Solar Sentinel Heads to Orbit

January 28, 2003 | An aircraft-launched Pegasus rocket lofted NASA’s Solar Radiation and Climate Experiment (SORCE) into orbit on January 25th. This 290-kilogram satellite carries four instruments to study minuscule variations in the Sun’s energy output and will be operated by the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder. Two instruments are descendants of payloads that have flown before: the Spectral Irradiance Monitor measures the Sun’s energy output at visual and near- to mid-infrared wavelengths, while the Total Irradiance Monitor evaluates the ultraviolet-to-infrared range to an accuracy of 0.01 percent. The third instrument has a pair of spectrometers to study variations in the Sun’s ultraviolet spectrum from 115 to 320 nanometers, while a fourth will monitor variations in the extreme ultraviolet, at wavelengths between 1 and 34 nanometers (10 and 340 angstroms). Solar physicists believe SORCE’s observations will be critical in assessing variations in Earth’s long-term climate and the interaction of solar ultraviolet radiation with our atmosphere’s protective ozone layer.

Details about the SORCE mission are found at

New Satellite To Study Interstellar Bubble

January 28, 2003 | Astronomers now have an important new tool for studying the bubble of hot, ionized gas surrounding our solar system. The Cosmic Hot Interstellar Plasma Spectrometer spacecraft, or CHIPSat, rocketed into orbit on January 12th from Vandenberg Air Force Base in California, sharing its Delta II launcher with ICESat, a NASA spacecraft for studying Earth’s climate. CHIPS is a small, 60-kilogram “University Explorer,” a mission class costing less than $13 million, and it carries a single instrument: an extreme-ultraviolet spectrograph developed by the University of California, Berkeley. CHIPS will record spectral lines in the 90- to 260-angstrom range, where million-degree gas in the local interstellar bubble emits most of its radiation. More-distant gas at this temperature can’t be studied because the galaxy is opaque in the extreme ultraviolet, so it’s not clear which atomic transitions are responsible for cooling interstellar gas in various astrophysical settings. Therefore, the CHIPS data will allow astronomers to refine the models used for simulating conditions in both local and extragalactic hot gas.

More information about the CHIPSat mission is available at
For pictures and video of the launch, see


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