how humans are changing the environment."
SORCE has greatly extended the spectral coverage with improved accuracy, covering wavelengths from soft x-ray bands and ultraviolet light through the visible and near-infrared spectral bands. This provides the first extensive infrared solar irradiance measurements from space, Rottman said.
"For the very first time we have observations capable of characterizing the variations in the visible and near-infrared part of the solar electromagnetic spectrum that are the dominant contributors to the sun's total energy that reaches the Earth's surface," said Research Physicist Judith Lean of the Naval Research Laboratories in Washington, D.C.
A performance evaluation of the SORCE mission last June by NASA rated it excellent in all categories, including quality, timeliness, cost and leadership, the highest ratings given. "LASP's commitment to mission success and their ability to work with NASA and industry exemplify how Principal Investigator Mode missions should be conducted in the future," wrote the evaluators.
"It is unusual for a project of this kind to score the highest possible points on a NASA evaluation," said SORCE Program Manager Tom Sparn of LASP. "Less than 4 percent of missions get excellent ratings across the board.
"Never have measurements of the sun achieved this quality," Sparn said. "The sun is a very stable source of light, and we are monitoring it at the most sensitive levels possible with today's technology."
CU scientists and engineers designed, built, calibrated and tested the four science instruments on the satellite. LASP subcontracted with Orbital Sciences Corp. for the spacecraft launch on the Pegasus Rocket.
LASP's Mission Operations Center Director, Randy Davis, said CU staff and students are operating the spacecraft over its five-year mission life, acquiring, managing, processing and distributing science data.
"SORCE is a wonderful example of how NASA, universities and industry can partner together," said Bill Ochs, SORCE's project manager at NASA's Goddard Space Flight Center in Greenbelt, Md. "In addition, the student involvement from CU in the instrument development and mission operations provides a great training ground for the aerospace engineers of the future."
For more information, see: http://lasp.colorado.edu/sorce/news_letter.html.