SORCE is the abbreviation for a NASA-sponsored satellite mission, the Solar Radiation and Climate Experiment, launched in 2003, which provides measurements of incoming radiation of all sorts – x-ray, ultraviolet, near-infrared, and total solar. This mission is actually the merging of the EOS Solar Stellar Irradiance Comparison Experiment (SOLSTICE) and the Total Solar Irradiance Mission (TSIM.) SORCE measurements address “long-term climate change, natural variability and enhanced climate prediction, and atmospheric ozone and UV-B radiation.”
The project’s home page is linked on the NASA website and both are very informative. The University of Colorado returned $3 million in cost savings to NASA to build and operate the mission satellite and equipment.
Solar energy is the most dominant and direct influence on the terrestrial eco-system in the form of radiation. This affects all physical, chemical and biological processes. The solar influence impacts Earth’s climate and atmosphere, and people must first understand the Sun’s role as scientists try to analyze and correct mankind’s impact on the environment.
SORCE’s satellite observatory includes many state-of-the-art instruments, including radiometers, spectrometers, photodiodes, detectors and bolometers. A bolometer is essentially a very sensitive thermometer, to measure infrared or heat radiation. The spectral measurements show us the energy and emissions of the sun in the form of color that can be interpreted into quantities and elements of matter. The instruments on board are the Total Irradiance Monitor (TIM), Solar Stellar Irradiance Comparison Experiment (SOLSTICE), Spectral Irradiance Monitor (SIM), and the XUV Photometer System (XPS). All of these instruments accumulate solar data as the satellite orbits around the Earth at a 645 km, 40 degree orbit.
The Laboratory for Atmospheric and Space Physics at the University of Colorado operates the monitors and uses this data to model the Sun’s output, including records and patterns of solar storms and variations. They hope to explain and predict the effects of the solar radiation on the Earth’s climate and atmosphere.
This ongoing mission was launched on January 25, 2003, and continues the precise total solar irradiance (TSI) measurements recorded since 1979 by the ERB instrument, followed by the ACRIM series of measurements. SORCE adds the measurement of solar spectral irradiance from 1nm to 2000nm, which account for 95% of the spectral contribution to TSI. Engineers are still developing new instrumentation to fine-tune the understanding of the physics and possibilities begun by Einstein and so many others.
SORCE is a part of NASA’s Earth Systematic Missions programs which encompasses a broad range of multidisciplinary science investigations with the goal of developing a scientific understanding of the Earth’s system and how it responds to “natural and human-induced forces.” Mitigation, if possible and appropriate, is indeed becoming an urgent issue.